What are plyometrics?
Plyometrics is any exercise in which the muscle contracts eccentrically, then immediately, concentrically. All of this means that the muscle is stretched. [loaded] before it contracts.
Plyometrics should 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 force 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 ‘ply and metric’ which means ‘more and measure’.
PLYOMETRICS is an advanced training technique that aims to link strength with speed of movement to produce POWER. By stretching a muscle and contracting it rapidly, you allow a muscle to reach maximum force in the shortest time possible. With plyometric training, we seek to train the body’s fast-twitch fibers. [type IIa and IIb] so they can load [stretch] faster and in turn discharge faster to produce more energy.
In terms of basic muscle physiology, a pre-stretched or loaded muscle is capable of generating more force than an unstretched one. Plyometrics “train” the muscles to respond quickly and powerfully.
Plyometrics is one of the best ways, if not the best, to improve POWER OUTPUT. Power is similar to force, except that you are ‘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 on takeoff has its takeoff foot in contact with the board for about 0.12 to 0.15 of a second, so reactive speed is a prerequisite. Specific plyometric training allows the jumper to approach at high speeds and still be able to produce an effective takeoff 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 are seeing is not just the muscle contraction, but HOW FAST it will contract. A muscle has been shown to contract faster when 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 / speed strength.
Research and studies over the past two decades have shown that plyometric training DECREASES the time it takes for muscles to contract, generating more power. Therefore, this type of training refers to very fast explosive exercises to improve power production and neuronal activation of the muscles, the ability of a muscle to contract rapidly.
Basically, plyometrics relies on an element of physiology called the stretch-shortening cycle. This stretch-shorten cycle means that the muscle stretches and then contracts rapidly, increasing the force applied to the muscle.
Bottom line: Plyometrics use the force of gravity to store energy in the muscles and then immediately release the energy in the opposite direction.