Identify the type of contraction where muscle length shortens.

The type of contraction where muscle length shortens is known as concentric contraction. During this type of contraction, the muscle generates enough force to overcome resistance, resulting in the muscle fibers shortening. This is commonly observed during movements such as lifting an object or performing a bicep curl, where the muscle contracts as it lifts the weight.

In contrast, isometric contraction occurs when the muscle generates force without changing length, such as holding a weight steady in one position. Eccentric contraction involves muscle lengthening while generating force, typically when controlling a descent, like lowering a weight back down. Static contraction, while not a standard term in muscle physiology, suggests muscle tension without movement, aligning more closely with isometric contractions. Understanding the distinctions between these types of contractions is vital in the study of kinesiology and muscle function.