Cinematographic analysis of the passive straight-leg-raising test for hamstring muscle length.

Cinematography was used to compare increases in the angle of straight leg raising in relation to the horizontal with increases in the angle of straight leg raising in relation to the pelvis during five minutes of passive straight leg raising. Cinematography was also used to monitor increases in the angle of the pelvis in relation to the horizontal. Eleven subjects underwent passive straight leg raising. Three methods similar to techniques reported in the literature were used in an attempt to stabilize each subject's pelvis during the procedure. Increases in the angle of straight leg raising in relation to the horizontal were found to be greater than increases in the angle of straight leg raising in relation to the pelvis. The differences in the increases had a high correlation with the increases in the angle of the pelvis in relation to the horizontal (r = .93). The findings suggest that pelvic stabilization is difficult and that methods used to indicate hamstring length should take pelvic rotation into account.