Plyometrics involve power jumping, repetitive bounding and quick force production. When your muscles eccentrically contract, or shorten, then immediately stretch and lengthen, they produce maximal power ideal for athletic situations. It is a fast movement that happens over a short period. Plyometrics are ideal for athletes or people looking to improve muscular power, speed and strength. They also help facilitate weight loss and help tone and define your muscles; however, these exercises are not without risk.
Power and Speed
Plyometrics were originally designed for power athletes like sprinters, football players and gymnasts. According to Brian Mac, professional sports coach, your muscles achieve maximum power during eccentric contractions, or muscle lengthening. When you immediately follow an eccentric contraction with a concentric -- or muscle-shortening -- contraction, your muscle produces a greater force. This is called the stretch-shortening cycle. Plyometric training decreases the time between your eccentric and concentric contractions and improves your muscular speed and power.
With power and speed come muscular strength gains. Plyometrics can improve strength in both your upper and lower body. Examples of lower body plyometrics are tuck jumps, squat jumps, box jumps and depth jumps. The goal of these jumps is to get higher, utilizing your leg strength to improve the height of your jump. Upper body plyometrics include clapping pushups, medicine ball chest press throw and overhead throws. These help improve strength in your upper body.
Weight Loss and Tone
Plyometric exercises require a lot of energy, because they are highly intense. They utilize the whole body and activate most muscle groups, therefore burning many calories in a single session and aiding in weight loss. The repetitive landing causes your entire leg muscles to contract, helping to improve overall tone and definition. Plyometrics combine strength training and cardiovascular exercise, allowing you to "kill two birds with one stone."
The only real disadvantage to plyometric training is the high risk of injury. Like all exercise and sports, plyometric training is a continuum, where beginners start with light exercise and low volume and then gradually progress with gained strength. The repetitive jumping and bounding can cause stress on the joints. Do not engage in plyometrics if you have arthritis or joint issues, unless cleared by your doctor. If you are untrained, risk of strains is elevated, because the muscles surrounding your joints are weaker and may not give you the support you need.
The National Strength and Conditioning Association recommends that beginners start with 60 to 80 foot contacts. After about four to six weeks of training, progress to 80 to 120 foot contacts. Advanced exercisers and athletes can do upward of 150 foot contacts. You can safely participate in plyometrics once or twice per week on nonconsecutive days. Before beginning, do a 10-minute light cardiovascular warmup to increase blood flow to your muscles and help prevent injury.