Comparison of Four Stretching Protocols on Short-Term Power

Authors: Joni M. Boyd, PhD, CSCS*D; Janet R. Wojcik, PhD; Alice J. McLaine, PhD; Zachary Hartman, MS, ATC; and Malik McGill

Corresponding Author:
Joni M. Boyd, PhD, CSCS*D
216 L West Center
Rock Hill, SC 29732
boydj@winthrop.edu
803-323-4936

Joni M. Boyd is an Associate Professor of Exercise Science & Coaching at Winthrop University.
Janet R. Wojcik is a Professor and Coordinator of Exercise Science at Winthrop University.
Alice J. McLaine is an Assistant Professor and Coordinator of Athletic Training at Winthrop University.
Zachary Hartman is an athletic trainer in Rock Hill, SC.
Malik McGill is a physical therapy student in Charleston, SC.

Comparison of Four Stretching Protocols on Short-Term Power

ABSTRACT

The purpose of the study was to compare different stretching protocols on vertical jump and long jump. Participants included 22 females and 16 males that completed four different stretching protocols in a randomized, cross-over treatment design. Protocols were performed on separate days, with at least 48 hours of rest in between. Each session began with a 5-minute self-paced jog, followed by one of the four stretching protocols: static-only stretch, dynamic-only stretch, ballistic-only stretch, and dynamic-plus-ballistic stretch. Each stretching protocol lasted for about five minutes. Either participants performed a vertical jump or long jump directly after finishing the stretching protocol, then switched testing conditions. There were no significant differences in vertical jump or long jump performance across the four conditions. Consequently, this study did not support previous research showing performance improvement after dynamic stretching.

Key Words:  Flexibility, Warm-up, dynamic, static, ballistic, vertical jump, long jump

INSTRODUCTION

Stretching before activity is routine for almost all who participate. The leading sport and fitness organizations recommend a warm-up that consists of a low intensity walk or jog, which breaks a sweat before completing stretching (1). For stretching, they recommend a static stretch and dynamic stretch, with static stretching being done for a 15-30 second count. The aim of warm-up and stretching is to increase flexibility through the increased elasticity of the muscle (1), and increase range of motion around a joint. There is support for an increase in joint range of motion to be an integral component of power-based moves in sport (12).

While benefits of performing a warm-up are accepted throughout the community, there is still debate on the type that aids in maximizing vertical jump and long jump performances. The large portion of research that compare static and dynamic stretching show dynamic stretching improves vertical jump and long jump performances more than static stretching (8). While dynamic stretching is considered more beneficial than static stretching, few studies look at how dynamic stretching tends to include both dynamic and ballistic stretching. Almost all of the studies found included both types of stretches. This brings up the question of do ballistic-only stretches or dynamic-only stretches influence the performance improvement that so many studies have found. Both stretching techniques increase the fast twitch response time in muscular power. Due to ballistic and dynamic stretching utilizing this response, having mixed stretches in one dynamic protocol clouds the results that state dynamic is better than ballistic. The thin amount of literature on ballistic-only stretching research is conflicting on its findings. Woolstenhulme et al (24) found improvements in ballistic stretching in basketball activity. The participants showed improvements after a six-week stretching program, only when coupled with basketball activity and ballistic stretching. A conflicting study by Bradley et al. (4) showed only little improvement in jumping height after ballistic stretching. The interesting finding in this study was that after 15 minutes, the jump heights went back to the baseline heights.

To test vertical jump, many different ways were done. The most popular was a force platform, allowing them to time how long the participants were in the air, and calculate how high the jump was (2-5, 8, 9, 11, 14-17, 19, 22, 23). The vertec was another reliable method, using the vertec apparatus (Hilliard, OH). The heights of jumps are measured every half inch slats (6, 7, 20, 21). For standing long jump, measuring tapes, tend to be used often. They allow the participants to complete a CMJ before jumping as far as possible. Before any stretching technique can be named “best” to prepare participants before activity, more research needs to be done comparing dynamic-only stretching to ballistic-only stretching. More consistent findings are needed either negative or positive.

