During which type of contraction do muscles shorten in length while developing tension?

Muscles shorten in length while developing tension during concentric contractions. This type of contraction occurs when a muscle generates enough force to overcome resistance, allowing it to shorten and produce movement. For instance, during a bicep curl, as the weight is lifted towards the shoulder, the bicep muscle shortens and contracts, demonstrating concentric contraction.

Isometric contractions, on the other hand, involve muscle tension without a change in length, meaning the muscle does not shorten or lengthen despite the exertion of force. Eccentric contractions involve lengthening of the muscle while it is under tension, such as when lowering a weight, where the muscle elongates as it resists the pull. Isotonic contractions are a broader category that includes both concentric and eccentric movements, thus while they involve shortening and lengthening through a range of motion, they do not specifically focus solely on the shortening aspect. Therefore, concentric is the precise term for when muscles shorten while developing tension.