ISSN: 1543-9518|Vol. 24

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Prevalence of Normal Weight Obesity Amongst Young Adults in the Southeastern United States

Authors: 1Helena Pavlovic, 2Tristen Dolesh, 3Christian Barnes, 4Angila Berni, 5Nicholas Castro, 6Michel Heijnen, 7Alexander McDaniel, 8Sarah Noland, 9Lindsey Schroeder, 10Tamlyn Shields, 11Jessica Van Meter, and 12Wayland Tseh*

1Northern Kentucky University, Highland Heights, Kentucky, USA

AUTHORS INSTITUATIONAL AFFILIATION:

School of Health and Applied Human Sciences, University of North Carolina Wilmington, Wilmington, North Carolina, United States of America

Corresponding Author:

*CORRESPONDING AUTHOR:  

Wayland Tseh, Ph.D. 

University of North Carolina Wilmington 

School of Health and Applied Human Sciences 

601 South College Road 

Wilmington, North Carolina, 28403-5956 

Phone Number: 910.962.2484 

E-Mail: [email protected] 

ABSTRACT

‘Normal weight obesity (NWO) is characterized by a normal or low body mass index (BMI) alongside a high percentage of body fat, which increases the risk for hypokinetic diseases. This study aims to investigate the prevalence of NWO among a sample of young, non-sedentary adults. Two hundred and fifty-four apparently healthy volunteers (Age = 22.2 ± 7.2 yrs; Height = 171.5 ± 9.6 cm; Body Mass = 69.9 ± 13.4 kg) provided informed consent prior to participation. Body mass index was calculated by dividing body mass (kg) by height squared (m2). Body fat percentage was measured using the BODPOD® G/S, which utilizes air displacement plethysmography to accurately estimate body composition. Class I Obesity and Low/Normal BMI categorizations were defined by the American College of Sports Medicine. Data revealed that 12.2% of the overall sample exhibited NWO, with a higher prevalence among males (17.2%) compared to females (9.8%). The study also seeks to evaluate whether individuals with NWO face greater health risks than those with similar BMI but lower body fat percentages. From a practical perspective, identifying individuals with NWO is an opportunity for clinicians to proactively educate their clients regarding the health risks associated with hypokinetic disease(s).

KEYWORDS: Body Mass Index, BODPOD, Percent Body Fat, Normal Weight Obesity

INTRODUCTION

Within the United States, the prevalence of obesity has dramatically increased over the past 50 years given the ubiquitous obesogenic environment (31). In 2019, Ward and colleagues yielded compelling predictive insights indicating a trajectory wherein, by the year 2030, nearly 50% of adults will be afflicted by obesity (48.9%) with heightened prevalence exceeding 50% in 29 states, demonstrating a pervasive nationwide trend (50). Moreover, no state is anticipated to exhibit a prevalence below 35% (50). Projections also indicate that a substantial proportion of the adult population is anticipated to experience severe obesity, with an estimated 24.2% affected by 2030 (50). Against this backdrop, the predictive analyses conducted by Ward and associates (50) underscored the widespread and escalating severity of the obesity epidemic across the United States. These findings are indicative of an impending public health challenge, necessitating strategic interventions and policy considerations to mitigate the escalating burden of obesity and its associated health implications. When delineating the magnitude of obesity, clinicians and practitioners must employ precise instrumentation capable of quantifying a client’s body composition in terms of percentage body fat. Numerous methodologies exist for this purpose, encompassing hydrostatic weighing, bioelectrical impedance analysis, air displacement plethysmography, skinfold assessment, and dual-energy x-ray absorptiometry scan.

Drawing from antecedent research studies, dual-energy X-ray absorptiometry (DXA) is acknowledged as the clinical gold standard for appraising body composition (9, 10, 12, 21, 25, 26, 42, 47). However, a notable drawback of DXA lies in its emission of low-level radiation (6, 9, 32, 45, 47), thereby subjecting clients to unnecessary radiation exposure (1, 33). An alternative method is utilizing the BOD POD® Gold Standard (GS), which employs air displacement plethysmography to estimate body composition. Previous literature has heralded the BOD POD® GS as the applied, pragmatic gold standard for assessing body composition due to its validity (2, 7, 38), as well as its within- and between-day reliability (48). Additionally, owing to the BOD POD® GS’s facile and non-invasive procedures, most individuals can attain accurate measures of body composition values, specifically pertaining to percent body fat, enabling the discernment of pounds of fat-free mass and fat mass.

According to the American College of Sports Medicine (ACSM), males with a percent body fat ≥ 25% and females ≥ 32% (4) are predisposed to an elevated risk of developing a myriad of hypokinetic diseases, notably cardiovascular disease(s), metabolic syndrome, and cardiometabolic dysfunction (14, 27, 35, 37, 39, 40, 43, 44, 46, 51, 56). Another evaluative approach involves the calculation of Body Mass Index (BMI), derived from dividing body weight in kilograms by square of height in meters (4). Given the ease and efficiency of calculating BMI, the obesity-related classification in which it provides at the individual level is potentially flawed (3, 8, 22, 24, 41, 53, 56).

Presently, within the United States, a dearth of research exists on the prevalence of normal weight obesity (NWO) amongst apparently healthy young adults (11,52). Normal weight obesity is characterized by individuals exhibiting a low BMI (<18.5 kg∙m-2) or normal BMI (18.5 – 24.9 kg∙m-2) yet manifesting obesity-related percentage body fat values (male = ≥20%; female = ≥30%) (5, 14, 20, 36, 37, 40, 43, 44, 57). Individuals with low/normal BMI and high percentage body fat values face an augmented risk of hypokinetic diseases, as their seemingly normal exterior masks a deleteriously high amount of body fat beneath the surface layer. Previous research endeavors have revealed the prevalence of NWO amongst a population of South Americans (14, 34, 40, 44), Central Europeans (15), and Asians (28-30, 37, 54, 55, 57, 58). Given that most aforesaid research studies on NWO have been conducted internationally, it is of paramount interest to ascertain the prevalence of NWO domestically. Consequently, the primary objective of this research study is to investigate the prevalence of normal-weight obesity among a sample of ostensibly healthy males and females.

METHODS

Participants

All participants were required to report to the Body Composition Laboratory to complete a singular session. Before the participants arrived, volunteers were instructed to abstain from consuming caffeinated sustenance or beverages that may acutely influence body mass. Moreover, researchers advised participants to refrain from vigorous physical activity/exercise the night before and prior to their appointed session. Upon arrival, volunteers read and signed an informed consent form approved by the University’s Institutional Review Board for human subject use (IRB#: H23-0499). As displayed in Table 1, a cohort comprising 254 male and female volunteers were recruited to participate in this study.

Table 1. Descriptive characteristics (Mean ± SD) of all male and female participants (N = 254). 

Variables Overall (N = 254) Male (n = 101) Female (n = 153) 
Age (yrs) 22.2 ± 7.2 22.5 ± 7.7 22.0 ± 6.8 
Height (cm) 171.5 ± 9.6 179.5 ± 7.2 166.2 ± 7.0 
Body Mass (kg) 69.9 ± 13.4 79.9 ± 11.6 63.2 ± 10.0 

Below highlights the details of the singular Session required for each participant.

Body Mass Index (BMI)

Before each assessment, participants were asked to remove any unattached item(s) from their body, such as shoes, socks, rings, bracelets, and/or glasses. Height was measured to the nearest 0.5 cm as participants stood barefoot, with both legs together, with their back to a Seca 217 Mobile Stadiometer (Model Number 2171821009, USA). Body mass was measured on a Tanita Multi-Frequency Total Body Composition Analyzer with Column (Model DC-430U, Tanita Corporation, Japan) to the nearest 0.1 kg. Body mass index was calculated using body mass expressed in kilograms (kg) divided by height expressed in meters squared (m2). Body mass index categorizations, set forth via ACSM (4), for low BMI was (<18.5 kg∙m-2) and normal BMI was (18.5 – 24.9 kg∙m-2).

BOD POD® Gold Standard (GS)

BOD POD® Gold Standard (GS) (COSMED USA Inc., USA) was calibrated daily according to the manufacturer’s instructions with a 50.238 Liter cylindrical volume provided by COSMED USA Inc. Specific details illustrating the technicalities of the calibration mechanism are published elsewhere (16, 18). Because different clothing schemes have been shown to underestimate percentage body fat (%BF) results from the BOD POD® (19, 49), female participants were instructed to wear one- or two-piece bathing suit or sports bra and compression shorts, while male participants were instructed to wear form-fitted compression shorts. All participants wore a swim-like cap provided by COSMED USA Inc. After race, height, and age were inputted by a technician into the BOD POD® GS kiosk, participants were asked to step on an electronic scale to determine body mass to the nearest .045 kg. Once the BOD POD® GS system recorded body mass, participants were instructed to sit comfortably and breathe normally within the BOD POD® GS for two trials lasting 40 seconds per trial. A third trial was conducted if Trials 1 and 2 had high variability. Once both (or three) trials were conducted, body composition values, specifically, body mass, percent body fat, fat-free mass, and fat mass, were immediately displayed on the kiosk viewer and recorded by a technician. Once height, body mass, and body composition assessments were completed, participants dressed back into their original clothing and exited the Body Composition Lab.

Statistical Analyses

Descriptive statistics (mean ± SD) were derived to describe the sample population. A Chi-Square Goodness of Fit Test was used to determine the prevalence of low/normal BMI values with obesity-related percent body fat. For all analyses, statistical significance was established at p < 0.05.

RESULTS

At the conclusion of the study, 254 volunteers were recruited, and zero dropped out, therefore, all 254 participants’ results were included in the statistical analyses. Table 2 displays the descriptive measures of the study participants.

Table 2. Body Mass Index, Class I Obesity, and Percent Normal Weight Obesity Amongst Males and Females. 

 Total Male Female 
Participants 254 101 153 
Low BMI (≤ 18.4 kg∙m-2) 2 0 2 
Normal BMI (18.5 – 24.9 kg∙m-2) 181 58 123 
Class I Obesity (F ≥ 32%; M ≥ 25%) 22 10 12 
Masked Obesity 12.2% 17.2% 9.8% 
High BMI (≥ 25.0 kg∙m-2) 71 43 28 

The chi-squared statistic was 1.886 (df = 1, p = 0.17) indicating no statistical difference in NWO between males (17.2%) and females (9.8%).

DISCUSSION

As stated previously, there is a dearth of data determining the prevalence of NWO domestically, more specifically, within the southeast region of the United States. Therefore, the primary objective of this research study was to investigate the frequency of NWO amongst a sample of apparently healthy individuals. Participants completed a singular data collection session whereby height, body mass, and percentage body fat were quantified via BOD POD® GS. Within this current study, low and normal BMI classifications were <18.5 kg∙m-2 and 18.5 – 24.9 kg∙m-2, respectively. Class I obesity for females and males were ≥ 32% and ≥ 25%, respectively. Given said thresholds, data revealed that 12.2% of the overall sample exhibited NWO, with a higher prevalence amongst males (17.2%) compared to females (9.8%). These findings are relatively comparable within other research investigating the prevalence of NWO amongst a sample of young adults (5, 35, 44, 57).

In 2017, Ramsaran and Maharaj investigated the prevalence of NWO within a cohort of 236 young adults (mean age = 21.3 ± 2.5 years). The quantification of %BF was accomplished using the Tanita Ironman body composition analyzer. Subsequent data analyses unveiled a heightened prevalence of NWO among the male participants (14.4%), surpassing their female counterparts (5.5%). The outcomes of the current study align with the findings reported by Ramsaran and Maharaj (44), wherein NWO manifested in 17.2% of males and 9.8% of females. A nuanced distinction between the two investigations lies in the designated thresholds for %BF. Ramsaran and Maharaj (44) set the elevated %BF thresholds at ≥ 23.1% for males and ≥ 33.3% for females. In contrast, the current study employed thresholds of ≥ 25.0% for males and ≥ 32.0% for females. Notwithstanding the marginal elevation (+1.9%) in the %BF threshold within the current study, males exhibited a greater prevalence (+2.8%) compared to Ramsaran and Maharaj’s (44) dataset. Conversely, the current study adopted a lower %BF threshold (–1.3%) for females and uncovered a higher prevalence of NWO (+4.4%). These subtle yet discernible variations in %BF thresholds may elucidate the divergent prevalence rates of NWO observed between the two scholarly investigations.

Akin to Ramsaran and Maharaj (44) and the present investigation, Anderson and colleagues (5) examined the incidence of NWO within a more modest cohort of 94 young adults (mean age = 19.6 ± 1.5 years). The quantification of %BF was assessed via DXA. The %BF thresholds were predicated on National Health and Nutrition Examination Survey standards, establishing obesity values of ≥ 30.0% for males and ≥ 35.0% for females. Findings elucidated an NWO prevalence in males (26.7%) and females (7.8%). Noteworthy is the marked elevation in male NWO rates (+9.5%) and marginal reduction (–2.0%) in female NWO rates compared to the current study. While discrepancies may be attributed to variances in sample size (254 in the present study vs. 94 in Anderson et al.), divergent methodologies for %BF assessment (utilizing BOD POD® GS presently as opposed to DXA in Anderson et al.), and distinct %BF thresholds (ACSM criteria in the current study versus NHANES in Anderson et al.), the overarching findings remain concordant. Specifically, data from all three research investigations underscore the consistent pattern wherein males manifest elevated NWO prevalence rates relative to their female counterparts.

In contradistinction to the two previous research investigations and the current study, Zhang et al. (57) explored the NWO prevalence amongst 383 young adults (mean age = 20.4 ± 1.6 years). Assessment of %BF was executed through bioelectrical impedance analyses (BIA) employing the InBody 720 device. Obesity classification was contingent upon threshold values of ≥20.0% for males and ≥30.0% for females, as established by Zhang and associates (57). Analyses unveiled an NWO prevalence of 13.2% in males and 27.5% in females, a prominent deviation from the present study’s findings. The contrasting NWO prevalence patterns observed between the two studies are notably discernible. Specifically, Zhang and colleagues (57) reported a higher prevalence in females than males, whereas the current investigation revealed the converse. This discordance is seemingly attributable to variances in the %BF thresholds implemented for obesity classification. Zhang et al. (57) utilized a considerably lower threshold for males at 20.0%, as opposed to the 25.0% threshold applied in the current study. Similarly, for females, Zhang et al. (57) employed a lower %BF threshold at 30.0%, whereas the present study utilized a more conservative threshold of 32.0%. Moreover, a salient methodological distinction lies in the apparatus employed for %BF quantification. The current study utilized the BOD POD® GS, acknowledged as the applied gold standard for assessing body composition, while Zhang et al. (57) employed the InBody 720 BIA. These methodological nuances likely contribute to the divergent findings between the present research and Zhang et al. (57), underscoring the importance of rigorously evaluating both threshold criteria and assessment modalities when interpreting and comparing NWO prevalence data.

