Hamstring Strains & Treatment

Overview of Hamstring Strains

Description

• A strain to a large muscle group such as the hamstrings is the result of a substantial force during contraction or a violent stretch which causes mechanical stress. This results in varying degrees of rupture within the fibres of the muscle.

• They are usually a non-contact injury and mostly occur during sprinting where quick eccentric contractions are regular.

• Hamstring muscle injuries are a common injury in sports that involve high-speed running and kicking and affects mainly sprinters, hurdlers, long jumpers, footballers and field hockey players.

• Epidemiology

  • They make up 15% of all injuries in AFL and 12% of all injuries in English football.

  • They also have the highest recurrence rate of all injuries with a recurrence rate of 34% in AFL and 12% in English football.

Anatomy

The hamstring muscle group consists of three main muscles: biceps femoris, semimembranosus and semitendinosus. Most hamstring muscle injuries occur in the biceps femoris muscle.

Presentation

• Sudden onset

• Moderately severe pain with localized tenderness

• Disabling - difficulty walking, unable to run

• Decreased length of the hamstring muscle

• Reduced strength against resistance

• Local bruising

Grades of Muscle Strain

Severity:

• Grade 0 - Muscle abnormality without evidence of pathology on imaging (Clinical syndrome)

• Grade 1 - Disruption of some muscle fibres / small tear

  • Pain during or after activity

  • May be pain on contraction, but no/minimal loss of strength

• Grade 2 - Moderate tear to muscle

  • Pain during activity which requires athlete to stop activity

  • Pain on contraction and detectable weakness

• Grade 3 - Extensive tear of muscle

  • Sudden onset of pain and may fall to ground

  • Significantly reduced ROM, pain on walking, obvious weakness

• Grade 4 - Complete tear to muscle or tendon

  • Sudden and onset of pain and significant / immediate limitation to activity

  • Palpable gap, less pain on contraction than grade 3 injury

Anatomical site:

• “a” Myofascial injury

  • Peripheral aspect of muscle

• “b Injury within muscle belly

  • Most common at muscle tendon junction

• “c” Injury extends into tendon

  • Or involves the central tendon of that muscle and generally these C type injuries have poorer prognosis, and that’s because the tendinous structures have a slower healing rate

Predisposing factors

• Intrinsic (personal-related)

  • Age: increasing age is a risk factor for hamstring injury. This relationship may be due to decreased strength and an age-related reduction in muscle fiber size and number.

  • Previous injury: past history of injury is associated with reduced strength.

  • Flexibility: prospective studies have shown either a significant association between pre-season hamstring muscle tightness and subsequent development of a hamstring muscle injury or a tendency towards a statistical relationship.

  • Strength: low hamstring strength has been shown to be a significant predictor of hamstring muscle strain injury.

• Extrinsic factors (environmental-related)

  • Warm-up: muscle strain injuries, in general, are more likely to occur without adequate warm-up

  • Fatigue: fatigued muscles are able to absorb less energy. Hamstring injuries are more common at the end of matches and training sessions.

  • Fitness level: Inadequate pre-season training resulting in low fi tness levels may contribute to an increased hamstring injury rate.

  • Training modalities: Too much emphasis on aerobic training instead of more high-intensity running/acceleration drills has been suggested as a causative factor. Abrupt increases in training volume and intensity may also contribute to injury risk.

Hamstring Strain Treatment

Treatment

• Acute Management (first 48hrs): RICE (Rest, Ice, Compression, Elevate) and pain free seated active knee extension.

• Soft tissue massage – hamstring and glute muscles.

• Strengthening:

  • Eccentric + concentric hamstring exercises – eccentric strength is particularly important in recovery and prevention of recurrence of hamstring strains.

  • Glute and adductor strengthening

• Progressive running program

• Manual therapy to lower back if indicated.

• Neural tension exercises if indicated

Prognosis

Most hamstring strains take 4-6 week to recover. However, recovering from a hamstring injury may take days, weeks or months, depending on its severity.