What is the term for an eccentric contraction immediately followed by a concentric contraction of the same muscle?

The term for an eccentric contraction immediately followed by a concentric contraction of the same muscle is the stretch-shortening cycle. This mechanism involves two distinct phases: first, during the eccentric phase, the muscle lengthens under tension, allowing it to store elastic potential energy. Subsequently, during the concentric phase, the muscle shortens, utilizing that stored energy to produce a more powerful contraction than if the concentric phase were performed alone. This cycle is particularly effective in athletic movements, enhancing performance in activities like jumping and sprinting.

Muscle fatigue refers to a decrease in muscle performance due to prolonged activity and is not specifically related to the sequence of eccentric and concentric contractions. Delayed onset muscle soreness (DOMS) is the discomfort felt after intense exercise, particularly after eccentric work, but it does not describe the contraction sequence itself. Active recovery involves engaging in low-intensity exercise post-strenuous activity to facilitate recovery, which is unrelated to the contraction types described. Thus, the stretch-shortening cycle best encapsulates the process discussed in the question.