In a recent investigation, Maitiniyazi et al. (35) endeavored to ascertain the prevalence of NWO within a cohort of 279 young adults (mean age = 21.7 ± 2.1 years). Percentage body fat was assessed utilizing the InBody 770 BIA method. Obesity classification thresholds were established at 20.0% for males and 30.0% for females. Parallel to the observed NWO patterns delineated by Zhang and colleagues (57), Maitiniyazi et al. also discerned a higher prevalence of NWO in females (40.1%) as opposed to males (25.5%). Notably, while these NWO trends align with the patterns identified by Zhang et al. (57), they markedly deviate from the outcomes of the current investigation. Such discordant findings may find elucidation in the nuanced disparities in the thresholds employed to categorize obesity and the instrumentation deployed for %BF quantification. Specifically, the divergence in %BF thresholds used for obesity classification emerges as a significant factor. Maitiniyazi et al. (35) employed thresholds different from those of Zhang et al. (57) and the current study, thereby contributing to the observed inconsistencies. Additionally, the equipment utilized to quantify %BF introduces another layer of methodological variation. While Zhang et al. (57) implemented InBody 720 BIA and the current study utilized BOD POD® GS, Maitiniyazi et al. deployed the InBody 770 BIA method. These divergent methodological approaches underscore the imperative of meticulous consideration when interpreting and comparing NWO prevalence data, highlighting the multifaceted nature of the interplay between obesity thresholds and assessment methodologies in elucidating NWO prevalence.

CONCLUSIONS

This comprehensive investigation contributes significantly to our understanding of NWO prevalence within a young adult population, particularly within the Southeast region of the United States. The study employed the BOD POD® GS for precise measurement of height, body mass, and percentage body fat, revealing a higher, but not statistically different, prevalence in NWO between males and females. These results align with similar studies collectively emphasizing the consistent pattern of elevated NWO prevalence in males relative to females. The study’s alignment with said research investigations further underscores the robustness of the findings, notwithstanding variations in sample size, methodology, and threshold criteria. Conversely, discrepancies with other research investigations highlight the sensitivity of NWO prevalence to %BF thresholds and assessment modalities. Despite the divergence in outcomes, these studies collectively reinforce the need for careful consideration of methodological nuances in interpreting and comparing NWO prevalence data.

APPLICATION IN SPORTS

From a practical perspective, the findings emphasize the importance of incorporating regional and demographic variations when assessing NWO prevalence. Furthermore, the study underscores the relevance of employing standardized methodologies in ensuring consistency and comparability across investigations. Future endeavors in this domain should continue to explore regional variations, refine %BF threshold criteria, and employ advanced methodologies for accurate NWO characterization. This knowledge is pivotal for tailoring preventive measures and interventions; more precisely, accurately identifying NWO individuals is an opportunity for clinicians to proactively educate their clients regarding the health risks associated with hypokinetic disease(s), particularly cardiovascular disease(s), metabolic syndrome, and cardiometabolic dysfunction.

ACKNOWLEDGMENTS

The author would like to personally thank the following research assistants that contributed to the success of this research investigation: Tristen, Brennan, Marisa, Maddie, Samantha, Caylin, and Ethan.

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2024-10-24T15:50:50-05:00October 25th, 2024|Research, Sports Health & Fitness, Sports Nutrition|Comments Off on Prevalence of Normal Weight Obesity Amongst Young Adults in the Southeastern United States
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Low Energy Availability (LEA) in Male Athletes: A Review of the Literature

Authors:Brandon L. Lee1

1The Department of Exercise, Health, and Sport Sciences, Pennsylvania Western University

Corresponding Author:

Brandon L. Lee, MS, RD, CCRP
10263 4th Armored Division Dr.
Fort Drum, NY 13603
[email protected]
315-772-0689

Brandon L. Lee, MS, RD, CCRP is a Holistic Health and Fitness (H2F) Dietitian for the U.S. Army Forces Command and a Doctor of Health Science (DHSc) student at Pennsylvania Western University. Brandon’s research interests include energy systems and metabolism, energy availability, andragogical methods for adult learning, and reflective practice to enhance learning in formal education..

ABSTRACT

Purpose: Low energy availability (LEA) is a physiological state when there is inadequate energy to meet the demands placed on the body, often through physical activity, exercise, or sports. LEA can impact any athlete engaged in a sport with low energy intake or excessive energy expenditure. LEA is a precursor to the onset of The Male Athlete Triad (MAT) and Relative Energy Deficiency in Sport (RED-S). There is no defined low energy availability threshold specific to male athletes engaged in high-energy expenditure sports leading to MAT and RED-S. This literature review evaluates the literature on the relationship between LEA and signs or symptoms of MAT and RED-S to establish a low energy availability threshold specific to male athletes engaged in high-energy expenditure sports.

Methods: The Pennsylvania Western University library electronic database was used for the literature search. Search terms included “male athletes”, “low energy availability”, “male athlete triad”, “relative energy deficiency in sport”, and “energy deficiency”. Research studies included cross-sectional, experimental, systematic reviews, meta-analyses, case studies, and some narrative and literature reviews. Studies must have been peer-reviewed and published within five years of the literature search (12/2018- 12/2023).

Results: A review of the literature shows that it is difficult to determine a LEA threshold due to present research gaps and inconsistent findings related to health and performance consequences. Based on the results of experimental studies, practitioners can expect an LEA threshold of 20-25kcal per kilogram (kg) of fat-free mass (FFM) per day in male athletes engaged in high energy-expenditure sports.

Conclusions: Athletes engaged in sports that lead to inadequate energy intake or high energy expenditure are at risk for LEA, MAT, and RED-S. Experimental research on the LEA threshold in athletes engaged in physiologically demanding sports is the greatest research gap. Based on present findings, male athletes may have an LEA threshold of <30kcal/kg of FFM/day.

Applications in Sport: Healthy nutritional practices are essential to sports performance. Interdisciplinary sports performance teams must collaborate with nutrition professionals to develop effective LEA prevention, screening, and intervention protocols.

Keywords: energy intake, energy deficiency, energy expenditure of exercise, male athlete triad, relative energy deficiency in sport, sports nutrition

Low Energy Availability (LEA) in Male Athletes: A Review of the Literature

Energy availability (EA) is the energy dedicated to body system functions. In sports nutrition, energy availability is defined as the amount of energy remaining to support an athlete’s bodily functions after energy expenditure of exercise (EEE) is deducted from energy intake (EI) (2). Health and athletic performance issues arise when athletes have inadequate energy intake or excessive energy expenditure, depleting their EA. The designated term for this is low energy availability (LEA). LEA is defined as a physiological state when there is inadequate energy to meet the demands placed on the body, often through physical activity, exercise, or sports (23). Causes of LEA include obsessive causes (disordered eating or eating disorders), intentional causes (attempts to modify body mass or composition), and inadvertent causes (byproduct of high EEE) (1).
LEA can impact any athlete engaged in a sport with low energy intake or excessive energy expenditure. LEA is most common in sports of high intensity, duration, volume, or frequency and in sports that emphasize low body weight/fat, aesthetics, or thinness, including distance cycling and running, triathlons, tactical (i.e., military), swimming, gymnastics, wrestling, bodybuilding, martial arts, boxing, soccer, tennis, rowing, horse racing, and volleyball. LEA is a precursor to the onset of both The Male Athlete Triad (MAT) and Relative Energy Deficiency in Sport (RED-S), two conditions that result in weakened physiological functions, with the former focused on reproductive and bone health decline (22). The problem is the prevalence of LEA among male athletes participating in high-energy expenditure sports, leading to potential health and performance issues. Additionally, there is no defined low energy availability threshold specific to male athletes engaged in high-energy expenditure sports leading to MAT and RED-S (3, 4, 5, 9, 11, 14, 17, 22, 26).
This literature review aims to evaluate the literature on the relationship between LEA and signs or symptoms of MAT and RED-S to establish a defined low energy availability threshold specific to male athletes engaged in high-energy expenditure sports. This literature review will report on LEA’s impact on health, body composition, athletic performance; establish LEA thresholds, and address research gaps.

RELATIVE ENERGY DEFICIENCY IN SPORT (RED-S)
LEA is a common precursor to many health and athletic performance issues. In 2014, the International Olympic Committee (IOC) developed a consensus statement titled “Beyond the Female Athlete Triad: Relative Energy Deficiency in Sport (RED-S)” and established RED-S as a new condition that refers to diminished physiological processes due to relative energy deficiency. The most current IOC RED-S models show that RED-S can impact the following systems: immunological, menstrual/reproductive function and bone health (related to athlete triad), endocrine, metabolic, hematological, growth and development, psychological, cardiovascular, and gastrointestinal. Moreover, another IOC RED-S model shows the potential performance effects of RED-S, including decreased endurance performance, increased injury risk, decreased training response, impaired judgment, decreased coordination, decreased concentration, irritability, depression, decreased glycogen stores, and decreased muscle strength (19). Much of the research on the impact of LEA and the cascade of events that lead to RED-S has primarily been conducted on female athletes, and the findings are extrapolated to their male counterparts; however, this is changing.

MALE ATHLETE TRIAD
The Male Athlete Triad (MAT) was first introduced in the 64th Annual Meeting of the American College of Sports Medicine (ACSM) in 2017 (6). MAT has comprised three essential components: LEA (sometimes referred to as energy deficiency), impaired bone health, and suppression of the hypothalamic-pituitary-gonadal (HPG) axis (22).
Prevention and treatment methods of MAT hinge on the EA or energetic status of the athlete at risk. Nattiv et al. (2021) explain that energy deficiency or LEA is confirmed when one of the following metabolic adaptations is presented: reduced RMR compared to body size or fat-free mass (FFM), unintentional weight loss resulting in a new low set point, underweight body mass index (BMI), and reduced metabolic hormones such as triiodothyronine (T3), leptin, and several more. Hypogonadotropic hypogonadism can manifest as oligospermia (deficiency of sperm in the semen) or decreased libido (reduced sexual drive). Lastly, poor bone health can manifest as osteopenia, osteoporosis, or bone stress injury (22).
The energetic status of the athlete can vary greatly depending on frequency, intensity, duration, type of sport, volume, and progression. Nattiv et al. (2021) have surmised that male athletes engaged in leanness sports typically have low energy intake compared to recommended amounts from the Institute of Medicine Daily Recommended Intakes or Food and Agriculture Organization of the United Nations/World Health Organization. Unfortunately, male leanness sports or weight-class athletes potentially consume up to 1000kcal/day less than required to support their exercise demands (22). Athletes consistently at risk for MAT include runners and cyclists, primarily if they compete in long-distance competitions.

Cardiovascular Health
Cardiovascular health (CVH) is essential to every athlete engaged in any sport. A healthy cardiovascular system effectively moves blood from one location to another to transport oxygen-containing blood cells for muscular activity. Langan-Evans et al. (2021) studied the impact of incorporating daily fluctuations in LEA on cardiorespiratory capacity via treadmill test in one combat athlete preparing to make weight for competition. The athlete experienced microcycle EA fluctuations ranging from 7 to 31 kcal per kilogram (kg) of FFM/day (mean EA of 20kcal/kg of FFM/day) for seven days and did not experience any significant changes in resting heart rate, cardio output, or overall CVH (14). Theoretically, LEA would have significant structural, conduction, repolarization, and peripheral vascular effects on CVH (17). However, a scant amount of research establishes any correlation between CVH and LEA, and primary research studies conducted within the past five years have yet to establish causation between the two.
On the other hand, Fagerberg (2018) has found that EA <25kcal/kg FFM over six months in bodybuilders preparing for a competition can impact CVH by reducing heart rate. According to Fagerberg (2018), low body fat percentages in bodybuilders worsen CVH risk (4). This heart rate reduction, paired with low body fat, is likely a physiological adaptation to conserve energy and sustain life. There needs to be more consistency in the literature regarding the impact of LEA on CVH.

Physiological Health
LEA and RED-S are both physiological and psychological health risks. Sports that emphasize leanness (e.g., cycling) or have weight divisions (e.g., combat sports) often place additional mental stress on athletes to perform well and possess a specific physique. For example, Schofield et al. (2021) found that male cyclists are at risk for LEA and RED-S due to rigid weight management practices, desire for leanness, disordered eating and eating disorders, and body dissatisfaction (26).
Elevating psychological health is commonly conducted via a questionnaire or interview. Langbein et al. (2021) explored the subjective experience of RED-S in endurance athletes through semi-structured, open-ended interviews. The first male participant commented on hitting “rock bottom” and the body’s sensitivity to energy intake changes. In addition, the other male athlete appeared to have a transactional relationship with food and exercise, void of any joy or performance goals. Both male athletes reported negative psychological consequences regarding RED-S; these consequences included increased rates of irritability because they were obsessed with food and exercise and feelings of helplessness and despair (15).
Perelman et al. (2022) also examined the male athlete’s psychological state by evaluating and intervening on body dissatisfaction, drive for muscularity, body-ideal internalization, and muscle dysmorphia. Male athlete participants (n=79) were from various sports, including baseball, golf, soccer, swimming, track and field, volleyball, and wrestling. The results showed that group sessions focused on reframing ideal body perception, the consequences of RED-S, encouraging positive self-talk, and reviewing strategies to modify energy balance healthfully can significantly reduce body dissatisfaction, body-ideal internalization, and drive for muscularity (p < .05) (24). The results demonstrate the value of understanding, supporting, and guiding an athlete’s psychological state toward personal health and satisfaction.

Reproductive Health
Functional hypogonadotropic hypogonadism is one of the three primary pillars of the MAT. LEA can induce disruptions to the hypothalamic-pituitary-gonadal (HPG) axis, resulting in functional hypogonadotropic hypogonadism. Signs of hypogonadotropic hypogonadism include (1) reductions of testosterone (T) and luteinizing hormone (LH), (2) decreased T and responsiveness of gonadotropins to gonadotropin-releasing hormone (GnRH) stimulation after training, (3) alterations in spermatogenesis, and (4) self-reported data on decreased libido and sexual desire (22). Most current research studies examine free and total T as an indicator of HPG axis suppression. Lundy et al. (2022) categorize low total T (<16nmol/L) and low free T (<333 pmol/L) as primary indicators for LEA (16).
A significant contribution to this area comes from the work by Jurov et al. (2021) who conducted a non-randomized experimental study with a crossover design to investigate the reproductive health impacts of progressively reducing EA by 50% for 14 days in well-trained and elite endurance male athletes. The results demonstrated a positive correlation between T levels and measured EA; as EA declined, so did T (9).
The empirical evidence on the causal relationship between LEA and T has been growing over recent years, with studies such as one conducted by Dr. Iva Jurov and colleagues. In three progressive steps, their quasi-experimental study reduced EA (via increasing EEE and controlling EI) in well-trained and elite male endurance athletes. Participants had statistically significant T changes starting at the 50% EA reduction phase with a mean EA of 17.3 ± 5.0kcal/kg of FFM/day for 14 days (p < 0.037). Furthermore, T levels continued to significantly decline at 75% EA reduction phase with a mean EA of 8.83 ± 3.33 for ten days (p < 0.095) (10). Conversely, in another quasi-experimental study by Jurov et al. (2022b), endurance male athletes had their EA reduced by 25% by increasing EEE and controlling EI for 14 days. The mean EA was 22.4 ± 6.3kcal/kg of FFM/day. The results show no significant changes to T levels, potentially indicating that a greater EA reduction was required to induce change (11).
Stenqvist et al. (2020) conducted four weeks of intensified endurance training designed to increase aerobic performance and determine the impact of T and T: cortisol ratio on well-trained male athletes. After the four weeks of intensified endurance training, the results showed that total T significantly increased by 8.1% (p=0.011) while free T (+4.1%, p=0.326), total T: cortisol ratio (+1.6%, p=0.789), and free T: cortisol ratio (-3.2%, p=0.556) did not have significant changes when compared to baseline (27). It is complex to determine the EA threshold defined by HPG axis suppression. Research on LEA and suppression of the HPG axis (i.e., T reduction) have demonstrated varied results based on athlete EA study design features (e.g., high EEE intensity or low EI duration); however, endurance athletes remain at the highest risk (18, 22, 26).

