What are ways to strengthen my diaphragm so I can scream longer and better.
it also helps to inhail air into your lower lungs e.g breathe in then out and you'll notice that your chest comes out and your shoulders go up but if you want to strengthen your diaphragm you'll breathe so that only your stomach goes out, obviously you wont breathe like that all day but it helps to do it often. oh and when you do it your stomach should'nt move at all.
Swimming underwater, try to stay longer under the water and control your breathing up to the limit. Be careful!