« Back to Glossary IndexBreathing out is normally passive, but during periods of active exhalation, such as during high-intensity exercise, coughing, or in critically ill patients, the expiratory muscles are recruited to force exhalation. These are your abdominal wall muscles (transversus abdominis muscle, internal oblique muscle, external oblique muscle, and rectus abdominis muscle) and some of your rib cage muscles, including the internal intercostal muscles and the triangularis sterni muscle. « Back to Glossary Index