Bone Health
The last pillar of the MAT is osteoporosis with or without bone stress injury (BSI). Impaired bone health is most common in athletes in sports that have low-impact loading patterns, such as cycling, swimming, or distance running. Bone mineral density (BMD) is the primary measurement method to evaluate overall bone health and risk for osteoporosis. Dual-energy x-ray absorptiometry (DXA) is the gold standard for assessing bone density, but quantitative computed tomography (QCT) is also emerging as an equally acceptable alternative. In outpatient or rehabilitation settings, frequency of DXA scans is recommended no sooner than every ten months to allow for detectable changes in bone mineral density (17).
Risk factors for low BMD include LEA, low body weight (<85% of ideal body weight), hypogonadism, running mileage >30/week, and a history of stress fractures (22). In addition to BMD, other indicators of bone health include bone mineral content (BMC), markers of bone formation including β-carboxyl-terminal cross-linked telopeptide of type I collagen (β-CTX), bone alkaline phosphatase, and osteocalcin, and markers of bone resorption including amino-terminal propeptide of type-1 procollagen (P1NP), tartrate-resistant acid phosphatase, and carboxy-terminal collagen cross-links (4, 17). Studies will occasionally implement biomarkers such as Vitamin D and calcium to evaluate dietary intake and risk of BSI or osteoporosis.
What is the prevalence of low BMD in athletes? Tam et al. (2018) evaluated the bone health and body composition of elite male Kenyan runners (n=15) compared to healthy individuals. The results showed that 40% of Kenyan runners have Z-scores indicating low bone mineral density in their lumbar spine for their respective age (z-score <−2.0). This study did not measure energy availability with bone mineral density (29). However, based on previous research, low bone mineral density may have LEA origins.
Heikura et al. (2018) studied the BMD of middle- and long-distance runners and race walkers and found that athletes had an LEA (21kcal/kg of FFM/day) (7). Athletes with a moderate EA generally had better z-scores than the LEA athletes; however, the differences were not statistically significant. Similarly, Õnnik et al. (2022) found that high-level Kenyan male distance runners had an average EI of 1581kcal, and male controls had an average EI of 1454kcal per day. The male athletes did not show a statistically significant difference in BMD (p = 0.293) compared to the male control group, with only one runner (out of 20) at risk for osteoporosis (lumbar spine z-score <1.0) (23).
Cyclists are at the highest risk for poor bone health due to chronic LEA, reduced osteogenic simulation, and low levels of impact or resistance (26). Keay et al. (2018) assessed the efficacy of a sport-specific EA questionnaire and clinical interview (SEAQ-I) in British professional cyclists at risk of developing RED-S. Based on the results of the SEAQ-I, 28% (n=14) were identified with LEA, and 44% of the cyclists had low lumbar spine BMD (z-score <-1.0) (p< 0.001). Also, cyclists with a history of lack of load-bearing sports or activities had the lowest BMD (p= 0.013) (13). This study demonstrates a clear association between LEA and reduced lumbar spine BMD in professional cyclists.
In a randomized controlled trial, Keay et al. (2019) investigated the efficacy of an educational intervention with British competitive cyclists to improve energy availability and bone health. The researchers induced LEA by 25% (mean EA of 22.4 ± 6.3kcal/kg of FFM/day) for 14 days. Athletes who implemented nutritional strategies (provided by nutrition professionals) to improve EA and strength training strategies to improve skeletal loading saw lumbar spine BMD improvements. Mean vitamin D levels significantly improved from pre-season (90.6 ± 23.8 nmol/L) to post-season (103.6nmol/L; p=0.0001). Calcium, correct calcium, and alkaline phosphatase had no statistically significant changes between pre-season and post-season (12). Keay et al. have established the prevalence of LEA and poor bone health in cyclists and demonstrated nutrition education efficacy for BMD improvements. Noteworthy findings such as these help to raise awareness in the cycling community and can inform preventative or rehabilitative strategies.

BODY COMPOSITION
Body composition is the distinction between fat mass and fat-free mass. Fat-free mass includes water, tissue, organs, bones, and muscle (e.g., skeletal muscle). Body composition control and maintenance are essential for an athlete’s health, performance, and mindset. Research measurements of body composition include weight, body mass index, body fat percentage, lean mass, and water content. According to Lundy et al. (2022), a body mass index <18.5 kg/m2 is a primary indicator of LEA; this suggests body composition changes in response to LEA (16).
What is the impact of LEA on body composition? Stenqvist et al. (2020) implemented a four-week intensified endurance training designed to increase aerobic performance and elevate body composition’s impact on well-trained cyclists. The results did not show statistically significant changes in energy intake, body weight, fat mass, or fat-free mass. Body weight loss was potentially averted due to reduced resting metabolic rate as a protective mechanism (27). Whereas Stenqvist et al. (2020) focused on increasing EEE, Jurov et al. (2021) attempted to induce LEA via EI manipulation. Jurov et al. (2021) progressively reduced EA by 50% for 14 days in well-trained and elite endurance male athletes; the results showed no significant changes in body mass and fat-free mass (9).
Regarding resistance training and LEA, Murphy and Koehler (2022) conducted a meta-analysis to quantify the discrepancy in lean mass accretion between interventions providing resistance training in an energy deficit and those without an energy deficit. The literature findings demonstrated lean mass gains impairment in athletes resistance training in an energy deficit compared to those training without an energy deficit (significantly, p = 0.02). The results also surmised that an energy deficit of as much as 500kcal/day could impede lean mass gains (21).
Roth et al. (2023) evaluated the impact of a relatively high- versus moderate volume resistance training program on alterations in lean mass during caloric restriction in male weightlifters. The results showed that whole-body lean mass significantly declined in both groups (high and moderate volume groups) following six weeks of energy restriction. The high-volume group had an EA of 31.7 ± 2.8kcal/kg of FFM/day, and the moderate-volume group had an EA of 29.3 ± 4.2kcal/kg of FFM/day (25). Both studies demonstrate that muscle hypertrophy is unattainable in the presence of LEA.
Furthermore, Murphy and Koehler (2020) found that three days of caloric restriction at an EA of 15kcal/kg of FFM/day in recreational weightlifters resulted in significant reductions in weight (p<0.01), fat mass (p<0.01), and lean mass (p<0.001). Also, the total mass loss was significant (p<0.01) when compared to a control group (EA of 40kcal/kg of FFM/day) (20). The results of studies focused on resistance training and caloric restriction hold applicability for athletes in sports that rely on lean mass gains while manipulating EI, such as bodybuilding (4).

CARDIORESPIRATORY ENDURANCE
Cardiorespiratory endurance (CRE) is the ability of the lungs, heart, and blood vessels to deliver sufficient oxygen to cells to meet the physiological demands of exercise and physical activity (8). Evaluating maximal oxygen uptake or VO2max is a standard CRE measure. A VO2 max of 67.9 ± 7.4 mL/kg/min is categorized as a high fitness level (28).
What is the impact of induced LEA on CRE performance outcomes? Jurov et al. (2021) investigated the endurance performance impact of progressively reducing energy availability by 50% for 14 days in well-trained and elite endurance male athletes. The researchers increased EEE to achieve a mean energy availability of 17.3 ± 5 kcal/kg of FFM/day. The results showed lowered EA reduced endurance performance, as indicated by respiratory compensation point (RC) and VO2max. Jurov et al. (2022b) reduced EA by 25% (by increasing EEE and controlling EI) in trained endurance male athletes and monitored for aerobic performance changes. The results showed that inducing LEA by 25% (mean EA of 22.4 ± 6.3kcal/kg of FFM/day) for 14 days reduced hemoglobin levels, indirectly impacting VO2max and aerobic performance (11). Beyond research conducted by Dr. Iva Jurov and colleagues, there is insufficient experimental research on LEA and CRE.

MUSCULAR STRENGTH AND ENDURANCE
In recent years, few experimental studies have evaluated the impact of LEA on muscular strength, endurance, and athletic performance. Research on athletic performance and LEA has shown that endurance athletes with an EA of 17.3 ± 5 kcal/kg of FFM/day show no reductions in agility t-tests, power output, or countermovement jump results, indicating no association with EA (9). Also, Jurov et al. (2022b) found that a mean EA of 22.4 +/- 6.3kcal/kg of FFM/day in endurance male athletes for 14 days results in significant changes to explosive power (countermovement jump) but not agility t-tests (11).
Furthermore, Jurov et al. (2022a) also reduced EA (via increasing exercise energy expenditure and controlling energy intake) in male endurance athletes to evaluate performance and muscular power impact. The results showed significant reductions in explosive power (measured via vertical jump height test) at a mean EA of 22.4, 17.3, and 8.82 kcal/kg of FFM/day. Based on these findings, athletes reach the LEA threshold after a long time in an energy-deficient state, such as ten to 14 days (10).
However, Stenqvist et al. (2020) aimed to measure peak power in male cyclists after four weeks of intensified endurance training. The results showed that the cyclists significantly improved their peak power output (4.8%, p < 0.001) and functional threshold power (6.5%, p < 0.001) measured via stationary bike. Possibly, the EEE of the intervention was insufficient to induce LEA but instead induced the Specific Adaptation to Imposed Demands (SAID) principle in the athletes (27).
Regarding weightlifters, Murphy and Koehler (2022) studied whether energy deficiency impairs strength gains in response to resistance training. This research study was a meta-analysis of randomized controlled trials. The study findings showed that strength gains were comparable between resistance training groups in either an energy deficit or a balance state. These results demonstrated that low energy availability for prolonged periods (i.e., RED-S) did not impede strength output (21). There are a few studies that report bodybuilders with strength declines with estimations of EA <20 kcal/kg of FFM/day (4). The theory remains that inadequate energy intake will inevitably reduce muscular strength and output.

LOW ENERGY AVAILABILITY THRESHOLD
To date, optimal EA levels and the threshold for LEA in male athletes are under investigation. However, many research studies are cross-sectional, only demonstrating a correlation between athletes and energy availability (e.g., LEA commonly found in endurance athletes). The scant number of current experimental studies often fail to induce LEA and thereby fail to establish clear LEA thresholds.
To prevent LEA and subsequent conditions such as RED-S and MAT, athletes need to maintain their energy availability. Primarily, athletes need to ensure adequate EI and carefully manage their EEE. Current EA “zones” for female athletes are also applied to male athletes until experimental research can demonstrate a need for separate guidelines. EA >45kcal/kg of FFM/day supports body mass gain and maintains healthy physiological functions; 45kcal/kg of FFM/day is optimal for weight maintenance and healthy physiological functions; 30-45kcal/kg of FFM/day is considered suboptimal and at-risk for reduced physiological functions; and ≤30kcal/kg of FFM/day is considered low energy availability (1, 3, 4, 9, 10, 14, 17, 26).
Research by Jurov and colleagues has demonstrated mixed results regarding performance outcomes, body composition, and bone health (9, 10, 11). Mean energy availability in those studies ranged between 17-22 kcal/kg of FFM/day (9, 11). Based on their research findings, Jurov and colleagues have proposed a range of 9-25kcal/kg of FFM/day (mean value of 17kcal/kg of FFM/day) for an LEA threshold (10).
Regarding performance and body composition outcomes, Murphy and Koehler (2020) conducted a randomized, single-blind, repeated-measures crossover trial that showed three days of caloric restriction at an EA of 15kcal/kg of FFM/day induced considerable anabolic resistance to a heavy resistance training bout (20).
In a case study by Langan-Evans et al. (2021), an EA of 20kcal/kg per FFM/day led to weight loss and fat loss without signs of MAT and RED-S. However, an EA of <10kcal/kg of FFM/day did result in signs and symptoms of MAT and RED-S, including disruptions to the hypothalamic-pituitary-gonadal axis, resting metabolic rate (measured), and resting metabolic rate (ratio) (14). Additionally, some LEA thresholds may need to be sport-specific. For instance, Fagerberg et al. (2018) suggest an LEA threshold of 20-25kcal/kg of FFM/day for male bodybuilders with a lower body fat percentage (4). Research to establish EA zones and an LEA threshold for male athletes continues, and guidelines primarily still consider ≤30kcal/kg of FFM/day appropriate for male athletes. However, some researchers have also contested that male athletes can go lower before exhibiting signs and symptoms of MAT and RED-S.

RESEARCH GAPS
There are sizable research gaps regarding LEA and RED-S. First, this literature was unable to address the impact of LEA on endocrine, metabolic, hematological, and gastrointestinal health due to insufficient research published in the past five years. Mountjoy et al. (2018) identified the following research gaps: (1) lack of practical tools to measure and detect LEA and RED-S, (2) lack of validated prevention interventions for RED-S, (3) RED-s in male athlete research, (4) health and performance consequences of RED-S research, and (5) lack of evidence-based guidelines for treatment and return-to-play for athletes with RED-S. Research gaps focused on male athletes with MAT are even more prominent (19).

Moreover, Fredericson et al. (2021) listed several research gaps that need scientific attention, including screening protocols to detect MAT in adolescent and young males, identification of MAT energetic and metabolic impact factors, prevalence of DEED in male athletes with MAT, evaluating the efficacy and effectiveness of clearance and return-to-play protocols, risk assessment for BSI and poor bone health, prevalence of MAT in military recruits, health interventions on the prevention and treatment of MAT, and lastly, cutoff values (or threshold) for LEA (5). Addressing these research gaps would enable sports and health practitioners to effectively prevent and treat LEA, RED-S, and MAT, ensuring athlete health and sports performance.

SUMMARY
LEA is defined as a physiological state when there is inadequate energy to meet the demands placed on the body, often through physical activity, exercise, or sports (23). LEA can impact any athlete engaged in a sport with low energy intake or excessive energy expenditure. LEA is a precursor to the onset of both The Male Athlete Triad (MAT) and Relative Energy Deficiency in Sport (RED-S), two conditions that result in weakened physiological functions, with the former focused on reproductive and bone health decline (22).

Recent literature has shown mixed results on LEA’s impact on immunological health, metabolic markers, bone health, body composition, cardiorespiratory endurance, and muscular strength and endurance. There has been little evidence to connect LEA and endocrine, metabolic, hematological, and gastrointestinal health. However, a notable causal relationship exists between LEA and psychological health and reproductive health. Currently, there is still no defined low energy availability threshold specific to male athletes, however, EA zones from 15-25kcal/kg of FFM/day may be appropriate based on current literature (4, 20, 10, 18, 22, 26).

APPLICATION TO SPORT
Healthy nutritional practices are essential to sports performance. Interdisciplinary sports performance teams must collaborate with nutrition professionals such as Registered Dietitians accredited by the Commission on Dietetic Registration to develop effective LEA prevention, screening, and intervention protocols. Preventative measures must prioritize energy availability, modify sporting culture to encourage energy intake, and mitigate barriers to calorie- and nutrient-dense foods in male athletes. Screening protocols must include EA evaluations based on dietary intake, exercise energy expenditure, and fat-free mass measured via DXA or bioelectrical impedance analysis. Male athletes with an EA ≤20-25kcal/kg of FFM/day must receive nutritional guidance to reduce health and performance impairments. Intervention protocols must be enacted when LEA is confirmed and should primarily focus on increasing energy intake, decreasing energy expenditure, and addressing other associated aspects such as psychological health. Athletes, coaches, and practitioners must raise LEA awareness, dispel energy consumption stigmas, and foster an environment where food and nutrition fuel peak performance.

