Influence of Required Coefficient of Friction on Rate of Shoe Wear

Details

• Personal Author:
  Beschorner K ; Hemler S ; Sider J
• Description:
  BACKGROUND AND AIM: Falls resulting from slipping are one of the leading causes of injury. Research has shown that shoes' ability to prevent a slip event degrades over time. Preliminary evidence suggests that shoes do not wear at the same rate for all individuals. Thus, identifying characteristics that predict wear rate for shoes may be useful in individualizing footwear replacement programs. Required coefficient of friction (RCOF), is a measure for how much friction is utilized during walking, and has previously been used as a metric individual risk of slipping. We assert that this metric also predicts the rate at which a shoe is worn down. Specifically, we expect that increased frictional demands during gait are correlated with faster shoe wear. METHODS: Eleven subjects completed gait assessments wearing two types of slip-resistant shoes while walking over force plates; peak RCOF was measured for each subject and shoe. Then, subjects wore each pair of shoes in their workplace for one month. At baseline and after the shoes were worn, silicone rubber molds of the heel tread were made. The tread volume of each mold was measured by filling the tread imprints with water and weighing the mass change. The volumetric difference between each month of wear was calculated and normalized to walking distance as measured by a pedometer attached to the shoes. This parameter was termed wear rate [mm3/km]. Only data for which the subjects walked at least 75 km were included. As such, there were three full data sets that included both types of shoes and six that included only one shoe. Statistical methods consisted of repeated measures ANOVA with incomplete data using maximum likelihood method. This method is suited for repeated measures with incomplete data. The dependent variable, wear rate, was log transformed to achieve normal residuals, and the independent variables were shoe type and peak RCOF. RESULTS: Peak RCOF ranged from 0.09 to 0.22. Wear rate was positively correlated with RCOF (p = 0.0247) across all shoes and subjects. It should be noted that the trend was largely driven by two subjects with low peak RCOF values and correspondingly low wear rates. CONCLUSIONS: This research provides preliminary evidence that an individual's peak RCOF is related to their wear rate. Therefore, peak RCOF may be able to predict individualized shoe replacement schedules. Given the limited number of subjects at present, the results should be monitored as the data set for this study becomes more complete. [Description provided by NIOSH]
• Subjects:
  Accidental Falls Accidents Biomechanical Phenomena Ergonomics Musculoskeletal System Occupational Health Safety
• Keywords:
  Biomechanics Footwear Posture Slips, Trips, And Falls STF
• Publisher:
  International Society for Postural & Gait Research (ISPGR)
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Abstract or Summary
• Place as Subject:
  OSHA Region 3 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• NIOSHTIC Number:
  nn:20063130
• Citation:
  2019 International Society for Postural & Gait Research (ISPGR) World Congress, June 30-July 4, 2019, Edinburgh, Scotland. Portland, OR: International Society for Postural & Gait Research (ISPGR), 2019 Jun; :632-633
• Federal Fiscal Year:
  2019
• Performing Organization:
  University of Pittsburgh
• Peer Reviewed:
  False
• Start Date:
  20150930
• Source Full Name:
  2019 International Society for Postural & Gait Research (ISPGR) World Congress, June 30-July 4, 2019, Edinburgh, Scotland
• End Date:
  20190929
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:ac78305284445708ca2734f99e2067453fa844d1b7e3483ad8ab73e056b7e2d5d0e8b78d07ab94e3acc6c18bb304bac5ce90284c026e942c6e8e6b1269f7326c
• Download URL:
  https://stacks.cdc.gov/view/cdc/226249/cdc_226249_DS1.pdf
• File Type:
  [PDF - 387.17 KB ]