Which contraction type allows for movement while keeping the muscle tension the same?

The correct choice is isotonic contraction, as it involves muscle shortening or lengthening while maintaining a constant tension throughout the movement. In isotonic contractions, the muscle generates enough force to overcome resistance, allowing for movement of the associated bone or joint. This is commonly seen in actions such as lifting a weight, where the muscle fibers actively contract to either lift the object (concentric contraction) or lower it in a controlled fashion (eccentric contraction).

Isometric contractions, by contrast, occur when the muscle generates tension without changing its length, meaning there is no movement of the joint despite the muscle being engaged. Isokinetic contractions involve a variable resistance that accommodates the muscle's effort throughout the full range of motion, which typically occurs with specialized equipment in a controlled setting.

Eccentric contraction refers specifically to the lengthening of the muscle under tension, such as when lowering a weight. While it does involve movement, it is characterized by the muscle elongating rather than maintaining the same tension throughout the action, which is distinct from what is described by isotonic contraction.