Which of the following is NOT a phase of the stretch-shortening cycle?

• A. amortization
• B. concentric
• C. eccentric
• D. isometric

Answer: (D)

The stretch-shortening cycle relies on three stages: the muscle is loaded eccentrically, a brief transition where the length change is minimal (the amortization phase), and then the muscle shortens concentrically to release the stored energy. The isometric state describes the muscle’s behavior during that brief transition, but it isn’t counted as a separate phase of the cycle. So, isometric isn’t a distinct phase; the cycle comprises eccentric, amortization, and concentric actions.