ACKNOWLEDGEMENTS
This work was supported by the Pennsylvania Western University Department of Exercise, Health, and Sport Sciences. The author would like to thank Dr. Marc Federico and Dr. Brian Oddi for their guidance and feedback on the manuscript

References

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2024-10-21T09:45:40-05:00October 23rd, 2024|Book Reveiws, Research, Sports Nutrition|Comments Off on Low Energy Availability (LEA) in Male Athletes: A Review of the Literature
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Selection and Performance Rationale of Wood vs. Aluminum Baseball Bats

Authors: Vilas G. Pol1

AUTHORS INSTITUATIONAL AFFILIATION:

1Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana, 47907, United States 

Corresponding Author:

Vilas G. Pol

Purdue University

Davidson School of Chemical Engineering

West Lafayette, Indiana 47906

[email protected]

Acknowledgments

We would like to express our sincere gratitude to Sunkalp Vilas Pol for his valuable contribution to this research. His assistance in this article is greatly appreciated and played an important role in the development of this paper. We commend his dedication and enthusiasm for learning.

Selection and Performance Rationale of Wood vs. Aluminum Baseball Bats 

ABSTRACT

USA Youth Baseball approves metal/alloy, composite, and wood (or a combination) bats for use in baseball games. However, players, parents, and coaches often face a dilemma when selecting a superior baseball bat, as bat quality depends on material, durability, performance, sensation, player preference, and balance. The purpose of this experimental investigation is to understand the maximum exit velocity of a baseball and overall performance of maple wood vs. aluminum bats. This is accomplished by hitting a stationary ball on a tee as well as with two different pitch speeds (30 and 40 MPH from a roller pitching machine), measured by a speed radar (accuracy ±1 MPH) in a controlled environment. It is hypothesized that when the material of the baseball bat changes, the exit velocity of the ball would change due to the trampoline effect (compression of the solid metal barrel) when hitting with the metal/aluminum bat compared to the solid wood bat. Apart from similar barrel size, length, and weight of the bats, it is observed that the metallic aluminum bat is slightly superior (2-3%) because of the trampoline effect when the balls were hit off the tee and with the machine at 30 MPH speed. Interestingly, for the 40 MPH automatic pitching machine test, the wood bat was 3-4% superior to the aluminum bat, possibly due to high impact speeds with less than 1 ms impact duration and minimum energy losses in the bat, or even due to the strength of the batter. The data were collected by a 12U youth baseball player in three different sessions for better accuracy and reproducibility. In fact, high-quality (hence expensive) wood or aluminum bats could lead to analogous outcomes (±1-2% variations) when used in a controlled environment, not significantly contributing to winning the baseball game.

Keywords: Exit velocity, Trampoline effect, Barrel size and length, Controlled environment, Efficiency  

INTRODUCTION

Baseball is a popular American game played between two teams of nine members with a bat, a ball, and gloves on a diamond-shaped field with alternating batters (offense) and fielders (defense). The batter’s goal is to hit the ball hard enough, putting it out of reach of the fielding team to make a complete circuit around the bases to obtain a ‘run,’ with the team scoring the highest number of runs winning the game. This is typically made of either of wood or a lightweight metal such as aluminum. Now the mystery question is which bat (wood or aluminum) should be selected for such an important task.

During the last century, there has been significant research and development in the baseball field including selection of bats, barrel diameter, shape, length, and composition. Naturally, wood and aluminum bats are considered based on their performance, affordability, and safety. Typically, the more expensive bats use higher quality materials, hence better properties such as lightweight materials leading to longer distances and more power while producing minimal vibrations.

Due to lots of discussion in the open literature arguing which material bats are superior, this study particularly focuses on the experimental investigation of the exit velocity of most common aluminum and wood bats. It was hypothesized that using a maple wood bat versus an aluminum baseball bat of the same length, barrel size, weight, and producers used to strike the ball might create a different exit velocity because of varied physical properties of bat materials, including the commonly known trampoline effect (barrel compresses and expands) while using the hollow aluminum bat compared to the solid wood bat.

In 2022, Sherwood et al. studied five aluminum and wood baseball bats and observed that the field performance of these bats strongly correlated with the ball–bat coefficient of restitution COR. They predicted the relationship between wood baseball bat profile and durability based on finite element modelling of 15 profiles used from 15 MLB players (1). Russell described the effect of cylindrical barrel and flexural bending vibrations (2) on softball and baseball bats with respect to their performance including understanding the sweet spot and the origin of the ping (3) sound. Shenoy et al. predicted a model for the performance of solid wood and hollow metal bats with an experimental agreement for the impact speed, ball types, bat models, and impact locations (4).  It is observed that the energy dissipation between the bat and the ball happens through ball deformation, elastic bat vibration and contact friction (4). In 2002, Sherwood et al. investigated the durability of the wooden bat based on the slope of grain impact and impact location, with statistical analysis and finite element modeling. In other study they predicted the relationship between wood baseball bat profile and durability (5). In 2003, Drane and Sherwood described the effect of moisture content on the wooden bat, increasing the velocity by a maximum of 1% (6). In 2002, Penna et al. described that the exit velocity can depend on the skill level of the player or a higher performing bat (7). The systematic literature review created a knowledge gap to investigate the dilemma in selecting the most effective bat that would contribute in winning the baseball game.

This article methodically answers that question with experimental evidence through carefully measuring and comparing the average exit velocities of an aluminum and a wood bat with reproducibility. Though both bats had similar speeds, exit velocity measurements show that the aluminum bat is 2-3% superior because of the hypothesized trampoline effect when the balls were hit off of the tee and against 30 MPH pitches from the ball roller pitching machine. Surprisingly, for the 40 MPH automatic pitching machine test wood bat was 3-4% superior to the aluminum bat possibly due to less than 1 ms impact duration with the minimum energy losses in the bat or even the strength of the batter. This article provides experimental evidence for 12U youth baseball players that high quality wood or aluminum bats could lead to the analogous outcomes with 1-2% variations when used in a controlled environment.

Methods

A standard pitching machine manufactured by Junior Hack Attack was utilized to set up the velocity of the ball being pitched. The speed radar was purchased from Bushnell with an accuracy of ±1 MPH. The velocity gun was calibrated utilizing the set speed of the pitching machine and reading of the radar to a 1 MPH accuracy. The aluminum bat with a length of 31 inches, 23 ounces, and a barrel size of 2 ¾ inches was purchased from Marucci. The maple wood bat with a length of 31 inches, and a barrel size of 2 ¾ inches was purchased from Victus Nox (The brand Marucci owns Victus Nox). A bucket of standard baseballs was purchased from Wilson. A standard batting tee manufactured by Tanners Tees was utilized for the tee tests. An indoor baseball and softball facility (Lifelong Sports, Lafayette, Indiana, USA) was used for these experiments. Figure 1 depicts all used baseball accessories.

Two different velocities of =30 and 40 MPH were set by adjusting left, bottom, and right knobs of a standard pitching machine (Figure 1). The balls were loaded into the pitching machine by a person with approximately 15 second intervals between the pitched balls. The batter wore the requisite safety equipment (helmet, arm guard, leg guard, and batting gloves) while hitting the balls as they were pitched. The speed radar was set up approximately 4 feet behind the batter and the exit velocity was measured after the bat had contacted the ball. Ten balls were set on the batting tee (one at a time) and hit within 15 second intervals. The handheld speed gun was used behind the batter and pointed at approximately where the ball would be headed. Three trial runs were carried out before the final experiment to find errors in the experiment and to correct them. After hitting ten balls with the aluminum bat, the wood bat was used to hit the next ten balls to minimize the error, assuming that the batter’s strength is similar between tests conducted sequentially. Within each set of experimental conditions, the exit velocity of the balls was categorized and reported as the highest (Hi), lowest (Low) and average (Avg) speeds. In some cases, the aluminum bat’s sound frequencies affected the speed gun measurements. These experiments and speed measurements were repeated. Newly purchased baseball balls were used for the measurements to minimize the error. Please note some of the concerns in wood versus aluminum bats are i) the wood bat breaking could happen due to the ball hitting around the handle area or the end, ii) the wood bat could hurt players’ hands due to high impact speeds and vibrations, and iii) the aluminum bat cracking could occur as the metal shrinks in the cold with unsafe storage.  

Results

Typically, commercial baseball pitching machines are arm type (stores balls on sides in an arm shape, which automatically dispenses balls) or roller type (person must manually put balls into the machine). Both machines can dispense different pitches (8) such as fastball, curveball, screwball, slider, etc. To carry out the experiments in a controlled air, moisture, and temperature environment for better accuracy, we used roller type dispenser at LifeLong Sports, Lafayette, Indiana, USA.

Fig. 2 depicts the exit velocity data from 10 balls that were hit off of the tee with maple wood and aluminum bats. The highest exit velocity for the balls that were hit by the wood bat ranges from 57 to 62 MPH, while more consistent 61 MPH for the aluminum bat. The lower velocity and average exit velocity data demonstrate that the effect of using either wood or aluminum bat is negligible when the balls were hit off the tee.

In Fig. 3, 10 balls were pitched at 30 MPH and the exit velocity data was collected for maple wood and aluminum bats. The highest exit velocity for the balls that were hit by aluminum bat ranges from 61 to 63 MPH, while being 55 to 61 MPH for the wood bat. The lowest exit velocity for the balls that were hit by wood bat ranges from 40 to 43 MPH, while 50 to 51 MPH for the aluminum bat. Overall, 2-3% superior performance of the metal bat was observed due to hollow vibrating wall of the bat (similar to a drum upon impact), producing a loud ping sound (9). The exit velocity of the balls was almost double the velocity of balls impacting to the bat.  In fact, the wall bends slightly in an inner direction retaining some of the vibrational energy and then coils back after impacting on the bat. The low frequency ping sound (1,000 Hz) indicates softer, thinner wall thickness of metal bat while high frequency (2,000 Hz) ping sound indicates bat wall is thicker, hence stiffer (9). The trampoline effect on the metal bat helps gain a little more speed compared to the wooden bat (9).

At high pitch speeds of the incoming balls (40 MPH), the obtained data show a slightly different trend, as seen in Fig. 4. The highest exit velocity for the balls that were hit by the aluminum bat ranges from 51 to 53 MPH, while being 57 to 58 MPH for the wood bat. The low exit velocity for the balls that were hit by the aluminum bat ranges from 40-41 MPH, while being 41-45 MPH for the wood bat. Namely, the wood bat showed a slightly superior exit velocity compared to the metal bat. This could be due to high impact speeds with less than 1 ms impact duration with the minimum energy percolation in the bat (9). As baseballs from the same batch were used for both the 30 MPH and 40 MPH pitch tests, these differences can be attributed to differences in the bat material rather than the baseballs themselves. In these conditions, a solid wood bat could perform better than the thin-walled metal bat because of minimized trampoline effect. The wood bat does not ping as loud as metal meaning that it imparts most of the stored elastic energy to the ball with less energy left in the wall of the bat to vibrate (9). Other possible reasons the wood bat was better with enhanced exit velocity are hitting with the harder grain or the shape of the balls (possibly deformed on the harder wood bat), and differences in manufacturing of the bats. These reasons also support why the wood bat performed superior in the 40 MPH test. When 10 balls were hit on both bats with 30 MPH and 40 MPH pitches, the measured exit velocity ranged from 40-63 MPH at low, medium and highest velocities confirming that most of the stored energy is returned to the ball without significant dissipation.  

Discussion

The trampoline effect describes noticeable elasticity in objects impacting at high speeds with applicability to sports such as baseball (the ball and bat), golf (the ball and club), and tennis (the ball and racquet) such that they act like a spring analogous to when we jump on the trampoline  and get bounced back. In baseball, the elasticity of a bat upon the impact of baseball is different for wood and aluminum bats. Typically, when the baseball hits a wood bat, the ball compresses losing more than half of its energy, but when using a hollow aluminum bat, the bat compresses rather than the ball.

The fundamental physics understanding of the trampoline effect in baseball and softball bats was documented by Nathan et al. two decades ago (10) who identified that upon the high-speed impact between a bat and baseball, the original center-of-mass kinetic energy is transformed into compressional energy. Certain energy is stowed in vibrational modes (hoop modes), providing this stored energy to the baseball with minimum dissipation of energy with larger ball exit velocity due to the trampoline effect (10). In other words, the elasticity of a bat upon the impact of baseball determines the magnitude of the resultant trampoline effect (Fig. 5). Typically, when the ball impacts on the aluminum bat, because of its hollow nature the bat barrel compresses to lose energy and returns it to the ball soon after. On the wood bat, the ball compresses and loses up to 75% of energy in frictional forces (10). Typically, during the bat-ball collision, the exit velocity of the ball would be dependent on the effective mass/weight of the bat. However, this is a negligible effect in the experiments reported in this work as both bats possess similar masses. The exit velocity is at its peak at the place on the bat where maximum power was applied on the surface of ball, storing more elastic energy, and subsequently imparting it back to the ball (9).  

Conclusions

Controlling for the barrel size, length, and weight of the bat, it is experimentally measured and observed that aluminum bat is 2-3% superior when balls were hit off of the tee and against 30 MPH machine-pitched balls because of the trampoline effect. Remarkably, for the 40 MPH automatic pitching machine test, the wood bat was 3-4 % superior to the aluminum bat possibly due to high impact speeds with less than 1 ms impact duration with the minimum energy losses in the wood bat or even the strength of the young batter. Even though both bats had similar speeds, exit velocity measurements were measurably different. Therefore, it can be concluded that high quality wood and aluminum bats could lead to analogous outcomes when used in a controlled environment.  

Application in Sport

The outstanding performance of a baseball player can be highly dependent on the selection of a metal or wood baseball bat, its balance, durability and feel in addition to the player’s capabilities. In general, metal bats are known to provide enhanced power, durability, and a broader sweet spot while wood bats provide a traditional feel, tailoring options, and a smaller sweet spot. This article offers insight into the rationale behind selecting a bat with peace of mind for the player, parent, and coach corroborating that high quality (hence expensive) wood or aluminum bats could lead to analogous outcomes with 1-2% variations when used in a controlled environment. Eventually, use of a metal or wood baseball bat is a personal choice, guided by player strength and abilities. 

