BJJ is fun. You can roll for 40 minutes and have fun. That is impossible in Judo or wrestling. In Judo and wrestling you have to try hard every time. They always train hard against the clock - and short - 5 -6 minutes ( the super unpleasant zone). There are no easy rolls. They practice having things suck. BJJ players have fun rolling around - it is a totally different mindset. Not surprsingly if you practise for character and toughness you get character and toughness.
Here is some science behind this:
- Athletes clearly have higher pain tolerance than the general population. That's a correlation, but what about causation? Does hard training increase your pain tolerance, or do naturally tough bastards tend to take up sports? There's no clear answer, but a strong hint comes from one 12-week study of non-athletes in which aerobic training significantly increased their pain tolerance. It could be a mix of both factors, though.
- These measurements of pain tolerance aren't taken during or immediately after exercise. It's well known that exercise helps you block out pain, but these are measurements of "baseline" pain tolerance, independent of adrenaline and endorphins and so on.
- While athletes showed increased pain tolerance, they didn't show any difference in pain threshold (the level of stimulus at which they start perceiving pain). In other words, it's not that athletes don't feel pain -- they feel it the same as everyone else, but they've learned to cope with or ignore it.
- "[E]ndurance athletes had a moderate tolerance for pain and their scores were fairly uniform. Athletes involved in game sports had a higher tolerance for pain than other athletes, but the results varied widely, suggesting that endurance athletes are more alike in their physical and psychological profiles, while athletes involved in game sports are more diverse. "
- The findings about pain threshold vs. pain tolerance are consistent with the literature on chronic pain management. Exercise helps pain patients improve their quality of life, but doesn't decrease the actual amount of pain they feel. They're just able to tolerate it better.
- A final quote from the paper, which I think is on the money: "Athletes are frequently exposed to unpleasant sensory experiences during their daily physical efforts, and high physical and psychological resistances must be overcome during competitions or very exhausting activities. However, athletes are forced to develop efficient pain-coping skills because of their systematic exposure to brief periods of intense pain. Therefore, pain coping is an integral part of athletic training, and coping skills are important features in the development of athletic character."