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The Effect of Coordination Training Program on Learning Tennis Skills

U.S. Sports Academy2013-11-22T22:53:34-06:00January 26th, 2012|Contemporary Sports Issues, Sports Studies and Sports Psychology|

### Abstract

The aim of this study was to define which coordination abilities are the most important in tennis and to identify whether a coordination training program will improve the learning process of tennis skills (backhand and forehand). Fifteen expert coaches in tennis completed a check list of five coordination abilities and suggested that the most important coordination abilities for tennis players are “kinaesthetic differentiation” and “reaction time”. Based on the results from the questionnaires, the program designed to practice the two most important coordination abilities. Participants were 48 novice children (age 11 ± 2 years). They were randomly divided into two group, the experimental group (EG, n=24) and the control group (CG, n=24). Both groups followed tennis training program 3 times/wk for eight weeks. Participants of the experimental group performed a specific coordination program for 20 min before the skills practice and participants of control group performed the traditional practice. The tennis skill performance and learning assessed using observation technique in five basic elements of every skill. There were three measurements, pre, post and retention test, one week after post test without practice. Analysis of Variance (ANOVA) with repeated measures (2 group X 3 measures) revealed that there was significant interaction between groups and measures. The Bonferroni post hoc analysis revealed that experimental group perform better than the control group in the post test and in the retention test in the two skills. The results of this study indicated that coordination training program help athletes to learn and perform the forehand and backhand tennis skills better.

**Key words:** Coordination abilities, kinaesthetic differentiation, reaction time, tennis skill

### Introduction

In sports where technique is of great importance, it is essential all athletes could perform refined skills. Tennis is a sport which demands high level of coordination abilities (1). The term “coordination” has been defined in the literature as the ability to perform complex motor skills. Hirtz, (2, 3) suggested a list of 5 basic coordination abilities: reaction, rhythm, balance, kinaesthetic differentiation and space – time orientation. Practicing the coordination abilities seem to be necessary and has to take place during childhood and adolescence, as a form of an “additional technique training” (4). This term includes additional drills that will improve virtuosity, stability and the coordination of special sport techniques. In most sports the training of skill alone is not enough for learning and stabilizing the new skill, thus, there is a need of specific drills which will facilitate the learning process of the skill. Previous studies (5, 6) developed a theory with regard to the coordination requirements for each sport. The abilities of coordination (specific for each sport) are “hidden” under each sport skill and facilitate athletes to maximize their performance in this skill (6, 7).

Derri, Mertznidou and Tzetzis (8) evaluated dynamic balance and body coordination between athletes (rhythm and gymnastics) and non athletes and found that athletes had significant better dynamic balance and body coordination. Also, it was proposed that the athletes should be practiced with sport specific coordination drills in order to optimize their performance.

Furthermore, Starosta, Rostkowska and Kokoszka (9) studied the water feeling at water sports with the use of questionnaires based on the 5 basic coordination abilities: reaction, rhythm, balance, kinaesthetic differentiation and orientation. The questionnaires were given to athletes from different water sports (swimming, synchronized swimming and diving) and to their coaches. The study showed that different swim phases depended differently on the coordination abilities.

The efficiency of coordination training in sports was supported by the results of experimental studies carried out on basketball players (17), handball players (10), football players (men and women) (11, 12) volleyball players and kick boxers, tae kwon do, single combats (Greco-Roman and free-style wrestling) (13) and on judo (14). A study with young tennis players (15) proposed that the abilities which contribute mostly on proper service motion were: body coordination, reaction time and the ability of throwing at a target.

Although coordination abilities are essential learning requirements in order to perform well and to develop optimal tennis strokes and movement technique (1), there are not many studies in tennis with regard the use of coordination abilities in learning process of basic skills.

The aim of the present study was to define which coordination abilities are the most important for tennis players and to identify if an additional coordination training program will improve the learning process of the tennis skills (backhand, and forehand).

### Method

#### Participants

In the present study participated 48 novice athletes (22 male and 26 female) of sport club, aged between 9 – 13 years old (11 ± 2 years). They were randomly divided into two groups, the experimental group (EG, n = 24) and the control group (CG, n = 24). The participants had training experience in tennis one year. These individuals voluntarily participated in this experiment.

#### Identification of coordination abilities

In order to identify which coordination abilities are the most important in tennis players, questionnaires were given to 15 expert tennis coaches. They were asked to evaluate the coordination abilities from the most important to the least important for tennis players. The coordination abilities that were valued: 1) kinaesthetic differentiation, 2) space and time orientation, 3) rhythm, 4) reaction and 5) balance. Based on these results the two most significant abilities were selected as tennis specific coordination abilities and an intervention programme was planned. Kinaesthetic differentiation, with regard to the movement perception, was defined as the ability that allows a player to control internal and external information, adapt it and use it correctly. Space and time orientation is the ability to determine and modify the position and movements of the body in space and time according to tennis court and/or an object in motion (tennis ball and opponent). Rhythm was defined as the ability to capture an acquire rhythm from an external source and to reproduce it in movement. Reaction is the ability to identify simple or complex situation rapidly and find the appropriate motor solution. Finally, balance was defined as the ability to maintain perfect body position during stroke performance (static) and recover the initial position (dynamic).

#### Intervention Program

Based on the results from the questionnaires, the coordination program designed to practice the two most important abilities: the kinaesthetic differentiation and reaction time. The intervention was a specific coordination program and performed before the tennis training session for eight weeks, three times per week. In each session the participants practiced four drills for five minutes each. Special attention was given given to make the drills fun and appropriate for athletes’ age and training experience.

#### Procedure of measurements

All participants had five minutes warm-up, and then performed 10 backhand and 10 forehand strokes period. These activities were recorded by a video-camera for the initial technique evaluation (pre-test). An expert tennis coach evaluated the backhand and forehand technique at five basic elements: i) the grip, ii) the side-way stance, iii) the elbow position before the touch, iv) the touch and v) the follow through.

A score was given for each participant (ten trials X the score of the sum of five elements of skill). After five weeks, when the intervention program was completed, a technique evaluation (post-test) for all players took place in the same way as the initial measurement. Finally after a week, without practice in these two skills, a technique evaluation (retention test) was performed to all players in order to examine if the participants learned the skills.

#### Statistical analysis

The Pearson (r) correlation was performed between the measurements from one day to the next day (test, retest) by an expert coach in tennis, in order to evaluate the observer’s internal reliability. There was high correlation in test and retest (r=0.97, p=0.000).

A one-way ANOVA determine if there were initial differences between groups in the two tennis skills. Two-way repeated measures ANOVA was used to test the difference in the technique performance of the skills in three measurements (pre, post, and retention test) between the two groups (EG and CG). The Bonferroni test was used for the post hoc analysis where appropriate. The level of statistical significance was set at p< 0.05.

### Results

#### Initial measurements

The data were normally distributed. The one-way ANOVA revealed no significant differences between the groups EG (Experimental) and CG (Control group) at pre-test in backhand (F_1,47 = 0,68 p > 0.05) and forehand (F_1,47 = 0,44 p > 0.05), which means that the two groups were began experiment with a similar level of technique.

#### Performance in Forehand

The two-way repeated measures ANOVA revealed significant interaction between the groups (F_2,92 = 46,36, p < 0.000) and measurements, main effect of measurements (F_2,92 = 161,22, p < 0.000) and main effect of group (F_1,46 = 73,58, p < 0.000). Mean and standard deviation for each group are presented in Table 1.

Specifically revealed significant differences in technique performance of forehand between groups EG and CG at post test (p < 0.05) and at retention test, a week after the completion of the intervention without practice, there was still a significant difference between group EG and CG (p < 0.05). LSD post-hoc analysis revealed that there were significant differences from pre to post-test and from pre-test to retention test of participants of experimental group. These means that the participants of experimental group were better than the participants of control group in forehand skill technique performance (Figure 1).

#### Performance in Backhand

Two-way repeated measures ANOVA revealed significant interaction between the groups (F_2,92 = 26,94, p < 0.001). In addition, a main effect for measurement (F_2,92 = 114,08, p < 0.000) and group (F_1,46 = 19,49, p < 0.000) was revealed.

Specifically revealed significant differences in technique performance of backhand between groups EG and CG at post test (p < 0.05) and at retention test, a week after the completion of the intervention without practice, there was still a significant difference between group EG and CG (p < 0.05). Mean and standard deviation for each group are presented in Table 2.

LSD post-hoc analysis revealed that there were significant differences from pre to post-test and from pre-test to retention test of participants of experimental group. This means that the participants of experimental group were better of participants of control group in backhand skill technique performance (Figure 2).

### Discussion

Coordination abilities are essential in order to develop and perform optimal tennis strokes (forehand and backhand) and the movement techniques (1). The aim of the present study was to define which coordination abilities are the most important for tennis players and to identify if an additional coordination training program will improve the learning process of the tennis skills (backhand, and forehand). Specifically it was suggested that kinaesthetic differentiation and reaction are the most important abilities for tennis. Thus, coordination exercises targeting those abilities as supplementary to tennis training sessions can improve the learning process of the backhand and forehand technical elements.

The results revealed that participants of the experimental group learned the two tennis skills (backhand, and forehand). The present findings for young tennis players aged 9 – 13 years old are in agreement with the bibliography (4). It was supported that coordination abilities are basic elements for an athletic skill. Also, practicing those abilities with specific exercises has a better result at improving the technique of those skills (16). Differentiation and reaction seem to be valuable in tennis as in other sports. Zwierko, Lesiakowski, and Florkiewick, (17) showed that coordination abilities such as orientation, differentiation, reaction, balance and the technical skills are necessary parts of the basketball players’ practice. Martin (18) claimed that kinaesthesia is very important for movement perception and motor skills learning. It has been suggested that kinaesthetic ability is developing rapidly until the age of ten and the well – trained persons are quite superb at this ability (8).

Roloff (19) suggested as a person’s kinesthia develops, the possibility of learning new motor skills increases. A study with volleyball players (20) found that rhythmic ability is important, while kinaesthetic differentiation ability is limited to this sport. In addition a study in rhythmic gymnastics (21) mentioned the importance of kinaesthesia to high performance. Also, it has been reported a relationship between reaction and the performance for basketball players (22, 23) karate athletes (24). A study which examined eye-hand and eye-foot reaction showed that there was significant difference between soccer players and non-athletes (25).