METHODS AND PROCEDURES

Participants & Recruitment

Participants included 38 healthy college students, aged 18 – 25 (females = 22; males =16). Participants were volunteers recruited from exercise science classes at a Division I university in Southeastern United States. Participants signed an informed consent and were screened prior to participation, and the study was approved by the Institutional Review Board (IRB). Screening tools included a Physical Activity Readiness Questionnaire (PAR-Q) and four items that asked about recent injuries.

Inclusionary criteria for this study consisted of the following:

1. Participants who were at least 18 years old.
2. Participants who were enrolled in exercise science activity class at the university during fall 2016.
3. Participants who were free from pregnancy, disease, or injury.
4. Participants with a Body Mass Index (BMI) lower than 30.

Exclusionary criteria for this study consisted of the following:

1. Participants who were under 18 years of age.
2. Participants who were not enrolled at the university during fall 2016.
3. Participants who were pregnant had diagnosed cardiac or pulmonary disease or diabetes, or had a recent lower body injury.
4. Participant with a BMI greater than 30 kg/m².

Research Design

The research was an experimental study using a randomized cross-over treatment design. The subjects were randomly assigned to one of four protocols: static-only stretching (control), dynamic-only stretching, ballistic-only stretching, and dynamic-plus-ballistic stretching protocols. Data collection occurred on four days over a three-week period from November to December 2016. Each group was randomly assigned to a different treatment protocol for each testing day. Independent variables for this study were the type of flexibility protocol implemented during the warm-up period. The dependent variables were the scores for the vertical jump and standing long jump assessments, both of which are a measure of high-speed power.

Procedures

Once participants consented and were approved for the study, they completed a five-minute jog (self-paced) and were randomized to flexibility protocol. Each flexibility protocol was completed in about 10 minutes, and the type of activities performed in each group are listed in Tables 1 – 4. Two groups went at one time. Facilitation of the groups was performed by two members of the research team, both of which are certified and qualified to teach flexibility protocols. This helped ensure conformity and consistency across the groups, as each protocol was performed identical across all four groups. Once a group completed the assigned flexibility protocol, they were directed to either the vertical jump assessment station or the standing long jump assessment station.

Table 1. Static-only Protocol

Static Stretches	Description	Time Held / Reps
Quadriceps stretch	In the standing position bend one knee and bring the heel to the buttocks then grab and hold the heel with the same side hand.	30 seconds / 2
Hip Flexor and Calf stretch	In the standing position participant puts left leg out while lunging towards the left leg, while attempting to push heel towards the ground. Then switch.	30 seconds / 2
Hamstring stretch	In a seated position participant, have both legs out in front, and the participant leans forward towards their toes while keeping their back straight.	30 seconds / 2
Figure four stretch	In a supine position, bring the left ankle over the right knee, participant, and then pulls the right knee up towards the right shoulder while bringing the left knee to the left shoulder. Repeat on the opposite side.	30 seconds / 2
Adductor stretch	While seated the participant brings the bottom of their feet together and pushes their knees outward towards the ground.	30 seconds / 2

Table 2. Dynamic-only Protocol

Dynamic Stretches	Description	Distance/Reps
Knee Hug	While walking forward bring knee to chest and pull knee towards chest with hands, and each step alternate	Half a basketball Court/ 1
Walking quad pull	While walking forward, participant pulls leg towards, and then alternates legs.	Half a basketball Court/ 1
Toe touch kicks	Participant walks forward kicking leg straight out and up until it hits their hands that are out straight. Repeat on opposite leg.	Half a basketball Court/ 1
Walking lunge	Participants moved forward while going into a lunge position, then returning to starting position and using opposite leg	Half a basketball Court/ 1

Table 3. Ballistic-only Protocol

Ballistic stretches	Description	Distance/Reps
Butt kick	Heel ups. Rapidly kick heels towards buttocks while moving forward	Half a basketball Court/ 1
Carioca	Participant moves laterally while crossing feet in front of each other. Repeat in opposite direction	Half a basketball Court/ 1
High knee run	While jogging forward bring knee to chest, and each step alternate	Half a basketball Court/ 1
Power Skip	Leading with your right leg, skip as high as you possibly can by raising your right knee to hip height and simultaneously extending your left arm straight overhead	Half a basketball Court/ 1

