The clinical observation of the walk is still the only current way to define the limp, but is obviously quite a rough valuation. Taking advantage of previous studies and recent improvements in electronics, the authors have built a measuring unit-including a computer-designed for daily clinical use. This unit provides in a few minutes the variations of the ground reaction to the human body during the walk, and the displacement of the point to which this reaction is applied. Seven to ten patients per hour may be examined, including previous analysis of the results by the computer.