Define isotonic contraction.

Isotonic contraction is characterized by a change in muscle length while the muscle generates force. This type of contraction can be further divided into two subcategories: concentric and eccentric contractions. In a concentric contraction, the muscle shortens as it contracts, allowing for movement, such as lifting a weight. In an eccentric contraction, the muscle lengthens while still producing force, such as when lowering a weight back to its starting position.

In essence, isotonic contractions involve the dynamic performance of muscle movements where the tension in the muscle remains relatively constant while it changes length, resulting in movement of the body parts or joints. This provides not only strength and power development but also functional movement capabilities that are crucial in various physical activities and exercises.