As previously discussed plyometrics are explosive based exercises that improve muscular power through a series of exercises challenging the stretch-shortening cycle (SSC).However, when training with certain exercises it is useful to understand how the exercises work to show improvements. In this article we will elaborate upon the application of plyometrics further giving a better insight into plyometric training. After this series of articles, you will have learnt the fundamentals of plyometrics that can be built upon with assistance.
Within the muscles there are receptors in that feed information to the body to help with the SSC. The two receptors are muscle spindles and the Golgi Tendon Organs (GTO) which were designed for the muscle as a safety mechanism to stop overstretching the muscle. However in sport, they play the part in rapid contraction of the SSC. The muscle spindles detect changes in muscle length and the speed of the stretch, when they see that there is an excessive stretch, they send information to the spinal cord to contract the muscle to prevent over stretching. The GTO are based in the origin and insertion of muscles and detect tension in the muscles, at excessive tension, they send information that tells the muscle to antagonist muscle to relax allowing a stretch to occur to prevent injury. We use plyometric training to make adaptation to how these receptors work.
We use plyometrics to ‘manipulate’ these receptors; we want to stop the safety mechanism to generate the greatest stretch to produce maximal elastic energy. As discussed in previous articles, the greater the elastic energy we can store the more force that we can produce over a short period of time. We look to desensitise the GTO to prevent relaxing the antagonist muscle as this is what will cause the rapid concentric contraction with the stored elastic energy. It also works to increase muscle tendon stiffness and muscular pre-activity to make the muscle contractions stronger. This is why we use plyometric exercises as part of training, to improve our SSC which is present in nearly every sport.
This training leads to the greater power output during short SSC plyometric movements, allowing for a greater reactive strength index (RSI). RSI is a measure of force compared to time and can tell us the efficiency of force production in certain movements. Plyometric training, if done, correctly will show an increase in RSI giving greater power output, giving rise to greater sporting performance. Therefore the effectiveness of plyometric training can be continuously tested to see for improvements or plateaus in training with a series of exercises.
Plyometrics should be an established part of all athletes training programmes, novice to elite. They provide the physiological adaptations that greatly enhance sporting performance, through simple exercises with no equipment. Yet when designing programmes, plyometrics are often overlooked for conventional weight training, although research has shown weights combined with plyometrics shows greater results than weights alone.