Your primary breathing muscle is your diaphragm; a dome shaped thin sheet of muscle separating your rib cage from your abdomen.
When you inhale this dome shape flattens out as your diaphragm contracts, pushing down on the contents of your abdomen (your gut) and increasing the space in your chest cavity.
Because your gut has to go somewhere as your diaphragm descends, it forces it down and out and your tummy expands. Because of this, this natural, healthy and proper way of breathing is often referred to as abdominal breathing or diaphragmatic breathing.
If you do already have a good breathing technique it can often go awry when you start exercising as you demand more air and your breathing increases to compensate. This is when your breathing technique can change from good diaphragmatic breathing to reverse breathing i.e. pulling in your tummy as you breathe in and letting your tummy go as you breathe out.
Because your diaphragm is a muscle, you can train it like any other muscle to become stronger and helping you retain that good diaphragmatic breathing even when pushed to your limit. POWERbreathe targets your inspiratory muscles – not only your diaphragm but also your intercostal muscles, the tiny muscles in between your ribs, which are recruited during a slightly forced respiration.
You’ll notice when training with POWERbreathe that you have to work harder to breathe in. This is the effect of resistance training acting on your inspiratory muscles. When breathing out, POWERbreathe offers no resistance because when you exhale normally, your diaphragm and intercostals naturally relax and move back up, pushing the air from your lungs.