The basis of plyometric exercises is that they toughen muscles and condition nerve cells, which trigger a pattern of muscle contractions. Specifically, the exercises engage the myotatic reflex — the release of power — when muscles are stretched to their maximum. This reflex in turn stimulates neurons called stretch sensory receptors. The ultimate goal is achieving as strong a muscle contraction as possible in the shortest amount of time possible. Plyometrics uses a key concept of exercise science: Muscle contractions that last the least amount of time produce more energy than a slower contraction or release regardless of the size or bulk of the muscle.
Another key element of plyometrics is concentric contraction. For a muscle to act, it first must “coil up,” which is actually stretching out to its maximum pre-action length. This loads the muscle, like cocking a gun. Then, as the muscle is held in this state, energy is stored, and energy grows as the muscle is held. That brief storage — lasting a second or less — allows for maximum storage and use of the energy.
There are three phases of the plyometric muscle contraction. The first is the eccentric phase, the rapid muscle-lengthening movement — that initial stretch or loading action. Next is the amortization phase, the very brief, power-building period of muscle rest or holding period. Finally comes the concentric phase, in which muscles are released to create the explosive muscle shortening movement. It’s the big payoff.
There’s also a neurological component: Plyometrics train the brain to treat muscles differently, to the athlete’s advantage. The brain is hardwired to limit force when a muscle is stretched out; the brain tells the muscle to hold, and the muscle can waver slightly, resulting in a loss of energy as it’s slowly released in a series of small contractions. Plyometric exercises can condition the brain to tell the muscles something different — they train neurons to learn that in sports situations, the needs of a muscle are quick muscle contractions and precise, powerful, singular releases that produce a surge of energy.
Benefits of Plyometrics
The benefits of plyometrics are the simple but elusive athletic needs of more speed, more stamina and more power, be it in running, jumping, throwing, swimming or another sport-specific movement. It’s about the efficient use and manipulation of muscles to produce consistent peak performance, not about building bulkier muscles.
These benefits come with practice, training and care. These exercises take competitive athletes who want a permanent, physical edge to the next level of competition by teaching their bodies to do what they want them to do. To attempt a plyometrics routine, you’ve got to already be in shape. While sometimes used to build muscle back as part of rehabilitation or physical therapy, plyometrics are still primarily for use by athletes who are in training and are already strong, fit and flexible. Flexibility prevents injury, while also ensuring that the plyometrics are used to their peak efficiency. It also helps to be strong and currently engaged in a strength-building routine. Can you back-squat (lifting with the bar of the weight held behind you at the base of your neck) double your bodyweight? Then you’re suited for lower-body plyometrics. If you can bench-press your bodyweight, you’re ready to try upper-body plyometrics.
While plyometics injuries aren’t common, they can happen. If you attempt, say, a jumping exercise from too high, you can land wrong and twist an ankle. Even if you’re doing everything right and under the guidance of a trainer, don’t overwork your muscles if they feel too tender, because that can lead to tears. A proper exercise surface is important, too. It’s best to avoid using a concrete or gym floor. Instead, train on soft ground or gym mats, which absorb the shock of plyometrics.
Article source:
http://adventure.howstuffworks.com/outdoor-activities/running/training/plyometrics.htm/printable
