What are plyometrics?

Plyometrics are any exercise in which the muscle contracts eccentrically and then immediately concentrically. All this means that the muscle is stretched [loaded] before it is hired.

Plyometric exercises must be used wisely with a basic understanding of the biomechanical and physiological concepts that govern training. Coaches need to know these basic principles that govern the development of the type of strength that jumpers require.

Plyometric training develops that explosive, elastic, and reactive strength that ALL jumpers need to “get off the ground.”

The word PLYOMETRIC is derived from the Greek word ‘pleythein’ which means to increase or from the Greek roots ‘plio and metric’ which means ‘more and measure’.

PLYOMETRY is an advanced training technique whose goal is to link strength with speed of movement to produce POWER. By stretching a muscle and rapidly contracting it, you allow a muscle to reach maximum force in the shortest possible time. With plyometric training we seek to train the fast fibers of the body [type IIa and IIb] so they can load [stretch] faster and, in turn, discharge faster to produce more power.

In terms of basic muscle physiology, a pre-stretched or loaded muscle is capable of generating more force than an unstretched one. Plyometric exercises ‘train’ the muscles to respond quickly and powerfully.

Plyometrics is one of the best, if not the best, ways to improve POWER OUTPUT. Power is similar to strength, except you’re ‘adding’ the time factor. Therefore, power is the relationship of force and speed that is what the jumper is looking for. Consider that a long jumper at takeoff has their takeoff foot in contact with the board for about 0.12 to 0.15 seconds, then reactive speed is a prerequisite. Specific plyometric training allows the jumper to approach at high speeds and still be able to produce an effective take off with limited time available.

But it is knowing WHAT exercises to select, what intensity and number of contacts. It is the application of plyometric principles that will determine the effectiveness of the training program.

So what we’re looking at is not just the muscle contracting, but HOW FAST it will contract. It has been shown that a muscle contracts faster when it has been loaded. So when you train using plyometric principles, the goal is to replicate landings and takeoffs with the correct muscle flexion and extension to develop this elastic force/speed.

Research and studies over the past two decades have shown that plyometric training DECREASES the time it takes your muscles to contract, which generates more power. Therefore, this type of training refers to very fast and explosive exercises to improve power output and neural activation of muscles, the ability of a muscle to contract rapidly.

Basically, plyometrics is based on an element of physiology called the stretch-shorten cycle. This cycle of stretching and shortening means that the muscle is quickly stretched and then contracted, increasing the force applied to the muscle.

Bottom line: Plyometrics use the force of gravity to store energy in the muscles, then immediately release the energy in the opposite direction.