Table 4. Combination Protocol

Combination Stretch	Description	Distance/Reps
Knee Hug	While walking forward bring knee to chest and pull knee towards chest with hands, and each step alternate	Half a basketball Court/ 1
Walking Quad Pulls	While walking forward, participant pulls leg towards, and then alternates legs.	Half a basketball Court/ 1
Walking Lunge	Participants moved forward while going into a lunge position, then returning to starting position and using opposite leg	Half a basketball Court/ 1
Toe Touch Kicking	Participant walks forward kicking leg straight out and up until it hits their hands that are out straight. Repeat on opposite leg.	Half a basketball Court/ 1
Butt kick	Heel ups. Rapidly kick heels towards buttocks while moving forward	Half a basketball Court/ 1
Carioca	Participant moves laterally while crossing feet in front of each other. Repeat in opposite direction	Half a basketball Court/ 1
High knee run	While jogging forward bring knee to chest, and each step alternate	Half a basketball Court/ 1
Power Skip	Leading with your right leg, skip as high as you possibly can by raising your right knee to hip height and simultaneously extending your left arm straight overhead	Half a basketball Court/ 1

INSTRUMENTATION

Vertical jump height was measured with the Vertec apparatus (Hilliard, OH). The reach height for the Vertec apparatus was found by having the participant stand erect, with both feet together and arms above their head, reaching as high as possible. Participants then performed a counter movement jump by flexing the hips and knees, to a depth of their preference. Once at the depth, they extended their knees, hips and plantar flexed their ankles explosively to generate the most power, and gain the highest jump possible. During the concentric jump, the participant would reach up to hit the colored strips (4). The participants continued to jump, until they missed on two consecutive jumps. Vertical jump height was recorded to the nearest half inch.

Standing long jump was measured with a tape measure adhered to the ground. Participants began the test standing just behind the 0 on the measuring tape, and performed a counter movement jump with both legs shoulder with apart and feet parallel. Only trials where the participant landed on both feet without additional movement were used. The length of the jump was measured from the back of the rearmost heel to the nearest inch (6). The participants completed 3 trials, and the highest score was recorded.

ANALYSIS

The vertical jump and long jump measurements were evaluated using the Statistical Package for the Social Sciences (SPSS) Program (IBM Corporation, Armonk, NY). Descriptive statistics of height of jump, length of jump, and specific stretching protocol were used to evaluate measurements completed by participants. Repeated measures analysis of variance (ANOVA) was used to evaluate the vertical and long jump heights for each subject.

RESULTS

The study initially began with 55 participants, 17 of which did not attend enough scheduled testing sessions to be considered for the study. The sample of 38 participants included 22 females and 16 males. Table 5 provides demographic information.

Table 5. Descriptive Statistics

	Mean	SD	N
LJ Static	76.342	1.58818	38
LJ Dynamic	77.500	1.56771	38
LJ Ballistic	77.32	1.5724	38
LJ Combination	78.42	1.5629	38
Vertical Jump Static	22.329	5.0273	38
VJ Dynamic	22.17	4.311	38
VJ Ballistic	22.12	5.212	38
VJ Combination	22.12	5.155	38

Vertical Jump

Table 6 represents the repeated measures ANOVA performed while comparing the vertical jump heights of static-only stretch, dynamic-only stretch, ballistic-only stretch, and combination of dynamic and ballistic stretch against each other. There were no violations of sphericity in the repeated measures test (χ ² = 7.138, p =.211); therefore, no corrections to the degrees of freedom were made. For vertical jump, there were no significant difference found for any of the stretching protocols either by time (F_(3,102)  = .310, p = .818) or group by time interaction (F _(3,9), = 1.00, p = .438) . The results that were found did not support the hypothesis that the dynamic-plus-ballistic stretching protocol would show higher vertical jump height over the other conditions.

