A pulled hamstring is a muscle injury resulting from a strain or tear in one or more of the muscles at the back of the thigh. When it happens, there may be a sudden, severe pain and a popping or snapping sound. There may also be swelling, pain, and bruising.

A pulled muscle, also known as a strain or tear, is a common injury, particularly among individuals who regularly participate in sports. The hamstrings are a muscle group at the back of the thigh that are prone to strains. These injuries typically occur when the muscle stretches beyond its limit or from a powerful muscle contraction.

Recovery typically involves rest and physical therapy. After a muscle strain injury, the muscle is vulnerable to reinjury. As such, it is important to let the muscle fully heal after an injury and to follow preventive guidelines.

In this article, we will discuss causes and treatments and provide prevention tips for a pulled hamstring.

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The hamstrings are a group of muscles in the back of the thigh. These muscles allow the hip and knee joints to bend and enable movement. A pulled hamstring describes when one or more of the hamstring muscles are stretched or contracted beyond their limit, tearing the muscle fibers.

Also known as the posterior muscle compartment of the thigh, the hamstring consists of three muscles in the back of the thigh, which are the:

The muscles that make up the hamstring start at the ischial tuberosity, which is at the bottom of the pelvis. The hamstring crosses over the knee and stops at the lower leg. The hamstring muscles help to stabilize the knees and the pelvis and play a significant role in everyday life. This muscle group primarily works to extend the hip and flex the knee. These muscles participate in the complex actions of standing, walking, and running.

The hamstring muscles work antagonistically with the quadriceps muscles, which are present at the front of the thigh. When one muscle group contracts, the other relaxes, allowing for flexion and extension of the knee. When the hamstring contracts, the knee joint flexes (bends), and when the quadriceps contracts, it extends (straightens) the leg.

A pulled hamstring can occur when the muscle becomes overloaded beyond its limits. This may occur if the hamstring sustains a sudden load that overstretches the muscle.

Usually, a pulled hamstring occurs due to a sports injury, such as sprinting or doing an activity that stretches the hamstring. For example, during running, the hamstring lengthens and sustains a certain amount of force necessary for forward motion. If that force exceeds the capacity of the muscle, it may result in a pulled hamstring.

According to research in Current Sports Medicine Reports, hamstring pulls are the most common type of muscle strain. A hamstring injury also has a high rate of reoccurrence.

Anyone can develop a pulled hamstring. But certain factors increase a person’s risk, such as:

  • participating in sports that require sudden running, sprinting, or stretching
  • having a hamstring injury in the past
  • poor flexibility in the hamstring
  • muscle imbalance, such as having stronger quadriceps than hamstrings

Pulled hamstrings also often occur in teens and young adult athletes. Hamstring injuries peak between 16–25 years of age.

The symptoms of a pulled hamstring may depend on the extent or severity of the injury. Typically, a person may notice sudden, severe pain in addition to a popping or snapping sound. A person may also notice swelling and noticeable bruising, and the area may be tender to the touch.

To classify the severity of the strain, there are three grades of pulled hamstrings, which include:

  • Grade 1: This grade of strain involves microscopic tears in the muscle fibers. Typically, an individual has mild symptoms and minimal limitations in their daily activities.
  • Grade 2: This grade of strain or pull involves a partial tear of the muscle fibers that results in moderate pain. Swelling and bruising may also occur. The injury may interfere with activities such as running.
  • Grade 3: This grade of injury involves a complete tear of the muscle fibers. Symptoms may include significant swelling and severe pain. The injury interferes with activities such as walking. Healing time can be a few months and may require surgery.

A healthcare professional diagnoses a pulled hamstring based on a review of symptoms and medical history and a physical exam. In some cases, additional tests help confirm a diagnosis. For instance, imaging studies, including an X-ray or ultrasound, may help rule out more serious injuries if suspected.

Usually, a doctor assesses the grade or severity of a pulled hamstring based on the muscle strength of the injured leg in comparison to the uninjured leg. The physician also evaluates the leg’s range of motion.

Treatment for a pulled hamstring depends on the severity of the strain. According to the American Academy of Orthopaedic Surgeons, most people with a pulled hamstring heal with nonsurgical treatment.

Typically, treatment includes the RICE method, which involves:

  • Rest: Limit participation in activities that cause pain in the hamstring until it heals.
  • Ice: Apply an ice pack for 20 minutes a few times a day.
  • Compression: Wear an elastic compression bandage to help prevent swelling.
  • Elevation: Place the thigh higher than the heart when sitting to reduce swelling.

For more severe pulled hamstrings, additional treatment may include:

  • Medications: Medications, such as over-the-counter anti-inflammatory drugs, may help ease the pain. But it is best to speak with a healthcare professional to determine which medication is best.
  • Immobilization: To immobilize the leg, an individual may need to wear a splint until the pain subsides.
  • Physical therapy: This involves utilizing exercises, stretches, and manual therapy to help strengthen the muscle and improve its range of motion. Physical therapy treatment may also help to accelerate healing.

In more severe cases, such as if the injury involves the tendon completely pulling away from the bone, a doctor may suggest surgery. Typically, this involves a surgeon pulling the tendon back into place and removing any scar tissue. Then they reattach the tendon to the bone using small devices known as anchors.

The amount of time it takes to recover from a pulled hamstring varies. Healing time depends on the grade or severity of the strain, a person’s age, and their overall health. An estimate for recovery timelines depending on the grade of injury are as follows:

  • Grade 1: 3 weeks
  • Grade 2: 4–8 weeks
  • Grade 3: 3 months

Most people who sustain a pulled hamstring recover full function after completing their treatment. Typically, the sooner someone initiates treatment, the quicker they can return to their everyday activities. People who have more severe hamstring injuries tend to require more time to heal.

There are several steps a person can take to reduce their risk of sustaining a pulled hamstring, such as:

  • warming up thoroughly before doing vigorous physical activity
  • gradually increasing the intensity of activity
  • doing resistance exercises to increase hamstring and glute strength
  • training both the hamstrings and quadriceps to help prevent imbalance
  • stretching after exercise

A pulled hamstring involves overstretching or overloading one or more of the three muscles in the back of the leg that make up the hamstring. The severity of a pulled hamstring can vary from mild symptoms to significant pain and limitation of activities.

Anyone can sustain a pulled hamstring. However, people who play sports that involve sudden bursts of running, such as football, soccer, and basketball, have an increased risk. Treatment for a pulled hamstring usually includes the RICE method and a few gentle exercises and stretches to encourage recovery.