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ASCPH02 Plyometric Training 20056202 Name: Karl Thorpe Proposed Title: Is plyometric training effective to increase power output and have direct impact in an athlete’s chosen sport? This article will outline the mechanics and physiology of plyometric exercise and with utilising data, will demonstrate the effects of plyometric training with regards to power output. The Eastern Europeans first used Plyometric training to develop Olympic Athletes strength and power in the 1970’s. Fred Wilt was the first person to brand the type of training he was using ‘Plyometrics’ in 1975. It is also known as ‘Shock Training’ and in 1977, plyometric training was developed by Yuriverkhoshansky. (Sankarmani et al., 2012:172-180) Physiology of Plyometric Exercise It is common knowledge that athletes have utilised effective methods in an attempt to develop explosive strength such as barbell squats or the Olympic lifts. (Verkhoshansky, 2012:1-74) Using heavy loads during exercises has been deemed to improve strength where using lighter loads and moving the load as fast as possible has been described as developing power. (Siff, 2004:265-275) Research has suggested that these methods are not the only means of developing explosive strength. Plyometric training has a plethora of exercises, which enable a muscle to reach a maximal force in the shortest possible time. Plyometric training is defined as a quick powerful movement involving an eccentric muscle action immediately followed by an explosive concentric muscle action. (Baechle and Earle, 2008:414-418) The strength shortening cycle (SSC) is involved in this process. Muscle force and power have consistently shown a development when plyometric training has been used correctly and two models are known as the mechanical and neurophysiological models which best explain this concept. Mechanical Model of Plyometric Exercise The result from a rapid stretch creates elastic energy to be stored within the muscles and tendons. (Verkhoshansky, 2012:1-74) The stored energy will only be released if after the stretch there is an immediate concentric muscle action. The effect is like a spring, which wants to return to its natural length. (Baechle and Earle, 2008:414-418) The spring is this case a component of the muscles and tendons called the Series Elastic Component (SEC) Mechanical model of skeletal muscle function (Potach & Chu 2008) Neurophysiological Model There is a response known as the stretch reflex, this resposnse takes place when a quick stretch is detected in the muscles and an involuntary, protective response occurs to prevent overstretching and injury. (Yessis, 2009:1-24) Muscle activity is increased within the muscles from the stretch reflex causing the muscle to act much more forcefully. (Verkhoshansky, 2012:1-74) This results in a powerful concentric muscle action. Both the mechanical and neurophysiological model causes the increase of force production within the muscles during plyometric exercises. (Baechle and Earle, 2008:414-418) Neurophysiological Model (Potach & Chu 2008) The Strength Shorterning Cycle (SSC) is made up of three phases, eccentric phase, amortization phase and concentric phase. (Yessis, 2009:1-24) Phase Action Phsiological Event Eccentric Stretch of the agonist Elastic energy is stored muscle in the series elastic component Muscle spindles are stimulated Amortization Pause between phases Type 1a afferent nerves 1 and 2 synapse with alpha motor neurons Alpha motor neurons transmit signals to agonist muscle group. Concentric Shortening of agonist Elastic energy is muscle fibres released from the series elastic component. Alpha motor neurons stimulate the agonist muscle group (Watkins, 2010:3-9) Is Plyometric Training Effective A study was carried out to determine the effects of plyometric training on maximal power output and jumping ability. The aim was to have minimum foot contact time with the floor when performing plyometric exercises with the aim of jumping as high as possible. Exercises included the one-legged hop, depth jumps and box jumps. (Makaruk and Sacewicz, 2010:17-18) The experiment took place over six weeks and there was a significant increase in the relative maximal power output when performing the plyometric exercises. This highlighted that depending on the aim of the training programme; plyometric exercises could be utilized to achieve certain gains. (Bompa, 2009:46-62) If the programme aim was to develop the athletes jumping ability/explosive power for their particular sport then plyometric exercises could be utilized to achieve this. (Myszka, 2012:1-5) By making use of the SSC, it has been proven that the movements can be made more explosive and powerful, as previously stated these movements are know as plyometric exercises. (Wu et al., 2009:1-7) Plyometric drills are designed to stimulate the series elastic component over and over again and plyometric drills can mimic an athletes sport and stimulate dynamic correspondence within their sport. (Sankarmani et al., 2012:172-180) A recent study was carried out to determine the effects of weight training using or not using plyometric training. It was carried out over six weeks involving 40 inter colligate athletes. (Sankarmani et al., 2012:172-180) The 40 athletes were randomly split into two groups of 20. One group performed a 6-week weight-training programme whilst the other group included plyometric training within the programme. Results outlined that there were significant increases in vertical jump and 1rm tests with the group who used plyometric training over the six weeks. A wide variety of training studies shows that plyometrics can improve performance in vertical jumping, long jumping, sprinting and sprint cycling. It appears also that a relatively small amount of plyometric training is required to improve performance in these tasks. (Verkhoshansky, 2012:1-74) Just one or two types of plyometric exercise completed 1-3 times a week for 6-12 weeks can significantly improve motor performance. Baechle and Earle, 2008:414418) Additionally, only a small amount of volume is required to bring about these positive changes i.e. 2-4 sets of 10 repetitions per session or 4 sets of 8 repetitions. (Makaruk, 2010:17-22) While upper body plyometrics has received less attention, three sessions of plyometric push ups a week has been shown to increase upper body power as measured by medicine ball throws. (Zatsiorsky and Kraemer, 2006:20-45) Using a variety of plyometric exercises such as depth jumps, counter- movement jumps, leg bounding and hopping etc., can improve motor performance. While the majority of studies have focused on untrained subjects, trained athletes such as soccer and basketball players have improved their performance with plyometrics. Baechle, T. and Earle, R. (2008) Essentials of strength training and conditioning. (3rd ed.) USA: National strength and conditioning association. Bompa, T. (2009) Periodization - Theory and Methodology . (5th ed.) USA: ISBN. Makaruk, H. and Sacewicz, T. (2010) Effects of plyometric training on maximal power output and jumping ability. Human Movement. Vol. 11, No. 1: 17-22. Myszka, S. (2012) Dynamic Correspondence: The Key to Strength Training Transfer. NSCA. Vol. 2: 1-5. Sankarmani, B., Ibrahim, S. and Rajeev, K. (2012) Effectiveness of Plyometrics and Weight Training in Anaerobic Power and Muscle Strength in Female Athletes . INTERNATIONAL JOURNAL OF PHARMACEUTICAL SCIENCE AND HEALTH CARE. Vol. 2, No. 2: 172-180. Siff, M. (2004) Supertraining. (6th ed.) USA: Supertraining Institute. Watkins, P. (2010) Augmented eccentric loading: theoretical and practical applications for the strength and conditioning professional. UKSCA. No. 17: 3-9. Wu, Y., Lien, Y. and Lin, K. (2009) Relationships between three potentiation effects of plyometric training and performance. Scandinavian Journal of Medicine and Science in Sports. Vol. 10, No. 11: 1-7. Verkhoshansky, N. (2012) Shock Method and Plyometrics: Updates and an In Depth Examination. Verkhoshansky: Special Strength Training Methodology. Vol. 2: 1-74. [Online] Available from: http://www.verkhoshansky.com/Portals/0/Presentations/Shock%20Meth od%20Plyometrics.pdf [accessed 15 June 2014] Yessis, M. (2009) Explosive Plyometrics. (1st ed.) USA: Elite Fitness Systems Zatsiorsky, V. and Kraemer, W. (2006) Science and Practice of Strength Training. (2nd ed.) USA: Human Kinetics..