5/05/2007

Plyometrics: Controlled Impact/Maximum Power


The Eastern Europeans first used plyometrics in the 1970s to develop greater strength and power in their Olympic athletes. They based their programs on scientific evidence that stretching muscles prior to contracting them recruits the ''myotactic'' or stretch reflex of muscle to enhance the power of contraction. This prestretching of muscles occurs when you perform jumps one after the other.

One study found that participants in a well-designed program of stretching, plyometric training and weight training reduced their landing forces from a jump by 20 percent, and increased their hamstrings strength by 44 percent. Both of these factors contribute to reducing an individual's potential risk of injury.

A safe and effective plyometric program stresses quality, not quantity of jumps. Safe landing techniques, such as landing from toe to heel from a vertical jump, and using the entire foot as a rocker to dissipate landing forces over a greater surface area, also are important to reduce impact forces. In addition, visualization cues, such as picturing yourself landing ''light as a feather'' and ''recoiling like a spring'' after impact promotes low-impact landings.

If you are considering plyometrics, proceed with caution. Carefully considering the type of jumps selected for the program, enlisting a coach or trainer for supervision, and gradually increasing to more difficult exercises can make a plyometric program both safe and effective.

You can contact me for more information, and read the full story from the American Council on Exercise by clicking here.