What is the concentric phase of muscle contraction?

The concentric phase of muscle contraction refers to the shortening of the muscle while it generates tension and overcomes resistance. During this phase, the muscle fibers contract, and the overall length of the muscle decreases as it pulls on the bones to produce movement. For example, in a bicep curl, when you lift the weight towards your shoulder, the biceps muscle contracts concentrically, resulting in its shortening.

This phase is crucial in exercises focusing on building strength and power because it is involved in overcoming gravity or any external load. Understanding this phase is essential for developing proper training protocols and effectively planning workouts for clients, allowing personal trainers to target specific muscle actions for improved performance and hypertrophy.

The other choices refer to different phases or characteristics of muscle contractions, such as eccentric contraction (lengthening of the muscle), isometric contraction (no change in muscle length), and variations in speed, which are not the core definition of concentric contraction.