Strain Vs. Sprain

Confused on how a strain differs from a sprain?

Woman holding her hurt ankle at a race.
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Strains are injuries that affect muscles or tendons, thick bands that attach muscles to bones. They occur in response to a quick tear, twist, or pull of the muscle. Strains are an acute type of injury that results from overstretching or over contraction. Pain, weakness, and muscle spasms are common symptoms experienced after a strain occurs.

What Causes Strains?

Muscle strains are caused by high velocity forces acting against a muscle.

A sudden motion may cause your muscle to quickly overstretch and then contract forcefully, leading to mild or severe tearing of the muscle tissue. Sometimes, but not always, bruising may be present if you strain a muscle.

How can you tell if you have strained a muscle? Typically, the muscle you strain will hurt when you try to contract it. For example, if you strain your hamstring, you will likely feel pain when you try to use the hamstring muscle to bend your knee. 

Overstretching a muscle that has suffered an acute strain may also cause pain. Stretching your hamstrings in the days following a hamstring muscle strain will likely be painful, indicating that your muscle is strained.

Muscle Strain Severity Grades

There are different grades of muscle strains, ranging from grade I to grade III.

  • Grade I muscle strains indicate that the muscle tissue is simply overstretched.
  • Grade II muscle strains occur when the muscle tissue is partially torn.
  • Grade III strains are full thickness tears through the muscle tissue. These typically are considered severe and are accompanied by significant pain, swelling, bruising, and functional mobility loss.

Ligament Sprains

Sprains are injuries that affect ligaments, thick bands of cartilage that attach bone to bone.

They occur in response to a stretch or tear of a ligament. Sprains are an acute type of injury that results from trauma such as a fall or outside force that displaces the surrounding joint from its normal alignment. Sprains can range from a mild ligamentous stretch to a complete tear. Bruising, swelling, instability, and painful movement are common symptoms experienced after a sprain occurs.

LIgament Sprain Severity Grades

Ligament sprains grading follows along similarly to muscle strain grades.

  • Grade I: the ligament is simply overstretched
  • Grade II: the ligament is partially torn
  • Grade III: the ligament is completely torn

Ligaments sprains are typically accompanied by excessive motion around the joint that is supported by the ligament. Many special tests, like the anterior drawer test for the ACL, rely on pulling on your joint to test if excessive mobility is present. An MRI is typically necessary to determine if a sprain or strain is a grade I, II, or III.

Physical Therapy for a Ligament Sprain

If you have a ligament sprain, you may benefit from physical therapy to help you fully recover.

Your physical therapist will use various techniques to improve your pain, swelling, and overall range of motion and strength around the area where your ligament is sprained.

Performing strengthening exercises to help support the joint where the ligament is injured may be necessary. Sometimes, bracing is needed while your ligament is healing and if you are planning on returning to high level sports. For severe grade III sprains, surgery may be necessary to stabilize your injury and to allow you to get back to normal activity.

If you are having pain or limited mobility after an injury, you should visit your doctor and physical therapist to determine if a sprain or strain may be the cause of your condition. Your PT can then help you return to your previous level of activity.

Edited by Brett Sears, PT.

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