In general, in tennis the ability to react quickly at the net or on the return of serve or to volley a high-speed passing shot is very important (1). In addition, the present study showed that improving the ability to react with an additional training program to tennis practice, has a positive effect on the learning process of the technique of backhand and forehand. It has been suggested that age is related to coordination abilities and that there was a linear relationship between age and coordination performance for ages 4 – 7 years old (26). Participation in tennis by itself cannot develop the coordination abilities. The training of children should be focused on versatile education corresponding to certain need. Delimitation of this study was that the intervention last only 8 weeks and the long learning and retention of skills were not assessed in the present experiment.

### Conclusions

According to the results of the present study, the ability of kinaesthetic differentiation and reaction are primary connected to high performance tennis skills. Furthermore, practicing those abilities will help to improve the learning procedure of the backhand and forehand complex technique.

### Applications In Sport

Coordination abilities are important during tennis play, and their development from the early age is essential. Specifically, coaches who work with young players will have to include coordination exercises into their daily training program through which these tennis specific coordination abilities will be practiced. In this way the learning procedure will be more fun, and not through a classic, “boring” program. The goal for the coaches is not only the technique improvement but also, to fulfil the need of young players for fun.

### Tables

#### Table 1
Means and standard deviations of participants of two groups in forehand skill

#### Table 2
Means and standard deviations of participants of two groups in backhand skill

### Figures

#### Figure 1
The performance in technique evaluation of groups in forehand


#### Figure 2
The performance in technique evaluation of groups in backhand


### References

1. Bourqouin, O. (2003). Coordination. In: Strength and Conditioning for tennis, A.Q. Machar Reid, and Miguel Crespo. London, UK: International Tennis Federation, ITF Ltd, 71-77.
2. Hirtz, P. (1985). Coordination abilities in school sports. Volk und Wissen, Berlin.
3. Hirtz, P. (1997). Coordination Training. In: Schnabel G., Harre D., Borde A. (Hrsg.): Trainingswissenschaft. Leistung. Training. Wettkampf. Berlin. 225-230.
4. Abernethy, B. (1988). The effects of age and expertise upon perceptual skill development in a racquet sport. Research Quarterly for Exercise and Sport, 59, 210-221.
5. Martin, D., Carl, K., & Lehnertz, K. (1995). Tecnica sportiva e allenamento della tecnica. Didattica del movimento, 97/98, 37-54.
6. Neumaier, A. (1999). Koordinatives Anforderungsprofil und Koordinationstraining. In: H. Mechling & A. Neumaier (Hrsg.). Reihe: Training der Bewegungskoordination. ln: Sport und Buch Strauss.
7. Neumaier, A., & Mechling, H. (1994). Taugt das Konzept “koordinative F?higkeiten” als Grundlage f?r sportartspezifisches Koordinationstraining? In: Steuer- und Regelvorg?nge der menschlichen Motorik, Blaser, P., Witte, K., Stucke, C., (Hrsg.). Sankt Augustin: Academia, 207-212.
8. Derri, V., Mertzanidou, O., & Tzetzis, G. (2000). Assessment of dynamic balance and body coordination in female athletes of rhythmic and gymnastics, 9 – 15 years old. Exercise and Society, 26, 55-62.
9. Starosta, W., Rostkowska, E., & Kokoszka, K. (2003). The Concept of “Water Feeling”, Its Significance, Determining Conditions and Formation in the Opinion of Coaches of Various Swimming Sports. Kinesiology, 13, 17-32.
10. Lidor, R., Argov, E. & Daniel, S. (1998). An exploratory study of perceptual-motor abilities of women: novice and skilled players of team handball. Perceptual and Motor Skills, 86, 279 – 288.
11. Witkowski, Z. (2003). Koordinacjonnyje sposobnosti junych futbolistow: diagnostika, struktura, ontogenez (praca doktorska) (in Russian). Moskwa.– 232 s
12. Witkowski, Z., & Ljach, W. (2004). Cwiczenia ksztaltujace koordynacyjne zdolnosci motoryczne w pilce noznej. Centralny Osrodek Sportu, Warszawa. – 198 s.
13. Gierczuk, D. (2004). Coordination Training as a Factor Streamlining of the Goal-Oriented and Special Stage during the Schooling of Wrestlers (Ph. D. Thesis)]. AWF, Kraków.
14. Pietrow, A.M. (1997). Centralnoje programmirowanie mechanizmow realizacji koordinacjonnych sposobnostej sportsmenow i ich pedagogiczeskoje obosnowanie. Awtoref. siss. …dokt.ped.nauk. Moskwa. – 48 s.
15. Mantis, K., Zachopoulou, E., & Mavridis, T. (1998). A battery of tests for evaluating abilities related to the tennis serve. Journal of Human Movement Studies, 35, 73 – 88.
16. Druckman, D., & Swets, J. A. (1988). Enhancing human performance. Washington: Washington: National Academy Press.
17. Zwierko, T., Lesiakowski, P., & Florkiewick, B. (2005). Selected aspects of motor coordination in young basketball players. Human Movement Science, 6, 124-128.
18. Martin, D. (1988). Training im Kindes und Jugendalter, ed. D. Karl Holfmann. Martin, Carl, K., & Lehnertz, K. Schorndorf, Deutschland.
19. Roloff, L. (1952). Kinesthesis in relation to the learning of selected motor skills. The Research Quarterly, 16, 210 – 217.
20. Kioumourtzoglou, E., Michalopoulou, M., Tzetzis, G., & Kourtessis, T. (2000). Ability profile of the elite volleyball player. Perceptual and motor Skill, 90, 757-770.
21. Kioumourtzoglou, E., Derri, V., Mertzanidou, O., & Tzetzis, G. (1997). Experience with perceptual and motor skills in rhythmic gymnastics. Perceptual and Motor Skills, 84, 1363 – 1372.
22. Brooks, M. A., Boleach, L. W., & Mayhew, J. L. (1987). Relationship of specific and non-specific variables to successful basketball performance among high school players. Perceptual and Motor Skills, 64, 823-827.
23. Pavlidou, S., Michalopoulou, M., Aggeloussis, N., & Kioumourtzoglou, E. (2006). Relationship between perceptual and motor abilities on fundamental basketball skills in 8-13 Years Old Children. Inquiries in Sport & Physical Education, 4, 399 – 408.
24. Mori, S., Ohtani, Y., & Imanaka, K. (2002). Reaction times and anticipatory skills of karate athletes. Human Movement Science, 21, 213-230.
25. Montes – Mico, R., Bueno, I., & Candel, J. (2000). Pons a M. Eye -hand and eye – foot visual reaction times of young soccer players. Optometry, 71, 775-780.
26. Kambas, Α., Fatouros, J., Aggelousis, Ν., Gourgoulis, V., & Taxildaris, Κ. (2003). Effect of age and sex on the coordination abilities in childhood. Inquiries in Sport & Physical Education, 1, 152 – 158,

### Corresponding Author

Eleni Zetou, Dr
Papanikolaou 148
57010 Pefka, Thessaloniki
<elzet@phyed.duth.gr>
0030-2310-675280

Dr Eleni Zetou is Assistant Professor in Motor Learning, in Department of Physical Education and Sport Sciences of Democritus University of Thrace. She was also national Volleyball coach, vice president of Greek Volleyball Federation and member of Greek Academy of Physical Education.

Throwing Techniques for Ultimate Frisbee

U.S. Sports Academy2013-11-22T22:54:13-06:00January 5th, 2012|Sports Coaching|

### Abstract

The goal of this study was to determine if certain throwing techniques for the sport of Ultimate Frisbee were advantageous relative to other techniques. The defense can attempt to force a thrower to utilize a specific throw; knowing the advantages of different throws can influence a defender’s decision to force the thrower to use a certain throw.

Motion capture was used to monitor the flight of a disc (Discraft Ultrastar 175g) for three throwing techniques. The two main groups of throws were backhand (BH) and forehand (FH) throws, with the forehand throws divided into a closed forehand grip (CF) and a split forehand grip (SF). Sixteen participants were recruited with experience ranging from 3 years to 8 years based on survey. Throws were analyzed with regards to linear velocity, angular velocity, precession, and accuracy. Players threw a total of 45 throws: five throws for all combinations of the three throwing techniques combined with three objectives: accuracy, maximum spin, and maximum velocity. The order of the nine throwing groups was randomized.

Throws were analyzed for linear velocity, angular velocity, precession, and accuracy. Linear velocity was calculated by measuring the distance traveled in the first 0.02 seconds of flight, and angular velocity was measured by calculating the time required for four unique points on the disc to complete one rotation. Precession was measured by calculating the average angular deviation from the average normal plane of the disc, and accuracy was measured by the distance between the center of the disc and the target at closest approach using a quadratic fit to the known flight path.

There was a very strong linear correlation between linear velocity and angular velocity. There was no difference in linear velocity between backhand and forehand throws, although the closed grip forehand had a higher linear velocity than the split grip forehand. Backhand throws had higher angular velocities than forehand throws for a given speed; there was no difference in angular velocity between closed grip and split grip forehand throws. Backhand throws had less precession than forehand throws, and there was no difference in precession between closed grip and split grip forehand throws. There were no statistically significant differences in accuracy between any of the throws.

These results show that backhand throws tend to have more spin and wobble less making the backhand a superior throw. Throws with less spin have greater instability; as a defender, forcing the thrower to utilize a forehand throw would result in a throw with less stability than a backhand throw. Forehand throws did not perform better than backhand throws for any category tested.

Additionally, new players are often taught that the split-grip forehand is a bad throw, and that the closed-grip forehand should be used instead. The results show that the split-grip forehand performs on par with the closed-grip forehand with the exception of maximum velocity. New players should not be discouraged from using a split-grip forehand while learning the mechanics of the forehand, as the only disadvantage is a slight decrease in maximum velocity.