References

  1. Patrick Drane, Joshua Fortin-Smith, James Sherwood, and David Kretschmann, Predict the relationship between wood baseball bat profile and durability, Procedia Engineering,  2016, 147, 425–430. 
  2. Alan M. Nathan, J. J. Crisco, R. M. Greenwald, D. A. Russell, Lloyd V. Smith, A Comparative study of baseball bat performance, Sports Engineering, 2011, 13, 153-162. 
  3. Daniel A. Russell, Acoustics and vibration of baseball and softball bats, Acoustics Today, 2017, 13(4), 35.  
  4. Mahesh M Shenoy, Lloyd V Smith, John T Axtell, Performance assessment of wood, metal and composite baseball bats, Structures, 2001, 397-404. 
  5. Blake Campshure, Patrick Drane and James A. Sherwood, An investigation of wood baseball bat durability as a function of bat profile and slope of grain using finite element modeling and statistical analysis, Appl. Sci. 2022, 12, 3494.  
  6. P. J. Drane & J.A. Sherwood, The effects of moisture content and work hardening on baseball bat performance, Materials Science, 2003, 1-7 (Corpus ID: 44456022). 
  7. J. J. Crisco, R. M. Greenwald, J. D. Blume, and L. H. Penna, Batting performance of wood and metal baseball bats. Med. Sci. Sports Exerc., 2002, 34, 10, 1675–1684. 
  8. Nippon Kikai Gakkai Ronbunshu, C Hen, Study on throw accuracy for baseball pitching machine with roller (Study of Seam of Ball and Roller), Transactions of the Japan Society of Mechanical Engineers, Part C, November 2007, 73(735):2962-2967. 
  9. R. Cross, Physics of Baseball & Softball, Springer Science Business Media, LLC 2011, Chapter 13, 221- 234. 
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2024-09-26T07:03:33-05:00September 28th, 2024|Sport Training, Sports Studies|Comments Off on Selection and Performance Rationale of Wood vs. Aluminum Baseball Bats
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An examination of studies related to Brazilian jiu-jitsu in enhancing mental and physical health among veterans and first responders: A scoping review

Authors: Richard O. Segovia PhD, EdD1, Alexander Buelna, PhD2, and Brian Sunderman, MA3

1School of Education, Liberty University, Lynchburg, VA, USA
2College of Social and Behavioral Health, Walden University, Minneapolis, MN, USA
3School of Security and Global Studies, American Military University, Charles Town, WV, USA



Corresponding Author:

Richard O. Segovia, PhD, EdD

1971 University Blvd

Lynchburg VA, 24515

[email protected]

737-330-6288

Richard O. Segovia, PhD, EdD, is an adjunct professor and dissertation chair at Liberty University in Lynchburg, VA, and an academic evaluator at Western Governors University in Salt Lake City, Utah. Dr. Segovia’s research interests focus on learning and teaching, combat sports, law enforcement practices, and educational leadership.

Alexander Buelna, PhD, is currently a deputy associate commissioner with Texas Health and Human Services. Dr. Buelna’s areas of research interest includes post-traumatic stress’s impact on veterans and efficient business processes.

Brian Sunderman, MA, is the officer in charge of the Texas Department of Public Safety’s Arrest and Control Tactics Unit. Lieutenant Sunderman’s research interests include the utility of Brazilian Jiu-Jitsu in law enforcement as a law enforcement force option

An examination of studies related to Brazilian jiu-jitsu in enhancing mental and physical health among veterans and first responders: A scoping review

ABSTRACT

Purpose: This scoping review explores the many benefits of Brazilian Jiu-Jitsu (BJJ) on veterans and first responders, focusing on physical health improvements, psychological benefits, and social integration. The purpose is to synthesize existing literature to identify research gaps and suggest directions for future studies. By examining both qualitative and quantitative research, this review seeks to show the utility of BJJ as a therapeutic modality option and propose it as a comprehensive intervention for enhancing the overall well-being of veterans and first responders. Methods: PubMed and Google Scholar searches were conducted to capture a broad range of studies involving BJJ with veterans or first responders. This review adheres to the PRISMA-ScR guidelines, focusing on studies discussing physical, mental, and social outcomes. Results: The initial search yielded numerous qualitative and quantitative studies. This review categorizes the findings into themes of physical health improvements, psychological benefits, and social integration, highlighting the variability and scope of the existing literature. Conclusions: The review highlights the need for well-structured research to substantiate BJJ’s therapeutic benefits. It recommends areas for in-depth exploration in future systematic reviews or primary studies, especially longitudinal studies on BJJ’s effects and specific therapeutic contributions. Application in Sport: For coaches and trainers, integrating BJJ into programs for veterans and first responders enhances physical fitness and mental health. BJJ improves cardiovascular health, strength, and endurance and reduces PTSD, depression, and anxiety symptoms. BJJ supports mental resilience and provides a supportive community, helping in social integration and reducing isolation. Incorporating BJJ can holistically enhance the recovery and effectiveness of veterans and first responders.

Key Words: Brazilian Jiu-Jitsu, veteran rehabilitation, PTSD management, therapeutic exercise, community integration

INTRODUCTION

In examining the multi-layered impacts of Brazilian Jiu-Jitsu (BJJ) on enhancing veterans’ and first responders’ mental and physical health, this scoping review examines a significant, emergent area of therapeutic practices. BJJ, a martial art known for its detailed focus on ground fighting and submission holds, offers more than physical training. It is a dynamic intervention that promotes psychological resilience and aids in social reintegration. By synthesizing various studies [6, 13], this review illuminates how BJJ improves physical mobility and mental health outcomes and facilitates the reintegration of veterans into civilian life. Through structured training sessions, BJJ fosters a supportive community environment, addressing the complex rehabilitation needs of veterans and first responders by bridging physical exertion and focus with mental health support. This review explores BJJ’s profound benefits across rehabilitative settings, substantiating its therapeutic value with empirical evidence and detailed analysis.

Although primarily a fighting style and a sport, many are beginning to embrace BJJ as a powerful therapeutic intervention for various purposes. Current research confirms potential scientific benefits from the use of BJJ in physical rehabilitation, psychological resilience, and social integration for populations experiencing high levels of stress – specifically, veterans and first responders. This review is essential at a historical moment when BJJ seems to have a place in therapeutic settings, yet anecdotal evidence essentially underpins current practice. At the same time, an emerging body of empirical literature supports its effectiveness as a sport and work of art. Drawing from qualitative and quantitative research metrics, this scoping review intends to synthesize and expand on the current understanding of BJJ’s multifaceted benefits. This review is relevant because the populations best served by BJJ’s transformative power experience complex physical, mental, and social challenges. These challenges significantly affect vulnerable populations, such as veterans and first responders, due to the cumulative (and sometimes unique) occupational stressors in their working environments.

The purpose of this scoping review is (1) to consider BJJ’s effect on physical health, (2) to assess the psychological benefits of BJJ, (3) to assess BJJ’s social integration utility, and (4) to identify research gaps and potential future studies as it applies to veterans and first responders.

Literature Review

As BJJ gains recognition not only as a martial art but also as a valuable tool for rehabilitation and recovery, it is important to critically examine the breadth and depth of its impact through scholarly research. This review examines the role of BJJ in enhancing the mental and physical health of veterans and first responders, drawing on a rich array of literature that spans clinical studies, systematic reviews, and observational research. This review aims to bridge the gap between theoretical approaches and practical applications in BJJ by synthesizing evidence from diverse academic sources, highlighting its efficacy in fostering physical resilience and psychological and social well-being. The literature discusses how BJJ contributes to rehabilitation processes, supports mental health recovery, and facilitates community reintegration, offering a comprehensive analysis of its benefits.

Rehabilitation and Recovery for Veterans

Rehabilitation and Recovery for Veterans

In recent years, BJJ has emerged as a pivotal intervention for enhancing veterans’ and first responders’ mental and physical well-being. As previously mentioned, this martial art is known for its emphasis on ground fighting and submission. It offers more than just physical training; it provides a structured environment that fosters psychological resilience and social reintegration. For example, studies [3, 16] have documented the significant benefits BJJ offers in rehabilitating soldiers and aiding veterans with PTSD, highlighting improvements in both physical mobility and mental health outcomes. Furthermore, a separate study [5] discusses BJJ’s role in easing veterans’ transition into civilian life, leveraging the discipline’s community-centric nature to combat isolation and build lasting social networks. These collective findings underscore BJJ’s unique position as a therapeutic modality capable of addressing the complex spectrum of veterans’ needs by bridging rigorous physical challenges with psychological and social support.

Physical Rehabilitation and Psychological Recovery

An article on the benefits of BJJ for solider rehabilitation [6] discusses the significant role of BJJ in soldiers’ physical rehabilitation and mental recovery. BJJ’s comprehensive approach helps improve physical mobility and flexibility, often compromised during active-duty service. Engaging in BJJ aids in building both strength and endurance, which is critical for the comprehensive recovery of injured soldiers. Moreover, the mental aspects of BJJ, such as focus and discipline, contribute significantly to psychological resilience, helping soldiers overcome trauma and stress-related challenges.

Additionally, BJJ provides a supportive community for soldiers, fostering a sense of belonging and mutual understanding among peers, which is vital during rehabilitation. This social support, combined with physical training, makes BJJ an effective rehabilitation tool, addressing recovering soldiers’ physical and psychological needs. By participating in BJJ, soldiers work on their physical rehabilitation and gain confidence and mental strength, which are vital for their successful reintegration into everyday life.

PTSD Management and Community Integration

BJJ provides veterans a therapeutic environment that fosters mental discipline and builds a strong community. Engaging in BJJ allows veterans to experience controlled physical interactions, which can be crucial for regaining trust in their bodily responses and reducing hyperarousal associated with PTSD [8]. The structured setting of BJJ classes offers a predictable and safe environment where veterans can learn new skills in a supportive atmosphere. This aspect of predictability and control is essential for helping veterans manage PTSD symptoms effectively.

In addition, the communal aspect of BJJ encourages veterans to form supportive relationships with peers who may share similar experiences. These social connections are invaluable as they help combat the isolation often felt after leaving military service [12]. Through regular training, veterans develop physical strength and emotional resilience, bolstered by the camaraderie found in BJJ gyms [12]. Participants frequently cite this community support as critical to their recovery and civilian life adjustment.

Sustained PTSD Relief

A study on BJJ training as a possible therapeutic modality [13] explored the specific benefits of BJJ for service members and veterans who have PTSD. The research [13] shows significant improvements in PTSD symptoms among participants attributed to the physical exertion and mental focus required in BJJ training. The study highlights how BJJ helps in developing coping strategies for stress and trauma, which are critical for long-term mental health recovery. The repetitive nature of drills and the controlled physical engagements provide a therapeutic outlet for aggression and pent-up emotions.

The study also emphasizes the sense of accomplishment and increased self-esteem from progressing in BJJ. These psychological benefits are crucial for veterans and service members who often struggle with self-worth after leaving service. Training in BJJ offers a structured environment to measure growth through skill levels, providing a tangible sense of progression usually needed after military service.

Reintegration and Social Reconnection

BJJ has also been studied [5] as a powerful tool for veterans’ reintegration into civilian life. The study [5] suggests that BJJ’s disciplined environment helps veterans transition by providing a structured routine similar to that experienced in the military. This similarity helps mitigate the culture shock many veterans experience post-service. Additionally, the physical demands of BJJ provide a healthy outlet for stress and aggression, which are common challenges for veterans adjusting to civilian life.

Furthermore, BJJ fosters a sense of community and brotherhood among its practitioners, which mirrors the camaraderie found in the military. This aspect of social support is crucial for veterans who may feel isolated after their service [5]. The shared experiences in training can lead to lasting friendships and a support network that assists with reintegration, making BJJ an influential social and psychological tool for veterans.

Enhancing Law Enforcement Capabilities

BJJ is also proving to be a transformative tool for law enforcement, offering a multifaceted approach to officer training that extends beyond physical tactics to include significant mental and emotional benefits. BJJ training enhances mental acuity, decision-making under pressure, and interpersonal skills, which are essential in the high-stress context of law enforcement work [9]. These skills help officers manage stressful encounters more effectively, promoting a mindset geared toward de-escalation and controlled responses rather than aggression.

Furthermore, another study [7] highlights the practical impacts of BJJ on use of force protocols, showing how these techniques help maintain calm and control during confrontations, reducing the likelihood of unreasonable or excessive force. This aspect of BJJ training not only improves officer safety but also the safety of the community by minimizing potentially harmful physical interactions. Meanwhile, positive changes in the Marietta Police Department, where BJJ training has reduced injuries and complaints regarding force use, demonstrate BJJ’s potential to enhance team morale and effectiveness [10].

Mental Acuity and Interpersonal Skills Improvement

Research [9] shows the extensive benefits of BJJ, emphasizing its impact beyond just physical techniques to include mental and emotional enhancements. BJJ training can significantly improve mental acuity and decision-making under pressure in law enforcement, where officers often encounter high-stress situations. The practice also fosters resilience and patience, skills that are beneficial in both personal and professional settings. BJJ’s focus on mindfulness and present-moment awareness helps officers handle stressful encounters more calmly and with greater understanding.

Furthermore, the training enhances interpersonal skills, essential for officers who must de-escalate tense situations without resorting to excessive force. BJJ teaches control and restraint, promoting a mindset of protection rather than aggression. Officers trained in BJJ are often better equipped to maintain their safety and that of others while minimizing harm and managing physical confrontations effectively [7]. This holistic approach to training makes BJJ an invaluable tool for law enforcement agencies.

Police Use of Force

An article on the impact of BJJ training on improving use-of-force protocols within law enforcement concluded that training helps officers maintain calm and control in high-stress situations, reducing the likelihood of excessive force [7]. BJJ provides officers with effective yet non-lethal techniques, crucial in safely managing physical confrontations. Additionally, the discipline and mental focus developed through consistent BJJ practice enhance officers’ decision-making abilities, allowing them to assess situations more accurately and respond appropriately. The article suggests that BJJ improves individual officer performance and fosters greater trust and cooperation between law enforcement and the communities they serve, ultimately contributing to safer and more effective policing practices.

The article also discusses the psychological benefits of BJJ training, such as increased confidence and reduced anxiety, which can significantly affect how officers perceive and respond to threats. The enhanced decision-making skills and better judgment officers develop through BJJ training can lead to more positive outcomes in policing encounters, promoting safer community interactions.

Improved Outcomes in Law Enforcement

Research [10] reports on successfully implementing a BJJ program in the Marietta Police Department. The program has led to measurable improvements in officer outcomes, including reduced injuries and fewer complaints regarding the use of force. The training emphasizes skill over strength, equipping officers with the knowledge to control situations effectively without escalating violence.

Furthermore, the program has been instrumental in building team morale and solidarity among officers. The shared experience of training and improving together has strengthened the department’s internal community, which translates into more effective teamwork in the field. This solidarity is crucial for maintaining high standards of police work and ensuring the safety of both officers and the community they serve.

Injury Prevention and Safety Enhancement

The 2021 BJJ Training Data Documents a Reduction in Injuries report from the Marietta (GA) Police Department (MPD), highlighting the tangible benefits of BJJ training in reducing injuries among police officers. The MPD report concludes that comprehensive physical training enhances flexibility, strength, and overall body awareness, leading to this reduction [10]. Officers trained in BJJ are better prepared to handle physical confrontations safely and efficiently, protecting themselves and the individuals with whom they interact. The skills learned in BJJ allow officers to apply force in a controlled manner, significantly lowering the risk of injury.

The data from MPD [3] also underscores the potential for BJJ training to transform standard police training protocols. By incorporating BJJ, departments can ensure that their officers are not only physically capable but also mentally prepared to handle the stresses of law enforcement. This proactive approach to training can reduce workers’ compensation claims, decrease sick leaves due to injuries, and improve overall morale within the department.

Enhancing Physical Fitness and Mental Health

BJJ is a profound physical discipline and a significant enhancer of mental health and community building [1]. This unique martial art offers physiological benefits and underscores how regular BJJ training improves cardiovascular health, muscular strength, and endurance [1]. The mental advantages, such as increased focus and stress reduction, are pivotal in making BJJ a holistic practice for personal health and fitness.

Further insights from the benefits of BJJ in managing PTSD [12] and BJJ as a form of social and psychological therapy [4] deepen our understanding of BJJ’s impact. One longitudinal study demonstrates the sustained effectiveness of BJJ in managing PTSD symptoms, offering a potential therapeutic pathway for veterans and others suffering from chronic stress disorders [12]. Parallelly, a review of BJJ’s social and psychological benefits emphasizes its role in forging strong community ties and enhancing cognitive functions through strategy formulation and problem-solving challenges [4]. Together, these studies [12, 4] present a compelling case for integrating BJJ into wellness and therapy programs to bolster physical robustness and foster a supportive social environment.

