Hamstring strain

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What this article covers

• Overview

  An acute muscle strain of the posterior thigh: a hamstring strain is an injury to the muscle-tendon unit of the posterior thigh muscle group, distinct from a sprain, which by definition is a ligament injury.

• Epidemiology

  A common sports medicine injury: hamstring strains occur across running and kicking sports whenever the muscle-tendon unit is loaded eccentrically at high speed, as in sprinting, hurdling, and soccer.

• Risk factors

  Prior hamstring strain: a history of a previous strain in the same muscle group is the strongest identifiable risk factor for a new injury, reflecting incomplete strength and flexibility recovery.

• Pathophysiology

  Eccentric overload tears the muscle-tendon unit: the hamstrings undergo maximal strain while contracting eccentrically during the late swing phase of sprinting (decelerating the swinging leg) or…

• Clinical features

  Sudden posterior thigh pain during forceful activity, with point tenderness reproduced by resisted knee flexion, establishes the diagnosis: patients report a sudden, sharp posterior thigh pain during…

• Differential diagnosis

  Piriformis syndrome: unilateral posterior thigh and buttock pain, tingling, and numbness radiating into the leg from sciatic nerve compression by the piriformis muscle, without an acute traumatic…

• Diagnosis

  Hamstring strain is a clinical diagnosis confirmed by the mechanism of injury plus point tenderness over the posterior thigh reproduced by resisted knee flexion: no imaging or laboratory testing is…

• Management

  First, stop the activity and rest the limb, avoiding further eccentric loading of the injured muscle-tendon unit, since continued loading risks converting a partial tear into a complete one.

• Complications

  Re-injury of the same muscle group: incomplete rehabilitation or premature return to sprinting and kicking activity is the most common complication, since the muscle-tendon unit remains mechanically vulnerable while healing.

• Prognosis

  Most strains recover with conservative management: injuries confined to the muscle belly or myotendinous junction, without a palpable defect, generally improve with rest, activity modification, and progressive rehabilitation.

• Prevention

  Complete a structured eccentric-strengthening program before returning to sport, rather than returning at a fixed calendar date, to reduce the well-documented risk of re-injury in the same muscle group.