**Key Words:** Forehand, Backhand, Flick, Frisbee

### Introduction

In the sport of Ultimate Frisbee, players use two primary throws: backhand and forehand. My hypothesis, from personal experience, is that backhand throws will wobble less, have less spin, be more accurate, and travel faster than forehand throws. The aim of this study was to determine if one throw had a comparative advantage with respect to linear velocity, angular velocity, precession, and accuracy. Also, the split-grip forehand is often thought of as an inferior throw relative to the closed-grip forehand. The closed-grip forehand is expected to outperform the split grip forehand.

Players must be able to utilize both throws as the defenders can force players to throw one way or the other by positioning their bodies on a certain side of the thrower. As a defender, knowing advantages and disadvantages of each throw can factor into defensive strategies to increase the chances of a disc being thrown with sub-optimal flight characteristics as a result of differing throwing techniques. This may cause a higher incidence of turnovers due to incomplete passes.

Previous research has shown that a disc thrown with less angular velocity will result in a throw with less stability (1). Therefore, whichever throw has higher angular velocities will be the more stable throw and will be more likely to reduce turnovers. The angular velocity of a disc in flight does not have a significant effect on lift and drag coefficients (2).

### Methods

#### Participants

Participants were recruited by open invitation to the St. Louis Ultimate Association and both the Washington University in St. Louis men’s and women’s club ultimate teams. Participants completed a questionnaire to determine experience and skill level. The skill level was a ten point scale with 1=Beginner, 4=Recreational, 7=Competitive college, and 10=Elite. Of the participants, 5 were placed in the ‘elite’ category and 11 were placed in the ‘non-elite’ category. Experience was divided into seven categories: 0-1 years, 1-2 years, 2-4 years, 4-5 years, 5-8 years, 8-15 years, and 15+ years (see Table 1). No participants were excluded from the study and all participants performed the same number of each test.

Testing occurred at the Washington University School of Medicine Human Performance Lab after the participant signed the IRB-approved informed consent form. No financial compensation was provided for participating in the study.

#### Data Collection

Data were collected using a Motion Analysis system consisting of six high-speed Eagle Digital Cameras at 250 Hz and Cortex software. Three cameras were located above and behind the thrower (relative to the direction of the throw) with one camera directly behind the thrower, and the other two cameras located a couple meters to either side. These cameras were focused on the latter portion of the throw. The other three cameras were located in the same arrangement, but above the target, and focused on the volume around the thrower. This set up provided the largest capture volume so the throw would be in view of at least two cameras at all times. Seven reflective markers were used. One marker was placed on the thumbnail of the throwing hand with one marker in the center of the disc and three markers placed approximately five inches from the center marker in a triangular formation. Additionally, one marker was placed adjacent to one of the perimeter markers to provide an asymmetric model. The final marker was placed on a target, used to evaluate accuracy. Participants stood approximately 2.5 meters from the target and net. Participants threw 45 total throws consisting of nine categories: Backhand Accuracy (BH_A), Backhand Spin (BH_S), Backhand Velocity (BH_V), Closed Forehand Accuracy (CF_A), Closed Forehand Spin (CF_S), Closed Forehand Velocity (CF_V), Split Forehand Accuracy (SF_A), Split Forehand Spin (SF_S), and Split Forehand Velocity (SF_V). The order was randomized for each participant prior to data collection. For each category, participants had two practice throws followed by three throws, which were used for analysis.

#### Variables

The following variables were calculated: linear velocity, angular velocity, precession, and accuracy. For each throw, data processing began when the marker on the disc closest to the thumb marker was 0.3 meters away from the thumb marker indicating the disc had left the thrower’s hand. Linear velocity was calculated by computing the distance traveled over the first 0.02 seconds (5 frames). Angular velocity was calculated by tracking the time required for five different pairs of markers to complete one cycle. A cycle began when one marker’s y-coordinate crossed the other marker’s y-coordinate. The cycle ends after the first marker’s y-coordinate crosses the second marker’s y-coordinate twice. The angular velocity was calculated by averaging the times for each of the five pairs. Precession was calculated by calculating the average angular deviation from the average plane of the disc. The angles were calculated by taking the cross product of two vectors defined by two of the perimeter markers and the center marker. Accuracy was calculated by measuring the closest approach of the projected flight path to the center of the target. The flight path projection was calculated using a quadratic fit to the known flight path.

#### Statistical Analysis

The data were analyzed using SPSS Statistics® and Microsoft Excel®. Two sample paired t-tests were used to compare different throws and two sample t-tests (assuming equal variance) were used to compare elite vs. non-elite players. The significant threshold employed was p < 0.05. Regression analysis was used to determine whether correlations existed between linear velocity and both angular velocity and precession. Since angular velocity varied by linear velocity, the ratio of angular velocity to linear velocity was used to determine which throw achieved the highest angular velocities.

### Results

#### Elite vs. Non-Elite

The only difference found between elite and non-elite players was the maximum speed of throws: elite players had higher maximum velocities than non-elite players. There was no difference in accuracy, precession, or angular velocity to linear velocity ratios. With the exception of maximum velocity, no differences were found between elite and non-elite players; as a result, throw comparisons included both elite and non-elite players (see Table 2).

#### Throw Comparison

No significant differences were found between backhand and closed grip forehand or backhand and split grip forehand velocities. Closed grip forehands were found to have higher maximum velocities than split grip forehands. Backhand throws had an average maximum velocity of 20.1 m/s, closed grip forehand throws had an average maximum velocity of 20.6 m/s, and split grip forehands had an average maximum velocity of 19.2 m/s.

Backhand throws were found to have a higher angular velocity / linear velocity ratio than both closed grip and split grip forehands by more than 4 RPM per meter per second. No differences were found in the angular velocity / linear velocity ratio for closed grip forehands vs. split grip forehands (see Figure 1).

When participants were instructed to throw for maximum spin, throws were found to have higher angular velocity to linear velocity ratios than throws for accuracy and velocity; differences of greater than 5.5 RPM per meter per second were found for all three grips (see Table 3).

No correlation was found between velocity and precession.

No differences were found in accuracy for backhand, closed grip forehand, or split grip forehand throws, with average distances varying by less than 0.03 meters (1.25 inches). Backhand throws were found to have less precession than both closed grip forehands and split grip forehands by more than 35%. No differences were found between closed grip forehands and split grip forehands (see Figure 2)

Strong linear correlations were found between angular velocity and linear velocity when considering throws for maximum velocity and accuracy. values of greater than 0.9 were found for all three categories.

### Discussion

This study has limits that should be taken into consideration. First of all, several of the subjects have learned their throwing techniques from the same group of players, so certain efficiencies or inefficiencies in technique may affect results. Secondly, all participants use a closed-grip forehand; closed-grip forehand throws have been practiced by the participants, whereas split-grip forehand throws have not been practiced. Additionally, participants were throwing in a room with expensive equipment; participants may have altered their throws to ensure they hit the net. Accuracy data may have been inconclusive because the target was located 2-3 meters from the thrower. Also, certain throws may be more accurate for shorter distances and less accurate for longer distances. Limitations of being in a confined space may have prevented any significant results related to accuracy. The cameras also had a difficult time of tracking the higher velocity throws (18+ m/s). As a result, flight paths had to be reconstructed from partial data.

Backhand throws appear to be superior to forehand throws due to the higher angular velocity (see Figure 1) and less precession (see Figure 2) than forehand throws. Morrison found that angular velocity increases the stability of the disc (1) as the angular momentum provides gyroscopic stability, so backhand throws should be more stable than forehand throws. There were no differences in maximum linear velocity or accuracy between backhand and forehand throws. The only difference between the two forehand throws was that closed-grip forehands were thrown faster than split-grip forehands (see Table 3). There were no differences in the angular velocity to linear velocity ratio, precession, or accuracy for split-grip and closed-grip forehands.

Angular velocity can be predicted accurately by knowing linear velocity and intent of throw (maximum linear velocity, angular velocity, or accuracy). No predictors of precession were found in the study.

No previous studies have compared flight characteristics of forehand and backhand throws.

### Conclusion

Based on the results obtained, it would be advantageous to force the opposing team to throw forehand throws. Doing so results in throws with less stability as a result of less angular momentum, and more precession. It is possible that lower angular velocity and higher precession could lead to a decrease in distance traveled and stability. Additionally, higher precession values could expose the disc to more drag, causing the wind to affect the throw more.

Based on the results for forehand throws, the only advantage to throwing with a closed grip is the maximum attainable velocity. By using a closed grip, participants did not show any improvement in angular velocity or precession. Thus, the only instance where a closed-grip forehand is advantageous relative to a split-grip forehand is when a player is trying to throw for distance.

The hypothesis that backhand throws would wobble less was shown to be true and that backhand throws would have less spin was shown to be false. The hypotheses that backhand throws would be more accurate and travel faster were not supported by any results.

Overall, it appears that it would be advantageous to force the offense to throw more forehand throws than backhand throws and new players should not be discouraged from learning to throw a split-grip forehand while learning throwing mechanics.

### Applications In Sport

From a strategic standpoint, teams can change defensive strategies to force the opposition to use an inferior throw. Additionally, new players can be taught advantages and disadvantages of different grips. New players are often taught that the split-grip forehand is inferior to the closed-grip forehand, although the only disadvantage of the split-grip forehand is the maximum speed of the throw. For new players, if the split-grip is more comfortable than the closed grip, they will achieve the same angular velocity and precession as a closed-grip throw.

### Acknowledgements

I would like to sincerely thank Dr. Jack Engsberg for making this research possible. He welcomed my research proposal with open arms, having nothing to gain from the study. Jack has a true passion for helping others and I am extremely fortunate to be one of the many persons he has helped. He has guided me through every step of the research process offering invaluable advice along the way. Jack, thank you for being an amazing mentor and great friend.

### REFERENCES

1. Morrison, V.R. (2005). The Physics of Frisbees. Mount Allison University Physics Department.
2. Hummel, Sarah Ann (2003). Frisbee Flight Simulation and Throw Biomechanics. Office of Graduated Studies of the University of California Davis.

### TABLES

#### Table 1
Participant Survey

**Note:** Standard Deviations appear in parentheses below the means.

#### Table 2
Comparison of Elite and Non-Elite Players

**Note:** BH is backhand, FH is forehand.

** Denotes significantly different from non-elite (p < 0.05)

#### Table 3
Throw Comparison

**Note:** BH is backhand, CF is closed grip forehand, and SF is split grip forehand. A is accuracy, V is velocity, and S is spin.

