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Hamstring Muscles Anatomy, Injuries, and Training

woman running on a sidewalk

The hamstring muscles are responsible for your hip and knee movements in walking, squatting, bending your knees, and tilting your pelvis.

Hamstring muscle injuries are the sports injury. These injuries often have long recovery times and . Stretches and strengthening exercises can help prevent injuries.

Let’s take a closer look.

The three major muscles of the hamstrings are the:

Soft tissues called connect these muscles to the bones of the , , and lower leg.

Biceps femoris

It allows your knee to flex and rotate and your hip to extend.

The biceps femoris is a long muscle. It begins in the thigh area and extends to the head of the bone near the knee. It’s on the outer part of your thigh.

The biceps femoris muscle has two parts:

  • a long slender head that attaches to the lower rear part of the hip bone (the ischium)
  • a shorter head that attaches to the (thigh) bone


The semimembranosus is a long muscle at the back of the thigh that begins at the pelvis and extends to the back of the (shin) bone. It’s the largest of the hamstrings.

It allows for the thigh to extend, knee to flex, and tibia to rotate.


The semitendinosus muscle is located between the semimembranosus and biceps femoris at the back of your thigh. It begins at the pelvis and extends to the tibia. It’s the longest of the hamstrings.

It allows the thigh to extend, tibia to rotate, and knee to flex.

The semitendinosus muscle mainly consists of fast-twitch muscle fibers that contract rapidly for short periods.

The hamstring muscles cross the hip and knee joints, except for the short head of the biceps femoris. That crosses only the knee joint.

Hamstring injuries are most often categorized as strains or contusions.

Strains range from minimal to severe. They’re in three grades:

  1. minimal muscle damage and rapid rehabilitation
  2. partial muscle rupture, pain, and some loss of function
  3. complete tissue rupture, pain, and functional disability

Contusions occur when an external force hits the hamstring muscle, as in contact sports. Contusions are characterized by:

  • pain
  • swelling
  • stiffness
  • restricted range of motion

Hamstring muscle injuries are common and range from mild to severe damage. The onset is often sudden.

You can treat at home with rest and over-the-counter pain medication.

If you have continuing hamstring pain or injury symptoms, see your doctor for a diagnosis and treatment.

Full rehabilitation before a return to a sport or other activity is necessary for preventing a relapse. Research estimates the recurrence rate of hamstring injuries is between .

Location of injury

The location of some hamstring injuries are characteristic of a particular activity.

People who participate in sports that involve sprinting (such as soccer, football, tennis, or track) injure the long head of the biceps femoris muscle.

The reason for this isn’t fully understood. It’s thought to be because the biceps femoris muscle exerts more force than the other hamstring muscles in sprinting.

The long head of the biceps femoris is to injury.

People who dance or kick injure the semimembranosus muscle. These movements involve extreme hip flexion and knee extension.

Prevention is better than cure, according to a of hamstring injuries. The subject is well studied because of the high hamstring injury rate in sports.

It’s a good idea to stretch your hamstrings before a sport or any strenuous activity.

Here are steps for two convenient stretches:

Seated hamstring stretch

  1. Sit with one leg straight in front of you and the other leg bent on the floor, with your foot touching your knee.
  2. Lean forward slowly, and reach your hand toward your toes until you feel a stretch.
  3. Hold the stretch for 30 seconds.
  4. Do two stretches daily with each leg.

Lying down hamstring stretch

  1. Lie on your back with your knees bent.
  2. Hold one leg with your hands behind your thigh.
  3. Raise the leg toward the ceiling, keeping your back flat.
  4. Hold the stretch for 30 seconds.
  5. Do two stretches daily with each leg.

You can find more hamstring stretches .

You might also try with a foam roller.

Hamstring strengthening

Strengthening your hamstrings is also important for daily activities as well as sports. Stronger hamstrings mean better knee stability. are some exercises to help strengthen your hamstrings, quads, and knees.

Have a hamstring injury?

Note that after you’ve injured your hamstrings, you shouldn’t do excessive stretching since it can .

If you’re active in sports or dance, you’ve likely experienced some hamstring discomfort or pain. With proper strengthening exercises, you can avoid having a more serious hamstring injury.

Discuss an exercise program with your coach, trainer, physical therapist, or other professional. have assessed the types of training exercises that work best for prevention and rehabilitation.