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Effect of Squats and Plyometric on Vertical Jump Exercise Mode Vertical Jump Increase Squats 3.30 cm Plyometrics 3.81 cm Squats & Plyometrics 10.67 cm Adams, K., O'Shea, J.P., O'Shea, K.L., Climstein, M. (1992). The effect of six weeks of squat, plyometric and squat-plyometric training on power production. Journal of Applied Sports Science Research. 6(1): 36-41. Also see Vertical Jump Calculator. Conditioning Work It is generally agreed athletes should complete a general conditioning program before incorporating plyometrics. The National Strength and Conditioning Associating suggests athletes should be strong in the squat before beginning a lower body plyometric program. In addition, high intensity plyometrics should not be performed year round (NSCA, 2000) Exercise Power Outputs Stone 1993   Absolute Power in Watts Exercise 100 kg Male 75 kg Female Jerk 5400 2600 Snatch 3000 (5500)* 1750 (2900)* Clean 2950 (5500)* 1750 (2650)* Squat 1100   Deadlift 1100   Bench Press 300   *Lift off to maximum vertical velocity (transitition until maximum vertical velocity) Varying Velocities and Forces Ideal exercise stimulus for both strength and power to achieve optimal performance gains includes varying forces and velocities (as in a periodized program): high force / low velocity low force / high velocity high force / high force Baker D (1996). Improving vertical jump performance throught general, special, and specific strength training: A brief review. J Strength Cond Res. 10131-136 Harris GR, Stone MH, O'Bryant HS, Prouix CM, Johnson RL (2000). Short-term performance effects of high speed, high force, or combined weight training methods. J Strength Cond Res. 14(1):14-20. Optimal Workload Power training should be performed with a workload of approximately 30%. Training at 30%-60% improves both force and velocity. Greater workloads improve primarily force. (Wilson, et al 1993; Kreighbaum, 1996) Stone Pulls: Power Output (W/Kg) Optimum weight results in 10-20% greater power out put as compared to 1 RM   Male Female 1 RM  50-56 30-40 70-80 % 1 RM  55-65 33-45

Muscular Hypertophy & Force Development Strength development may associated with muscle hypertrophy whereas force development may be related with alterations in neural activation (Sale 1988; Hakkinen, et al 1989). However, hypertophy of Type II fibers may also improve force development (Hakkinen & Komi 1986). Plyometric Depth Jump Heights Jumping from heights greater than 40 cm (16") does not seem to produce greater force development since a deeper flexion is required for shock absortion which may disapate elastic energy and slow the speed of recoil (Kreighbaum, 1996). A height of no more than 20 cm (8") has been suggested for reduced risk of injury (Kreighbaum, 1996). Other experts suggest a 46 cm (18") bench height is optimal for a high jump height at a low injury occurrence. Also see Stretch-shortening Cycle. Speed of Contraction A greater contractile force was achieved from a quick bounce-jump executed as soon as possible after landing from a drop-jump as compared to a deeper knee bend jump (Kreighbaum, 1996). Dr. Michael Yessis states the jump must be executed in 0.15 seconds or less. (Fitness Management, Oct 1999) Strength, Velocity, Progress, and Volume It appears that in the early stages of training, increased strength gains contribute to maximum power output. As potential strength gains diminish, then other velocity-oriented means contribute to maximum power output. A diminished relationship relationship between changes in strength and changes in maximum power must occur with increased training experience. Training volume has more impact on power than strength. Baker, Daniel (2001), The effects of concurrent training on the maintenance of maximal strength and power in professional and college-age rugdy league football players, Journal of Strength and conditioning Research, 15(2), 172-177. Contrasting Load Enhance Power Contrasting loads and/or exercises results in short-term enhancement of power output. Alternating sets of a strength exercise and load (>85% 1RM) with sets of a power exercise and/or load (30-45% 1RM). Baker, Daniel (2001), A series of studies on training of high-intensity muscle power in rugby league football players, Journal of Strength and Conditioning Research, 15(2), 198-209. Smilios I, Pilianidis T, Sotiropoulos K, Antonakis M, Tokmakidis SP (2005). Short-term effects of selected exercise and load in contrast training on vertical jump performance, Journal of Strength and Conditioning Research, 19(1):135-9 Slow Exercise Can Impair Power Development Explosive exercise can enhance power production where as regular slow exercise may impair power development. Hakkinen K, Myllyla E (1990). Acute effects of muscle fatigue and recovery on force proction and relaxation in endurance, power, and strength athletes. J Sports Med Phys Fitness. 30: 5-12. Viitasalo JT, Aura O (1984). Seasonal fluctuations of force production in high jumpers. Can J Appl Sports Sci. 9: 209-213. Velocity Specificity Training To maximize force production at a joint, it is not enough to just do activities which are task specific movements (to allow neural drive and multi joint coordination to develop). Specific movements at the correct velocity must be performed. An increase in strength does not transfer to all speeds which the movement was performed. The greatest increases in strength occur near or below the velocity of the exercise. Behm & Sale (1993) subjects trained at 1.05, 3.14, 5.24 rad/sec, 8 weeks slow speed training group showed greatest strength increases at slow speed test fast speed training group showed greatest strength increases at fast speed test middle speed training group showed similar strength increases at all speeds Behm & Sale (1993); Narici et. al., (1989) subjects who trained at a slow speed (36 degrees / second) only achieved increases in force at the slow training speed subjects who trained at a fast speed (108 degrees / second) achieved increases in force all testing speeds (0-108 degrees / second) Sale (1988) Comparison of explosive jump training and heavy resistance weight training on rate of rapid increase in force and EMG during maximal isometric contractions. resistance training caused the greatest increase in peak force explosive training caused the greatest increase in rate of force development and more rapid EMG onset Theories of velocity specificity training: increase in neural activation pattern increased synchronization of motor units development of a motor program for the rapid movement changes in contractile properties of muscle, specific for the speed trained Untrained vs Trained Depth Jump During a depth jump of 110 cm, an untrained individual responds with a period of inhibition during the eccentric phase after landing (stretch load). In contrast, a trained jumper responds with a period of facilitation, or increased agonist activation (Schmidtbleicher & Gollhofer, 1982). Premovement Silence (PMS) Just prior to ballistic movements, agonist muscles may exhibit a premovement silence (PMS) where there is little or no motor unit activity. Increased frequency of PMS may be learned; a neural adaptation to high velocity training. The PMS may increase peak force and the rate of force development of ballistic movement by inducing a brief stretch-shortening cycle. Furthermore, the brief silent period may bring motoneurones into a non-refractory state increasing their potential to be more readily recruited and to be able to execute higher firing rates. Ski Jumper's Peak Force Komi (1984) found although ski jumpers were able to achieve peak leg extension force more rapidly than untrained men, they did not have greater leg extension peak force as untrained men. Repetition Range Power exercises like the snatch and cleans & jerk typically do not exceed 5 repetitions. No more than 6 repetitions are usually performed on partial power exercises such as hang cleans and hang snatch. Glen Pendley explains: Most who try sets of 5 on the clean and jerk with any decent load quickly abandon the notion that the competitive lifts can be trained with high reps. Most (maybe all?) accomplished lifters use sets of 1-3 almost exclusively for a reason. And singles or doubles are probably far more popular than triples. Also see Periodization Training.