Which type of contraction involves muscle lengthening under tension?

• A. Isometric contraction
• B. Eccentric contraction
• C. Concentric contraction
• D. Plyometric contraction

Answer: (B)

Lengthening under tension is the hallmark of an eccentric contraction. In this type, the muscle is actively generating force while its fibers lengthen, such as when you slowly lower a dumbbell or descend stairs. The external load pulls the limb downward faster than the muscle can shorten, so the muscle length increases even though it’s active.

In contrast, isometric contraction produces force without changing length, and concentric contraction shortens the muscle as it generates force. Plyometric training involves an eccentric preload followed by a rapid concentric action, but it isn’t itself a single basic contraction type.