Which type of contraction occurs when tension is developed without a change in length?

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

Answer: (A)

When a muscle develops force without changing its length, that is an isometric contraction. In this type, active tension is produced by cross-bridge cycling, but the external load holds the muscle at a constant length, so there’s no joint movement. A common example is holding a weight steady or pushing against an immovable object—the muscle stays the same length while tension rises to maintain the posture or balance.

Concentric contractions shorten the muscle as it generates force to move a segment, while eccentric contractions produce tension while the muscle lengthens as it controls an opposing force. Isokinetic contractions involve moving a limb at a constant speed with specialized equipment, which still entails movement and thus a change in muscle length.