Which phase is the transition that reduces energy loss and, when shortened, increases power?

• A. Amortization
• B. Eccentric
• C. Concentric
• D. Isometric

Answer: (A)

In the stretch-shortening cycle, movement starts with eccentric loading (the muscle lengthens under tension), followed by a brief transition, and then the concentric phase where the muscle shortens to produce propulsion. The transition phase, called amortization, is the moment that prepares and transfers the stored elastic energy from the eccentric action into active shortening. If this transition lasts too long, energy leaks away as heat and the switch to forceful shortening is slower, reducing power. Shortening the amortization phase makes the energy release quicker and more efficient, boosting explosive power. The other phases—eccentric (lengthening under load), concentric (shortening to produce movement), and isometric (no change in length)—do not serve this rapid energy transfer in the same way.