Friday, August 26, 2011

Plyometrics Improves Explosive Power and Speed

Power, which is improved with plyometric exercises, is often overlooked when athletes are strength training.

Power and dynamic balance are the two best physical predictors of athletic success. Power is defined as the ability to exert maximum force in the shortest amount of time (rate-of-force production).

Sports power can be trained for and improved. There is a point at which increasing strength will not result in an increase in power.

There are five purposes for sports power training:

1. Improve the excitability, sensitivity and reactivity of the neuromuscular system.

2. Improve the rate-of-force production.

3. Increase motor-unit recruitment.

4. Increase motor-unit firing frequency.

5. Increase motor-unit synchronization.

Sports power training teaches you how to activate the right muscles (prime movers and synergists) at the right time. Sports power training also provides you with optimal neuromuscular efficiency.

It doesn't help you to continually get stronger if power development is not there also. Power, or speed strength (how fast your muscles can produce force) is one of the best physical predictors of success in sports.

Plyometric exercises help you to increase leg power and arm power. Traditional barbell and dumbbell strength exercises do not allow you to move at the speeds necessary to improve power. Strength training gives you the muscular and nervous system development needed to develop optimal power.

So how does plyometrics work (Integrated Performance Paradigm)? Primarily through the use of two components: 1) elasticity of the muscles and 2) the stretch shortening cycle.

Plyometric exercises always follow the same order: a landing phase, an amortization phase and the take off. The landing phase starts when the muscles start an eccentric contraction. The rapid eccentric contraction stretches the elastic component of the muscle and activates the stretch reflex.

A high level of eccentric strength is needed during the landing phase. Inadequate strength will result in a slow rate of stretch and less activation of the stretch reflex. The amortization phase, the time on the ground, is the most important part of a plyometric exercise.

It represents the time between the landing and the take off and is critical for power development. If the amortization phase is too long, the stretch reflex is lost and there is no plyometric effect. The take off is the concentric contraction that follows the landing. During this phase the stored elastic energy is used to increase jump height and explosive power.

Plyometrics represent high intensity training, placing great stress on the bones, joints, and connective tissue. While plyometrics can improve your speed, power, and performance, they also place you at greater risk of injury than less intense training exercises.

It is important to perform the exercises correctly before implementation of full-speed exercises. Jumping and landing techniques should be mastered. Exercises should also be performed on safe surfaces such as rubber mats, sprung floors, grass or sand. Concrete or other similar hard surfaces expose you to injury.

You should have good core strength and lower body strength to enhance the plyometric effect and reduce chances of injury.

The training exercises should mimic the movements in your sport (mechanical, physiological and metabolic similarity).

Training progressions should follow this path:

1. Simple to Complex
2. Stable to Unstable
3. Body Weight Exercises to Resistance Exercises
4. Low Loads to High Loads

Signs of over-training include:

1. Prolonged foot contact with the ground
2. Lack of control
3. Decreased vertical height or horizontal distance
4. Longer rest periods are needed by the athlete

Safety concerns during plyometric training are:

1. Proper footwear for the athlete
2. Proper training surfaces (hard surfaces should be avoided)
3. Program design and supervision by a fitness professional

There are literally dozens of plyometric drills and exercises that can be tailored to your sport and position played. Bigger, faster and stronger! Every athlete wants this to happen. Don't rush the strength and power building process!

Download your FREE 10-Minute Strength and Power Workouts now!

Mark Dilworth, BA, PES
Your Fitness University
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1 comment:

  1. Sweet! Thanks for putting this post together -- I enjoyed it.


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