Plyometric exercises are where the muscle is loaded with an eccentric or lengthened action followed immediately by a concentric or shortened action. Plyometrics are explosive exercises that will increase speed and strength.
The pre stretch lengthening of the muscle where elastic energy is stored produces a more explosive contraction of the muscle. The stretch-shortening cycle is the 3 step process of pre-stretching the muscle, transition or amortization phase, and muscle contraction. A faster or shorter transition or amortization phase equals more power generated by the muscle contraction.
The stick figure diagram at the top of the page shows some great exercises to begin your training. Increasing vertical jump, speed, reaction, and overall explosive strength are benefits from plyometric training. Explosive push ups can be added to your training to increase upper body strength as well.
Be sure and work into plyometrics slowly, give yourself adequate rest, and warm up properly beforehand. Always use proper technique. Sloppy reps can result in injury and will promote ill technique. Take your time and concentrate on control and balance.