Hamstring injuries are the most common muscle injury, and are very common in athletes and can cause a significant loss of playing time depending on the sport.
On this page:
Epidemiology
Amongst professional athletes, hamstring injuries are reported to make up 15% of all injuries in Australian Football players and 12% of injuries among soccer players 1.
Pathology
Location
As with any muscle injury, the hamstrings can be injured at multiple possible points 1,4:
proximal free tendon
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myotendinous junction (most common)
proximal more commonly injured than distal
biceps femoris most common hamstring muscle injured
epimysial/myofascial: most common in biceps femoris proximal to the fusion of the short and long heads
intramuscular (rare)
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distal free tendon
semitendinosus distal tendon injury (most common)
Mechanism
Hamstring injuries can result from 1,4:
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acute injury
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type 1
eccentric contraction during high-speed running for limb deceleration in preparation for a foot strike
proximal myotendinous junction of biceps femoris most commonly injured
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type 2
excessive lengthening of the hamstring (e.g. dancing, slide tackles, high kicking)
proximal free tendon of semimembranosus
-
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chronic overuse
most commonly seen in runners (over all distances)
proximal hamstring origin tendinopathy, with semimembranosus, most commonly affected
Classification
Clinically, hamstring injuries can be graded as 2:
grade 1: no appreciable muscle tearing, <5% loss of function/strength
grade 2: damage to the musculotendinous junction (MTJ); reduced strength; some residual function
grade 3: complete tear of the myotendinous junction; loss function +/- a palpable gap
There are numerous imaging classification systems including:
British Athletics muscle injury classification (MRI-based)
Radiographic features
There are no unique features of hamstring-specific injuries. Please see the general articles on muscle injury and tendon pathology for further details.
Treatment and prognosis
Return to play is largely predicted by clinical assessment with a poor correlation between imaging-based grading systems and time to return to play 4. Prognostic factors affecting a longer rehabilitation and thus delayed return to play include 3,4:
proximal free tendon injury
proximity to the ischial tuberosity
≥ grade 3 injury (i.e. grade 1 and 2 injuries are not associated with time to return to play) 4
The recurrence rate is ~20% (range 12-31%) and can occur within a short timeframe (e.g. 2 weeks) after return to play 1,3.
Differential diagnosis
Patients presenting with posterior thigh pain suspicious of a hamstring injury but have a negative MRI (so-called "MRI-negative hamstring injury") may have symptoms from 4:
lumbar spine referred pain
fascial injury
gluteal trigger points
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