One of the fascinating aspects about martial arts, at least to me, is that there's so many different dimensions to it. Of course there is technique, cardio and fight IQ, but what I find less information on is the physiological transformation your body goes through. Practitioners that have been fighting for years will have conditioned their limbs and torso to dish out as well as absorb damage. However, it only goes so far; there are limits to what the body can be put through and there are plenty of instances where pros have had to hang up the gloves due to injury.
Floyd Mayweather despite his defensive and evasive prowess has admitted his hands have grown more brittle due to all the training and fights. Same may apply to other parts of the body too. One of the half-joking axioms out there is "one cannot condition one's chin." But on balance, I think the point still stands that fighting entails a unique kind of physiological conditioning. And without it, holding all other factors equal, we might see very different results if one combatant had the bone and muscle conditioning for fighting while the other did not. Two examples off the top of my head:
- Exhibition match of Pacqiao vs Shaquel O'Neil. Of course it was mostly in good fun, but Pacqiao is reported to have felt fine afterwords whereas O'Neil despite his size advantage was in considerable pain. After all, in basketball contact results in a stop of play and a foul.
- The early days of the UFC where pure karate / taekwando athletes would square off against muaithai and wrestlers. While there may be some expertise deficiencies for take downs and ground game, but I'd wager if taekwando practitioners had more hours invested in full contact sparring and less stylized striking or hitting a makiwara the result might surprise us. For it was quite easy to see that the muaithai strikers were way more resilient to getting hit because of the training style; there bodies were more acclimated to MMA.