The analysis of normal stepping movements as a possible basis for locomotor assessment of the lower limbs.

Sagittal plane rotations of the thigh and shank when leading or trailing during forward or backward and during upward or downward stepping manoeuvres (one step, starting and finishing with erect stance) were recorded by polarized light goniometry in the form of thigh-knee angle diagrams. Angles and limb projections corresponding to key features of the diagrams were measured for 21 normal subjects and at three step heights. Correlations of the measurements with the height of step relative to stature were examined and predicted norms presented for a step equal to 10% of stature. The eight possible movements on a given step consist of four conjugate pairs; the members of a pair have reversed time-sequences and gravity assists one while opposing the other. The similarities of the conjugate manoeuvres were analysed statistically. A test of locomotor function is suggested on the premise that disturbances of function would be revealed by within-subject comparisons of conjugate manoeuvres. The suitability of 10% step tests for clinical use and the problems of selecting data of manageable proportions are discussed.