Which type of contraction describes the muscle lengthening while lowering a weight?

Eccentric contraction occurs when a muscle lengthens while under tension, which is precisely what happens when lowering a weight. During this type of contraction, the muscle works to control the descent of the load, allowing it to stretch rather than shorten. This is essential for maintaining joint stability and controlling movement, especially in activities like lowering weights during strength training.

In contrast, concentric contractions involve muscle shortening as it contracts, typically seen when lifting a weight. Isometric contractions occur when a muscle generates force without changing its length, such as holding a weight in place without moving it. Dynamic contractions encompass both concentric and eccentric contractions, but the specific action described in the question—lengthening while lowering a weight—aligns specifically with eccentric contraction. Thus, understanding the characteristics of each contraction type helps clarify why eccentric is the right choice in this context.