What type of contraction involves muscle lengthening under tension?

The type of contraction that involves muscle lengthening under tension is known as eccentric contraction. During an eccentric contraction, the muscle generates force while simultaneously elongating, which often occurs during the lowering phase of a movement. For example, when lowering a weight in a bicep curl, the bicep muscle lengthens as it controls the descent of the weight, effectively resisting the pull of gravity while under tension.

This type of contraction plays a crucial role in movement efficiency and injury prevention, as it helps to absorb impact and control dynamic movements. In contrast, isometric contractions involve muscle tension without changing length, concentric contractions involve shortening of the muscle while generating force, and the term "stationary contraction" is not commonly used in exercise physiology. Understanding the characteristics of eccentric contractions can help fitness professionals design effective training programs that maximize strength and control.