A hamstring strain or pull is a stretch or tear of the hamstring muscles or tendons. This is a very common injury, especially in activities that involve sprinting or explosive accelerations. A common case of a hamstring strain is muscle imbalance between the hamstring and quadriceps, with the quadriceps being much stronger.
Any of the hamstring muscles can be strained. Commonly minor tears happen in the belly of the biceps femoris muscle closest to the knee. Complete tears or ruptures usually pull away from this attachment as well. Excessive force against the muscles, especially during eccentric contraction (when the muscle is contracting and lengthening, against force) can cause stretching, minor tears or even complete rupture.
Cause of injury
Strength imbalance between the hamstrings and quadriceps. Forceful stretching of the muscle, especially during contraction. Excessive overload on the muscle.
Signs and symptoms
Grade 1: Mildly tender and painful. Little or no swelling. Full muscular strength.
Grade 2: More marked pain and tenderness. Moderate swelling and possible bruising. Gait affected – limping.
Grade 3: Extreme pain. Marked swelling and bruising. Inability to bear weight.
Complications if left unattended
Pain and tightness in the hamstring muscles will get worse without treatment. Tightness in the hamstrings can lead to lower back and hip problems. Untreated strains can progress to a full rupture.
Grade 1: Ice. Anti-inflammatory medication.
Grade 2: and 3: RICER. Anti-inflammatory medication. Seek medical help if a complete rupture is suspected or if the patient is unable to walk unaided. Then heat and massage to promote blood flow and healing.
Rehabilitation and prevention
Stretching after the initial pain subsides will help speed recovery and prevent future recurrences. Strengthening the hamstrings to balance them with the quadriceps is also important. When re-entering activity, proper warm-up must be stressed and a gradual increase in intensity is important.
Hamstring strains that are rehabilitated fully seldom leave any lingering effects. Complete ruptures may require surgery to repair and long-term rehabilitation.