Triathlon is an individual endurance sport consisting of swimming, biking, and running. The sport has evolved drastically from when it started in 1978 to encompass a wide variety of athletes competing at different distances. There are three separate phases, with two transition periods separating them. The first phase is a swim, followed by a transition to biking. The bike portion is immediately followed by a transition to the final phase, running. Many are drawn to the sport because it allows them to cross-train without overtraining in one discipline and aggravating injuries sustained in the past. However, overuse injuries are reported in anywhere from 37-85% of athletes in various studies. The most common locations for these injuries are in the low back and the knee. Important points to consider include differing muscle recruitment patterns, training hours and injury occurrence, bicycle saddle height and overall positioning on the bike, and neuromuscular adaptation at the T2 phase. With the increase in injuries and rapidly growing popularity of endurance racing, knowledge of the sport becomes important for the physical therapists who will be seeing these multi-sport athletes in the clinic. As a clinician, it will be important to understand the demands of each sport, and factors that include biomechanics and tissue strain that can contribute to overuse injuries.