Still More plyometrics?
However, for maximum return of energy, minimum time must elapse from when the forces are received to when they are returned. The greater the time between receiving the forces and giving them back, the less is the return and the less the height that can be achieved in the jump. Most of the lengthening and shortening occurs in the respective muscle tendons which have greater elasticity.
Another way of saying this is that the faster the switching from the eccentric to the concentric contraction, the greater will be the force produced and the greater will be the return movement. The speed of the switching is extremely fast; 0.20 seconds or less. For example, high-level sprinters execute the switch from the eccentric contraction that occurs when the foot hits the ground to the concentric contraction when the foot breaks contact with the ground, in less than 0.10 seconds. In world-class sprinters, the time is approximately 0.08 seconds. The exact platform height used by most athletes in the depth jump should be less than 30 inches in the early stages of training. Most athletes start at approximately 12 inches after doing some jump training. They then gradually work up to 20 inches and then to 30 inches depending upon how well the jumps are executed. The main criterion is to make sure that the athlete is jumping as high as possible on every jump.