Brief Outline of Hamstring Strain
A hamstring strain, or a pulled hamstring as it is commonly referred to, 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 cause of a hamstring strain is a muscle imbalance between the hamstring and quadriceps, with the quadriceps being much stronger.
Anatomy and physiology
The hamstrings are three separate muscles that work together to extend the hip and flex the knee, and correspond to the flexors of the elbow in the upper limb. During running, the hamstrings slow down the leg at the end of its forward swing and prevent the trunk from flexing at the hip joint. The three muscles are the biceps femoris, semitendinosus, and the semimembranosus. Any of the muscles can be strained. Commonly tears or ruptures usually pull away from this attachment as well. Excessive force against the muscles, especially during eccentric contraction (when the muscle is stretching against force), can cause stretching, minor tears, or even a complete rupture.
Cause of Hamstring Strain Injury
Strength imbalance between the hamstrings and quadriceps. Forceful stretching of the muscle, especially during contraction. Excessive overload on the muscle.
Signs and symptoms
Pain and tenderness in the hamstrings; very little in a grade 1, to debilitating in a grade 3. May affect the ability to walk, from causing a limp, to a complete inability to bear weight. Swelling with grades 2 and 3.
Complications if left unattended
Pain and tightness in the hamstring will continue to get worse without treatment. The tightness in the hamstring could lead to lower back and hip problems. Untreated strains can continue to progress to a full rupture.
Grade 1: Ice, anti-inflammatory medicines
Grade 2 and 3: anti-inflammatory medicines; seek medical help if a complete rupture is suspected or if the patient is unable to walk without aid. Then physiotherapy to promote 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 should be followed.
Hamstring strains that are rehabilitated fully seldom leave any lingering effects. Complete ruptures may require surgery to repair and long-term rehabilitation.