One thing to be mindful of is not coming back to obstacle racing too soon after an injury without taking proper precautions. “Overuse injuries occur in the muscles and tendons and are probably more common in Spartan Racers,” says Dr. Michael Fredericson, Director of Physical Medicine and Rehabilitation (PM&R) Sports Medicine in the Department of Orthopedic Surgery at the Stanford University Medical Center. “Returning to high-intensity athletics from an overuse injury too early won’t necessarily predispose you to arthritis, but if you have a ligament tear, those are usually traumatic. Coming back from one of those too soon can cause arthritic problems because of the unstabilized and unequal forces on your knee.”