Combat athletes compete in many different sports. While some—such as wrestling, boxing, and karate—have been practiced for hundreds or even thousands of years, others, such as mixed martial arts (MMA) and Brazilian jiu jitsu (BJJ), are new to the scene. (The term "combat sports" describes a competition whose essence consists of direct combat between 2 competing athletes.¹ See "Combat Sports and Terminology in Brief" on page 19 for descriptions of different combat sports and definitions of terms.)

Similar to athletes in other pro sports—as well as to tactical athletes, including military personnel, police, and firefighters²—combat sports athletes' continued employment relies on their physical performance and, ideally, avoiding injury. However, the physical demands of combat sports mean that injuries occur more frequently than in other sports. In MMA, for example, a number of studies have found an injury rate of 24-29 per 100 fight participations.^3,4