What term best describes the tearing of muscle fibers due to sudden contraction or excessive stretching?

The term that best describes the tearing of muscle fibers due to sudden contraction or excessive stretching is "strain." A strain specifically refers to an injury that affects the muscle or tendon, which connects the muscle to the bone. When the muscle fibers are overstressed, they can become damaged, leading to partial or complete tears of the muscle tissue. This often results in pain, swelling, and a decrease in the ability to use the affected muscle.

The other terms have different meanings: a contusion refers to a bruise caused by a direct blow to the muscle, leading to bleeding under the skin but not a tear of the muscle fibers. A sprain, on the other hand, involves injury to ligaments, which connect bones to each other, rather than muscles. The term "muscle tear" is somewhat generic and not as medically precise as "strain," which specifically conveys the nature of the injury. Each of these terms is related to musculoskeletal injuries but focuses on different tissues and types of injuries.