Physiological and Psychological Benefits

One systematic review [1] of the extensive physical and physiological demands placed on individuals who practice Brazilian Jiu-Jitsu suggests that BJJ is effective in enhancing cardiovascular health, muscular strength, and endurance. The review also notes the mental benefits of regular, intense physical activity, such as improved focus and stress reduction. The comprehensive nature of BJJ training makes it an excellent form of exercise for improving overall fitness and health.

Furthermore, the review discusses how BJJ athletes develop unique physiological adaptations that enhance their performance. These include increased aerobic capacity, better body composition, and superior muscular endurance. The insights provided by this review suggest that BJJ could be beneficial in cross-training for various activities due to its all-encompassing physical demands and the mental toughness it develops.

Longitudinal Insights

Research provides compelling evidence through a longitudinal study that BJJ has sustained benefits in managing PTSD among veterans [12]. This longitudinal study followed participants over a period, noting significant and lasting decreases in PTSD symptoms among those who regularly engage in BJJ. The work suggests that the combination of physical activity, mental focus, and social interaction inherent in BJJ practice contributes to these positive outcomes.

In addition, the study also highlights how the repetitive and immersive nature of BJJ training can serve as a form of exposure therapy, where participants gradually face and gain control over stress triggers in a controlled environment. Although the work focused on PTSD management among veterans, PTSD is not exclusive only to that group (e.g., law enforcement officers or others who have PTSD after a traumatic event). This method of coping can lead to profound changes in how individuals who suffer from PTSD process and react to stress, potentially providing a blueprint for integrating BJJ into broader PTSD treatment programs.

Building Resilience and Community

In a systematic review, a researcher examined the role of BJJ as both a social and psychological therapy [4]. The review consolidates findings from multiple studies, illustrating how BJJ aids in building strong community ties, which is essential for mental health. The physical closeness and mutual trust required in BJJ training create a unique social dynamic that fosters interpersonal relationships and a supportive network, offering a sense of belonging and community that is often therapeutic. Moreover, the review details how the mental challenges presented in BJJ—such as strategy formulation and problem-solving—enhance cognitive functions and contribute to psychological resilience. These mental benefits complement the physical aspects of BJJ, creating a holistic therapy modality that addresses multiple facets of psychological health.

METHODS

A scoping review of the literature was appropriate to meet the objectives of this study and answer the research question: What benefits does Brazilian Jiu-Jitsu (BJJ) training provide for veterans and first responders in terms of physical, mental, and social health?

This study’s protocol was developed using the scoping review methodological framework [2]. The draft protocol for this review was analyzed by research colleagues and implemented. The protocol consisted of a series of five stages, details of the search strategy and steps of the review process included:

Identifying and collecting relevant studies: Literature searches were conducted across four electronic bibliographic databases: PubMed and Google Scholar. An initial search using the search terms “Brazilian Jiu-Jitsu,” “veterans,” “first responders,” “rehabilitation,” “physical health,” “mental health,” and “community integration” was conducted. This search established salient parameters and eight key search terms to conduct additional searches across the four databases. Those eight critical terms included: (i) Brazilian Jiu-Jitsu and veterans; (ii) Brazilian Jiu-Jitsu and first responders; (iii) BJJ and PTSD; (iv) BJJ for physical rehabilitation; (v) BJJ and conflict resolution; (vi) mental health benefits of BJJ; (vii) physical health benefits of BJJ; and (viii) social integration through BJJ. The collected literature was then screened for relevance to the research question. After removing duplicates, studies were assessed for eligibility. Reference lists of eligible studies were further screened for additional relevant studies.

Study selection: Inclusion and exclusion criteria were established to filter and guide searches for relevant literature. To be included, literature from searches had to meet four inclusion criteria: (i) be from a peer-reviewed journal, a conference presentation, or a published thesis; (ii) published in the English language; (iii) include documented interventions or analysis related to BJJ; and (iv) be quantitative or qualitative. The literature was not restricted by time frame, study population, geographical publication, or type/design of journal article. Collected literature that did not meet all criteria was excluded. However, two colleagues analyzed conflicting literature to reach a consensus for inclusion. By applying the eligibility criteria, two reviewers screened the articles for selection. Blinding was applied at this stage to ensure no bias between reviewers in the selection process. All conflicts between the two reviewers, generated through screening, were discussed to reach a consensus. When conflict remained, the opinion of a third reviewer was sought to reach a consensus. Initially, articles were selected from the title and abstract screening. A second, more in-depth selection was then conducted through full-text screening. December 3, 2023, was the last date that the search was executed.

Charting the data: Once included articles were selected, data was extracted and charted according to author, title, journal, publication year, geographical location, purpose, sample size and type, methodology, intervention type, outcomes, key findings, and barriers. One author extracted and grouped the data, and another validated the data to ensure accuracy. Data were organized and grouped into subtopics according to the identified study purposes: (i) physical health benefits of BJJ; (ii) mental health benefits of BJJ; (iii) social integration through BJJ; (iv) PTSD and BJJ; (v) conflict resolution skills through BJJ; and (vi) physical rehabilitation through BJJ.

Summarizing and synthesizing the results: Authors collectively compared and discussed the charted data. Descriptive statistics were performed to characterize the research literature and to identify the breadth and gaps. Trends across geographic locations and decades of publication of included studies were evaluated. The study results were examined and discussed within each thematic area to determine trends and commonalities. Barriers and gaps were identified within the literature to suggest future areas of study. A consensus between all three authors regarding the critical information generated from the review was reached.

In addition to the scoping review methodological framework proposed by leading scholars in the scoping review methodologies [2]. The researchers for this review followed the PRISMA Extension for Scoping Reviews (PRISMA-ScR) checklist [11]. No risk of bias assessment, summary measures, or additional analyses were conducted in this scoping review following the PRISMA-ScR [11]. No formal review protocol exists.

Figure 1. PRISMA 2020 Flow Diagram. 

Physical Health Benefits

The studies reviewed consistently demonstrated that BJJ training significantly enhances physical fitness, mobility, and injury rehabilitation. According to one study [1], participants showed marked improvements in cardiovascular health, muscular strength, and endurance. These findings align with the report from MPD, which documented a reduction in injuries among law enforcement officers engaged in BJJ, attributing these benefits to the increased physical conditioning that BJJ provides [3]. This comprehensive approach to physical health not only aids in immediate injury recovery but also contributes to long-term physical wellness.

In one example, the graph below adapted data from a study of physical and physiological profiles of BJJ athletes [1] and shows the peak and mean power values for those who train in BJJ, highlighting its intense physical demands.

The graph displays anaerobic power values from two distinct studies. The study of physical and physiological profiles of BJJ athletes [1] dataset provides measurements for both peak power and mean power: 

  • Peak Power: This represents the highest instantaneous power output achieved by the athletes during the test. 
  • Mean Power: Reflects the average power maintained throughout the Wingate test, typically 30 seconds. 

The colors differentiate the types of power measured: 

  • Red Bars: Peak power values from two studies. 
  • Green Bars: Mean power values from the same studies. 

The graph highlights variations between studies, underscoring the need for consistent testing methodologies to compare anaerobic capacity accurately across different research. However, the researcher concluded that BJJ athletes possess considerable anaerobic capacity, with peak power outputs exceeding 10 W/kg and mean power outputs close to 10 W/kg. These values demonstrate the athletes’ proficiency in generating and sustaining high levels of power, essential during competitive grappling engagements, such as executing takedowns, resisting submissions, or applying forceful maneuvers. 

In another example, the chart below adapted data from MPD. It showed three distinct bars, each representing the percentage reduction in incidents due to BJJ training within the Marietta Police Department in 2020. 

  • The first bar shows a 48% reduction in injuries to officers who used force, indicating significant safety improvements for the officers involved. 
  • The second bar illustrates a 53% reduction in injuries to persons who required force during arrest, highlighting the training’s role in protecting the officers and those they encounter. 
  • The third bar indicates a 23% reduction in Taser use, demonstrating a shift towards less reliance on electronic control devices, which can be critical in high-tension situations. 

Mental Health Benefits 

The mental health improvements associated with BJJ are particularly significant. Researchers who explored BJJ training for U.S. service members and veterans with symptoms of PTSD found substantial reductions in PTSD symptoms among veterans participating in BJJ, with benefits extending to decreased levels of depression and anxiety [13]. Interestingly, researchers who studied BJJ benefits in managing PTSD further supported these findings in their longitudinal study [12], which noted lasting mental health benefits from regular BJJ practice. The mental discipline and focus required in BJJ training foster an environment conducive to psychological healing and emotional stability, making it a valuable tool in mental health therapy. 

For example, this review adapted data from research on BJJ training for U.S. service members and veterans with symptoms of PTSD [13] and graphs the effect sizes calculated from PCL-5 assessments for veterans participating in BJJ training. The graph illustrates the effect sizes at two key intervals of their study: pre-treatment to mid-treatment and pre-treatment to post-treatment. To assess the impact of BJJ on PTSD symptoms among veterans and first responders, researchers measured changes in PTSD symptomatology using the PTSD Checklist for DSM-5 (PCL-5) and concluded decreased levels of depression and anxiety. 

Effect Sizes and Confidence Intervals 

The graph depicts effect sizes (Cohen’s d) and their corresponding 95% confidence intervals to illustrate the magnitude and precision of changes in PTSD symptoms from pre-treatment to mid-treatment and from pre-treatment to post-treatment. 

Statistical Significance 

The p-values associated with these findings underscore the statistical significance of the observed improvements, suggesting that the effects are attributable to the BJJ intervention. 

Social and Community Aspects 

The findings illustrated BJJ’s role in enhancing social interactions and building community ties. For example, one researcher examined BJJ as a possible social and psychological therapeutic modality and underscored how BJJ promotes camaraderie and supports systems among participants, creating a sense of belonging and mutual trust [4]. This community aspect is crucial, especially for veterans and first responders, who often experience isolation in their professional roles. The shared experience of BJJ training fosters solid interpersonal relationships and provides a supportive network that enhances the social well-being of its members. 

These results collectively illustrate BJJ’s comprehensive benefits, affirming its effectiveness across physical, mental, and social domains. Integrating BJJ into therapeutic and training programs offers a holistic approach to health and wellness, supporting individuals’ physical conditioning and psychological and social rehabilitation. 

For instance, this work adapted data from a study on BJJ as social and psychological therapy [4] and crafted a thematic map to illustrate the complex relationships between various aspects of BJJ and their outcomes.  

Reduces Negative Behaviors

he thematic map distinguishes between direct benefits and the pathways that facilitate these benefits, using color coding to enhance readability and understanding. It effectively encapsulates how BJJ is a multifaceted enhancer of psychosocial health. By detailing both the outcomes and the mechanisms, the map serves as a tool for understanding BJJ’s broad and nuanced impacts beyond the mat, supporting its integration into psychological and social rehabilitation programs.  

THEMES 

Multiple themes emerged from the outcomes assessed in the literature. One researcher with expertise in BJJ identified and categorized these themes, and studies were grouped into key categories inspired by different domains related to veterans and first responders. Most studies evaluated one specific theme within the context of BJJ while acknowledging others to a lesser degree; however, some overlap of themes emerged in studies. Table 1 groups all studies by theme, variable, citation, and geographical region. 

Table 1. Summary of all themes, the variable(s) assessed in each theme, and the studies that assessed the variable(s). 

Theme Variable(s) Assessed Studies Geographical Region 
Physical Health Benefits Cardiovascular health, muscular strength, endurance [1] Brazil 
Mental Health Benefits PTSD symptom reduction, depression, anxiety [12, 13] USA 
Social Integration Community participation, support networks [4] Sweden 
PTSD Management PTSD symptomatology [13] USA 
Conflict Resolution Skills De-escalation techniques, stress management [7, 9] USA 
Physical Rehabilitation Mobility, injury recovery [6] USA 
Law Enforcement Training Use of force, injury reduction [10] USA 
Psychological Resilience Mental focus, emotional stability [4, 12] USA, Sweden 
Community Building and Support Systems Camaraderie, mutual trust [4] Sweden 
Implementation Strategies Integration into therapy programs Various Various 

From the included literature: (1) physical health benefits of BJJ; (2) mental health benefits of BJJ; (3) social integration through BJJ; (4) BJJ’s role in PTSD management; (5) BJJ for conflict resolution skills; and (6) BJJ for physical rehabilitation, all occupied the primary purpose of the greatest number of studies. Other pertinent topics included: (7) BJJ’s impact on law enforcement training; (8) psychological resilience through BJJ; (9) community building and support systems through BJJ; and (10) strategies for implementing BJJ in therapeutic settings, which were the secondary focus of some studies and integrated into studies with another primary focus. 

DISCUSSION 

This scoping review aimed to define and evaluate the quantitative and qualitative data regarding the effects of BJJ on veterans and first responders. It was conducted through standard methods outlined by leading scholars in the field [2] to identify, select, and synthesize the findings from 11 studies. The current knowledge of BJJ was documented by analyzing the geographic scope of studies, the year of publication, and the specific themes that emerged from the literature. Provided below are significant results of this review that can be relevant for future researchers, practitioners, and BJJ instructors. 

The included studies revealed evidence of BJJ’s physical health benefits. Participants showed marked improvements in cardiovascular health, muscular strength, and endurance [1]. These physical health benefits were consistent across different populations and settings, highlighting BJJ’s utility in enhancing overall fitness and aiding injury rehabilitation [10]. Despite these positive findings, further research is needed to establish standardized protocols for measuring these benefits across diverse groups. 

The literature also prominently discussed BJJ’s mental health benefits. Substantial reductions in PTSD symptoms, depression, and anxiety were reported among veterans participating in BJJ [12, 13] These findings suggest that BJJ provides a supportive environment conducive to psychological healing and emotional stability. The mental discipline and focus required in BJJ training foster an environment that encourages mindfulness and stress reduction. However, the mechanisms underlying these mental health benefits are not fully understood and warrant further investigation. 

Social integration emerged as a significant theme, with BJJ promoting camaraderie and support systems among participants. Studies highlighted how BJJ fosters a sense of belonging and mutual trust, crucial for veterans and first responders who often experience isolation in their professional roles [4]. The communal aspect of BJJ training helps build strong interpersonal relationships and provides a supportive network that enhances social well-being. Future research should explore how these social benefits can be optimized further to support the reintegration of veterans into civilian life. 

BJJ’s role in enhancing law enforcement capabilities was another key finding. BJJ training improves mental acuity, decision-making under pressure, and interpersonal skills, which are essential in the high-stress context of law enforcement work [7, 9]. The practical impacts of BJJ as a response to resistance option were also noted, with reduced injuries and complaints regarding the use of force in departments that implemented BJJ training programs [10]. These findings underscore the importance of incorporating BJJ into law enforcement training to enhance officer safety and effectiveness. 

Technological advancements in BJJ training were less frequently discussed but are becoming increasingly relevant. Integrating AI and other technologies to enhance training and performance tracking could revolutionize how BJJ practitioners train and improve [12]. Future research should explore the potential of these technologies in providing more precise and individualized training programs. 

Comparisons across gender and skill levels revealed essential insights into how different populations benefit from BJJ training. Differences in physical and psychological responses to BJJ were noted, suggesting that tailored training programs may be necessary to optimize benefits for diverse groups [1]. Future studies should continue to explore these differences to develop more inclusive and effective training methodologies. 

The inclusion of wheelchair BJJ and adaptive training for individuals with disabilities was minimal but highlighted the need for more inclusive research. Studies focused on the biomechanics of BJJ for wheelchair users and its potential benefits in promoting physical and mental health [6]. Expanding research in this area could lead to better support and training for individuals with disabilities. 

