High heels and polished floors: The ultimate challenge in research on slip-resistance

Abstract

The walking traction test was put to the ultimate test by measuring the coefficient of friction (cof) of six pairs of women's shoes including one with a flat profiled rubber sole and no separate heel and five with a range of raised heels (high heels), on a variety of dry and wet floors. The effect of applying three types of floor polish to vinyl and vinyl asbestos was also investigated. The pair of flat profiled rubber soled women's shoes could not be induced to slip on any surface either wet or dry. On dry, buffed vinyl only one of the high heel shoes slipped close to the maximum attainable cof of 0.42. The addition of two types of wax polish caused all high heel shoes to slip and they also slipped on dry terrazzo. When water containing a wetting agent was applied to these (wet) surfaces one of the high heel shoes did not slip on terrazzo, but all the high heel shoes slipped on the other floor surfaces. On wet terrazzo and wet waxed plywood the cof was higher than on dry surfaces. Kendall's coefficient of concordance ( w) for rank orders of the womens' shoes was 0.72 for five dry surfaces and 0.47 on eight wet surfaces, p < 0.001. Rank orders on dry and wet surfaces were significantly similar p < 0.01 (Spearman's rank correlation coefficient). These experiments showed that very slip-resistant and safe women's shoes are available and they support the commonly held belief that high heel shoes are less safe. With this test method it is relatively easy to obtain cof values for all footwear and for barefeet and socks. The latter can be extremely slippery and probably cause many domestic injuries. The method can also be used to measure the cof of all floor surfaces including swimming pool tiles. Two shoe samples used in earlier experiments to assess the slip-resistance of soling compound T66/103 (T66) provided additional evidence that T66 has a high cof on dry surfaces.