Hamstring tear is an injury to a muscle at the back of the thigh, that is caused by a rapid extensive contraction or a violent stretch of the hamstring muscle group, causing high mechanical stress. They account for up to 29% of lower limb injuries in sport, due to the involvement of high speeds such as sprinting and football, however older age can increase the risk due to a loss of flexibility.
Some experiences of hamstring tears involve pain and tenderness, with limited range of motion, where others experience additional symptoms, such as swelling or a ‘popping’ or tearing sensation.
Grade 1 and 2 hamstring tears can heal within 3 to 8 weeks, however can take months to heal depending on the severity of symptoms.
Anatomy
The hamstrings are a group of three muscles: semitendinosus, semimembranosus, and bicep femoris (long head), that predominantly acts to flex and extend the knee.
Most hamstring tears occur in the central part of the muscle, or where the muscle fibres and tendon fibres intersect (MTJ). Tendons can tear away from a small bone fragment (ischial tuberosity), that typically occur at the proximal origin (top) of the hamstring, however, can occur from the distal origin (bottom), although less common.
Symptoms
- Sudden and sharp pain
- Tenderness
- A “popping sensation” at the time of injury
- Swelling and bruising (or discolouration) in the first few hours and days
- Weakness and a loss of strength in the leg
Causes
Overload of the hamstrings typically the cause of hamstring tears, that occurs when the muscle is stretches beyond its limit or challenged with sudden load, typically during an eccentric contraction. Previous hamstring injuries can increase the risk of developing a tear, particularly if the body is compensating for another limb injury, or if there is muscle weakness and a lack of flexibility.
Diagnosis
Physical examinations are often performed, such as palpation to pinpoint the area of the hamstring tear, however precise location may be difficult to determine without medical imaging.
Other physical examinations involve performing various movement to evaluate strength and range of motion, to determine the severity or the classification (grade 1 to 3) according to the pain and physical limitations.
Neurological examination may be performed to assess the sciatic nerve, to check any entrapment or irritation in healing scar tissue. Imaging such X-rays and MRI may be advised in severe cases, to detect the location of the tear and the extent of the injury, however for grade 1 and 2 tears, only physical examination if typically required.
Treatment
There are 3 phases of treatment to aid recovery and function of the hamstring injury (grade 1 and 2):
Phase 1 (inflammation phase) -Exercises and excessive stretching should be avoided, to control pain and help scar tissue develop. At the phase, crutches may be required to reduce weight bearing and facilitate recovery.
Phase 2 (reparative phase) – Exercises are introduced to try and regain full range of motion. Progressions of more challenging exercises are included in this stage, however, should be performed tolerably and pain-free. Such exercises could include hamstring curls, hip extension (with added resistance band for progression), hamstring wall stretch, and single leg balance.
Phase 3 (remodelling phase) – specific to patients playing sport to allow return to sport, and their level of function. This phase is specific to the patient, where sport or activity-specific drills such as agility are advised to promote tissue remodelling, or drills involving quick movements such as plyometric exercises.
Exercises
- Hamstring stretch: Sit on the floor with your legs straight out in front of you. Lean forward, reaching your hands towards your toes until you feel a stretch in your hamstrings. Hold for 30 seconds and repeat 3 times.
- Hamstring curl: Stand facing a wall or chair, with your feet shoulder-width apart. Lift one foot towards your buttocks, keeping your knee bent. Lower your foot and repeat for 10-15 repetitions on each leg.
- Deadlift: Stand with your feet shoulder-width apart, holding a barbell or dumbbells in front of your thighs. Hinge forward from your hips, keeping your back straight, and lower the weights towards the floor. Return to the starting position and repeat for 10-15 repetitions.
- Romanian deadlift: Stand with your feet shoulder-width apart, holding a barbell or dumbbells in front of your thighs. Hinge forward from your hips, keeping your back straight, and lower the weights towards the floor. Keep your knees slightly bent and your hips back as you lower the weight. Return to the starting position and repeat for 10-15 repetitions.
- Glute bridge: Lie on your back with your knees bent and your feet flat on the floor. Lift your hips towards the ceiling, squeezing your glutes at the top. Lower your hips and repeat for 10-15 repetitions. This exercise strengthens the glutes and hamstrings.
Prevention
- Warm-up properly: Warming up properly before any physical activity is essential to prevent hamstring tears. It increases blood flow to the muscles, making them more pliable and less prone to injury.
- Stretch regularly: Regular stretching, especially before and after exercise, can help prevent hamstring tears. Incorporate stretching exercises such as hamstring stretches, quadriceps stretches, and hip flexor stretches into your routine.
- Build strength gradually: Gradually increasing the intensity and duration of your exercise routine can help prevent overloading the hamstrings. Focus on building strength in the hamstrings and surrounding muscles to improve overall stability and reduce your risk of injury.
- Use proper technique: Using proper technique when performing exercises that involve the hamstrings, such as running and weightlifting, can help prevent hamstring tears. Avoid over-striding, sudden changes of direction, and landing heavily on your heels.
- Wear appropriate footwear: Wearing appropriate footwear that provides adequate support can help prevent hamstring tears. Choose shoes that fit well and have good shock absorption.