RT Journal Article SR Electronic T1 Hamstrings stretch reflex in human spasticity JF Journal of Neurology, Neurosurgery & Psychiatry JO J Neurol Neurosurg Psychiatry FD BMJ Publishing Group Ltd SP 231 OP 235 DO 10.1136/jnnp.34.3.231 VO 34 IS 3 A1 David Burke A1 J. D. Gillies A1 James W. Lance YR 1971 UL http://jnnp.bmj.com/content/34/3/231.abstract AB In 16 patients with spastic paralysis the hamstrings stretch reflex was found to increase as the velocity of stretch increased, and generally to subside after movement ceased. These effects are attributable to the dynamic property of the primary spindle ending. The stretch reflex commonly appeared in only the last third of the stretching movement and was maximal as the knee became fully extended. This is consistent with the static properties of the primary and secondary spindle endings, and accounts for the absence of the clasp-knife phenomenon in the spastic hamstrings. The difference in the nature of the stretch reflex in spastic flexor and extensor muscles is best explained by the differential reflex effects of group II afferent fibres which facilitate flexor motoneurones and inhibit extensor motoneurones.