A fan has asked at what age an MMA fighter hits their peak, and at what age they should retire. I think this varies for each athlete. There are many factors that you have to take into account. Some of those include how well you train, how much time you take to heal or rest, how you eat or take care of you body in general, as well as genetics.
I believe MMA athletes peak in their early to mid 30’s. For most athletes, the time to quit is when you begin losing. Nobody gets the itch to quit when they are winning every fight. The desire or the necessity to quit comes when you start losing fights. That’s when you start questioning your ability to continue in such a strenuous sport.

