What type of muscular contraction occurs when a muscle lengthens under tension?

Eccentric contraction occurs when a muscle lengthens while under tension. This type of contraction typically happens when a muscle is actively resisting a force that is greater than the force being produced by the muscle itself. For example, during the lowering phase of a bicep curl, the bicep muscle lengthens as you slowly lower the weight back down.

Eccentric contractions are important for various functions in movement and are known to play a significant role in muscle strengthening and injury prevention. They allow for controlled movements and are critical in activities like running, where muscles need to absorb energy to decelerate the body.

Other types of contractions, such as isometric, concentric, and static, involve different muscle actions. Isometric contractions maintain muscle length without change (think of pushing against a wall), concentric contractions occur when a muscle shortens while producing tension (like lifting a weight), and static contraction often refers to holding a position without changing muscle length. Each of these plays its own role in various physical activities, but only eccentric contractions involve lengthening under tension, which is essential for effective muscle function and recovery.