This is a Calisthenic Study that I use regularly, it should be treated in the same fashion as a Carmine Caruso Exercise, stay calm and relaxed and keep the air moving gently throughout. When you get to the point where you can proceed no further, take a break for 10 minutes and then resume at the point you left off. I am very much an exponent of the Bill Adam Method and use his advisory words to remind myself how important it is to keep a full beautiful sound always in all practice periods… go be awesome.