Experience seems to be the best teacher IMO in this aspect of martial arts. Point in case: when I first started MA, I would come home with bruises on my legs and abrasions on my feet. Thanks to my naturally high pain tolerance, I didn't take much notice until after class, usally the next day. Fast forward untill more recently I started at a Isshin Ryu school that I am sorta helping with. Being the student with the most experience, I not only get to help with warmups and exercises, but I also get to be the human heavy bag. First night of sparring 'twas me against all of the class in point sparring. 14 people later and I have no bruises, bumps, cuts, or any other injuries. I left several people with bruises on their legs from my shin blocks. (not intentionally of course, just executing technique) The point being, The only way to physical endurance is repetition, regardless of method. I've noticed this basic principle among various styles, Goju, Kyokushin, traditonal Shorin ryu, Muay Thai, etc.