Accessory muscle breathing means using muscles other than those typically used for breathing to take in and expel air. One example is the subclavius — between the collarbone and the top rib — which ...

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.

Your deltoid muscles make up a main muscle group in your upper body. They’re connected with many other muscles and bones in your upper back, neck, and shoulder region and are extremely mobile. They ...

slow-twitch muscle fibers, which move more slowly but help to keep you moving longer fast-twitch muscle fibers, which help you move faster, but for shorter periods “Twitch” refers to the contraction, ...