Which type of muscle contraction occurs when a muscle lengthens under tension?

The correct response refers to eccentric contraction, which occurs when a muscle lengthens while maintaining tension. This type of contraction is particularly important in activities that involve controlled lowering of weights, such as gently returning a loaded barbell to the floor or during activities like walking downhill or descending stairs.

Eccentric contractions play a vital role in muscle damage and subsequent repair, which is beneficial for muscle growth and strength development. When a muscle lengthens while contracting, it can absorb more force, which is essential for controlling movements and preventing injuries.

The other contraction types differ in how they interact with resistance and muscle length:

• Isometric contractions occur when a muscle generates tension without changing its length, such as holding a weight steady.

• Concentric contractions involve the muscle shortening while generating force, like lifting a weight against gravity.

• Isokinetic contractions occur at a constant speed throughout the range of motion, typically requiring specialized equipment.

Understanding these distinctions helps in assessing muscle function during different physical activities and can assist in designing effective training programs.