Effect of a 6 week Depth Jump Training Program on Agility and Vertical Jump in Varsity Female Athletes

Introduction

Methods

References

DiscussionPurpose

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Plyometric training is used in athletic training programs to increase power output (Fatourors et al, 2000). Power is defined as the amount of work a muscle can produce per unit of time (Adams. O’Shea, O’Shea & Climstein 1992). Plyometric exercises are characterized by a rapid eccentric muscle action followed immediately by a concentric muscle action (Miller, Herniman, Ricard, Cheatham & Micheal, 2006). By repeatedly performing these muscle actions, individuals are able to increase their power by increasing the amount of work (force output) the muscle can produce and decreasing the time to create the force. An example of plyometric exercises is the depth jump (Luebbers et al, 2006; Asadi, 2012). Depth jumps involve the individual stepping from a height and upon landing flexing at the ankles, knees and hips and immediately performing a maximal jump, including a coordinated arm swing.

An increase in power from plyometric exercises may also increase their agility. Agility is defined as an ability to maintain and control correct body position while quickly changing direction (Yap & Brown, 2000). Agility is prevalent in sports such as hockey and soccer where athletes are consistently stopping, starting and changing directions. During a change in direction, an individual will plant their foot, and then push off in a different direction, requiring a high force output (Young, James & Montgomery, 2002). If one’s power is increased through plyometrics, it is possible this will increase their ability to change directions and control their body movements.

Participants: 20 St Francis Xavier Female Varsity soccer and hockey athletes participated in this study. Participants, within their sports, were randomly divided into either an experimental or control group.

Instrumentation: Agility was determined using the Illinois Agility Test (Figure 1) and T-Test (Figure 2). Timing was recorded using Brower Timing System’s infrared timing sensors to ensure accuracy. Agility was judged using time to completion of the agility drill, with the smaller the score, the more agile the individual was deemed. Vertical jump height was measured using a force plate: PasPort 2-Axis Force Platform Model PS, No 2142.

Procedure: All participants completed 2 sessions of testing: pre and post testing. During testing, participants completed 2 trials of each test with the quickest and highest jumps being analyzed. The experimental group underwent the 6-week depth jump training protocol. Depth jumps were performed off a 40 cm box, and subjects were instructed to minimize contact time while maximizing their vertical jump. The first week consisted of 2 sets of 8 repetitions for familiarization with the exercise. The next 5 weeks consisted of 3 sets of 10 repetitions. Between each jump, subjects had an 15 second rest, followed by a 3 minute rest between sets to ensure adequate recovery of the muscles. The investigators were present at each training and testing session to ensure the athletes were had proper form and were completing the training.

Figure 1:Illinois Agility Test Protocol

Sadie Whaley, Jeff Vossen & Dr. Angie Kolen Department of Human Kinetics

The purpose of this study was to determine if a 6-week depth jump training program would increase agility and vertical jump performance in varsity female athletes.

Results

Table 1. Vertical Jump Height Results of Pre and Post Testing in the Experimental and Control Group

Figure 2: T-Test Agility Results of Average Pre and Post testing in the Experimental and Control

Group* Experienced a significant improvement

Adams, K., O'Shea, J., O'Shea, K., & Climstein, M. (1992). The effect of six weeks of squat, plyometric and squat-plyometric training on power production. The Journal of Strength & Conditioning Research, 6(1), 36-41.Asadi, A. (2012). Effects of six weeks of depth jump and countermovement jump training on agility performance. Sport Science, 5(1), 67-70.Fatouros, I., Jamurtas, A., Leontsini, D, Taxildaris, K., Aggelousis, N., Kostopoulos, N., & Buckenmeyer, P. (2000). Evaluation of plyometric exercise training, weight training, and their combination on vertical jumping performance and leg strength. The Journal of Strength & Conditioning Research, 14(4), 470-476.Luebbers, P., Potteiger, J., Hulver, M., Thyfault, J., Carper, M., & Lockwood, R. (2003). Effects of plyometric training and recovery on vertical jump performance and anaerobic power. The Journal of Strength & Conditioning Research, 17(4), 704-709.Miller, M., Herniman, J., Ricard, M., Cheatham, C., & Michael, T. (2006). The effects of a 6-week plyometric training program on agility. Journal of Sports Science and Medicine, 5(3), 459-465.Yap, C. W., & Brown, L. E. (2000). Development of speed, agility, and quickness for the female soccer athlete. Strength & Conditioning Journal, 22(1), 9.Young, W. B., James, R., & Montgomery, I. (2002). Is muscle power related to running speed with changes of direction?. Journal of Sports Medicine and Physical Fitness, 42(3), 282-288.

Figure 2: T-Test Protocol

Group PreTest (m) PostTest (m) Difference (m)

Control 0.239 ± 0.0297 0.227 ± 0.0481 - 0.012

Experimental 0.216 ± 0.0277 0.206 ± 0.0298 - 0.010

* Negative difference represents a decrease in performance

Figure 1:Illinois Agility Test Results of Average Pre and Post Test Values in the Experimental

and Control Group

Consistent with previous research, agility improved in the experimental group and not the control group. This suggests that plyometric exercises improve individuals ability to quickly change directions. This is most likely caused by an increased coordination of the muscles involved in changing directions as there was no increase in force output as determined by the vertical jump height. Reasons for lack of an increase in power include: an inappropriate stimulus (not enough reps, sets or a non-individualized depth jump height) or external factors (diet, sleep, etc) not controlled.

Since the subjects were varsity athletes with high baseline levels of agility and power, it is difficult to gain further increases in fitness.. Future research could increase the load of the depth jump height to elicit improvements or use healthy, active individuals with a lower baseline level of agility and power. Improved agility is also beneficial to performing tasks of daily living.

Although the hockey athletes were in-season and the soccer athletes off-season, both experienced improvements in agility.

In conclusion, plyometrics should be used in on and off season athletic training regimens as it improves agility which is key component of sport competition.