What does plyometrics do?
In order to understand how plyometrics work, you first need to know a little bit about what they are.
Plyometrics is any type of muscle exercise that is fashioned to produce fast, powerful movements of those muscles. The term plyometrics comes from a Greek word, which basically means "to increase". This type of exercise is one of the best ways to improve the power of your muscles. Power being similar to strength, except that you are adding "time" as a factor. You can think of plyometrics as simultaneously increasing the strength and speed (power) of your muscles.
When moving, your muscles contract in two ways: concentric contaction and eccentric contraction.
Concentric contraction takes place when the muscle shortens while generating force sufficient enough to overcome a given ammount of resistance. In plain English, it is the "flexing" of the muscle!
Eccentric contraction is the lengthening or "stretching" of the muscle, but it is also still contracted. It is used to decelerate a body part or object. Think: lowering a load rather than letting it drop.
What a plyometric exercise does is it forces a rapid contraction of the muscle on the concentric, and then also immediately on the eccentric. The key is that this is done in rapid sequence while still maintaining balance and control. A great example is doing push-ups with a clap in-between each push-up.
With plyometric exercise, you can train yourself to jump higher, run faster, hit harder, etc. It has many benefits besides increasing power alone. Plyometrics has also been shown to help with injury prevention as well!
Plyometric exercises can have an increased risk of injury (when training) due to the large forces generated, and therefore should only be performed by well-conditioned individuals who are under supervision. Good levels of strength, balance, and flexibility should be achieved before starting on any type of plyometric training.