Effects of plyometric training on soccer players

Abstract

Plyometric training (PT) is a technique used to increase strength and explosiveness. It consists of physical exercises in which muscles exert maximum force at short intervals to increase dynamic performances. In such a training, muscles undergo a rapid elongation followed by an immediate shortening (stretch-shortening contraction), utilizing the elastic energy stored during the stretching phase. There is consensus on the fact that when used, PT contributes to improvement in vertical jump performance, acceleration, leg strength, muscular power, increase of joint awareness and overall sport-specific skills. Consequently, PT which was primarily used by martial artists, sprinters and high jumpers to improve performances has gained in popularity and has been used by athletes in all types of sports. However, although PT has been shown to increase performance variables in many sports, little scientific information is currently available to determine whether PT actually enhances skill performance in soccer players, considering that soccer is an extremely demanding sport. Soccer players require dynamic muscular performance for fighting at all levels of training status, including rapid movements such as acceleration and deceleration of the body, change of direction, vertical and horizontal jumps, endurance, speed as well as power for kicking and tackling. In this review we discussed the effects of PT on soccer players by considering gender and age categories.

Keywords: depth jump; force; muscular performance; plyometrics training; soccer players; stretch-shortening cycle.

Figure 1.

Basis of PT. The three basis phase of PT include: phase I or eccentric (A) correspond to the preactivation phase or stretch of agonist muscle. Elastic energy is stored in the series elastic component. Muscle spindles are stimulated; phase II or amortization (B) is the pause between phases I and III. Type la afferent nerves synapse with α motor neurons. α motor neurons transmit a signal to agonist muscle group. The phase III or concentric (C) is the shortening of agonist muscle fibers. Elastic energy is released from the series elastic component. α motor neurons stimulate the agonist muscle group. PT, plyometric training.