Plyometric training is a type of strength training that develops speed and power in a short span of time, think sprinting and jumping. This type of training utilizes the elastic properties of muscle fibers to generate a maximal force. Plyometric training aims to bridge the gap between pure strength and sport related speed and power, making this a very popular form of exercise for athletes looking to improve their on field performance or to rehabilitate an injury.
Training in this style allows the muscles to reach their maximum force in a short period of time, but how does this happen?
Plyometric Training targets the stretch shortening cycle of the muscle fiber with a series of explosive body weight resistance exercises to produce a maximal force. There are three phases of the stretch shortening cycle: Eccentric, Amortization and Concentric.
The Eccentric Phase: Loading
The eccentric phase of the stretch shortening cycle is described as the pre-stretch phase or the loading phase of the movement. This is where the agonist muscle of the movement is stretched and “loaded” as a spring. The elastic energy stored during this time will enhance the resultant concentric muscle contraction, creating the maximal force. The magnitude of stretch, rate of stretch and duration of the stretch all have a significant impact on the amount of energy stored during this phase.
The Amortization Phase: Time to Rebound
The amortization phase is the short time between the eccentric and concentric phase. It is crucial here that the energy stored during the loading phase of the muscle is not lost and effectively transferred during the concentric or unloading phase. The amortization phase is the key to the performance of plyometrics. The shorter this phase is, the more effective and powerful the plyometric movement is. If this phase is delayed, the stored energy is wasted as heat and the “loaded spring” is not activated. One of the primary goals of plyometric training is to decrease the time to rebound as much as possible.
The Concentric Phase: Unloading
The concentric phase of plyometric training is the resultant power production and performance phase. After the short amortization phase, the agonist muscle begins to contract to produce the maximal force during the plyometric movement.
The blending of these three phases to perform a plyometric movement is used to enhance the muscles power performance. This enables athletes to train to jump higher, sprint faster and change direction at higher speeds, giving them a cutting edge in the world of sports performance.
Davies, G., Riemann, B. L., & Manske, R. (2015). CURRENT CONCEPTS OF PLYOMETRIC EXERCISE. International journal of sports physical therapy, 10(6), 760–786.
