After completion of this chapter, the physical therapist should be able to do the following:
WHAT IS PLYOMETRIC EXERCISE?
In sports training and rehabilitation of athletic injuries, the concept of specificity has emerged as an important parameter in determining the proper choice and sequence of exercise in a training program. The jumping movement is inherent in numerous sport activities, such as basketball, volleyball, gymnastics, and aerobic dancing. Even running is a repeated series of jump-landing cycles. Consequently, jump training should be used in the design and implementation of the overall training program.
Peak performance in sport requires technical skill and power. Skill in most activities combines natural athletic ability and learned specialized proficiency in an activity. Success in most activities is dependent upon the speed at which muscular force or power can be generated. Strength and conditioning programs throughout the years have attempted to augment the force production system to maximize the power generation. Because power combines strength and speed, it can be increased by increasing the amount of work or force that is produced by the muscles or by decreasing the amount of time required to produce the force. Although weight training can produce increased gains in strength, the speed of movement is limited. The amount of time required to produce muscular force is an important variable for increasing the power output. Plyometrics is a form of training that attempts to combine speed of movement with strength.
The roots of plyometric training can be traced to Eastern Europe, where it was known simply as jump training.1–5 The term plyometrics was coined by an American track and field coach, Fred Wilt.6 The development of the term is confusing. Plyo- comes from the Greek word plythein, which means “to increase.” Plio is the Greek word for “ore,” and metric literally means “to measure.” Practically, plyometrics is defined as a quick, powerful movement involving prestretching the muscle and activating the stretch-shortening cycle to produce a subsequently stronger concentric contraction. It takes advantage of the length-shortening cycle to increase muscular power.7
In the late 1960s and early 1970s, when the Eastern Bloc countries began to dominate sports requiring power, their training methods became the focus of attention. After the 1972 Olympics, articles began to appear in coaching magazines outlining a strange new system of jumps and bounds that had been used by the Soviets to increase speed. ...