Plyometrics, also known as jump training or plyos, are exercises in which muscles exert maximum force in short intervals of time, with the goal of increasing power (speed-strength). This training focuses on learning to move from a muscle extension to a contraction in a rapid or "explosive" manner, such as in specialized repeated jumping. Plyometrics are primarily used by athletes, especially martial artists, sprinters and high jumpers, to improve performance, and are used in the fitness field to a much lesser degree. Overview Plyometrics include explosive exercises to activate the quick response and elastic properties of the major muscles. It was initially adopted by Soviet Olympians in the 1950s, and then by sportspeople worldwide. Sports using plyometrics include basketball, tennis, badminton, squash and volleyball as well as the various codes of football. The term "plyometrics" was coined by Fred Wilt after watching Soviet athletes prepare for their events in track and field. He began a collaboration with trainer Michael Yessis to promote plyometrics. Since its introduction in the early 1980s, two forms of plyometrics have evolved. In the original version, created by Russian scientist Yuri Verkhoshansky, it was defined as the shock method. In this, the athlete would drop down from a height and experience a "shock" upon landing. This in turn would bring about a forced eccentric contraction which was then immediately switched to a concentric contraction as the athlete jumped upward. The landing and takeoff were executed in an extremely short period of time, in the range of 0.1–0.2 second. Explosive plyometrics describes the approach originally created by Verkhoshansky. He experimented with many different exercises, but the depth jump appeared to be the best for duplicating the forces in the landing and takeoff. The second version of plyometrics, seen to a greater extent in the United States, involves any form of jump regardless of execution time. Etymology The term plyometric is a combination of Greek roots that means to increase measurement—plio- means "more" and metric means "length". Plyo- comes from the Greek word plythein, which means “to increase.” Plio is the Greek word for “more,” and metric literally means “to measure.” History Fred Wilt, a former US Olympic long-distance runner, is credited with coining the term plyometrics. He admits that it is not a very good term, but it was the best he could come up with after watching the Russians execute jumps in their warm-ups prior to