What are the three types of muscle contractions?

The three types of muscle contractions are isometric, isotonic, and isokinetic.

Isometric contractions occur when the muscle exerts force without changing its length; this typically happens when you hold a position, such as during a plank or wall sit. In isotonic contractions, the muscle changes length while maintaining a constant force; this includes both concentric (muscle shortening) and eccentric (muscle lengthening) actions, such as during a bicep curl. Isokinetic contractions occur at a constant speed, often requiring specialized equipment, and ensure that the muscle's strength is maximally exerted throughout the full range of motion.

Recognizing these distinct types provides a comprehensive understanding of how muscles function during various physical activities and can help in designing training programs that capitalize on these different contraction types for targeted outcomes in strength and endurance. Other options do not accurately represent the classifications recognized in muscle physiology.