I get tired of the "I'm bigger, so I tire faster" excuse. I get they have more muscles mass to feed but aren't their lungs larger as well?
I'm kind of small and have heard throughout my life that's why I can climb ropes or do more pull-ups than a larger fellow. I disagree but if you want to present that point then please agree that's why you can bench more. Not because you're stronger but because you're heavier.
Bigger and stronger people have a natural advantage over us smaller guys in many athletic areas, so we have to work harder, get better at our technique, ect. In something like BJJ you hear big guys making excuses like that all the time when a smaller guy beats them cause its embarrassing to them. The really good players realize it means they have to get better, work harder, learn more, ect. The mediocre ones just keep trying to get by on their size, strength and athleticism, and make excuses when it isn't enough.
That's what is so awesome and inspiring about Keenan, he's big lanky kid gifted with incredible athleticism, and a work ethic like no other. Instead of taking that for granted he works like someone who doesn't have those natural advantages, which is what makes him so scary good, imo.