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, ...

Time under tension (TUT) is a weightlifting technique designed to build muscle mass by increasing the time muscles spend activated during an exercise. We cover if it works and what its benefits are.