** Denotes significantly different from CF (p<0.05), ^ Denotes significantly different from SF (p<0.05)

† Denotes significantly different from V (p<0.05)

‡ Denotes significantly different from S (p<0.05)

### Figures

#### Figure 1
Graph of Angular Velocity vs. Linear Velocity


#### Figure 2
Graph of Precession vs. Linear Velocity


### Corresponding Author

Jack R. Engsberg, PhD
Washington University School of Medicine: Human Performance Laboratory
4444 Forest Park, Campus Box 8505
St. Louis, MO 63108
<engsbergj@wustl.edu>
314 – 286 – 1632

### Main Author

Evan Winograd
Washington University School of Engineering and Applied Science
6985 Snow Way Drive Box 6861
St. Louis, MO 63130
<ewinograd@go.wustl.edu>
713-805-8609

### Author Bios

#### Evan Winograd
Evan Winograd is an undergraduate student studying Mechanical Engineering at the Washington University in St. Louis School of Engineering and Applied Science.

#### Jack Engsberg
Jack Engsberg is a Professor of Occupational Therapy and Neurosurgery at Washington University School of Medicine in St. Louis. His work in the Human Performance Laboratory focuses on rehabilitation for persons with disabilities including cerebral palsy, stroke, scoliosis, spinal deformity, spinal cord injuries, and amputations using high-speed motion capture systems, force plates, electromyography, and an isokinetic dynamometer.

The Lifestyle and Sport Activity of Secretaries

U.S. Sports Academy2013-11-22T22:54:24-06:00January 5th, 2012|Contemporary Sports Issues, Sports Exercise Science, Sports Studies and Sports Psychology, Women and Sports|

### Abstract

#### Purpose
The aim of the study was to analyse the sports activity and lifestyle of secretaries in Slovenia.

#### Methods
A questionnaire with 37 variables was completed by 104 secretaries from different places within Slovenia. We calculated the frequencies and contingency tables, whereas the statistical characteristics were determined on the basis of a 5% risk level.

#### Results
We established that 26% of the secretaries were obese; most of the time secretaries are sitting down, working with their fingers, and are in forced positions. 56% of the secretaries occasionally take medicines; most of their pain occurs in the neck region, of the back, the shoulder region and in the loins; other common problems include insomnia, emotional exhaustion, and headache. The majority of secretaries engage in sporting activities on the weekend and 2 – 3 times weekly; most of them practiced sport in an unorganized way, with their family or by themselves. A good 20% engaged in an organized sport in a sport club or society, where fitness can also be classified. A good 20% practiced sport in an unorganized way, with their friends. It was established that those secretaries who engaged in an unorganized sport activity were accompanied by their friends or family. Those practicing an organized sport were mainly alone.

#### Conslusion
Secretaries who are frequently active often have a lower Body Mass Index (BMI), take painkillers less often or never, and believe that sport has a great impact on their health.

#### Applications in Sports
Sports clubs and associations should prepare appropriate activities for secretaries which will fullfil their interest, health, and wellbeing.

**Key words:** working conditions, wellbeing, health.

### Introduction

Modern professions are completely different from those undertaken in the past. Cutting-edge technology, robotics, and computer science have disburdened the human labour force and thus caused an increase in the demand and supply of office workers (secretaries, administrators, clerks etc.) whose sedentary jobs are characterized by long hours in forced postures. It is clear to see that the working conditions have drastically changed. Besides that, the leisure time and leisure activity preferences have also changed. According to the results of the latest studies, sport and recreation activities are being promoted and are increasingly gaining ground (13). The effects were first seen with highly educated people as they are aware of the potential negative consequences of a sedentary lifestyle, which is why they include a suitable sport activity in their everyday life (7, 9, 10). The fact that Slovenia is among the top European Union (EU) member states in terms of the physical activity of the population is more than encouraging. However, the latest studies show that 37.91% of adult residents of Slovenia are physically inactive (11). Due to the pressure to achieve higher productivity at work, the desire to be promoted and the aspirations for a higher income there is simply not enough time to engage in sport (8). People of different professions find themselves constantly pressed for time.

The work of secretaries is highly specific. Secretaries spend most of their working time in forced postures, sitting in unventilated offices, looking at a computer monitor most of the time, memorising huge amounts of information, and this all burdens them psychically and physically. Due to the many positive impacts of sport on physical, emotional and mental well-being (the condition of being contented, healthy, or successful) and given the nature of their work, it is highly recommended that secretaries engage in a sport activity (12). Long hours of sitting in front of a computer in a bent posture are detrimental to the human body. An appropriate sport activity can alleviate or even eliminate problems caused by a sedentary job (6). What is meant by appropriate sport activity is a recreational physical activity which positively affects both health and well-being (mood, sleep and self-confidence) (1).

This study aimed to establish the correlation between the sport activity of secretaries and some selected healthy lifestyle factors. For this purpose, a sample of secretaries was surveyed to establish the correlation between secretaries’ sport activity and the characteristics of their living environment as well as between the state of their nutrition and the type of their sport activity. We also established the frequency of health problems which precondition secretaries’ active engagement in sport activities.

### Methods

#### Sample of subjects

The sample included 104 randomly selected secretaries from different parts of Slovenia. The sample was selected at the congress of secretaries. The subjects were aged 23 to 61 years, while their average age was 41. Their jobs included personal assistant, business secretary and administrator.

#### Sample of variables

The study was based on a survey questionnaire consisting of 37 questions which enquired about social, environmental and work factors, the frequency and type of sport activity, nutrition, health condition, and psychical well-being (14). The data acquisition process was carried out in compliance with the Personal Data Protection Act. Subject gave informed consent for this study. The study was approved from the Etics Commission.

#### Data-processing methods

The data were processed using the SPSS-15.0 statistical program at the Computer Data Processing Department at the Faculty of Sport in Ljubljana. The basic statistical parameters and contingency tables were calculated. The subprograms FREQUENCIES and CROSSTABS were used for the calculation. The probability of a correlation between the variables was tested by a contingency coefficient. The statistical significance of the differences was accepted at a two-way 5% alpha error level.

### Results

#### Body characteristics

Body weight and height were self-reported. BMI was calculated from those data. Average BMI for secretaries was 23.7, indicating that the secretaries participating in the study had a normal body weight.

#### Working conditions

The secretaries’ working conditions varied (Table 1): sitting, standing – straight, standing – bending, lots of walking, working with fingers, working with hands, frequent forced posture (head and neck, turn of the torso, deep bending posture). Most secretaries spend almost all day sitting on a chair, working with their fingers and are in a forced postures. 10% of them stated these three combinations and 10% the combination of sitting and working with fingers

#### Taking work home

Secretaries often take work home with them. Sometimes they have to finish assignments at home, at other times they bring home their stress, problems, and burdens. Nearly 70% of the secretaries confirmed they sometimes feel the pressures of their work when at home (Figure 1).

#### Secretaries’ current health condition and their taking of painkillers

Most secretaries (57.7%) assessed their health condition as good. As many as 56% of them occasionally take medicines. It is statistically characteristic that those secretaries who take medicines more frequently less frequently engage in a sport activity. We established that nearly 40% of the surveyed secretaries never take any painkillers. Occasional use was reported by 56% and frequent use by 5%.

#### Secretaries’ injuries in the past three months and health problems

91.3% of the secretaries reported no injuries had been sustained in the past three months. The most frequent pains occurred in the neck, shoulder girdle, and the lumbar part of the spine. Also frequently reported were insomnia, emotional exhaustion, and headache. Other pains occur less frequently.

#### Secretaries’ absences from work

We established that 75.5% of the secretaries had not been absent on sick leave in the past six months. In the same period, 17.6% of the secretaries were on sick leave for less than 14 days. The reasons for their sick leave mainly included respiratory diseases (53.3%), care for other family members (16.7%), and injury at work or outside work (6.7%).

#### Secretaries’ assessment of the impact of sport on their health

It was established that the secretaries were aware of the importance of sport activity for their health, as nearly one-half (45.6%) of them assessed the positive impacts of sport on their health as strong, whereas the rest (53.4%) assessed them as very strong.

#### Frequency of engaging in sport

Most of the secretaries engaged in sport on weekends and 2-3 times a week. Only 4.9% of them stated they never engaged in sport (Figure 2). The time most of the secretaries dedicate to sport ranges from 35 minutes to 2 hours.

#### Types of sport activities

It was established that the secretaries engaged in several different sports at a time. The most practiced sports include cycling, fast walking, mountaineering, and swimming; skiing is also popular. One-quarter of the secretaries practice racquet sports. These sports constitute a type of physical activity which one may adapt to one’s momentary well-being and general physical fitness and, what is more, they enable the venting of psychical tensions typical of a secretary’s work. Degenerative changes in the body are not an obstacle to practicing racquet sports.

#### Method of practicing sport

Most of the secretaries practice sport in an unorganized way, with their family or by themselves. A good 20% of them engage in an organized sport in a sport club or society and the same percentage practice sport with their friends in an unorganized way. Racquet sports are undoubtedly among those activities which require only a small financial input and can be practiced nearly everywhere due to the availability of sport facilities and grounds and the fact that they can be modified to suit individual needs. It was established that those secretaries who engaged in a sport in an unorganized way were accompanied by their friends or family. Those who practiced an organized sport were mainly doing it by themselves.

#### Sport inactivity and motives for sport activity and against it

The reasons for sport inactivity lie primarily in the lack of time, fatigue, and lack of motivation, as well as inadequate organization. The motives for sport activity relate to different reasons: practice sport means to relax, maintain and improve one’s health, maintain and improve one’s physical fitness, and have a good feeling from doing something for oneself.

#### Impact of sport activity on well-being

Most of the secretaries who practice sport are more self-confident and efficient in their work. A good mood and relaxation are typical indicators of well-being and the secretaries reported being full of vitality and energy. They also enjoy better sleep after a sport activity. They reported that their tenacity, strength, flexibility, and adroitness have improved. Most of them claimed they were able to better withstand psychological pressures. All but one agreed they were not tired more than usual after engaging in a sport activity. The same was true for pain in the legs. Only three of them thought that pain in their legs was due to sport activity.

