The hamstring muscle group includes 3 muscles along the back of the thigh that connect the pelvis to the leg. They are the primary muscle group responsible for straightening (extending) the hip and bending (flexing) the knee. The 3 muscles are:
The anatomy of muscles includes the muscle “belly,” the portion that contracts or relaxes to move a limb, and the tendon, the portion that connects the muscle belly to the bone. Hamstring strain injuries occur when there is damage to the muscle belly caused by excessive force being generated while the muscle is being stretched. This typically happens during high-speed running, with sudden starts or changes in direction, or when the muscle is overstretched by activities such as sprinting, hurdling, kicking, or heavy lifting.
Risk factors for hamstring strain injuries include:
When a person experiences a hamstring strain injury, a sudden onset of pain is felt in the back of the thigh. It happens very quickly and causes the individual to stop performing an activity. The symptoms caused by a mild injury may only last for a few days; symptoms of a more severe injury can last for weeks. Common symptoms include:
Diagnosis of a hamstring strain injury starts with a thorough understanding of your health history and the cause of the injury. The questions your physical therapist may ask include:
Your physical therapist will also perform a clinical evaluation, including some of the following tests and measures to determine the nature of your injury:
Typically, hamstring strain injuries are classified as Grade I, II, or III depending on the severity of the injury:
If your physical therapist suspects a severe injury (Grade III), you will likely be referred to an orthopedic physician for medical diagnostic imaging, such as an X-ray or MRI, to evaluate the extent of the injury. In the event of a fracture of the ischial tuberosity (the “sit-bone,” part of the pelvis) and/or a complete rupture of the muscle, surgery may be recommended.
Immediately after experiencing a hamstring strain injury, seek help from a physical therapist. Prior to your physical therapy session, you can:
Your physical therapist will design an individualized treatment program specific to the exact nature of your injury and your goals. Your treatment may include:
Manual therapy. Physical therapists are trained in manual (hands-on) therapy to gently move and manipulate muscles and joints to improve motion, flexibility, and strength. Your physical therapist may gently massage and move the affected area to encourage healing. These techniques can target areas that are difficult to treat on your own.
Range-of-motion exercises. Although it is common for your hamstring muscles to feel stiff after an injury, it is important not to stretch these muscles early in the recovery process. Your physical therapist will indicate when it is safe and appropriate to begin gentle flexibility exercises, and will guide you through how to do them in the clinic and at home.
Muscle strengthening exercises. Hamstring strengthening will be an essential part of your rehabilitation program. Your physical therapist will compare the strength of the muscle groups in each leg, and prescribe and teach you specific exercises to target areas of weakness.
Functional training. As you regain the strength in your hamstrings, your movement quality will need to be assessed so you no longer put excessive stress on the previously injured area. Your physical therapist will develop a functional training program for the hamstring muscle group, with a gradual progression back to more demanding activities.
In the event that the severity of your hamstring strain injury requires surgical treatment, a physical therapist will guide your postoperative rehabilitation. Your physical therapist will communicate with your surgeon to ensure complete and consistent postoperative care.
You can decrease your risk of a hamstring strain injury in the following ways:
All physical therapists are prepared through education and experience to treat hamstring strain injuries. However, you may want to consider:
You can find physical therapists who have these and other credentials by using Find a PT, the online tool built by the American Physical Therapy Association, to help you search for physical therapists with specific clinical expertise in your geographic area.
General tips when you’re looking for a physical therapist (or any other health care provider):