Is Accelerative Activity an Inherent Characteristic of Human Movement?
The phenomenon known as the stretch-shortening cycle (or SSC) strongly hints that the body is, in fact, designed for ballistic and accelerative stress (5). To illustrate this concept, I ll ask you to imagine the act of throwing a baseball, overhand style.You grab the ball, extend your throwing arm behind you, and, just as the arm nears complete extension (the eccentric portion of the throw), you rapidly reverse the motion (the concentric phase) and release the ball. Now, just as an experiment, extend the arm back, and pause for three seconds before you throw. It s intuitively obvious that the second throw, aside from feeling totally unnatural, will travel much slower and result in a shorter throw. When you throw (or jump, hit, etc) correctly, the musculo-tendinous unit stores potential kinetic energy during the eccentric phase of the movement. At full stretch, the muscle begins its reversal into the concentric phase. If you use proper timing (the switch between eccentric and concentric
