Clinical Concerns Swim. Bike. Run. Repeat. Welcome to the world of injuries waiting to happen. The successful treatment of triathletes depends on many factors, but to keep things simple, the following will address the most common repetitive ailments you are likely to see with this patient demographic. The research shows some alarming numbers pertaining to shoulder pain. And competitive swimming has long been associated with shoulder pain because 90 percent of a swimmer’s propulsion comes from the upper extremities.