Table 6. Tests of Within-Subjects Effects Vertical Jump

	Source	Type III Sum of Squares	df	Mean Square	F	Sig.
tests	Sphericity Assumed	1.625	3	.542	.310	.818
	Greenhouse-Geisser	1.625	2.595	.626	.310	.789
	Huynh-Feldt	1.625	3.000	.542	.310	.818
	Lower-bound	1.625	1.000	1.625	.310	.582
tests * Group	Sphericity Assumed	15.879	9	1.764	1.009	.438
	Greenhouse-Geisser	15.879	7.785	2.040	1.009	.434
	Huynh-Feldt	15.879	9.000	1.764	1.009	.438
	Lower-bound	15.879	3.000	5.293	1.009	.401
Error(tests)	Sphericity Assumed	178.365	102	1.749
	Greenhouse-Geisser	178.365	88.233	2.022
	Huynh-Feldt	178.365	102.000	1.749
	Lower-bound	178.365	34.000	5.246

Long Jump

Table 7 shows the repeated measures ANOVA, which compared long jump distance for four different conditions. The conditions compared were static-only stretch, dynamic-only stretch, ballistic-only stretch, and combination of dynamic and ballistic stretch. There were violations of sphericity in the repeated measures test (χ ² = 31.19, p <.001); therefore, corrections to the degrees of freedom were made using the Greenhouse-Geisser ε = 1.300. For long jump, there were no significant difference found for any of the stretching protocols either by time (F_(1.3,45)  = 1.252, p = .291) or group by time interaction (F _(1.3,3.9), = 1.002, p = .429). The results that were found did not support the hypothesis that the dynamic-plus-ballistic stretching protocol would show higher long jump scores over the other conditions.

Table 7. Tests of Within-Subjects Effects Long Jump

	Source	Type III Sum of Squares	df	Mean Square	F	Sig.
tests	Sphericity Assumed	194.509	3	64.836	1.252	.302
	Greenhouse-Geisser	194.509	1.300	149.607	1.252	.291
	Huynh-Feldt	194.509	1.657	117.376	1.252	.297
	Lower-bound	194.509	1.000	194.509	1.252	.281
tests * Group	Sphericity Assumed	466.889	9	51.877	1.002	.453
	Greenhouse-Geisser	466.889	3.900	119.703	1.002	.429
	Huynh-Feldt	466.889	4.971	93.915	1.002	.437
	Lower-bound	466.889	3.000	155.630	1.002	.419
Error(tests)	Sphericity Assumed	2330.558	45	51.790
	Greenhouse-Geisser	2330.558	19.502	119.503
	Huynh-Feldt	2330.558	24.857	93.758
	Lower-bound	2330.558	15.000	155.371

DISCUSSION

The purpose of this study was to determine if a specific stretching protocol had a greater effect on short-term power in active college aged students. This study aimed to assist coaches make more informed decisions on the stretching protocol to use in the warm-up. With almost all sports and activities, stretching should be performed before participation, in hopes that it will increase the level of performance by the participant (5). Through much of the research on stretching, dynamic and static stretching protocols are most often studied, and most conclude that dynamic stretching is more beneficial for the production of short-term power. The concern with the previous literature is the activities that many researchers are using in the “dynamic” protocol are ballistic movements. Faigenbaum et al. (8) suggests that one-way that dynamic has an improved performance in majority of research is due to post activation potential. This occurs when moderate to high intensity stretches are completed leading to an environment suitable for force production. By increasing the fast twitch response to power activity, an exercise that requires large amount of power fast could benefit from the potential to improve performance. This would also be true for ballistic movements, thus providing the rationale for our purpose and hypothesis.

