I used to be able to do over 50 pull-ups with a kip without stopping and 35 real, dead hang, pull-ups (without kipping), or resting. I could almost get a 1-arm pull-up but couldn't get the last inch. Seeing this young lady do 30 with a muscle-up midway through is extremely impressive. I had both rotator cuffs surgically repaired and now avoid pull-ups entirely because I'm worried about tearing them again. As long as you're not hurting yourself they're one of the best exercises you can do.