Stochastic distribution of the required coefficient of friction for level walking--an in-depth study.
This study investigated the stochastic distribution of the required coefficient of friction (RCOF) which is a critical element for estimating slip probability. Fifty participants walked under four walking conditions. The results of the Kolmogorov-Smirnov two-sample test indicate that 76% of the RCOF data showed a difference in distribution between both feet for the same participant under each walking condition; the data from both feet were kept separate. The results of the Kolmogorov-Smirnov goodness-of-fit test indicate that most of the distribution of the RCOF appears to have a good match with the normal (85.5%), log-normal (84.5%) and Weibull distributions (81.5%). However, approximately 7.75% of the cases did not have a match with any of these distributions. It is reasonable to use the normal distribution for representation of the RCOF distribution due to its simplicity and familiarity, but each foot had a different distribution from the other foot in 76% of cases.
The stochastic distribution of the required coefficient of friction (RCOF) was investigated for use in a statistical model to improve the estimate of slip probability in risk assessment. The results indicate that 85.5% of the distribution of the RCOF appears to have a good match with the normal distribution.
Liberty Mutual Research Institute for Safety, Hopkinton, MA 01748, USA. wen.chang@libertymutual.com
Wen-Ruey
WR
Chang
Simon
S
Matz
Chien-Chi
CC
Chang
D000058:Accidental Falls / Q000517:prevention & control*; D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D017276:Friction; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011336:Probability; D018570:Risk Assessment / Q000379:methods*; D012775:Shoes; D018709:Statistics, Nonparametric; D013269:Stochastic Processes; D016138:Walking / Q000502:physiology*; D055815:Young Adult