From the results, it was found no difference in vertical jump or long jump scores across the four stretching protocols (static-only, dynamic-only, ballistic-only, and dynamic-plus-ballistic). Previous literature has shown increase in short term power in dynamic stretching protocols when compared to static stretching protocols, and in a combination of dynamic and ballistic stretches (1, 2 ,3, 5, 6, 11, 12, 15, 19, 20, 21, 23). Other research by Paradisis et al. (16) and Turki-Belkhira et al. (22) supported this study’s findings when they found that dynamic stretching had no improvement over static stretching when compared to vertical and long jump. The data collected on long jump in the current study, also, did not support previous research that showed long jump improving with dynamic stretching and decreasing with static stretching (6).

It is possible that our participants experienced a learning effect on their jumping. The effect was minimized due to practice jumps, but participants may have become more comfortable with the test the more sessions they attended. It is possible other confounders affected our data collection. Participants were exercise science students from a particular class, and even in smaller groups, there was a wait period for participants to complete the vertical jump assessment. Additionally, it is possible that allowing the participants multiple jumps for each test created an additional “warm-up” effect. This effect could have been minimized by allowing the participant no more than two jumps for each test, with the highest score recorded. This would also be more generalizable, as game-like or activity conditions may not allow for repeated attempts at muscular power production. There was a high percentage of attrition of those that started the study (n=55) but did not complete all four protocols (n = 17; 32%).

Limitations of this study included the attrition of participants across the protocols, effort put forth by participants during each test, inability to blind participants to which group they belonged. We did not control for sleep, nutrition, or other exercise protocols that may have affected the outcome of the study. We did not control for footwear or attire, although all participants completed protocol in athletic shoes and moveable clothing. Finally, participants were healthy college students, not athletes. This limits the ability to generalize our findings to the athletic population.

Strengths of the study include the sample size and the cross-over treatment design. Most research on stretching protocols have used sample sizes of 10 – 30 participants. The robust sample of 38 shows to be a strength of the current study. Additionally, because there was a randomized, cross-over design, can be confident there was no unexplained differences between groups. The use of healthy college males and females allows generalization to generalize to the entire general population.

CONCLUSION

The results of this study suggest that static-only stretching, dynamic-only stretching, ballistic-only stretching, and combination of ballistic and dynamic stretching will not improve vertical jump heights or long jump distance for participants. These findings are similar to the studies by Paradisis et al. (16) and Turki-Belkhira et al. (22). This study’s findings suggest that participants can complete any of the four stretching protocols in their warm-up. Future research should continue to compare all protocols, specifying differences in static-only, dynamic-only, and ballistic-only stretching. Additionally, PNF stretching and plyometric jumps within the ballistic protocol would enhance future understanding.

