What common sports injury involves inflammation of a tendon?

Tendonitis is the correct choice, as it specifically refers to the inflammation of a tendon, which is the fibrous connective tissue that attaches muscle to bone. This condition is often characterized by pain, swelling, and tenderness around a joint, typically resulting from overuse, repetitive motion, or acute injury. Athletes frequently experience tendonitis in various regions of the body, such as the elbow (commonly known as "tennis elbow") or the shoulder.

In contrast, a strain involves the overstretching or tearing of muscles or tendons, but does not specifically refer to inflammation. A sprain involves injury to ligaments, which connect bones to other bones, rather than tendons, and generally presents differently from tendonitis. A fracture refers to a break in a bone, which is an entirely different type of injury and does not involve tendon inflammation. Understanding these distinctions helps clarify why tendonitis is the correct answer when identifying a condition specifically related to inflammation of a tendon.