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.

The flow of water within a muscle fiber may dictate how quickly muscle can contract, according to a new study. The flow of water within a muscle fiber may dictate how quickly muscle can contract, ...

Muscle twitches fall into two main types. There’s myoclonus, where a whole muscle or group of muscles twitch or spasm. Then ...