There are two types of sprains and strains. A strain is a type of injury to the muscles or tendons and is caused by overstretching or tearing of a muscle or tendon. A sprain is another type of injury and is caused by overstretching or tearing of ligaments. Sprains and strains are treated by a surgeon. Orthopedic doctors treat sprains and strains by making the ligaments and tendons more elastic. This is done by stretching and using an orthopedic brace.