DOI: 10.5061/dryad.9s4mw6mgp
title: Traction performance across the life of slip-resistant footwear

description: Slips, trips, and falls are a major cause of injury in the workplace.
 Footwear is an important factor in preventing slips. Furthermore, traction
 performance (friction and under-shoe fluid drainage) are believed to
 change throughout the life of footwear. However, a paucity of data is
 available for how traction performance changes for naturally worn,
 slip-resistant footwear. Participants wore slip-resistant
 footwear while their distance walked was monitored. Friction and
 under-shoe fluid pressures were measured using a robotic slip tester under
 a diluted glycerol contaminant condition after each month of wear for the
 left and right shoes. The wear volume and the size of the worn region was
 also measured. Prior to wearing shoes at work, participants completed dry
 walking trials during which ground reaction forces were recorded across
 different types of shoes. The peak normal force, shear force, and required
 coefficient of friction (RCOF) were calculated. Friction
 initially increased and then steadily decreased as the distance walked and
 the size of the worn region increased. Fluid pressures increased as the
 shoes were worn and were associated with increased walking distance and
 size of the worn region. Consistent with previous research, increases in
 the size of the worn region are associated with increased under-shoe fluid
 pressures and decreased traction. These trends are presumably due to
 reduced fluid drainage between the shoe-floor interface when the shoe
 becomes worn. Wear rate was positively associated with peak RCOF
 and with peak shear force, but was not significantly related to peak
 normal forces. Traction performance changes with natural wear. The
 distance walked in the shoe and the size of the worn region may be
 valuable indicators for assessing loss of traction
 performance. Current shoe replacement recommendations for
 slip-resistant shoes are based upon age and tread depth. This study
 suggests that tools measuring the size of the worn region and/or distance
 traveled in the shoes are appropriate alternatives for tracking traction
 performance loss due to shoe wear. The finding that shear forces
 and particularly the peak RCOF are related to wear suggests that a
 person’s gait characteristics can influence wear. Therefore, individual
 gait kinetics may be used to predict wear rate based on the fatigue
 failure shoe wear mechanism.
description: This data set describes
 data from a progressive wear experiment. Shoes were tested at baseline
 (Month of Wear = 0) and after each month of use. Between tests,
 participants wore the shoe at their work environment for a period of 1
 month. Multiple months of data were collected for each
 participant. Progressive Wear Experiment
 Column Numbers 1.
 Column A (“Subject”) represents the assigned subject ID [1, 2].
 2. Column B (“Month of
 Wear”) represents the completed number of months the shoes were worn [1,
 2]. 3. Column C
 (“Total Distance [km]”) represents the distance walked that the shoes were
 worn [1, 2]. 4.
 Column D (“Distance per month [km]”) represents the distance walked the
 shoes were worn in the previous month [1]. 5. Column E (“Shoe Brand”)
 represents the brand of the shoe. 6. Column F (“Shoe Code 3
 (A/B/C)”) represents the shoe code designation between A, B, and C [1,
 2]. 7. Column G
 (“Hardness”) represents the Shore A hardness of the shoe outsole
 [2]. 8. Column H
 (“Side”) represents the left or right shoe of the pair [1].
 9. Column I (“ACOF”)
 represents the shoe average available coefficient of friction from the
 five slip testing trials [1]. 10. Column J (“%ACOF from
 Baseline”) represents the shoe available coefficient of friction relative
 to the new condition [1]. 11. Column K (“Fluid Force [N]”)
 represents the load supported by the fluid during slip testing
 [1]. 12. Column L
 (“Peak Fluid Pressure [kPa]”) represents the peak fluid pressure measured
 between the shoe and flooring during slip testing. 13. Column M (“Contact Area [sq
 in]”) represents the measured contact area between the shoe and flooring
 during slip testing. 14. Column N (“Untreaded Length
 [mm]”) represents the length of the continuous worn region along the long
 axis of the shoe [1]. 15. Column O (“Untreaded Width
 [mm]”) represents the width of the continuous worn region along the short
 axis of the shoe [1]. 16. Column P (“Untreaded Region
 Location”) represents the location on the shoe heel where the measurement
 was acquired. 17.
 Column Q (“Worn Region Size [mm^2]”) represents the product of the
 untreaded length and width in mm2 [1]. This variable is known as the size
 of the worn region in [1]. References: 1.         Hemler, S.L., Pliner, E.M.,
 Redfern, M.S., Haight, J.M. and Beschorner, K.E., 2020,
 Traction performance across the life of slip-resistant footwear:
 preliminary results from a longitudinal study. <i>Journal of Safety
 Research </i>74, 219-225. 2.         Hemler, S.L., Sider,
 J, Redfern, M.S., Beschorner, K.E., 2021, Gait Kinetics Impact Shoe Tread
 Wear Rate. Gait & posture 86, 157-161.
description: Throughout the document, "null" indicates missing data.
 For the "Untreaded Region Location", values of "n/a"
 indicate that no untreaded region had yet formed on the shoe.