#### Employers’ role in the secretaries’ sport activity

Most of the secretaries believed that sport and recreation belonged to the private sphere of each individual. 20% of them thought that their employer should support their sport activity at least morally. The same percentage of secretaries said their employer sponsored sports events and employees’ sport clubs. Only three secretaries wished for sport activities to be included in the work process (exercises in the workplace, recreational facilities in the company). The employers did not award their employees for sport achievements (Figure 3).

The selected variables (14) were cross-checked using contingency tables in the CROSSTABS subprogram of the SPSS statistical package and the results showed a statistically significant correlation between the BMI and frequency of engaging in sport (k = 0.644, p = 0.001). A more frequent engagement in sport conditioned a lower BMI. The differences between taking medication and a frequent engagement in sport were also statistically significant (k = 0.444, p = 0.034). The more physically active secretaries only rarely took painkillers or never. The assessed health condition and frequency of engaging in sport were also statistically significantly correlated (k = 0.490, p = 0.004). A more frequent engagement in sport preconditioned a good health condition. The secretaries’ opinion on the impact of sport on their health and the frequency of engaging in sport were also statistically significantly correlated (k = 0.593, p = 0.002). The physically active secretaries believed that sport had a strong impact on their health.

### Discussion

The World Health Organization (WHO) defines obesity as excessive fat accumulation that presents a risk to health (1977). Women generally have more body fat than men. Men and women whose fat exceeds 25% and 30%, respectively, are obese. The results of our study showed that 26% of the secretaries were obese. In an extensive study involving the adult population of Slovenia, Zaletel Kragelj and Fras (15) established that as many as 40.1% of the individuals surveyed were obese and 38.5% had a normal weight. This leads us to conclude that the surveyed secretaries had a lower BMI than the Slovenian average. With reference to the above, in the future it would be reasonable to establish the ratio between the muscle mass and fat mass.

Good working conditions are certainly an essential element of the better performance of an employee, which is why good employers always strive for a better working environment for their employees (12). It was established in our research that the secretaries mainly work in the following working conditions: sitting, standing – straight or bending, and lots of walking. The study results showed that the secretaries most frequently sit, work with fingers and in forced postures. Due to such working conditions they should do specific gymnastic exercises several times a day to compensate for their long maintained sedentary positions.

Another important finding of our study was the frequency of taking medication. It these research was established that as many as 56% of the secretaries occasionally take medicines. Other researchers have found similar findings (14). In their research was namely established that the majority of people (even 70%) suffer from various intestinal difficulties for several years as a result of taking painkillers such as ibuprofen. They reported taking painkillers all too often.

Our findings about the secretaries’ injuries in the previous three months are encouraging because as many as 91.3% of the secretaries had sustained no injuries in the said period. We established that 75.5% of the secretaries had not been absent on sick leave in the past six months. In the same period, 17.6% of the secretaries were on sick leave for less than 14 days. The reasons for their sick leave mainly include respiratory diseases (53.3%), looking after other family members (16.7%) and injury at work or outside work (6.7%). The predominant diseases in terms of the percentage of absences on sick leave were diseases of the skeleton and bone system and connective tissues, followed by injuries and infections outside work, with injuries and infections at work occupying third place. In women, frequent reasons for an absence include pregnancy and diseases in the prenatal and postnatal periods (2). This is also comparable with the findings of our research.

As regards the secretaries’ current health conditions, it can be concluded that they correspond with the Slovenian average; however, the latter is considerably higher than that in the EU. A comparison with a relevant EU study reveals that Slovenians are more burdened by health problems caused by work. Nearly every second employee reports pain in the back (45.9%), one-quarter (25.7%) complain about frequent headaches and four employees out of ten (38.2%) suffer from muscle pain. The EU averages are considerably lower (3, 5).

The analysis of the secretaries’ opinions about the importance of sport, frequency, type and method of engaging in sport yielded the results presented in the continuation. We assess the secretaries’ opinion about the importance of sport activity as good. An opinion as such is not enough, but the findings show that the secretaries corroborate their views with concrete activities. Namely, 55.7% of them practice a sport between 35 minutes and two hours mainly two to three times a week. In view of the Slovenian average established by Doupona Topič and Sila (4), namely that the Slovenian active population engages in sport 3.25 hours a week on average, we realised that the secretaries can be classified among the physically active population of Slovenia. In terms of the chosen type of sport activity, with the most popular being cycling, fast walking, mountaineering and swimming, this can be compared to the Slovenian average, for women, where high percentages also represented morning gymnastics, equestrian sports and martial arts (4). Most of the secretaries practiced sport in an unorganized way, with their family or by themselves. A good 20% engaged in an organized sport in a sport club or society, where fitness can also be classified. A good 20% practiced sport in an unorganized way, with their friends. It was established that those secretaries who engaged in an unorganized sport activity were accompanied by their friends or family. Those practicing an organized sport were mainly alone. The results of the Slovenian average show that unorganized sport activities are still predominant in Slovenia as 40.2% of people practice sport in this way. Less than 25% of the population practice organized sports (4). We believe that an employee’s opinion about sport and their method of engaging in sport (unorganized) is also influenced by their employer. Most secretaries (59.3%) answered the question about their employer’s support of their sport activity by saying that the employer considered sport activity as a private sphere of life. 25.3% of employers support sport activity at least morally.

### Conclusion

It has been established that sport activity plays an increasingly important role in the everyday life of the secretaries. Due to specificity of their work which exerts psychical and physical pressure on them secretaries are engaging in sport more frequently. This positively affects their well-being, health, general fitness, and lifestyle. In our sample, the frequency of practicing a sport and the time of practice were comparable to and higher than the Slovenian average for adults of the same age. The type of sport activity was also comparable. In our opinion, more attention should be paid to the organization of sport activities as the majority of secretaries engage in an unorganized physical activity. It was also established that the secretaries hoped for some organized types of sport that would be provided by their employers. The latter insufficiently support their secretaries’ sport activity. Most of them believe that sport is a private sphere of life, not part of work. They support sport activity only morally as they mainly fail to award sport achievements, sponsor sport events or include sport activities in the work process.

### Applications In Sport

The secretaries are aware of their work, presumptions, and life. They proved this with their low rate of absences on sick leave. They should be offered more possibilities for engaging in organized sport activities and be supported by their employers financially, not only morally. Consequently, they will reduce their excessive use of painkillers and alleviate the pain in their neck, lumbar part of the spine and shoulder girdle, which are consequences of the frequent forced postures they must adopt. At the same time, they will also improve their psychical, physical, and social life.

### Acknowledgments

Authors agree that this research has non-financial conflicts or interest. This includes all monetary reimbursement, salary, stocks, or shares in any company.

### References

1. Backović Juričan, A., Kranjc Kušlan M., & Mlakar Novak, D. (2002). Slovenia on the move project – move to health. International conference: Promoting health through physical activity and nutrition. Radenci: 68-70.
2. Bolniški staž. [Sickness absence of the job]. Retrieved August 5, 2010, from Institute of Public Health of the Republic of Slovenia, Web site: <http://www.ivz.si/Mp.aspx?ni=78&pi=6&_6_id=52&_6_PageIndex=0&_6_groupId=2&_6_newsCategory=IVZ+kategorija&_6_action=ShowNewsFull&pl=78-6.0>
3. Dobre delovne razmere v Sloveniji ogrožata visoka stopnja delovne intenzivnosti in zdravstvene težave, ki jih povzroča delo. [Good working conditions in Slovenia threatens a high degree of labor intensity and health problems caused by work]. Retrieved May 17, 2009, from Eurofound, Web site: <http://www.eurofound.europa.eu/press/releases/2007/070917_sl.htm>.
4. Doupona Topič, M., & Sila, B. (2007). Oblike in načini športne aktivnosti v povezavi s socialno stratifikacijo [Types and methods of sport activity in relation to social stratification]. Šport, 3: 12-16.
5. Gibson, S., Lambert, J., & Neate, D. (2004). Associations between weight status, physical activity, and consumption of biscuits, cakes and confectionery among young people in Britain. Nutrition Bulletin, 4: 301.
6. Görner, K., Boraczyński, T., & Štihec, J. (2009). Physical activity, body mass, body composition and the level of aerobic capacity among young, adult women and men. Sport scientific and practical aspects, 2: 5-12.ž
7. Meško, M., Videmšek, M., Štihec, J., Meško Štok, Z., & Karpljuk, D. (2010). Razlike med spoloma pri nekaterih simptomih stresa ter intenzivnost doživljanja stresnih simptomov. [Gender differences in some symptoms of stress and intensity of experiencing stress symptoms] Management, 2: 149-161.
8. Mlinar, S., Štihec, J., Karpljuk, D., & Videmšek, M. (2009). Sports activity and state of health at the casino employees. Zdravstveno varstvo, 3: 122-130.
9. Mlinar, S., Videmšek, M., Štihec, J., & Karpljuk, D. (2009). Physical activity and lifestyles of Hit casino employees. Raziskave in razprave, 3: 63-88.
10. Morabia, A., & Costanza, M.C. (2004). Does walking 15 minutes per day keep the obesity epidemic away? American Journal of Public Health, 3: 437-440.
11. Sila, B. (2007). Leto 2006 in 16. študija o športnorekreativni dejavnosti Slovencev [Year 2006 and the 16th study on sport-recreational activity of Slovenians]. Šport, 3: 3-11.
12. Videmšek, M., Karpljuk, D., Meško, M., & Štihec, J. (2009). Športna dejavnost in življenjski slog oseb nekaterih poklicev v Sloveniji. [Sports activities and lifestyle of some employers in Slovenia]. Ljubljana: Faculty of sport, Institute for kineziology.
13. Videmšek, M., Štihec, J., Karpljuk, D. & Starman, A. (2008). Sport activity and eating habits of people who were attending special obesity treatment program. Collegium antropologicum, 3: 813-819.
14. Zajec, J. (2006). Povezanost športne dejavnosti tajnic z izbranimi dejavniki zdravega načina življenja. (Unpublished bachelor’s thesis). Ljubljana: Faculty of sport.
15. Zaletel-Kragelj, L., & Fras, Z. (2005). Stanje gibanja za zdravje pri odraslih prebivalcih v Sloveniji [The status of the exercise for health of adult population of Slovenia]. In: Expert conference ‘Exercise for Adults’ Health – status, problems, supportive environments. Ljubljana: Institute of Public Health of the Republic of Slovenia, 23-26.