Future Research 

Understanding the many benefits of BJJ for veterans and first responders is unquestionable. Continued research should aim to standardize measurement protocols and explore the long-term impacts of BJJ training. Future studies should also consider integrating technological advancements and developing adaptive training programs to support diverse populations. By expanding the scope of research to include mixed-double formats and other variations of BJJ, researchers can develop a more comprehensive understanding of its benefits and applications. 

Strengths and Limitations of this Scoping Review 

This scoping review applied a systematic and rigorous search strategy to retrieve a comprehensive range of articles addressing the benefits of BJJ for veterans and first responders. Considering both peer-reviewed journal articles and grey literature, the review captured a broad spectrum of knowledge, including unpublished theses and conference presentations. However, some studies were unintentionally omitted due to limited access, and the exclusion of non-English language studies may have skewed the geographic analysis of the literature. Additionally, the reliance on self-reported data in many studies introduces potential biases that should be addressed in future research. 

CONCLUSIONS 

This study sought to review the literature on the benefits of BJJ for veterans and first responders, focusing on physical, mental, and social health outcomes. It answers this study’s research question and presents the current knowledge for each identified theme, providing opportunities for future research. This scoping review will aid in building a more comprehensive understanding of BJJ’s therapeutic mechanisms and significantly contribute to optimizing its application in rehabilitative and therapeutic settings. A growing body of research is being conducted globally on BJJ’s benefits. The current literature reveals substantial evidence of BJJ’s positive impact on physical fitness, mental health, and social integration. However, the varying methodologies and outcomes of the included studies indicate that more rigorous research is needed to elucidate BJJ’s mechanisms of action fully. This scoping review provides an impetus for further research on BJJ’s effects on specific populations, including adaptive training for individuals with disabilities and integrating technological advancements in training. Studies included in this scoping review only scratched the surface of these variables and their impact on the well-being of veterans and first responders. Future research should aim to expand on these findings to develop a more comprehensive understanding of BJJ’s potential as a therapeutic tool.  

APPLICATIONS IN SPORT 

Integrating BJJ into training programs for veterans and first responders provides a versatile approach to enhancing their physical, mental, and social well-being. Coaches and trainers can leverage BJJ to significantly improve cardiovascular health, muscular strength, and endurance, which are essential for the physically demanding roles of these professionals. The mental health benefits of BJJ are particularly noteworthy; the studies in this review show it reduces symptoms of PTSD, depression, and anxiety, thereby promoting emotional resilience and effective stress management. Furthermore, BJJ’s structured and strategic nature supports mental acuity and decision-making under pressure, which are necessary skills for operational effectiveness. Socially, BJJ offers a sense of community and mutual support, aiding in the social integration of veterans and first responders and mitigating feelings of isolation. By incorporating BJJ into their training regimes, coaches and trainers can deliver a holistic program that enhances physical fitness and supports psychological health and social connectivity, ultimately improving the overall recovery, resilience, and operational readiness of veterans and first responders. This comprehensive approach underscores BJJ’s value as a therapeutic intervention in sports training programs for these populations. 

ACKNOWLEDGEMENTS 

The authors confirm that all the research in this work has met ethical guidelines and adhered to the legal requirements of the United States of America. In addition, the principal investigator is compliant with the Collaborative Institutional Training Initiative (CITI) Program on social and behavioral researchers and social and behavioral responsible conduct of research training. Furthermore, this work was not funded, the authors declare no conflict of interest, and it did not contain studies with human participants or animals performed by the principal investigator. 

References

1Andreato, L., Lara, F., Andrade, A., & Branco, B. (2017). Physical and physiological profiles of Brazilian jiu-jitsu athletes: A systematic review. Sports Medicine – Open, 3(1). https://doi.org/10.1186/s40798-016-0069-5

2Arksey, H., & O’malley, L. (2005). Scoping studies: towards a methodological framework. International journal of social research methodology, 8(1), 19-32.

3BJJ training data documents a reduction in injuries. (2021). Marietta, GA. https://www.mariettaga.gov/CivicAlerts.aspx?AID=3116#:~:text=MPD%20officers%20participating%20in%20Brazilian,arrested%20when%20force%20was%20required

4Blomqvist Mickelsson, T. (2021). Brazilian jiu-jitsu as social and psychological therapy: a systematic review. Journal of Physical Education and Sport, 21(3), 1544-1552.

5Collura, G. L. (2018). Brazilian Jiu Jitsu: A tool for veteran reassimilation. University of South Florida.

6Fender, R. (2024). Benefits of Brazilian jiu-jitsu for soldier rehabilitation. www.army.mil. https://www.army.mil/article/273135/benefits_of_brazilian_jiu_jitsu_for_soldier_rehabilitation

7Howard, R. (2022). Improving Use of Force Training for Officers. Florida Department of Law Enforcement. https://www.fdle.state.fl.us/FCJEI/Programs/SLP/Documents/Full-Text/Howard,-Rocky-paper.aspx

8Jiu-jitsu supporting veterans with PTSD. (n.d.). Mad Science Judo & Jiu-Jitsu. https://madsciencejudoandjiujitsu.com/blog/142261/Jiu-Jitsu-Supporting-Veterans-with-PTSD

9Kilby, T. (2022). The benefits of jiu-jitsu beyond technique. Police1. https://www.police1.com/health-wellness/articles/the-benefits-of-jiu-jitsu-beyond-technique-WaVZI8zAQXh9Gx5S/

10Rogers, K., Jones, P., & Burne, K. (2021). Marietta Police Department measurably improves officer outcomes with the BJJ program. Jitsmagazine.com. https://jitsmagazine.com/marietta-police-department-measurably-improves-officer-outcomes-with-bjj-program/.

11Tricco, A. C., Lillie, E., Zarin, W., O’Brien, K. K., Colquhoun, H., Levac, D., … & Straus, S. E. (2018). PRISMA extension for scoping reviews (PRISMA-ScR): checklist and explanation. Annals of internal medicine, 169(7), 467-473.

12Weinberger, K., & Burraston, T. (2021). Benefits of Brazilian Jiu-Jitsu in Managing Post-Traumatic Stress Disorder: A Longitudinal Study. Journal of Community Engagement & Scholarship, 13(4).

13Willing, A. E., Girling, S., Deichert, R., Wood-Deichert, R., Gonzalez, J., Hernandez, D., Foran, E., Sanberg, P. R., & Kip, K. E. (2019). Brazilian jiu-jitsu training for us service members and veterans with symptoms of PTSD. Military Medicine, 184(11-12), e626–e631. https://doi.org/10.1093/milmed/usz074

2024-08-27T15:53:24-05:00August 30th, 2024|General, Sport Training, Sports Exercise Science|Comments Off on An examination of studies related to Brazilian jiu-jitsu in enhancing mental and physical health among veterans and first responders: A scoping review
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Effective use of Imagery Assisted Virtual Reality in Pitch Recognition and Sport Imagery Ability Development

Authors: Lindsay Ross-Stewart1, Landon Braun2, & Victoria Hardcastle3

1Department of Applied Health, Southern Illinois University Edwardsville
2College of Health Professions and Sciences, University of Wisconsin Milwaukee
3Department of Intercollegiate Athletics, Savannah State University

Corresponding Author:
Dr. Lindsay Ross-Stewart
Campus Box 1126
Southern Illinois University Edwardsville
Edwardsville, IL, 62026
[email protected]
(618) 650-2410

Lindsay Ross-Stewart, PhD is an Associate Professor in the Department of Applied Health at Southern Illinois University Edwardsville. Dr. Ross-Stewart is a CMPC® and a Canadian Sport Psychology Association Mental Performance Consultant (MPC).

Landon Braun, M.S., is a Doctoral Student at the University of Wisconsin-Milwaukee in the College of Health Professions & Sciences. At UWM Landon works as a Teaching Assistant in the School of Rehabilitation Sciences & Technology where he teaches courses related sport and performance psychology to both undergraduate and graduate students.

Victoria Hardcastle, M.S., is an Assistant Softball Coach at Savannah State University.

Effective use of Imagery Assisted Virtual Reality in Pitch Recognition and Sport Imagery Ability Development

ABSTRACT

Abstract: Imagery can be described as experience that mimics real world experiences through the combination of using different sensory modalities in the absence of actual perceptions (43). One uses visual, auditory, kinesthetic (touch), smell, and taste to create a picture simulating real world environments and scenarios. Imagery can be used to enhance various aspects of performance by mentally preparing someone for an upcoming competition or helping an athlete focus specifically on a task (19). Virtual reality, understood in this study as a first-person filmed, computer presented, immersive simulation of a real environment (32), has become increasingly more utilized in sport performance settings (7, 37, 44). Combing these two elements, the purpose of this study was to investigate an applied Imagery Assisted Virtual Reality (IAVR) intervention on imagery ability and pitch recognition in a sample of eleven National Collegiate Athletic Association (NCAA) Division One softball players at a Midwestern University. This study’s results indicated a significant increase in global imagery ability as well as in four of the five functions of imagery (CS, CG, MG-A, MG-A) and in pitch type recognition. Practically, the results from this study suggest that the IAVR intervention can create an impactful experience to assist athletes in improving their performance and psychological skills.

Keywords: Psychological Skills, Pitching Ability, Softball, Virtual Reality, Collegiate Sport

Virtual reality technology has become an increasingly common tool used in sport (e.g., 3 – 4, 7, 14, 17, 24, 26; 28, 31, 37, 44) with application in areas such as injury rehabilitation (31), and performance enhancement (2, 27, Wood et al., 2020). In fact, virtual reality has been labeled the next step forward for athletic training (47) and has been the subject of several states of the field (e.g., 7, 26).


Virtual reality was originally defined as a computer-generated, artificial, or simulated environment created by technological software (38). Within sport, it has been defined as instances when individuals are engaged in a sport that is represented in a computer-simulated environment which aims to induce a sense of being mentally or physically present and enables interactivity with the environment (28). One important aspect that virtual reality training is lacking is a focus on how virtual reality can assist in increasing an athlete’s psychological skill development (32). While virtual reality can impressively replicate environments and simulate real-world reactions; it still lacks the ability to capture an emotional response to the environment (32). As we know that how one feels and their perceptions of the sporting environment are necessary for performance, past research has shown this to be a challenge in traditional VR interventions (11) Research on the incorporation of imagery into a virtual reality training program has shown it to be a promising way to gain the advantages of VR and to overcome this potential challenge (32, 33; 34).


In the context of sport, White and Hardy (45) defined mental imagery as: an experience that mimics real experience. We can be aware of “seeing” an image, feeling movements as an image, or experiencing an image of smell, tastes, or sounds without actually experiencing the real thing (23). One approach to the application of imagery in sport is the revised applied model of imagery, which states that athletes may use it to achieve different outcomes (10). To achieve desired outcomes, imagery type, what athlete’s images and imagery function, the why or the purpose of an athlete’s image should be considered (29). Imagery type is split into two categories, cognitive and motivational, with each operating at specific and general levels (43). Cognitive refers to performance enhancement while motivational focuses on confidence enhancement (5). Imagery types and functions have been defined as: Cognitive specific (CS) helps an athlete to work on skill learning, development, and execution. Cognitive general (CG) affords the athlete the ability to image different strategies and routines. Motivational specific (MS) imagery focuses on enhancing motivation through goal setting and goal achievement. Motivational general arousal (MGA) imagery focuses on somatic and emotional experiences such as regulating stress and arousal. Motivational general mastery (MGM) imagery concentrates on coping, gaining, and maintaining self-confidence, and staying focused (10, 18) identify. Athletes might use each of the imagery types alone or in combination with one another, depending on the meaning an athlete applies to the image (29). For example, an athlete can use cognitive specific imagery (CS type) to image themselves executing a skill successfully (CS function), but this image may also increase their confidence, which would be for the function type MG-M (10).


Focusing on the way in which Imagery and Virtual Reality could be used together, Ross-Stewart and colleagues developed Imagery Assisted Virtual Reality (IAVR), a training protocol that involves an immersive virtual reality experience for users in which kinesthetic awareness is incorporated with users being able to see a first-person simulated scenario coupled with an individualized imagery script aimed at enhancing psychological skills and performance (32). IAVR entailed a first-person filmed batting environment from an on-deck position all the way up to batting and taking swings. This video was then followed by a blank screen with an individualized guided imagery script tailored to each individual player that was either audio recorded in the video itself or written down. In their initial study they found that participants who completed an IAVR intervention increased their skills imagery (CS), goal imagery (MS) and mastery imagery (MG-M) as measured by the Sport Imagery Ability Questionnaire (SIAQ; 43). Furthermore, results suggested an increase in overall imagery use, positive self-talk and automaticity in both practice and competition through the length of the study. Additionally, negative thinking during competition decreased, as measured by the Test of Performance Strategies (TOPS; 39). The finding that imagery and virtual reality used together can impact psychological constructs was supported by Frank et al (2022) who found self-efficacy to increase in a physical activity task using imagery and virtual reality. Furthering the support for IAVR, a recent study on the impact of VR on imagery ability and emotional affect found that VR can “induce emotional arousal and affect the mental imagery skills and positive affect of athletes” (46).


Baseball hall of famer Ted Williams referred to batting as “the hardest thing to do in sports” (35). If a softball pitcher throws a 60-mph fastball, it will reach Homeplate in .45 seconds. However, if she throws a changeup at 50 mph, it will reach Homeplate in .55 seconds. Batters have a brief window of opportunity in which they must recognize the pitch and decide to swing or not swing (20). Pitch recognition is the batter’s ability to recognize which way the seams on the ball are spinning/rotating and the trajectory of the ball (20). These two components can be categorized by pitch type (fastball, change-up, drop ball, rise ball) and prediction of eventual location of the pitch (strike, ball, inside, outside) (13). Being able to recognize pitches is an essential aspect of batting. However, there exists little agreement on what the skill of pitch recognition consists of and how to improve it (13).
Each pitch is comprised of different combinations of velocity, rotation, and trajectory cues. Outside of rotation and trajectory cues, there are other sources of information a batter might be receiving information from without being aware of it. These cues include knowledge of the pitcher, game situation, and batter’s count (20). A batter’s ability to recognize which pitch is being thrown will allow them to conduct their swing accordingly and increase performance. This recognition will allow a batter to make more solid hits and recognize the difference between a ball and strike. This recognition will also allow them to either look for pitches they want to hit or draw more walks. Therefore, pitch recognition is a pivotal skill for softball players to obtain if they want to achieve top performance.


The use of VR has been shown to be an effective tool for the increase of strike zone and pitch recognition (16). Virtual reality training has also been shown to lead to a greater sensitivity to visual information provided by the ball trajectory, seam rotation, and improved ability to use monocular cues to determine whether a pitch would cross the plate in the strike zone or not (16). Furthermore, Ranganathan and Carlton (30) found that VR was effective when baseball players had visual information of an entire pitch in their VR environment and ball trajectory yielded a higher prediction accuracy.


