Tendons are the thick cords of tissue that connect muscle to bone. Tendonitis is a condition in which a tendon becomes irritated or inflamed, usually as the result of repetitive motion at the affected site. In some cases, it can result from a sudden, more serious injury or trauma. Activities that can lead to tendinitis include gardening, raking, building and carpentry, shoveling, painting, landscaping, playing sports (especially tennis, golf, and skiing), and throwing. Contributing risk factors include poor posture—either at home or at work—or failure to properly stretch prior to exercising or playing sports. The condition also is more common in people with abnormally positioned bones or joints and people with arthritis, gout, thyroid problems, or severe reactions to certain medications. It also can result from infection in some rare cases. More commonly, though, it affects people who attempt to perform exercise that is too intense for their level of conditioning (e.g., “weekend warriors”). While tendonitis can affect anyone, it’s more common among adults who are older than 40. This is because tendons lose their elasticity and their ability to tolerate stress as a person ages. The most common sites for tendonitis are in the thumb, elbow, shoulder, hip, knee, and Achilles tendon (heel). Treatments include rest, ice, anti-inflammatory medications, corticosteroid injections, physical therapy (usually range-of-motion exercises and splinting), and in severe cases, surgery.