Long COVID Self-Management - The Mechanics of Breathing
As you breathe in, your diaphragm moves down towards your stomach and your intercostal muscles move your ribs up and out. These two movements occur at the same time and cause air to enter your lungs.
As you breathe out, your intercostal muscles relax. Your diaphragm moves up and, at the same time, your rib cage moves down and in. This moves the air from your lungs.