In a concentric contraction, does the muscle lengthen or shorten?

In a concentric contraction, the muscle shortens as it generates force, typically while overcoming resistance. This type of contraction occurs when a muscle is activated and moves a load against gravity or resistance, such as when lifting weights. During this process, the muscle fibers contract and pull the two ends of the muscle closer together, resulting in a decrease in the muscle's overall length.

For instance, during a bicep curl, when you lift the weight towards your shoulder, the biceps muscle undergoes a concentric contraction. This shortening of the muscle is essential for movements requiring force production and is a fundamental aspect of resistance training and various athletic activities.