Physical educators have long used various apparatus—including medicine balls, jump ropes, and Indian clubs—for specific training needs in a technique known as plyometric training. The science of plyometrics rests on the finding that muscles respond especially well to being subjected to rapid alternation of lengthening and shortening while resistance is being continuously applied to them.

One application of the plyometric principle involves catching and tossing a medicine ball to an assistant while the exerciser lies on his back. The triceps and chest muscles are working both while they are lengthening (catch phase) and while contracting (toss phase). Plyometric exercises carry increased risk of injury, and should only be performed by well-conditioned individuals who are under supervision.

Plyometrics is used to develop explosive speed, and focuses on power instead of raw strength. Plyometrics may be used to, for example, improve the effectiveness of a boxer's punch, or increase the vertical jumping ability of a basketball player.