Read his website. One, he's not very tall and is pretty big for his height. 5'9" according to his official website. http://www.calisthenicskingz.net/george_bio.htm
He does a lot of higher volume work, which absolutely leads to more size than focusing on low volume higher intensity work. He has also been doing this stuff for over a decade and seems to have done a good job at pacing his development since he keeps getting stronger. It takes a long time for ANYONE to build a body like that. Hit also has a very high protein, very low carb diet which also serves to increase metabolism(sort of, you induce a small "calorie deficit" when you digest protein, research on google) and keep his water weight down. Many people have found this sort of diet allows them to stay much leaner as well. I do not know what he was like when he started, but he has certainly sculpted a massively powerful and capable physique. I am impressed by him. 5-6 years down the line he will be impressed by ME. ![]()
Hit has shown what dedication and consistency can accomplish.