Hamstring Muscles: Anatomy, Function, and Common Injuries

What Are Hamstring Muscles?

The hamstring muscles are a group of three muscles that run along the back of your thigh, from your hip to just below your knee. These muscles work together to bend your knee, extend your hip, and control leg movement during activities like walking, running, and jumping. The hamstrings are essential for maintaining stability and power in your lower body.

Anatomy of the Hamstrings

The three hamstring muscles are:

• Biceps femoris: The outermost hamstring muscle, with two heads—a short head and a long head.
• Semitendinosus: Located on the inner side of the back of your thigh, this long, cord-like muscle helps flex your knee.
• Semimembranosus: This broad, flat muscle lies deep to the semitendinosus and also assists in knee flexion.

All three hamstring muscles originate at the ischial tuberosity, a bony projection at the base of your pelvis. They then travel down the back of your thigh, crossing the knee joint before attaching to the bones of your lower leg.

Functions of the Hamstring Muscles

The main functions of the hamstring muscles include:

• Flexing (bending) the knee: The hamstrings are the primary muscles responsible for bending your knee, allowing you to bring your heel towards your buttocks.
• Extending (straightening) the hip: When your trunk is fixed, the hamstrings help extend your leg behind you, as when taking a step backwards.
• Rotating the lower leg: When your knee is bent, the hamstrings help rotate your lower leg inward (medially) or outward (laterally).

These hamstring functions are essential for activities like walking, running, jumping, and climbing stairs. The hamstrings also work with other leg muscles to stabilise your pelvis and knees during movement.

Common Injuries of the Hamstring

Understanding the difference between a hamstring strain vs tear is important for proper treatment and recovery planning. Here are some of the most common hamstring injuries:

1. Hamstring Strain

A hamstring strain, also known as a pulled hamstring, occurs when one or more of the hamstring muscles are overstretched or partially torn. This typically happens during activities that involve sudden acceleration or deceleration, like sprinting or jumping. Symptoms of a hamstring strain include sudden pain, tenderness, swelling, and bruising at the back of your thigh. You may also experience weakness and difficulty moving your leg.

2. Hamstring Tear

A hamstring tear is a more severe injury that involves a complete or partial rupture of the muscle fibres. This can happen due to a sudden, forceful contraction of the hamstrings, often during explosive movements. A hamstring tear can cause severe pain, swelling, and significant weakness in the affected leg. You may hear a popping sound at the time of injury and find it difficult to walk or bear weight on the injured leg.

3. Tendinopathy

Hamstring tendinopathy refers to inflammation or degeneration of one or more of the hamstring tendons, which attach the muscles to the bones. This condition is often caused by overuse or repetitive strain, particularly in runners or athletes who frequently perform hamstring-intensive activities. Symptoms of hamstring tendinopathy include persistent pain and stiffness at the back of the thigh, especially near the buttocks or knee. The pain may worsen with activity and improve with rest.

Hamstring injuries are common, especially among athletes who engage in sports involving sprinting, sudden starts and stops, or quick changes in direction.

Risk Factors for Hamstring Injuries

Several factors can increase your risk of developing hamstring injuries, including:

• Previous hamstring injury
• Poor flexibility or tightness in the hamstrings
• Muscle imbalances, particularly between the quadriceps and hamstrings
• Inadequate warm-up before physical activity
• Fatigue or overuse
• Participating in sports that involve sprinting, jumping, or quick direction changes.

What Conditions and Disorders Affect Hamstring Muscles?

In addition to strains and tears, other conditions can affect the hamstring muscles:

• Avulsion fractures: This occurs when a tendon pulls away a piece of bone at its attachment point.
• Muscle contusions: A direct blow to the hamstrings can cause a bruise or haematoma within the muscle.
• Sciatic nerve irritation: Compression or inflammation of the sciatic nerve can cause pain, tingling, or weakness in the hamstrings.
• Referred pain: Discomfort in the hamstrings can sometimes originate from issues in the lower back, hip, or knee.

What Are the Risk Factors for Hamstring Muscle Injuries?

Certain factors can make you more prone to hamstring muscles injuries:

• Age: Muscle flexibility and strength tend to decrease with age.
• Sports participation: Athletes who engage in sprinting, hurdling, or sports with rapid acceleration/deceleration have a higher risk.
• Poor conditioning: Weak or imbalanced hamstrings are more susceptible to injury.
• Muscle tightness: Tight hamstrings are more likely to be overstretched during activity.
• Previous injury: A history of hamstring strains or tears increases your risk of re-injury.

How Can We Keep Our Hamstrings Healthy?

To prevent hamstring injuries and keep your muscles healthy:

• Warm up properly before physical activity to increase muscle flexibility and reduce injury risk.
• Perform regular stretching exercises to maintain or improve hamstring flexibility.
• Strengthen your hamstrings with exercises like hamstring curls, bridges, and Nordic curls.
• Cross-train with low-impact activities like swimming or cycling to prevent overuse injuries.
• Gradually increase the intensity and duration of your workouts to avoid overloading the hamstrings.
• Listen to your body and rest if you experience pain or tightness in your hamstrings.

Read: Ligaments: Structure, Function, and Common Injuries

Conclusion

At Metropolis Healthcare, we understand the importance of timely and accurate diagnosis in managing musculoskeletal conditions. Our team of qualified blood collection technicians can perform convenient at-home visits to collect samples, which are then processed at our advanced diagnostic labs. With reliable results and personalised care, Metropolis empowers you to prioritise your health and make informed decisions about your well-being.

Also Read: Anterior Cruciate Ligament (ACL) Injury or Tear: Treatment & Recovery Tips

FAQs

What are the 3 hamstring muscles?

The three hamstring muscles are the biceps femoris, semitendinosus, and semimembranosus. They are located at the back of your thigh and work together to flex your knee and extend your hip.

How do I know if I have pulled my hamstring?

If you have pulled your hamstring, you may experience sudden pain at the back of your thigh during activity, along with tenderness, swelling, and bruising. You may also have difficulty moving your leg or bearing weight on it.

How do I strengthen my hamstrings?

You can strengthen your hamstring muscles with exercises like hamstring curls (using a machine or resistance band), bridges, deadlifts, and Nordic curls. Focus on performing the hamstring muscles exercises with proper form and gradually increasing the resistance or number of repetitions.

Can you walk with a torn hamstring?

The ability to walk with a torn hamstring depends on the severity of the tear. With a mild tear, you may be able to walk with a limp. However, a severe tear can cause significant pain and weakness, making it difficult or impossible to bear weight on the affected leg.

How long does a hamstring injury take to heal?

The healing time for a hamstring injury varies depending on the severity of the strain or tear. Mild strains may heal within a few days to a couple of weeks, while more severe strains can take several weeks to months. Complete tears may require surgery and a longer recovery period.