I was watching this video...
...and one of the top comments says, "Belive it or no this guy is 5'11".
My first thought was that his height doesn't matter, but after thinking about it longer I couldn't imagine someone only 4' doing that. I think its all about the length of a persons legs, but why? Its his feet (from the ground) that he has to get above the thingamajig. Everyone jumps from the ground, zero feet, so no one would have an advantage in a competition to see who could get their feet the highest off the ground, right?