Medically reviewed by Brigid Dwyer, MD Key Takeaways Clonus causes involuntary, rhythmic muscle contractions when a muscle is stretched.It is often observed in conditions like multiple sclerosis, ...

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.

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.

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 ...

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, ...

Scientists discover that muscles repair themselves by moving thousands of internal nuclei, a rapid process that is key after ...

Muscles and nerve fibers allow a person to move their body and enable the internal organs to function. There are more than 600 muscles in the human body. People also have different types of muscle. A ...