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, ...

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.

Isometric exercises are exercises that involve the contraction of muscles without any movement in the surrounding joints. Most muscle strengthening exercises involve moving the joints, using the ...