REFERENCES

1. American College of Sports Medicine (2013). Guidelines for Exercise Testing and Prescription. LWW.
2. Behm, D., Plewe, S., Grage, P., Rabbani, A., Taghi Beigi, H., Byrne, J.M. & Button, D.C. (2011). Realistic static stretch-induced impairments and dynamic stretch-induced enhancements are similar in young and middle-aged men. Applied Physiology, Nutrition, and Metabolism, 36(6), 790-798.
3. Bishop, D. & Middleton, G. (2013). Effects of static stretching following a dynamic warm-up on speed, agility and power. Journal of Human Sport and Exercise, 8(2), 391-400. DOI: 10.4100/jhse.2012.82.07
4. Bradley, P.S., Olsen, P.D. & Portas, M.D. (2007). The effect of static, ballistic, and proprioceptive neuromuscular facilitation stretching on vertical jump performance. Journal of Strength and Conditioning Research, 21(1), 223-226.
5. Carvalho, F.L.P., Carvalho, M.C.G.A., Simao, R., Gomes, T.M., Costa, P.B., Neto, L.B., Carvalho, R.L.P. & Dantas, E.H.M. (2012). Acute effects of a warm-up including active, passive, and dynamic stretching on vertical jump performance. Journal of Strength and Conditioning Research, 26(9), 2447-2453.
6. Ertugrul, G. (2011). Acute effects of different warm-up methods on jump performance in children. Biology of Sport, 28(2), 133-139.
7. Faigenbaum, A.D., Bellucci, M., Bernieri, A., Bakker, B. & Hoorens, K. (2005). Acute effects of different warm-up protocols on fitness performance in children. Journal of Strength and Conditioning Research, 19(2), 376-382.
8. Faigenbaum, A., Kang, J., McFarland, J., Bloom, J.M., Magnatta, J., Ratamess, N.A. & Hoffman, J. (2006). Acute effects of different warm-up protocols on anaerobic performance in teenage athletes. Pediatric Exercise Science, 18(1), 64-78.
9. Fortier, J., Lattier, G., & Babault, N. (2013). Acute effect of short-duration isolated static stretching or combined with dynamic exercises on strength, jump and sprint performance. Science & Sports, 28(5), 111-117.
10. Haff G. & Triplett T. (2015). Essentials of Strength Training and Conditioning. Human Kinetics.
11. Hough, P.A., Ross, E.Z. & Howatson, G. (2009). Effects of dynamic and static stretching on vertical jump performance and electromyographic activity Journal of Strength and Conditioning Research, 23(2), 507-513.
12. McMillian, D.J., Moore, J.H., Hatler, B.S. & Taylor, D.C. (2006). Dynamic vs. static-stretching warm up: the effect on power and agility performance. Journal of Strength and Conditioning Research, 20(3), 492-500.
13. McNeal, J.R. & Sands, W.R. (2003). Acute static stretching reduces lower extremity power in trained children. Pediatric Exercise Science, 15(2), 139-146.
14. Morrin, N., & Redding, E. (2013). Acute effects of warm-up stretch protocols on balance, vertical jump height, and range of motion in dancers. Journal of Dance Medicine and Science, 17(1), 34-41.
15. Pagaduan, J.C., Pojskic, H., Uzicanin, E., & Babajic, F. (2012). Effect of various warm-up protocols on jump performance in college football players. Journal of Human Kinetics, 35(0), 127- 133.
16. Paradisis, G.P., Pappas, P.T., Theodorou, A.S., Zacharogiannis, E.G., Skordilis, E.K. & Smirniotou, A.S. (2014) Effects of static and dynamic stretching on sprint and jump performance in boys and girls. Journal of Strength and Conditioning Research, 28(1) 154-161.
17. Power, K., Behm, D., Cahill, F., Carroll, M., & Young, W. (2004). An acute bout of static stretching: effects on force and jumping performance. Medicine and Science in Sports Exercise, 36(8), 1389-1396.
18. Prentice, W. E. (2013). Principles of Athletic Training: A Competency-Based Approach. New York, NY: McGraw-Hill.
19. Ryan, E.D, Everett, K.L., Smith, D.B., Pollner, C., Thompson, B.J., Sobolewsk, E.J., & Fiddler, R.E. (2014). Acute effects of different volumes of dynamic stretching on vertical jump performance, flexibility and muscular endurance. Clinical Physiology and Functional Imaging, 34(6), 485-491.
20. Sudhakar, S., & Padmasheela, V. (2012). To investigate the effects of different warm-up protocols in vertical jump performance in male collegiate volleyball players. International Journal of Sports Sciences & Fitness, 2(1), 142-154.
21. Taylor, K.L., Sheppard, J.M., Lee, H., & Plummer, N. (2009). Negative effect of static stretching restored when combined with a sport specific warm-up component. Journal of Science and Medicine in Sport, 12(6), 657-662.
22. Turki-Belkhiria, L., Chaouachi, A., Turki, O., Chtourou, H., Chtara, M., Chamari, K., Amri, M., & Behm, D.G. (2014). Eight weeks of dynamic stretching during warm-ups improves jump power but not repeated or single sprint performance. European Journal of Sport Science, 14(1), 19-28.
23. Vanderka, M. (2011). The acute effects of stretching on explosive power. Acta Facultatis Educationis Physicae Universitatis Comenianae, 51(2), 23-35.
24. Woolstenhulme, M.T., Griffiths, C.M., Woolstenhulme, E.M. & Parcell, A.C. (2006). Ballistic stretching increases flexibility and acute vertical jump height when combined with basketball activity. Journal of Strength and Conditioning Research, 20(4), 799-803.