Muscle contraction is the tightening, shortening, or lengthening of muscles when you do some activity. It can happen when you hold or pick up something, or when you stretch or exercise with weights.

Time under contraction is not directly measured in a typical weight training program. Most people really don't even think about the number of seconds a given muscle is forced to work. Indirectly, ...

A concentric contraction is a type of muscle activation that causes tension on your muscle as it shortens. As your muscle shortens, it generates enough force to move an object. This is the most ...