Endurance adaptations for activities like marathons primarily involve slow-twitch muscle fibers, capillaries, and mitochondria, which are not sufficient for high-intensity sports like MMA.

“the endurance of being able to do triathlon or Swim a very long distance the adaptations are primarily taking place in the slow fibers and you have some very specific uh adaptations to the capillaries and the mitochondria so many things but in a very specific way and that's not going to help you let's say if you're a fighter it's happened over and over where a guy who's been uh marathoner he takes up MMA MMA and he starts getting gassed really rapidly because while he has uh his slow fibers can keep going forever but not at the intensity that's required for this particular sport”