What is the correct definition of eccentric contraction?

Eccentric contraction refers to the process where a muscle lengthens while still under tension. This occurs during movements where the muscle is actively controlling the elongation against external resistance, such as when lowering a weight or during the downward phase of a squat. During this type of contraction, the muscle fibers are generating force but, instead of shortening, they are extending, which is essential for deceleration and control in various physical activities. This mechanism plays a key role in injury prevention and strength training, as it helps to stabilize joints and absorb shock. Understanding eccentric contraction is crucial for fitness professionals, as it informs how exercises are prescribed and performed for strength development and rehabilitation.