PT Tip of the Month Archive

Hamstring StrainsAnatomy


The hamstrings are a group of three muscles located in the back of your thigh. They include the semimembranosus, semitendinosus, and the biceps femoris (short and long heads). With the exception of the short head of the biceps femoris, these muscles originate from the ischial tuberosity. The ischial tuberosities can be felt in the center of each buttock and are the bones you sit on. The short head of the biceps femoris originates on the back portion of your femur (thigh bone).

The semimembranosus and semitendinosus tendons can be felt along the back, inner portion of the knee as they insert onto the tibia (shinbone). The tendon of the biceps femoris can be felt along the back, outside part of the knee as it inserts onto the head of the fibula.

As a group, the hamstrings flex (bend) the knee and extend the hip backward.

Classes of hamstring strainsClassification of Hamstring Strains

Hamstring strains occur in three different grades. A grade I hamstring strain is a mild injury in which the muscle is over-stretched or “pulled”. This type of strain does not affect your ability to walk and usually only hurts with excessive stretching of the hamstrings. A grade II hamstring strain involves partial tearing of the muscle and is usually painful while walking, bending the knee against resistance, and stretching the hamstrings. Some muscle weakness along with bruising, swelling, and muscle spasm may be noticed. A grade III hamstring strain represents a complete rupture of the muscle and can be severely painful. Crutches are usually required to walk and severe weakness, bruising, swelling, and muscle spasm will be present.

Mechanism of Injury

Hamstring strains are commonly seen in athletes who engage in running, jumping, and kicking activities. Most hamstring injuries occur during sprinting and other strenuous, high-speed exercises.

The most common factors involved in hamstring injuries are lack of flexibility, inadequate warm-up, overall conditioning, fatigue, and strength imbalances. Differences in strength between the right and left hamstrings, as well as abnormal strength ratios between the hamstrings and quadriceps on the same side can increase the likelihood of injury.

Many individuals report feeling a pop and pain in the back of the thigh while running or decelerating which forces them to stop.


Immediately after a hamstring strain occurs, the PRICE method (protection, rest, ice, compression, and elevation) of treatment should be followed. If your symptoms do not improve within a few days of this conservative treatment and you are having difficulty walking, you should contact your physician. If appropriate, your doctor may refer you to physical therapy.

One of our licensed physical therapists can evaluate the extent of your hamstring strain and create an individualized plan of care based on your needs and stage of healing. Initially, your treatment may consist of modalities to help decrease your pain and inflammation followed by the initiation of range of motion, stretching, and gentle strengthening exercises. As your symptoms improve, treatment focused on strengthening, flexibility, and muscular endurance will be introduced. Emphasis on prevention of future injury will also be discussed due to the chronic nature of hamstring strains. Please contact one of our two locations if you have questions regarding the treatment of your hamstring strain.
33 Pond Avenue, Suite 107B Brookline, MA 02445 Tel: (617) 232-PAIN (7246) Fax: (617) 232-5196
1208B VFW Parkway, Suite 202 West Roxbury, MA 02132 Tel: (617) 325-PAIN (7246) Fax: (617) 325-7282