Hamstring tears are often a discrete event, characterized by a sudden, sharp pain in the posterior thigh and buttock. Chronic tendinopathies of the hamstring tendon present more insidiously and are more difficult to distinguish from an S1 radiculopathy.

 Tendinopathy of the hamstrings is a chronic degenerative process produced by repetitive mechanical overload.  Runners and athletes putting their hamstrings at repetitive stretch—such as hurdlers, dancers, and gymnasts—are at the highest risk.  Hamstring tendinopathy presents as vague pain made worse with sitting, running, or other athletic activity.  There maybe no findings on physical examination, but many patients will have pain to palpation at the origin at the ischial tuberosity. There are several provocative tests with high validity and reliability, including resisted knee flexion in the prone position and the bent knee stretch test. The latter begins by first placing the affected hip in extension, then maximally flexing the hip and knee, and then finally rapidly extending the knee, which when positive causes posterior thigh pain.  MRI is considered the gold standard for the diagnosis of ham-string pathology. Specific exercise protocols include eccentric exercises, though heavy slow resistance exercises might be superior.  Ultrasound-guided corticosteroid injections consistently provide short term relief that decreases significantly by 6 months, with no reported short or long-term side effects.  Platelet-rich plasma has been used with some benefit in small, non-blinded studies, but other studies have shown no benefit, and currently there are no large, controlled studies to support its use.  Shock-wave therapy has been shown to work better than typical conservative measures but is not widely available.