What type of muscle contraction involves lengthening of the muscle?

The correct answer is based on the understanding of muscle contractions and their classifications. Eccentric contraction occurs when a muscle lengthens while under tension. This typically happens when the muscle is actively engaged in a movement that involves controlling the descent of weight or resisting a force, such as when lowering a dumbbell during a bicep curl or descending from a squat.

In terms of types of muscle contractions, eccentric contractions are important for activities requiring deceleration and stability. They not only contribute to muscle strength and hypertrophy but also play a significant role in injury prevention by allowing muscles to absorb forces effectively.

Isometric contractions involve muscle tension without any change in muscle length; concentric contractions result in shortening of the muscle as it contracts; and isokinetic contractions occur at a constant speed throughout the range of motion, which does not necessarily specify a change in length. Understanding these distinctions clarifies why eccentric contraction is recognized as the type that specifically entails lengthening of the muscle during the contraction process.