A muscle strain is an injury to a muscle or a tendon — the fibrous tissue that connects muscles to bones. Minor injuries may only overstretch a muscle or tendon, while more severe injuries may involve partial or complete tears in these tissues.

Sometimes called pulled muscles, strains commonly occur in the lower back and in the muscles at the back of the thigh (hamstrings).

The difference between a strain and a sprain is that a strain involves an injury to a muscle or to the band of tissue that attaches a muscle to a bone, while a sprain injures the bands of tissue that connect two bones together.

Initial treatment includes rest, ice, compression and elevation. Mild strains can be successfully treated at home. Severe strains sometimes require surgical repair.

Signs and symptoms will vary, depending on the severity of the injury, and may include:

• Pain or tenderness
• Redness or bruising
• Limited motion
• Muscle spasms
• Swelling
• Muscle weakness

When to see the doctor

Mild strains can be treated at home. See a doctor if your symptoms worsen despite treatment — especially if your pain becomes intolerable, or you experience numbness or tingling.

Acute strains can be caused by one event, such as using poor body mechanics to lift something heavy. Chronic muscle strains can result from repetitive injuries when you stress a muscle by doing the same motion over and over.

Participating in contact sports — such as soccer, football, hockey, boxing and wrestling — can increase your risk of muscle strains.

Certain parts of the body are more susceptible to strains during participation in certain sports. Examples include:

• Legs and ankles. Sports that feature quick starts and jumping, such as hurdling and basketball, can be particularly tough on the Achilles tendon in your ankle.
• Hands. Gripping sports, such as gymnastics or golf, can increase your risk of muscle strains in your hands.
• Elbows. Elbow strains are often caused by throwing sports and racquet sports.

Regular stretching and strengthening exercises for your sport, fitness or work activity, as part of an overall physical conditioning program, can help to minimize your risk of muscle strains. Try to be in shape to play your sport; don't play your sport to get in shape. If you have a physically demanding occupation, regular conditioning can help prevent injuries.

During the physical exam, your doctor will check for swelling and points of tenderness. The location and intensity of your pain can help determine the extent and nature of the damage.

In more severe injuries, where the muscle or tendon has been completely ruptured, your doctor may be able to see or feel a defect in the area of injury. Ultrasound often can help distinguish among several different types of soft tissue injuries.

For immediate self-care of a muscle strain, try the R.I.C.E. approach — rest, ice, compression, elevation:

• Rest. Avoid activities that cause pain, swelling or discomfort. But don't avoid all physical activity.
• Ice. Even if you're seeking medical help, ice the area immediately. Use an ice pack or slush bath of ice and water for 15 to 20 minutes each time and repeat every two to three hours while you're awake for the first few days after the injury.
• Compression. To help stop swelling, compress the area with an elastic bandage until the swelling stops. Don't wrap it too tightly or you may hinder circulation. Begin wrapping at the end farthest from your heart. Loosen the wrap if the pain increases, the area becomes numb or swelling is occurring below the wrapped area.
• Elevation. Elevate the injured area above the level of your heart, especially at night, which allows gravity to help reduce swelling.

Some doctors recommend avoiding over-the-counter pain medications that can increase your risk of bleeding — such as aspirin, ibuprofen (Advil, Motrin IB, others) and naproxen sodium (Aleve) — during the first 48 hours after a muscle strain. Acetaminophen (Tylenol, others) can be helpful for pain relief during this time period.

A physical therapist can help you to maximize stability and strength of the injured joint or limb. Your doctor may suggest that you immobilize the area with a brace or splint. For some injuries, such as a torn tendon, surgery may be considered.

While you may initially consult your family physician, he or she may refer you to a doctor who specializes in sports medicine or orthopedic surgery.

What you can do

You may want to write a list that includes:

• Detailed descriptions of your symptoms
• Information about medical problems you've had
• Information about the medical problems of your parents or siblings
• All the medications and dietary supplements you take
• Questions you want to ask the doctor

What to expect from your doctor

Your doctor may ask some of the following questions:

• How exactly were you moving when the injury occurred?
• Did you hear or feel a pop or snap?
• When did it happen?
• What types of home treatments have you tried?
• Have you ever injured this part of your body before?
• If so, how did that injury occur?