Sprains and strains are usually minor injuries that often result from sports, exercise, or other physical activity. Sprains refer to an injury to a ligament (the connective tissue that links bones together at joints), most often in the ankle, knee, elbow, or wrist. Strains are tears in muscle tissue, commonly occurring in the muscles that support the calf, thigh, groin, and shoulder. Sometimes sprains and strains can be severe, leading to weeks of rehabilitation.
Sprains generally result from a twisting force applied to a joint while it is bearing weight, causing the ligament to stretch beyond its natural limit. Sprains usually occur with sudden, unexpected movement (a fall or a twist). Muscle strains occur when the weight load on a muscle is greater than the weakest part of the muscle can bear. Strains usually happen during activities that require your muscle to stretch and bear weight at the same time. Some evidence suggests that previous injuries or limited flexibility contributes to sprains. You are at risk for a sprain or strain if you do the following: