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.

Using powerful new visualization technologies, researchers have captured the first 3-D images of the structure of a key muscle receptor, providing new insights on how muscles develop across the animal ...

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 ...

Actomyosin is a protein complex composed of actin and myosin. It is found in muscle fibers where it plays a role in muscle contraction. Actin is one of the most abundant proteins in eukaryotes. It ...

Though many people experience muscle twitching, it's often incorrectly identified as a muscle spasm. While both are involuntary contractions of a muscle, muscle spasms and muscle twitching aren't ...

Proprioceptive neuromuscular facilitation (PNF) is a form of assisted stretching. It combines passive stretching with muscle contraction. First, your partner applies force to stretch your muscle ...

You’re relaxing on the sofa when suddenly your eyelid starts twitching. Or perhaps it’s a muscle in your arm, your leg, or your foot that begins to spasm – sometimes for a few seconds, sometimes for ...

A new study provides evidence that COVID-19 patients' heart damage is caused by the virus invading and replicating inside heart muscle cells, leading to cell death and interfering with heart muscle ...

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.