What type of muscle action is referred to as concentric contraction?

• A. Muscle lengthens while maintaining tension
• B. No movement occurs while muscle tension increases
• C. Muscle shortens while maintaining tension
• D. Muscle remains relaxed and inactive

Answer: (C)

Concentric contraction refers specifically to the type of muscle action where the muscle generates force while shortening. During this process, the muscle fibers actively contract and overcome an external load, which usually results in movement. For example, when performing a bicep curl, as you lift the dumbbell towards your shoulder, the biceps muscle contracts concentrically, shortening in length to produce the upward movement. This action is distinct from eccentric contraction, where the muscle lengthens under tension, and isometric contraction, where the muscle does not change length despite tension. Understanding this distinction is crucial for recognizing how different muscle actions contribute to strength training and overall performance in various physical activities.