### Tables

#### Table 1
Secretaries’ working conditions

#### Table 2
Types of sport activities

### Figures

#### Figure 1
Percentage of feeling the pressures of work at home


#### Figure 2
Percentage of engaging in sport


### Corresponding Author

assist. Jera Zajec, Ph.D.
University of Ljubljana
Faculty of Education
Kardeljeva ploščad 16, 1000 Ljubljana, Slovenia, Europa
<jera.zajec@pef.uni-lj.si>
gsm: 0038640757335

Jera Zajec, Ph.D. is the assistant professor in Faculty of Education in Ljubljana. She is a member of sport cathedra. Her bibliography contains article all over the word. Her interests in researching are wilde and contains development in motopedagogic for preschool children to adults.

Acute Effects of Combined Elastic and Free-weight Tension on Power in the Bench Press Lift

U.S. Sports Academy2013-11-22T22:55:06-06:00January 4th, 2012|Contemporary Sports Issues, Sports Coaching, Sports Facilities, Sports Management|

### Abstract

The present study investigated the acute effects on power following the bench press exercise with a combination of elastic band and free-weights vs. free weight only. Eight college-aged males and females participated in this study. All 8 subjects were college track and field athletes that participated in throwing events. The participants performed two bench press training sessions that consisted of three sets of five repetitions. One session used a combination of elastic band (15% of total resistance) and free-weight exercise (85% of total resistance), while the other session consisted only of a free-weight exercise (100%). Power was measured twice at 50% of their one repetition maximum (1 RM) at the conclusion of each lifting session. Analysis via repeated measures Ancova (Treatment by Time covaried for gender) revealed a significant effect for Time (F= 5.951, p=0.05) and a significant two way interaction for Treatment*Time (F=54.093, p<0.001). The present investigation demonstrated an initial power measurement that was greater for the combined group rather than the free-weight only group. This information is potentially beneficial for many different groups of trainee’s.

**Key Words:** Elastic tension, Strength Training, Acute Training Effect

### Introduction

Recently, there have been a number of investigations that have assessed the impact of combined elastic band and free-weight exercise. These bands have been shown to provide predictable variable resistance when applied to free weight exercises such as the back squat and bench press (5,7). Exercise professionals are continually trying to discover novel ways to increase strength and power gains. Wallace et al. (12) demonstrated that power was acutely increased in the back squat exercise with the addition of elastic tension. It was suggested from this research that an 80% free-weight/20% elastic tension ratio might be optimal. Stevenson et al. (10) also found that the combination of elastic band and free-weight exercise during the back squat can significantly increase rate of force development. Experienced power lifters and strength and conditioning professionals have claimed elastic band resistance combined with traditional training produces strength gains for several years (4,8,9). Anderson et al. (1) demonstrated an increase in the bench press and squat exercise strength after training with the addition of elastic tension for an athletic population. In this study, the back squat 1-RM improvement was nearly three times higher for the combined group. In addition, the bench press increase was doubled for the combined group. Furthermore, the combined group’s lower body average power increase was nearly three times better than the free-weight only group. Anderson et al. (2008) used the 80/20 ratio that was suggested by earlier studies. Anderson’s study demonstrated that combined elastic band and free-weight exercise was a viable option to use to train experienced lifters. That study also demonstrated that the group using the combination exercise experienced slightly less resistance at the bottom of the movement when the joints may be under maximal stress in free-weight training. Thus, band training may also provide reduced risk in back squat and bench press exercises.

Triber et al. (11) concluded that the combination of elastic and free-weight exercise provided beneficial effects on strength and functional performance in college-level tennis players. The experimental group experienced significant gains in both internal and external rotation torque. That same study concluded that an elastic band training program strengthened the rotator cuff muscles of collegiate baseball pitchers (11). Band training has the unique ability to target specific muscles, which can be beneficial for numerous sports teams. Using a combination of elastic band and free-weight exercise can also mimic the strength curve of most muscles better. A muscle’s strength curve denotes the alteration in strength of that muscle during the entire range of motion in a certain movement (13). Along these lines, it has been reported that combined elastic and free-weight exercises provided greater force during the first 25 percent of the eccentric phase and last ten percent of the concentric phase of a lift as compared to free-weights alone (3).

Elastic tension has also been reported to impact the neuromuscular performance. Page and Ellenbecker (6) claim that elastic band exercise imparts a higher neuromuscular control resulting in improved balance, gait and mobility. As stated, the gains resulting from the combination of elastic band and free-weight exercise are abundant and the use of this treatment is growing among professionals; though the acute effects on power have yet to be documented. Therefore, the purpose of the present investigation was to determine how if at all, combined elastic tension applied to a normal bench press training session affects power.

### Methods

The present investigation was approved by the local institutional review board and employed a within subjects design, with random assignment. The participants gave informed consent prior to participating and included: four male (age: 20.5±2.1yrs, height:1.82±0.07m, weight: 112.68±15.03kg) and four female (age: 19.9±1.7yrs, height: 1.76±0.05m, weight: 100.78±28.47kg) college track and field athletes involved in the throwing events (shot put, discus, hammer). The participants performed in a counterbalanced within-subjects design, two bench press training sessions that consisted of 3 sets of 5 repetitions at 85% of their 1-RM. The athletes had recently undergone a 1-RM assessment as part of practice; which was supervised by the research team and the weight selected for the treatment was based on this assessment.

One session consisted solely of resistance provided by a standard Olympic barbell with plates, which equated to 85% of the athletes previously determined one repetition maximum, the second session consisted of combined resistance where 85% of 1 RM was derived from 85% tension provided by an Olympic barbell with plates and 15% provided by Elastic Bands (Jump Stretch Inc., Youngstown, OH.). The 85% free weight and 15% elastic tension treatment was based upon previous research performed in our laboratory that suggested that this was an appropriate split for effective training between the isotonic tension provided via free weight and variable resistance by the elastic bands (2).

Immediately after the training sessions, the participants were asked to bench press 50% of 1RM at maximum velocity, in order to generate the greatest amount of watts possible. The participants performed two lifts at 50% of 1RM after each treatment, separated by a rest period of 90 seconds. The two sessions were separated by a 72 hour wash out period as to avoid undo fatigue affecting the results. The order of treatment was randomized so that half the participants lifting under the combined elastic band and free weight condition went first, with the other half lifting in the free weight only condition went first. During the second visit the participants lifted under the other treatment.

Instruments

Power was measured twice, with a minimum of 90 sec rest between measurements at 50% of 1-RM, following the conclusion of both lifting sessions, using a Max Factor tether type potentiometer (Max Rack Inc, Columbus, OH.). This instrument demonstrated reliability in pilot testing with Intraclass correlations of greater than 0.99 on repeated measures testing.

Statistical Analysis

Results of the present investigation were analyzed via a treatment (Combined free-weight and elastic tension vs. free weight only) by time (attempts 1,2) repeated measures Ancova (covaried for gender). The inclusion of the covariate was necessary based upon the natural differences in strength that existed between the male and female athletes in the present investigation. All statistical tests were performed with the use of a modern statistical software package (SPSS ver 17.0 for Macintosh). The criteria for statistical significance was set a priori at alpha <0.05.

### Results

Intraclass correlation analysis suggested good reliability on all measures for the present investigation (>0.99). Analysis performed via repeated measures Ancova (Treatment by Time covaried for gender) revealed a significant main effect for Time (F= 5.951, p=0.05) and a significant two way interaction for Treatment*Time (F=54.093, p<0.001).

The subjects initial measurements of power immediately following the training session was higher in the combined elastic treatment (437.5+34.89 watts) as compared to the free-weight only condition (391.88+41.01 watts). (see Table 2)

### Discussion

The current study extended previous studies by using both male and female participants that were college track and field athletes. All 8 subjects were involved in throwing events and therefore trained regularly with resistance exercises such as a bench press with the involvement of both elastic and free-weight training. The present investigation revealed a differential response in power following training sessions that utilized combined elastic and free weight tension as compared to free weight only.

Affects have been seen with a combination of elastic band and free-weight tension in the past. Bellar et al. (2011) reported around a 5lbs increase in 1RM bench strength after only 3wks of training with a combination of elastic bands and free weights. Anderson et al. (2008) reported changes in power production with athletes who utilized a combination of elastic and free-weight tension. The current study builds upon these findings and notions by experts in the field (Mannie 2005, Simmons, 2007) who suggest adding elastic tension can have acute effects. Based upon these data, during the course of an upper body lifting session it appears that athletes are able to maintain more power when training with a combination of elastic tension and free-weights.

The recorded power was notably different between the sessions that used a combination of an Olympic barbell and an elastic band and those that only used an Olympic barbell. The difference between the two separate 50% 1-RM power assessments for the combination group was only 1 watt, while the difference between the free-weight only group was close to 46 watts. This finding is notable as the attempts post combined training were essentially identical, whereas the first attempt under the free weight only treatment was lower than the second by 46 watts. This suggests that the free weight only treatment may have acutely resulted in a reduction in power production capability that was washed out by the second attempt. The first power output between the two treatments differed by almost 35 watts. After the 90 second rest, the second power output of each group was extremely close, differing by 10 watts. The initial measurement of power following the training was higher for the group that performed the bench press with the combination of the elastic band and the free-weight, but the two different groups seemed to retain the same amount of power at the end. The overall results of the study suggest that in the immediate period following bench press training, athletes who use combined elastic and free weight tension will be better suited to activities that rely on greater power production, such as throwing a shot put. This finding is important as coaches often pair activities in complex training schemes.

### Conclusions

The present investigation has shed light onto the acute affects of combining elastic tension with free-weight exercise on power production in athletes. Further research should continue to explore the effects of power, strength, rate of force development, velocity, eccentric activity and neuromuscular stimuli when performing combination activities with both elastic band and free-weight exercises. It is plausible that given the data from the present investigation, chronic adaptations to training with elastic resistance in combination with free-weights may have been caused by lesser reductions in power during acute training sessions. If this acute effect does manifest in this fashion, then it would have ramifications as to the training volumes athletes utilize with this modality to gain maximum adaptations. The current research on the topic of combining elastic and free weight training is very limited and mostly focused on the back squat and bench press. Hence, investigations and applications on diverse exercises should be considered in forthcoming research.

