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Shoe sole tread designs and outcomes of slipping and falling on slippery floor surfaces.

Liu LW, Lee YH, Lin CJ, Li KW, Chen CY - PLoS ONE (2013)

Bottom Line: Gait parameters were calculated based on the motion data.The condition with shoe sole and floor had both tread grooves parallel to the walking direction had the lowest COF and the longest slip distance among all experimental conditions.The Pearson's correlation coefficients between slip distance and slip velocity, time to foot flat, foot angle, and compensatory step length were 0.82 (p<0.0001), 0.33 (p<0.0001), -0.54 (p<0.0001), and -0.51 (p<0.0001), respectively.

View Article: PubMed Central - PubMed

Affiliation: Department of Industrial Management, National Taiwan University of Science and Technology, Taipei, Taiwan, ROC. liwen@mail.iosh.gov.tw

ABSTRACT
A gait experiment was conducted under two shoe sole and three floor conditions. The shoe soles and floors were characterized by the tread and groove designs on the surface. The coefficients of friction (COF) on the floor in the target area were measured. The subjects were required to walk on a walkway and stepping on a target area covered with glycerol. The motions of the feet of the subjects were captured. Gait parameters were calculated based on the motion data. Among the 240 trials, there were 37 no-slips, 81 microslips, 45 slides, and 77 slips. It was found that the condition with shoe sole and floor had both tread grooves perpendicular to the walking direction had the highest COF, the shortest slip distance, and the lowest percentages of slide and slip. The condition with shoe sole and floor had both tread grooves parallel to the walking direction had the lowest COF and the longest slip distance among all experimental conditions. The Pearson's correlation coefficients between slip distance and slip velocity, time to foot flat, foot angle, and compensatory step length were 0.82 (p<0.0001), 0.33 (p<0.0001), -0.54 (p<0.0001), and -0.51 (p<0.0001), respectively.

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Floor: (a) flat ceramic floor; (b) unglazed ceramic floor with molded trapezoid groove design; (c) dimensions of the groove.
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pone-0068989-g002: Floor: (a) flat ceramic floor; (b) unglazed ceramic floor with molded trapezoid groove design; (c) dimensions of the groove.

Mentions: In the target area on the walkway, three floors were prepared. The first one was a flat ceramic floor (FF) surface with Ra, also known as the center line average of surface heights (CLA), of 11.1 (±1.0) µm). The second one was an unglazed ceramic floor with molded trapezoid groove design (see Fig. 2). The grooves were perpendicular (FP) to that of the walking direction. The third one was the same unglazed ceramic floor as the second but the grooves were parallel (FL) to that of the walking direction. The Ra values at the peaks of those of the second and third floors were both 6.7 (±0.5) µm. In order to generate a slippery floor surface so as to observe slipping of the foot on the floor, an amount (3 ml) of glycerol (weight ratio of 98) was applied evenly on the target area using a paint brush. For the floors with grooves, the glycerol was applied evenly on the top of the peaks. Both the shoe soles and floors were cleaned using a 50% ethanol solution, rinsed with tap water and dried after each test. The same glycerol applying protocol and floor cleaning procedure were adopted for all the subsequent trials.


Shoe sole tread designs and outcomes of slipping and falling on slippery floor surfaces.

Liu LW, Lee YH, Lin CJ, Li KW, Chen CY - PLoS ONE (2013)

Floor: (a) flat ceramic floor; (b) unglazed ceramic floor with molded trapezoid groove design; (c) dimensions of the groove.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3722216&req=5

pone-0068989-g002: Floor: (a) flat ceramic floor; (b) unglazed ceramic floor with molded trapezoid groove design; (c) dimensions of the groove.
Mentions: In the target area on the walkway, three floors were prepared. The first one was a flat ceramic floor (FF) surface with Ra, also known as the center line average of surface heights (CLA), of 11.1 (±1.0) µm). The second one was an unglazed ceramic floor with molded trapezoid groove design (see Fig. 2). The grooves were perpendicular (FP) to that of the walking direction. The third one was the same unglazed ceramic floor as the second but the grooves were parallel (FL) to that of the walking direction. The Ra values at the peaks of those of the second and third floors were both 6.7 (±0.5) µm. In order to generate a slippery floor surface so as to observe slipping of the foot on the floor, an amount (3 ml) of glycerol (weight ratio of 98) was applied evenly on the target area using a paint brush. For the floors with grooves, the glycerol was applied evenly on the top of the peaks. Both the shoe soles and floors were cleaned using a 50% ethanol solution, rinsed with tap water and dried after each test. The same glycerol applying protocol and floor cleaning procedure were adopted for all the subsequent trials.

Bottom Line: Gait parameters were calculated based on the motion data.The condition with shoe sole and floor had both tread grooves parallel to the walking direction had the lowest COF and the longest slip distance among all experimental conditions.The Pearson's correlation coefficients between slip distance and slip velocity, time to foot flat, foot angle, and compensatory step length were 0.82 (p<0.0001), 0.33 (p<0.0001), -0.54 (p<0.0001), and -0.51 (p<0.0001), respectively.

View Article: PubMed Central - PubMed

Affiliation: Department of Industrial Management, National Taiwan University of Science and Technology, Taipei, Taiwan, ROC. liwen@mail.iosh.gov.tw

ABSTRACT
A gait experiment was conducted under two shoe sole and three floor conditions. The shoe soles and floors were characterized by the tread and groove designs on the surface. The coefficients of friction (COF) on the floor in the target area were measured. The subjects were required to walk on a walkway and stepping on a target area covered with glycerol. The motions of the feet of the subjects were captured. Gait parameters were calculated based on the motion data. Among the 240 trials, there were 37 no-slips, 81 microslips, 45 slides, and 77 slips. It was found that the condition with shoe sole and floor had both tread grooves perpendicular to the walking direction had the highest COF, the shortest slip distance, and the lowest percentages of slide and slip. The condition with shoe sole and floor had both tread grooves parallel to the walking direction had the lowest COF and the longest slip distance among all experimental conditions. The Pearson's correlation coefficients between slip distance and slip velocity, time to foot flat, foot angle, and compensatory step length were 0.82 (p<0.0001), 0.33 (p<0.0001), -0.54 (p<0.0001), and -0.51 (p<0.0001), respectively.

Show MeSH