The term "muscle strain" describes an injury to either muscle tissue or a tendon, the flexible tissue that connects bones and muscles. Also known as a pulled muscle, a strain occurs when you damage a muscle or tendon after pulling, tearing or twisting it. Such injuries are common, especially in people who participate in athletic activities.
Features
A muscle strain damages the tissue fibers inside of the injured muscle or tendon. The damage can range from a microscopically small tear to a larger tear capable of causing bleeding. Signs of a strain include cramps, discoloration, pain, spasms, swelling and tenderness in or around the affected muscle or tendon. Some strains can also reduce the strength of the relevant muscle or make the muscle unable to function as well or at all. Symptoms can worsen while you use the injured muscle or tendon, too, and they often decrease when you stop using the muscle or tendon.
Types
Health care professionals typically divide muscle strains into three basic groups, called grades, which indicate the extent of the injury. Grade I muscle strains, also referred to as first-degree tears, are mild and only affect a few fibers in the injured tissue. Alternatively called second-degree tears, grade II muscle strains are moderate and affect more fibers than a mild strain. Grade III muscle strains, or third-degree tears, represent a complete tear, the severest form of strain.
Severity
Injured muscles and tendons classified as grade I strains, or first-degree tears, are usually painful and sore, although they remain as strong as they were before the injury occurred. Muscles and tendons labeled as grade II, or second-degree tears, frequently cause greater pain and soreness than grade I, in addition to reduced strength, some swelling and possibly bruising. Injured muscles and tendons ranked as grade III strains, or third-degree tears, generally produce substantial discoloration, pain, soreness and swelling. They are also completely incapable of functioning.
Causes
Muscle strains are often the result of stretching a muscle or tendon too extensively or rapidly, contracting it too forcefully or overusing it without giving it enough time to rest. Situations that frequently cause strains include lifting heavy items, playing sports, working out too intensely and not stretching properly before engaging in strenuous physical activities. Muscles in certain areas of your body, such as your back, calf, groin and hamstrings, have a higher risk of suffering a strain, however.
Recovery
The location of the injury and the amount of damage are the two most important factors that influence how long it will take for a muscle strain to heal. Mild Grade I strains in areas such as your back typically start getting better in 7 to 14 days and go away in four to six weeks. However, Grade I and II strains in your legs can require up to a month or longer to heal entirely. Grade III strains are the most resistant to healing and usually do not recover without surgery to repair the tear.
