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.

Labor contractions are the physical way your uterus tightens to promote delivery of your baby. All body muscles tighten and shorten (contract) when they’re being used. And the uterus is one of the ...

Isometric Muscle Contraction: A type of muscle contraction in which activation of motor units and the production of force does not result in joint motion or a change in muscle length. This occurs when ...