What is Plyometrics?
Plyometrics is an exercise regimen designed to make movements faster and more powerful at the same time. This method aims for the conversion of strength to speed in the shortest amount of time possible. It has many uses in the field of sports training which includes improving the height of the vertical jump.
The jumping process involves squatting and then suddenly straightening your legs in an explosive movement so that you are forced up into the air. Now, imagine that your calf muscles are replaced by an elastic material such as a rubber band. If you bend your legs, the calf muscles undergoes a stretch process much like stretching a rubber band. This phase in the jump when you load the elastic material (your muscles) with energy is referred to as the eccentric contraction. A subsequent phase of the jump is that of shortening the elastic material or your calf muscles which is just the process of releasing the energy by straightening your legs. This is referred to as the concentric contraction.
In between the eccentric and concentric contractions, there is a resting phase where your feet are forced into the ground. This very brief moment is called the amortization phase which is the phase just before the stored energy during the eccentric contraction is released explosively through the very quick concentric contraction. To achieve the release of maximum force, you need the squat and the straightening of your legs to happen rapidly in sequence in order for your jump to be more powerful. In other words, you need to go from eccentric to concentric contractions rapidly since the longer you stay in the resting phase or amortization phase, the more energy dissipates for the concentric contraction, which means less strength is available to be converted to speed, which directly affects the height of the jump.
The objective of plyometric exercises when used in training how to jump higher is to have the eccentric contraction be very quickly followed by the concentric contraction. The key is to have the resting moment reduced as much as possible to maximize the transfer of energy from your body to the ground.
Plyometrics is a training exercise method that aims to improve an athlete’s power and speed by working out the necessary muscles and improving the nervous system response in using those muscles. Such training exercises are usually performed to improve hitting power (boxing), quicken running speed (sprinter), stretch throwing distance and increase vertical jump (basketball/volleyball player).
Definition: Plyometric movements, in which a muscle is loaded and then contracted in rapid sequence, use the strength, elasticity and innervation of muscle and surrounding tissues to jump higher, run faster, throw farther, or hit harder, depending on the desired training goal. (Source: Wikipedia)
How does plyometrics work?
Plyometrics work through the use of plyometric movements to exercise muscles and to train nerve cells to stimulate and generate powerful plyometric contractions at very very short periods of time. These contractions are the heart and soul of plyometrics. It starts with a very quick “muscle lengthening movement”, followed by a very short rest period, then that quick and explosive muscle contraction that does all the magic. Plyometric exercises utilize these explosive muscle movements to develop the muscle power needed for the athlete’s training goal. Here’s a geekier explanation of what are plyometrics training programs really and how they work.
Plyometric exercises have a higher amount of injury risk attached to them because they involve forceful and quick movements in the training. This is why this should only be done by people that are in good physical condition and are already built to withstand the muscular and skeletal stresses caused by plyometric movements. This type of jump training is one of those sports training programs where it is advisable to have a personal trainer to supervise you.
What you need to be able to reduce the risk of injury: good physical condition and strength, good flexibility and proprioception.
It is recommended that to be able to start plyometrics training, minimum strength should be at the level where you are able to do squat exercises at 5 repetitions with weights at 60% of your body weight. Good core strength is also a big MUST. Flexibility and proprioception are important to prevent injury and to improve balance, agility and form which are essential requirements for optimum plyometrics training. (Source: Chu, D. (1998). Jumping into plyometrics (2nd ed.). Champaign, Illinois: Human Kinetics)
Tailor-fit plyometrics training to minimize risk
The best way to reduce risk of injuries to very minimal levels would be to get a personal jump trainer to help you learn how to jump higher correctly. This way you will have someone to assess your needs before you start your training and to create a customized regimen that will ensure you have all the things you need before you start with the high intensity training that plyometrics is known for.