Sports physicians treat musculoskeletal injuries that occur as a result of participation in sports, such as knee and shoulder injuries, ankle sprains, head injuries, tendonitis and fractures. Additionally, primary care sports physicians may treat chronic health conditions that can affect athletic performance, such as asthma and diabetes. Sports physicians counsel athletes, helping them maximize performance, prevent injuries and lead a healthy lifestyle. They may suggest supplements, diet plans or exercise regimens to address performance issues. They may also help athletes with psychological or substance abuse issues related to sports. Sports physicians collaborate with physical therapists, athletic trainers and other healthcare professionals to plan courses of treatment and rehabilitation for their patients.