The available coefficient of friction associated with different slip probabilities for level straight walking

This paper presents an investigation on different slip probabilities for level straight walking obtained when comparing a given available coefficient of friction (ACOF) value with the stochastic distribution of the required coefficient of friction (RCOF). In an early study, data from both feet of 48 participants were pooled to construct a normal distribution for the RCOF without considering the potential effects of different factors such as the walking speed, footwear type, age, gender and foot. In the current study, the RCOF of each foot for each walking condition by each participant was assumed to have a normal distribution. The slip probability was obtained by averaging the cumulative probabilities of the RCOF exceeding a given ACOF from both feet and evaluated at five levels, one out of 20, 200, 10,000, 100,000 and 1,000,000. The ANOVA results indicated that age group and walking speed had a statistically significant effect on the ACOF associated with all slip probabilities evaluated. The ACOF value obtained in that early study was lower than that with the current study for higher slip probabilities, while the opposite was true for lower slip probabilities. (C) 2013 Elsevier Ltd. All rights reserved.