The study of gait by verbal expression of visual impressions has been difficult, laborious and inaccurate. In 1836, the Weber1brothers reported observations by which they established the fact that, in walking, the trunk and the center of gravity sink to a lower level than when the erect position is maintained. They also noted that the sinking increases with the length of the stride. Marey,2in 1872, devised a chronographic method for recording the stride of man. His apparatus consisted of special shoes with soles containing a compressible air chamber, connected by rubber tubing to a Marey writing tambour, which was carried in the hands while the subject walked. When each foot touched the ground, a wave of air pressure caused the respective tambour to record an ascending curve on a revolving drum. Marey's method did not give much useful information but it did reveal the length of