Power Training Tidbits


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.


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)


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)


Exercise Power Outputs

Stone 1993
 

Absolute Power (Watts)
Exercise 100 kg Male 75 kg Female
Jerk 5400 2600
Snatch 3000 1750
Clean 2950 1750
Squat 1100  
Deadlift 1100  
Bench Press 300  


Varying Velocities and Forces

Ideal exercise stimulus for both strength and power to achive optimal performance gains includes varying forces and velocities (as in a periodized program):

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)


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).


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.


Depth Height

One researcher recommends a height of no more than 20 cm (8") 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.


Muscle Spindle Reflex

The greater force is exerted by the muscles following a prestretch (eccentric contraction followed immediately by a concentric contraction) than without this storage of elastic energy (Kreighbaum, 1996).


Strength, Velocity, Progress, and Volume

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 rugdy league football players, Journal of Strength and conditioning Research, 15(2), 198-209.


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)

Behm & Sale (1993); Narici et. al., (1989)

Sale (1988)

Theories of velocity specificity training:


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 cleans and snatches typically do not exceed 5 repetitions. No more than 6 repetitions are ussually performed on partial power exercises such as hang cleans and hang snatch. Also see Periodization Training.


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