### Applications In Sport

Based upon the present investigation, it would immediately appear at the conclusion of a training session that athletes retain more power production post combined elastic and free-weight training as compared to free-weight training alone. This information is potentially beneficial to professionals who work with athletes, as complex training is often incorporated into the program design. This form of training often involves the performance of a skill related activity post-resistance training bout.

### Tables

#### Table 1
Participant characteristics given in Means ± SD.

#### Table 2
Watts Produced by Treatment and Attempt given in Means ± SD.

### References

1. Anderson, C.E., Sforza, G.A., Sigg, J.A. (2008) The effects of combining elastic and free weight resistance on strength and power in athletes. Journal of Strength and Conditioning Research, 22(2), 567-574.
2. Bellar, D., Muller, M., Ryan, E.J., Bliss, M.V., Kim, C-H, Ida, K Barkley, J.E., Glickman, E.L. (2011) The Effects of Combined Elastic and Free Weight Tension vs Free Weight Tension on 1 RM Strength in the Bench Press. Journal of Strength and Conditioning Research, 25(2), 459-463.
3. Israetel, M.A., McBride, J.M., Nuzzo, J.L., Skinner, J.W., Dayne, A.M. (2010) Kinetic and kinematic differences between squats performed with and without elastic bands. Journal of Strength and Conditioning Research, 24(1): 190-194.
4. Mannie K. Strike up the band training, the benefits of variable resistance. (2005) Coach Athletic Director, 75, 8-13.
5. Neelly, K., Carter, S.A., Terry, J.G. (2010) A study of the resistive forces provided by elastic supplemental band resistance during the back squat exercise: a case report. Journal of Strength and Conditioning Research, in press. Epub ahead of print retrieved June 20, 2011, from <http://journals.lww.com/nscajscr/Abstract/2010/01001/A_Study_Of_The_Resistive_Forces_Provided_By.119.aspx>
6. Page, P., & Ellenbecker, T. S. (2005). Strength Band Training. In Strength Training with Elastic Resistance [Excerpt]. Retrieved from Farnsworth Group website: <http://www.champaign411.com/sports_fitness/excerpts/strength_training_with_elastic_resistance>
7. Shoepe, T.C., Ramirez, D.A., Almstedt, H.C. (2010) Elastic band prediction equations for combined free-weight and elastic band bench presses and squats. Journal of Strength and Conditioning Research, 24(1), 195-200.
8. Simmons, L. (2007, March 5). Advanced programs for beginners. In Elite Fitness Systems [Article]. Retrieved March 22, 2011, from Elite Fitness Systems website: <http://totalphysiqueonline.com/2007/03/05/advanced-program-for-beginners/>
9. Simmons, L. (2009, July 15). Training athletes vs. full meet powerlifters [Web log post]. Retrieved from <http://www.wannabebig.com/training/powerlifting-and-functional-strength-for-athletics/q-a-with-westside-barbells-louie-simmons/>
10. Stevenson, M. W., Warpeha, J. M., Dietz, C. C., Giveans, R. M., & Erdman, A. G. (2010). Acute effects of elastic bands during the free-weight barbell squat exercise on velocity, power, and force production. Journal of Strength and Conditioning Research, 24(11), 2944-54.
11. Treiber, F. A., Lott, J., Duncan, J., Slavens, G., & Davis, H. (1998, July). Effects of theraband and lightweight dumbbell training on shoulder rotation torque and serve performance in college tennis players. Am J Sports Med, 26(4), 510-15.
12. Wallace, B.J., Winchester, J.B., McGuigan, M.R. (2006) Effects of elastic bands on force and power characteristics during the back squat exercise. J. Strength Cond. Res., 20(2), 268-27.
13. Woodrup, J. (2008). Band Training for Explosive Vertical Gains. In Vertical jumping [Article]. Retrieved March 22, 2011, from Vertical Jumping website: <http://www.verticaljumping.com/band_training.html>

### Corresponding Author

David Bellar
225 Cajundome Blvd
Department of Kinesiology
University of Louisiana Lafayette
<dmb1527@louisiana.edu>

### Author Bios

#### Sara Prejean

Sarah Prejean is an undergraduate student studying exercise science in the department of kinesiology at the University of Louisiana at Lafayette

#### Lawrence Judge

Lawrence Judge is an associate professor and coordinator of the graduate coaching program at Ball State University. Dr. Judge has a long-established background in coaching track and field athletes and an extensive research background in coaching behavior, moral issues, and competitiveness versus participation in athletics, specifically in youth sports.

#### Tiffany Patrick

Tiffany Patrick is an undergraduate student studying exercise science in the department of kinesiology at the University of Louisiana at Lafayette

#### David Bellar

David Bellar is an assistant professor and director of the human performance lab in the department of kinesiology at the University of Louisiana at Lafayette. Dr. Bellar has a background in coaching track and field athletes, and researching performance attributes within this population.

NBA Gambling Inefficiencies: A Second Look

U.S. Sports Academy2013-11-22T22:55:25-06:00January 4th, 2012|Contemporary Sports Issues, Sports Studies and Sports Psychology|

### Abstract

Our study used the log likelihood ratio methodology proposed by Even and Noble (2) to test the market efficiency of both point spread betting and totals betting for consecutive National Basketball Association (NBA) seasons from 2000–01 to 2007–08. It was motivated by recent contradictory evidence that both support and reject opportunities to exploit inefficiencies in NBA gambling by Paul and Weinbach (9, 11) as well as other evidence suggesting that these opportunities fade as the market responds to new information (12).

Based on the results of over 10,000 games in eight consecutive NBA seasons, betting the over on the total points per game is a fair bet, indicating an efficient market. For the higher totals (totals 211-220), the winning percentage on betting the over was above 52.38% (the percentage necessary to cover commissions) in eight of 10 cases, but the null hypothesis of a fair bet could not be rejected. The results for point spread betting also showed strong support for an efficient market in NBA gambling, with one exception: betting the home underdog was profitable for underdogs of 10 points or more. However, this was only true for a very small sub-sample and the inefficiency fades in the most recent sample period.

The few cases of big home underdogs beating the spread are consistent with the model of spread betting where bookmakers exploit the uninformed investor’s home favorite bias, shade the point-spread and maximize profits by betting on the underdog (7,6). Informed bettors may also bet the underdog but will not drive the point spread to the true value but only to the point where the probability of winning is no more than 52.38% (11). While bookmaker’s point shading activity is constrained by the action of informed bettors, the persistence of profit opportunities in a very small sub-sample can be explained by betting market constraints such as low limits on bets and the relative volume of bets placed by informed and uninformed bettors (9).

**Key Words:** point spreads, totals, National Basketball Association, NBA, gambling

### Introduction

Studies of market efficiency in sport betting are similar to those in the financial markets for good reason. Both markets involve many market participants and large sums of money, both involve informed and uninformed traders, market frictions, asymmetric information, and, as the weight of the evidence shows, both are heavily influenced by market psychology. In both markets, however, claims of abnormal returns and profitable strategies always raise a red flag. Like the anomalies literature in financial markets, claims of exploitable inefficiencies must be validated with out-of-sample tests to confirm that these inefficiencies are not confined to specific periods, or are driven by a few outliers in the data, or are simply artifacts of extensive data mining. Sport betting provides a unique test for market efficiency since the payoffs are known with certainty in advance of the outcome and the final outcome is determined when the game is played. This is not the case with equity investing (1).

The market for sports betting consists of a market maker, called a bookmaker or sports book, and a bettor. The bookmaker establishes the lines at which betting commences and then moves the line as bets are wagered on both sides of the line. Bettors typically pay the bookmaker $11 to win $10, providing the bookmaker a commission profit if money on both sides of the bet are balanced. Because of this commission, commonly called the “vig” or “juice”, bettors must win 52.38% of their bets to break even. A winning percentage greater than 52.38% insures a profit for the bettor. Recent evidence using data on dollars wagered has rejected the claim that bookmakers strive to balance the dollar on both sides of a wager and lends support to the argument that bookmakers attempt to set the line to accurately reflect actual game outcomes (6,7,11).

In the sports gambling world, an over/under or totals wager is a bet that is won or lost depending upon the combined score of both teams in a game. A bookmaker will predict the combined score of the two teams and bettors will bet that the actual number of points scored in the game will be higher or lower than that combined score. For example, in an NBA game of the Miami Heat versus the San Antonio Spurs the over/under for the score of the game was set at 195. A bet on the under wins the wager if the combined score at the end of the game is 194. If the combined score is 196 or more, then the over bet wins. If the combined score equals 195, then it is a tie and the bettor’s money is returned.

### Data And Methodology

This study was designed to test for the presence of exploitable inefficiencies in NBA sport gambling. Recent research in NBA gambling has produced evidence of over betting the over in totals betting, and over betting the favorite by uninformed bettors in point spread betting. The research also claims that there are profitable opportunities in betting the big underdog. This study tests those claims by examining both totals betting and point spread betting using updated data.

The data for studying the totals and point spread markets for National Basketball Association games was taken from the Gold Sheet, a well-known handicapping company, for eight NBA seasons 2000-01 through 2007-08. The data included all games from these years, both regular season and playoffs, except for games where totals or point spreads were not posted. Table 1 shows the summary statistics for the 10,325 games included in the sample. Five of the games had no line posted for the over/under and 175 games were ties. The average or mean actual total score for our sample of NBA games was 192.72 points and the average or mean over/under total for the sample was 192.27 total points per game.

The log likelihood ratio methodology proposed by Even and Noble (2) was used to test for market efficiency for the over/under betting market in the NBA. From the perspective of the over bettor, the value of the unrestricted log likelihood function (Lu) takes the form

> Lu = n[ln(q)] + (N – n)ln(1 – q) (1)

where N is the total number of NBA games where the over bettor or under bettor won the bet. The n is the number of games where the over covers the bet, and q is the proportion of games where the over covers the bet. If the betting market is efficient and a fair bet, then q = 0.5.

