I doubt if you could find any player in the NBA with a better work ethic than Blake. I think it started with the summer he and Taylor spent with a trainer in California (can't remember his name). He said it was like a boot camp that included grueling daily workouts, like running up sand dunes to get in shape. When his sophomore season started that fall, he was unstoppable.
Judging by everything I have read and heard, Blake continues to work harder than anyone else. Doc Rivers say no one on the team works harder than him. Obviously BG's dedication and hard work have paid huge dividends.