Muscle Ups are the one of the most advanced body weight exercises out there. When I performed my first muscle up, I got hooked and, I wanted to do them all the time. Soon after this, I was experiencing some shoulder pain. Years later, I worked with a crossfit coach and he told me that I should wait at least 5 days between each time I work on my muscle ups. Muscle Ups take a huge toll on your shoulders and it is very important that you get adequate amount of rest between each muscle up sessions. If you haven't performed your first muscle up yet. Check out video below.