Based on both past research in VR and IAVR, merging imagery and virtual reality may enhance the psychological skill and strategy development of athletes more than if they are used alone. Taken with recent suggestions for more research on the effectiveness of VR on both skill acquisition and psychological change in sport (e.g., 7 17, 26, 28 31, 41), specifically, Cotterill’s assertion that “there is also a need for more applied case studies that outline the procedures adopted and reflect on the outcomes obtained using VR in sport psychology–relevant ways”(7, p.22). The purpose of this paper is to highlight an applied Imagery Assisted Virtual Reality intervention that was used with a National Collegiate Athletic Association (NCAA) Division I softball team. Specifically, hitters were given the opportunity to participate in an intervention that designed individualized imagery assisted virtual reality video for them and then they were assessed to see how it impacted their imagery ability, and pitch recognition. Based on past research, it was hypothesized that both global imagery ability and pitch recognition would increase from baseline to post intervention. Furthermore, based on past research on IAVR (32) it was hypothesized that CS, CG, and MG-M imagery would significantly increase from baseline to post intervention. No hypothesis was made related to MS and MG-A imagery due to lack of past research, at the time of data collection, supporting the use of this imagery increasing using IAVR.

Materials and Methods

Methods

Participants
Participants were 11 NCAA Division One female softball players at a Midwestern University. Of the 11 participants five were right-handed batters and six were left-handed batters. Their ages ranged from 18-24 years old.


Measures
Sport Imagery Ability Questionnaire (43; SIAQ): The SIAQ was designed to measure an athlete’s ability to image different content (i.e., strategies, skills, feelings, and goals) and the frequency that an athlete images. The questionnaire has 15 questions rated from 1 (very hard to image) to 7 (very easy to image). The questions are divided into five different subscales; skill imagery ability (e.g., defining a specific skill), strategy imagery ability (e.g., making/executing strategies), goal imagery ability (e.g., winning the game), affect imagery ability (e.g., positive emotions connected with the sport), and mastery imagery ability (e.g., positive outlook when things are not going well). An overall sport imagery ability score and all subscales were calculated separately. To score each of the five subscales, questions for the subscale were summed and divided by the number of questions for each source. The SIAQ has been found to have good validity and reliability (43)


Pitch recognition test: A Pitch Recognition test was designed for this study to assess a participant’s ability to recognize a pitch type (fastball. change-up, etc.) and pitch location (strike/ball). Participants viewed twelve pitches via GoPro film from a pitcher. The film the participants viewed was from the same film they viewed in their IAVR. There were five seconds between each pitch allowing for the participants to circle both the pitch type and pitch location of the previously viewed pitch. The pitch recognition test had twelve different pitches for the baseline testing and the post intervention testing. The number of pitches they correctly identified for both type and location divided by twelve was their total pitch recognition scores. Both pitch type and pitch location were scored as subscale.

Procedure
Institution IRB was obtained. Players were recruited from an NCAA (National Collegiate Athletic Association) Division I softball team. Eleven players signed up to participate in the intervention. Participants who gave consent were assigned a time to film their first-person VR film. Filming was done both on the players’ field and in their indoor hitting facility to make sure it properly mimicked where they were currently practicing. During filming, participants wore dual mounted GoPro headsets on top of their batting helmets to gain first person filming perspectives. Participants were instructed to go through their whole routine starting with preparation for the on-deck circle by stepping into the batter’s box. Filming was also done to gain a third person perspective using a dual mounted GoPro headset strapped to a tripod and placed in the batter’s box. For this film day, three pitchers from the same team, who volunteered to help with the study were filmed pitching from the mound (one left-handed, two right-handed). All three of the pitchers threw their pitches (fastball, change-up, rise ball, etc.) for both right-handed batter and left-handed batter viewpoints. Ninety-six pitches were filmed to allow for a variety of options for the pitching videos.
After the filming was complete the research team used Shotcut to edit the film into two pitch recognition videos, and an individualized VR video for each participant. Videos of the pitches were made to assess pitch recognition at baseline and time 2. To make these videos, the third-person video was edited by clipping each pitcher’s pitch into its own. This allowed the researchers to integrate all three pitchers’ pitches into a specific order. Researchers then went through and selected twelve pitches out of the right-handed batter’s film and a separate twelve out of the left-handed batter’s film. These clips were arranged to simulate two full at bats, with a five second black screen between each pitch. This method was replicated to make the pitch recognition video that would be used for the post test.


To make the IAVR videos, first-person perspective film was edited to start when participants start their pre-at bat routine. The clip ended when the batter received a pitch from the pitcher while they were in the batter’s box. In these videos pitch clips were aligned to simulate a real world at bat, including timing between bats. To develop the guided imagery scripts that would be recorded as audio into the Virtual Reality videos, participants individually met with the research team to discuss their experiences at bat. The imagery scripts were written according to the guidelines suggested by (42) making sure to incorporate both stimulus and response propositions (8, 22) to the imagery scripts. The imagery scripts were broken down and recorded into two audio files. The first recording consisted of each participant’s rituals and routines starting when they are “in the hole” all the way to being in the batter’s box. This included getting equipment on (batting gloves, elbow guard, etc.), walking to the on-deck circle, on deck circle rituals, walking to the batter’s box, and pre at bat rituals. Some participants opted to have their walk-up song playing in the background during their imagery script when walking from the on-deck circle to the batter’s box.


The second recording started when each participant was in the batter’s box. Depending on how the participant wanted their imagery script written, they might receive a ball or strike first. Then, hitting to a designated spot of their choosing. Participants then had a choice of running through first, running to second, or sliding into second. The scenarios and cues they picked up from the first base coach were all individualized to each participant. These individual imagery scripts were turned into audio files and then embedded into the participants corresponding virtual reality film to make the Imagery Assisted Virtual Reality interventions for each participant. The IAVR was set up as the following: imagery script of preparation for an at bat, 3rd person pitch film, first person film from the dugout to the batter’s box, and then imagery script of hitting the ball and making it to a base safe.
Before being given their IAVR film, participants watched the baseline pitch recognition video and marked the pitch type and location of each video. Each player was provided with a pair of virtual reality goggles and a locked cell phone loaded with their individualized video. Instructions were also provided to participants on how to download the videos onto their personal phone if they preferred to have it on their own phone. Participants were instructed to watch their IAVR video at least once a day using virtual reality goggles. Participants were also informed that if they requested any changes to their IAVR (i.e., imagery speed, tone, pitch order) the research team would make the changes at any time during the intervention.
After participants had the IAVR video for six weeks they completed a post intervention pitch recognition test where they watched the second pitching video that had been made and once again recorded what type and location, they believed they saw for each pitch. They also completed the SIAQ at this time.


Results
Review of the data indicated that two participants had missed one question each. The means for each question were used as a replacement so the participants data could still be used in the analysis, as deemed appropriate in inferential statistics (21). Next descriptive statistics for baseline and post intervention were calculated for each of the five imagery ability subscales and global imagery ability score, as well as total pitch recognition, pitch type and pitch location. Paired samples t-tests were run to assess mean changes from baseline to post intervention for all imagery ability subscales and total imagery score as well as for the three pitch assessments. As the data were expected to increase from baseline to post intervention across all variables a one tailed test was employed with an alpha level of 0.05. Cohens d were calculated for all pairs with 0.21 – 0.59 considered a small effect .60 – .79 a medium effect and 0.80 to 100 a large effect (6).


Imagery
Participants’ global imagery ability was higher at post-testing (m = 5.69, sd = 0.79) as opposed to baseline (m = 5.02, sd = 0.69), which was found to be a statistically significant difference, t(10) = -2.70, p = .01, d = 0.91). Skill imagery ability change from baseline to post intervention was also significant (t(10) = -2.51, p = 0.02, d = 0.73), indicating that the participants increased their skill imagery ability from baseline (m = 4.79, sd = 1.12) to post intervention (m = 5.63, sd = 1.20). Strategy imagery ability was found to have a statistically significant change (t(10) = -2.05, p = .03, d = 0.63). Means indicated an increase from 4.73 (sd =0.94) at baseline to 5.30 (sd =0.88) at post intervention. The affect imagery ability increase was statistically significant (t(10) = -2.07 p = 0.03, d = 0.81). Means indicated a change from 5.55 (sd = 0.83) at baseline to 6.22 at post intervention (sd = 0.79). Mastery imagery ability from baseline (m = 4.88, sd = 0.86) to post test (m = 5.60, sd = 0.79) was also statistically significant (t(10) = -2.05, p = 0.02, d = 0.88). Goal imagery did not have a statistically significant change from baseline (m = 5.15, sd = 1.02) to post intervention (m = 5.70, sd = 1.03, (p = 0.07, d = 0.53).


Pitch Statistics
Pitch type recognition was found to be statistically significant from baseline (m = 6.60, sd = 3.13) to post intervention (m = 9.10, sd = 2.08), t(10) = -2.28, p = .04) with a large effect size (d = 0.94). Pitch location recognition and total pitch recognition both increased, however neither were statistically significant changes (p >0.05). Percentage change was also recorded for pitch type as that is the common way to assess these statistics in applied softball scenarios. See Table 1 for full statistics for Pitch.

Table 1. Average Number and percentage of pitches accurately identified at baseline and Post Intervention

# Correct Baseline# Correct  Post Intervention# Correct Pitch Type Baseline# Correct Pitch Type Post Intervention# Correct Pitch Location Baseline# Correct Pitch Location Post Intervention
#%#%#%#%#%#%
4.134.175.949.176.6559.175.83758.337.260

Discussion
This study investigated the effect of an applied Imagery Assisted Virtual Reality intervention on NCAA Division I softball players’ imagery ability and pitch recognition. This study hypothesized an increase in global imagery ability, pitch recognition as well as increases in skill (CS), strategy (CG), and Confidence (MG-M) imagery. Overall, the hypotheses were supported by the findings of this study.


This study’s results indicated a significant increase in the participants’ global imagery ability with this change indicating a large effect size. Furthermore, of the five imagery subscales all showed increases from baseline to post intervention, with Skill, Strategy, Mastery and Affect imagery ability increasing from baseline to post intervention. The increase in global imagery ability and subscale increases equates to the athlete’s ability to image being easier in real sport situations (49). This is of applied significance as this increase in global imagery could assist athletes in mental preparation before engaging in sport specific performance endeavors. It is also of importance as we have few studies demonstrating how to increase imagery ability even though we know the ability to image is important for athletes who want to use imagery to increase their sport performance. As imagery has been shown over and over again to increase sport performance (e.g., 9), knowing how to increase imagery ability is an important step in pursuit of maximizing the benefits of this psychological strategy.
This study demonstrates how virtual reality can assist a person’s imagery ability when showing real world video in correlation to their imagery script. We can postulate that global imagery ability increased in part due to the IAVR increasing the functional equivalency of the intervention (32). These results align with research on functional equivalence (22 and the PETTLEP model of imagery which states that all senses need to be engaged to be fully immersed in an imagery script (e.g., 1, 19; 36, 40).


The results indicated significant increases in confidence (MG-M) and affect (MG-A) imagery ability which equates to an athlete’s ability to image and be in control and cope during difficult sporting situations, and image positive content withing their sport (43). It may be that these motivational imagery subscales had a significant increase due to cue words (e.g., calm, focus, confidently) that were inserted into each participants imagery script to stimulate an emotional response. These cue words, chosen by each participant, were combined with repeated phrases such as “take a deep breath,” “feel yourself,” and “you are confident” were also used to stimulate an emotional response from participants. Some participants also opted to have their walk-up song play during their imagery assisted virtual reality. This auditory connection between virtual reality film and real-world stimulus may have allowed participants to emotionally connect to the IAVR and use it to regulate arousal. It should be noted that although it was not hypothesized that affect imagery (MG-A) would increase due to lack of research at the time of study, this finding is supported by recent research that has come out since data was collected for this study (46). The increase in MG-A imagery ability indicates that athletes experienced some type of realistic emotion within the imagery experience. This finding coincides with previous research (25, 27) that posits increases in affect imagery within virtual reality films may be attributed to social presence within these virtual reality films. Lee and colleagues (25) believed that responses to social presence within virtual environments may be due to the players’ expectations of interactions during an actual game. Within this study, social presence was maintained throughout virtual reality film by incorporating the presence of teammates in the videos. Finally, there were significant increases in skill (CS), and strategy (CG) imagery ability, which supported the hypothesis and is in line with past research (32). This makes sense as the IAVR gave the players extra opportunities to see themselves engaging in the skill of hitting and through imagery incorporated their individual strategies for how they were going to hit the ball.


Pitch Statistics
The hypothesis that pitch recognition would increase was partially supported. Pitch type recognition was found to be significantly increased from pre to post intervention. However, although pitch location recognition and total pitch recognition both increased, neither change was statistically significant. Percentage change was also recorded for pitch type as that is the common way to assess these statistics in applied softball scenarios and gave real world application information when it came to pitch recognition change. Of particular importance in this study was the finding that pitch type recognition increased by over 20% (from recognizing 6.6/12 – 9.1/12) from baseline to post intervention. Although not statistically significant the change in total pitch recognition increased by two pitches (4.1/12 to 5.9/12, 15%) which in an applied setting is a noteworthy performance increase. As the IAVR in this study was not filmed with 360-degree cameras it may be that this affected the batter’s sense of where the pitch was over the base, leading to a lack of pitch location increase. However, the IAVR focus on first person perspective of the pitch coming at them just as it would in a real game essentially gave them more reps “reading” the pitch where they did not have to think about anything else (what they were going to do), which may be part of why their pitch type recognition increased. These findings are important for those within the softball world as we know that recognizing a pitch can predict accuracy of an at bat (e.g., 30, 16). Although it is noted that pitch recognition is an essential aspect to batting, there is little agreement on how to improve it (13). This study’s results demonstrate the effectiveness of IAVR on increasing pitch type recognition and could therefore be a low-cost tool used by teams to increase the skill of pitch recognition, and therefore batting percentages.


While this study is an important addition to the new area of Imagery Assisted Virtual Reality, there are limitations to consider. The first limitation of this study was the sample size. Although the small sample size is acknowledged as a limitation it should be noted that even with this small sample size, the effect sizes in this study were medium to high indicating that with a larger sample these findings may be even more pronounced. As this was an applied study using players who were in season, it was considered unethical to make some of them a control group. Specifically, having some players given an advantage over others, an advantage that is not shown to disappear over time, would be unfair to those in the control group, impacting both individual athletes and the team as a whole. Therefore, not having a control group, although a deliberate decision, does lead to the lack of knowledge as to whether another unexpected variable may have impacted these results.


As IAVR is a new strategy for increasing imagery ability and sport performance, there are several areas future researchers should consider. Current research on IAVR has focused on the effect of IAVR on imagery ability it may be useful to focus on imagery use (facilitative and debilitative) as the ability to image is of importance only in that it effects imagery use effectiveness (12). Therefore, future research should focus specifically on the effect of IAVR on amount of deliberate imagery use both during and after they complete the IAVR protocol. To that point, future applied research on IAVR would benefit from tracking season performance post intervention, or by athletes who use IAVR throughout a season. Additionally, the impact of IAVR on pitch recognition during in game would be a worthy pursuit. At this time, we do not know what the optimal length of an IAVR protocol would be for athlete imagery, psychological skill, or athletic performance. All these areas are ripe for future research to investigate.


Conclusion
Overall, the results of this study further support the value of an Imagery Assisted Virtual Reality protocol being used in sport. Specifically, this study showed that IAVR can increase performance statistics (pitch recognition) and imagery ability.


Applications in Sport
These findings have practical significance as they lend support for IAVR to be used by softball players to further both their in-game skills and psychological skills development. Furthermore, these findings add to the existing literature that indicates IAVR may be a cost effective and impactful tool for athletes in various sports.

References

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2024-07-18T10:12:55-05:00August 2nd, 2024|Research, Sport Training, Sports Coaching|Comments Off on Effective use of Imagery Assisted Virtual Reality in Pitch Recognition and Sport Imagery Ability Development
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