Is it true you scream when you're climbing?

Yes, some people do scream when climbing and it can help by blocking out any lingering negative thoughts that may be holding them back from performing to their full potential.
 
Transcript: "Is it true? You scream when you're climbing some people do some people don't I certainly do give a little power scream when I'm really trying hard sometimes a little grunt it's the same thing that you see in tennis players when they go to smash the ball down the court, they give a yell. Now, the way I see it is, sometimes you have a little - lingering thoughts when you're trying really hard. Hard and sometimes, just giving a little power scream, giving a little grunt can help, kind of just block out any negative thoughts. You've got in there, that might be holding you back from performing to your very maximal level."