What type of muscle contraction occurs when a muscle contracts but there is no change in its length?

The type of muscle contraction that occurs when a muscle contracts without any change in length is known as an isometric contraction. During an isometric contraction, the muscle generates force, but the tension in the muscle does not result in movement of the joint or a change in the muscle's length. This often happens during activities where the muscle is held in a fixed position, such as pushing against an immovable object or holding a weight in a stabilized position.

In contrast, isotonic contractions involve a change in muscle length as the muscle shortens (concentric) or lengthens (eccentric) while maintaining tension. Both concentric and eccentric contractions result in joint movement, differentiating them from isometric contractions.