This creates the restricted log likelihood function (Lr), which was obtained by substituting 0.5 for q in Equation 2. The log likelihood ratio statistic for the null hypothesis that q = 0.5 is

> 2(Lu – Lr) = 2{n[ln(q) – ln(0.5)] + (N – n)[ln(1 – q) – ln(0.5)]} (2)

where q is the actual percentage of overs winning the over/under bet from our sample. To test for profitability, where the bettor must win enough to offset the commission or vigorish of the bookmaker, the test ratio changes into

> 2(Lu – Lr ) = 2{n[ln(q) – ln(0.524)] + (N – n)[ln(1 – q) – ln(0.476)]}. (3)

### Results And Discussion

#### Totals Betting

In a 2004 study, covering the seven NBA seasons from 1995-96 through 2001-2002, Paul et al.(8) found that, for all games, a bet on the underdog won about 50% of the time, as is expected in an efficient market. However, for the high scoring games (games above 200), they found a pattern of over betting the over, and this pattern increased as game totals increased. For every one point increase from 200 to 210, the winning percentage of the under bet was greater than 50%. In eight of those totals the winning percentage was greater than 52.38%, enough to cover the vigorish, and in five of those totals, the null hypothesis of a fair bet was rejected. However, none of the totals in their study produced a result that rejected the null of no profitability when accounting for commissions. Taking the contrarian bet, and betting against market sentiment, was not profitable. In a later study, using data on actual dollar amounts wagered, Paul and Weinbach (11) found that overs received a much higher percentage of bets compared to unders, but here again it was shown that informed bettors pushed the total to where it was not profitable to bet the under.

The results found the opposite of the 2004 study (8) for the high scoring games. For all games in the eight seasons from 2000-01 through 2007-08, a bet on the underdog still won about 50% of the time. However, a bet on the over won more often than a bet on the under for high scoring games. The game results, and the log likelihood test of efficiency, are reported in Table 2. For game totals between 200 and 210, the winning percentage of the over bets hover right around 50%, indicating an efficient market. When we extended the testing to higher totals (211-220) the percentage of over winners was more than the commission breakeven point (52.38%) for eight of the 10 totals. However, in no instance was the log likelihood ratio large enough to reject the null hypothesis of a fair bet.

Point Spread Betting and Betting the Underdog

When an NBA gambler bets the point spread of an NBA game he is not interested in who wins the game, only the final score. For example, if the point spread for a National Basketball Association game reads

> Heat -4 Pacers +4

The (-) before the 4 indicates that the Heat is the point spread favorite. The (+) indicates that the Pacers are the point spread underdog. If one bets on the Heat, the Heat would have to win by a total of five points for the bettor to win. If one bets on the Pacers, the Pacers would have to win outright or lose by no more than three points for the bettor to win. A four point victory by the Heat (four point loss by the Pacers) would equal a tie and the money bet by the NBA gambler is returned to him.

Prior evidence suggests that there are systemic bettor misperceptions in the NBA point spread gambling market. In a 2005 study Paul and Weinbach (9) presented evidence from the 1995-96 through 2001-2002 seasons that favorites are over bet by uninformed bettors. In that study, a strategy of betting big underdogs rejected the null hypothesis of a fair bet, and betting big home underdogs not only rejected a fair bet was also profitable. Levitt (7) provides us with a model where bookmakers do not attempt to balance the dollars wagered, but rather they shade the point spread to exploit uninformed bettor bias and then take positions on the opposite side, betting the big underdog. Informed bettors may attempt to exploit this inefficiency by also betting the big underdog but will only bet to the point where it is profitable to do so, meaning that they may bet on the underdog and push the point spread only to where there is no less than 52.38% chance of winning the bet. Other studies (6, 11), using data on actual dollars wagered, have found that a majority of dollars are wagered on the stronger or favorite team by uninformed bettors.

This study examined the NBA betting market on point spreads for the seasons 2000-01 through 2007-08 to see if this underdog anomaly persists. It used the closing line on point spreads for NBA games for the same seasons that we examined in the over/under analysis performed in the previous section of the paper. For the market to be efficient the actions of the informed bettors should offset any bias shown by uninformed bettors and the bookmakers closing line should equal the actual game score outcome. Recent studies have shown that the betting public removes biases in sport book’s opening lines in NBA betting by game time (3-5).

Table 3 is a summary of the data for point-spread betting. The sample contained 10,325 games with five of the games posting no closing line to bet on and 90 games posting a closing line of zero. This is called a push and these games were not included when betting favorites and underdogs. There were 141 ties which indicate that the difference in the score (underdog – favorite) was equal to the closing point spread. The average closing line based on the favorite score minus the underdog score was 5.89 and actual difference in score in the NBA games in the sample was 5.38. For the entire sample of games the underdog won 49.86% of the games, indicating that a strategy of betting the underdog was a fair bet, based on the log likelihood ratio test.

The results in Table 4 indicate that the betting public appears to over bet the heavy favorite by a slight margin, but, unlike the study by Paul and Weinbach (9), we found that the winning percentage of betting the big underdog (10 points or more) hovered around 50% and thus we failed to reject the null hypothesis of a fair bet. The same result occurred for the sub-sample of games for seasons 2000-01 through 2003-04 and for the sub-sample of games for seasons 2004-05 through 2007-08. In all of these cases the null hypothesis of a fair bet could not be rejected.

The results for the small sample of games involving the home underdog of 10 points or more had significant results for both a fair bet and profitability. For the entire sample of games (50 games over the entire seasons) the null hypothesis of a fair bet was rejected at a 10% significance level. For the small sample of games in the earlier sub-period (25 games) we found that a bet on the home underdog also rejected the null hypothesis of no profitability.

### Conclusion

This study found that gambling markets for both point spread betting and totals betting for NBA seasons spanning from 2000–01 to 2007–08 are efficient. Based on the results of over 10,000 games in eight consecutive NBA seasons, betting the over on the total points per game is a fair bet. Although for higher totals (211-220) the winning percentage on betting the over was above 52.38% (the percentage necessary to cover commissions), in eight of 10 cases the null hypothesis of a fair bet could not be rejected. The results for point spread betting also showed strong support for an efficient market in NBA gambling, with one exception: betting the home underdog was profitable for underdogs of 10 points or more. However, this was only true for a very small sub-sample and the inefficiency fades in the most recent sample period.

### Applications In Sports

Many fans enjoy wagering on their favorite sport whether it is NBA basketball or another sport. Gambling can be fun and can enhance the excitement of the game by adding a financial component. The evidence suggests that the average bettor is biased toward high scores and prefers betting on the favorite. However, utilizing this knowledge and betting on the underdog will probably not be a profitable strategy for a fan wagering on NBA games because of the actions of informed (professional) gamblers. The informed gambler will bet on the underdog until it is not profitable for him to do so. This activity drives the point spread to a level where a fan cannot make a profit on an underdog bet after accounting for commission. Therefore, the average gambler should focus on having fun and not count on making a profit when gambling on NBA games.

### Tables

#### Table 1
NBA Seasons 2000-01 Through 2007-08 Summary Statistics for Over/Under Betting for All NBA Games

#### Table 2
Winning Percentages for Betting the Overs

Note. The log likelihood test statistics have a chi-square distribution with one degree of freedom.

Critical values are 2.706 (for an α = 0.10), 3.841 (for an α = 0.05), 6.635 (for an α = 0.01).

* is significant at 10%.

** is significant at 5%.

*** is significant at 1%.

#### Table 3
Closing Line Betting Seasons 2000-01 Through 2007-08

#### Table 4
Betting the NBA Underdog Seasons 2000-01 Through 2007-08

Note. The log likelihood test statistics have a chi-square distribution with one degree of freedom.

Critical values are 2.706 (for an α = 0.10), 3.841 (for an α = 0.05), 6.635 (for an α = 0.01).

* is significant at 10%.

** is significant at 5%.

*** is significant at 1%.

NA – not applicable

### References

1. Brown, W., Sauer, R. (1993). Fundamentals or noise? Evidence from the professional basketball betting market. Journal of Finance, 48, 1193–1209.
2. Evan, W. E., & Noble, N. R. (1992). Testing efficiency in gambling markets. Applied Economics, 24, 85-88.
3. Gandar, J., Zuber, R., O’Brien, T., & Russo, B. (1988). Testing rationality in the point spread betting market. Journal of Finance, 43, 995-1007.
4. Gandar, J., Dare, W., Brown, C., Zuber, R. (1998). Informed traders and price variations in the betting market for professional basketball games. Journal of Finance, 53, 385–401.
5. Gandar, J, Zuber, R. & Lamb, R. (2000). The home field advantage revisited: a search for the bias in other sports betting markets. Journal of Economics and Business, (53) 4, 439-453.
6. Humphreys, B. (2010). Point spread shading and behavioral biases in NBA betting market. Rivista Di Diritto Economia Dello Sport, 13-26.
7. Levitt, S. (2004). Why are gambling markets organized so differently? The Economics Journal, 114, 223-246.
8. Paul, R., Weinbach, A., Wilson, M. (2004). Efficient markets, fair bets, and profitability in NBA totals 1995–1996 to 2001–2002. The Quarterly Review of Economics, 44, 624–632.
9. Paul, R. J. & Weinbach, A. P. (2005). Bettor misperceptions in the NBA, Journal of Sports Economics, (6) 4, 390-400.
10. Paul, R. J. & Weinbach, A. P. (2007). Does Sportsbook.com set pointspreads to maximize profits? Tests of the Levitt model of sportsbook behavior. Journal of Prediction Markets, (1) 3, 209-218.
11. Paul, R. J. & Weinbach, A. P. (2008). Price setting in the NBA gambling market: Tests of the Levitt model of sportsbook behavior. International Journal of Sports Finance, (3) 3, 2-18.
12. Wever, S., & Aadland, D. (2010). Herd Behavior and the Underdogs in the NFL. Applied Economics Letters, (forthcoming).

### Corresponding Author

Kevin Sigler, PhD
601 S. College Road
Cameron School of Business
University of North Carolina-Wilmington
Wilmington, NC 28403
<siglerk@uncw.edu>
910-962-3605

William Compton is Associate Professor of Finance in the Cameron School of Business, UNCW Kevin Sigler is Professor of Finance in the Cameron School of Business, UNCW