The Slump Test and Posterior Thigh Disorders

Introduction: The slump test is used in athletes with suspected hamstring strains to determine the presence of neural mechanosensitivity. Other than cadaveric investigations, limited evidence exists regarding this test with respect to the neuromuscular system. Aim: To examine the effect of the slump test on local muscular and neural structures in the posterior thigh in athletes with hamstring injury. Methods: Electromyography and ultrasound were utilised to determine hamstring muscle activity onset and sciatic nerve excursion respectively. Predictability of the slump test with respect to hamstring injury occurrence was also investigated. Results: 96% (n=26) of therapists used the slump test diagnostically, whilst 63% utilised it as a treatment tool. The slump test was ineffective at predicting hamstring injury occurrence. In hamstring injured athletes (n=10) the slump test with cervical flexion, was found to activate biceps femoris significantly earlier (p<0.008) than semitendinosus, also pain and resistance, in the injured limb. Reduced sciatic nerve longitudinal excursion in the injured limb of two athletes with no radiological evidence of hamstring muscle damage was observed during the slump test with cervical flexion and ankle dorsi-flexion; a finding not replicated in the one athlete who had an actual hamstring muscle injury. Conclusions: Biceps femoris appears to act to protect the local neural system in the posterior thigh in hamstring injured athletes. Considering two athletes with posterior thigh pain had no muscle damage to the hamstring muscles, yet presented with reduced sciatic nerve excursion in the injured limb during the slump test, the possibility of biceps femoris acting to protect the nervous system is feasible. This thesis is novel in its demonstration of the protective nature of biceps femoris acting during the slump test, in addition to quantifying sciatic nerve excursion in athletes with posterior thigh pain.