In an isotonic contraction, which statement is true?

In an isotonic contraction, the primary characteristic is that the muscle changes in length while maintaining a relatively constant level of tension throughout the movement. This occurs during activities like lifting a weight, where the muscle must shorten to produce movement, but the force exerted remains stable.

During isotonic contractions, the muscle fibers develop tension to overcome a load, resulting in either a concentric contraction (muscle shortening) or an eccentric contraction (muscle lengthening), while the overall tension remains consistent. This differentiates isotonic contractions from isometric contractions, where the muscle does not change in length despite the tension developing.

Thus, the essence of isotonic contraction is this relationship between muscle length and tension, which leads to the accurate assertion that the muscle changes in length with no change in tension.