Pulled hamstring

A pulled hamstring, or hamstring strain, happens when muscle fibers and nearby tissues are overstretched or torn. This injury is especially common among athletes, with sprinters being particularly vulnerable—studies estimate that 29% of all injuries in sprinters involve the hamstring. The long head of the biceps femoris is the part most often hurt, possibly because it generates less force at the knee and hip compared to the inner hamstring muscles.

The main cause is the explosive, forceful movements in sports that overload or overstretch the hamstring group. Other contributing factors include a previous injury, weak muscles, poor flexibility, insufficient warm-up, fatigue, muscle imbalances, and overuse. This condition is frequently seen in football, baseball, American football, and rugby players, as well as dancers, water skiers, and participants in cross-country skiing, downhill skiing, judo, cricket, and bull riding.

Diagnosis is based on severity grades. A Grade 1 strain feels like cramping or tightness, with mild pain when the muscle is stretched or contracted. Grade 2 involves immediate, more intense pain, confirmed by pain during stretching, swelling, and muscle contraction. Grade 3 is severe: a burning or stabbing pain, inability to walk without pain, and a complete muscle tear, often with a lump of tissue above a depression. For Grades 2 and 3, a large bruise may appear below the injury site after a few days due to internal bleeding.

Treatment starts with the RICE protocol—rest, ice, compression, and elevation—to reduce bleeding and tissue damage. Lower-grade strains can worsen if not rested properly. Complete ruptures need surgery and rehabilitation. For the first five days, regardless of severity, the leg is rested and elevated, with ice applied for 20 minutes every two hours, and a compression bandage to limit swelling. After five days, active rehabilitation begins.

Hamstring strains are the most common musculoskeletal injury worldwide. They account for 15% of all injuries per club per season, with a 34% chance of recurrence. A previous injury is a major risk factor; about one-third of active individuals experience a re-injury overall, though the specific 2-week timeframe is not a standard canonical figure. Older age and a history of injury increase risk. Men and master athletes (over 40) are at higher risk than women and younger athletes.