Final answer:
Isotonic activities are dynamic exercises that involve a range of motion against constant resistance. Examples include weight lifting, cycling, and swimming, all of which help in building muscle strength and endurance. These exercises contrast with isometric exercises, which involve muscle contraction without movement.
Step-by-step explanation:
Isotonic activities are dynamic exercises that involve moving muscles through a range of motion against a constant resistance. In isotonic exercises, the muscle length changes, leading to motion. These exercises can be divided into two categories: concentric (muscle shortening) and eccentric (muscle lengthening) movements.
Examples of isotonic activities include activities like weight lifting, cycling, swimming, and walking. In weight lifting, for instance, lifting the weight up during a bicep curl is a concentric action, while lowering it back down is an eccentric action. Each stroke in swimming or cycling propels the athlete forward through the concentric contraction of various muscle groups.
These dynamic exercises are important in building muscle strength, endurance, and are a key component of most fitness routines. They contrast isometric exercises, which involve no joint movement, with the muscles contracting against a static resistance.