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 muscle twitch creates short, involuntary muscle contractions, which affect tiny muscle areas that lie beneath the skin.

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 ...

Medically reviewed by Mallory Christopherson, DC Key Takeaways Back spasms are involuntary muscle contractions. They can ...

Muscle twitches can occur for many reasons, such as a lack of sleep, caffeine use, nutrient deficiencies, overexertion, and stress. Depending on the cause, treatments and remedies may help relieve ...

In a serendipitous discovery, UC San Diego researchers using cryo-EM technology captured the first visualizations of the 3-D structure of the muscle acetylcholine receptor in fetal and adult muscles.

This is a common strength training technique that involves manipulating the muscle lengthening portion of an exercise, usually by slowing down the movement. Share on Pinterest Getty Images/Eugenio ...

Matt Hill receives funding from the Wellcome Trust. Every activity we do requires our muscles to either shorten or lengthen. For example, when we climb a flight of stairs or get out of a chair, our ...