What is the term for muscular movement in which the muscle shortens?

The term for muscular movement in which the muscle shortens is concentric contraction. In a concentric contraction, the muscle fibers generate enough force to overcome resistance, leading to a shortening of the muscle as it contracts. This type of movement is commonly observed when a weight is lifted, such as during a bicep curl when raising the weight towards the shoulder.

While isotonic contractions encompass both concentric and eccentric actions, it specifically refers to movements where the muscle changes length under constant tension and does not distinctly specify the shortening aspect, which is why it is not the correct answer for this question. Understanding the differentiation between these types of contractions is essential for grasping basic biomechanics and the various ways muscles function during movement.