Measurement of Slip Between the Shoe and Ground During Walking

The ratio between horizontal and vertical force components (H/V) exerted by a shoe on the ground during walking has been measured using a force platform. Results have suggested that dangerous slip is most likely during the landing phase. Practical slip experiments, using a number of male subjects walking in rubber-soled shoes on an oily steel surface, have confirmed this and have shown that the severity of a slip can be measured by the distance through which the shoe slips, Experimentally the slip distance is inversely dependent on the static friction coefficient. The occurrence of slip in wear has been linked to specific peaks on the H/V trace and using stroboscope photography, it has been shown that most dangerous slips on oily steel start when the shoe is stationary. It is concluded that the static friction coefficient is the most relevant for slip-resxistance testing, but it is essential to reproduce the short time of contact of the shoe with the surface.