Human gait cyclograms: conventions, speed relationships and clinical applications.

Angle/Angle cyclograms of the thigh/knee interaction during slow gait are now well established in the literature on normal and pathological gaits, particularly in the pre- and post-operative analyses associated with total hip replacement. Other possible combinations have not been previously investigated for comparison of specific gait abnormalities against reliable normative data. This paper presents speed-related normative data on three important cyclograms: the thigh/knee diagram, the knee/ankle interaction and the thigh/foot pattern. The population providing our data base was a group of thirteen healthy young adult females free of any abnormality of the locomotor system. Analysis of three speeds (normalised for differences in stature of the subjects and presented in units of "relative speed", i.e. statures/s-1 so that all subjects were equally physically taxed) namely, 0.5; 0.9 and 1.3 statures/s-1 was undertaken to profile the range of walking speeds in three broad categories: slow, medium and fast. Having presented the convention for, and some normative speed-related data on the three cyclograms, this paper then shows the clinical significance of angle/angle diagrams by comparing one patient with a unilateral quadriceps paralysis against the normal thigh/knee diagram, and one patient with unilateral paralysis of m. tibialis anterior against the normal knee/ankle and thigh/foot cyclograms. The extent of malfunction in the selected gait pathologies is highlighted, providing implications as to the direction which rehabilitative measures should take. Suggestions are made as to how angle/angle cyclograms might practically be obtained and interpreted by clinical assistants who are not expert gait analysts.