Repeated exercise, or wasting, can change the way key genes work.

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.

Researchers have identified the role of the large Maf transcription factor family in regulating fast twitch muscle fibers. A mouse model lacking Maf expression in the skeletal muscles exhibited a ...