Shoe–Floor Frictional Requirements During Gait after Experiencing an Unexpected Slip

Abstract

OCCUPATIONAL APPLICATIONS This study provides the first description of gait changes after a slip experience with no threat of additional slippery surfaces. The age-related differences found after experiencing an unexpected slip provide valuable information that should be considered when designing slip paradigms, slip-prevention measures, and the workplace. Specifically, the possibility of generating more than one unexpected slip would allow researchers to further investigate this unique event to prevent falls in the workplace. It is important to understand how frictional requirements and other gait adaptations are impacted by experiencing a slip to ensure that ergonomic interventions, such as shoe–floor design, slip-prevention training, and warning systems, can be effective. Safety warning systems should also be a focus of slip prevention in the workplace, since experiencing a slip alone may not have a long-lasting effect on gait adaptations that could minimize future slip risk, especially in young adults. TECHNICAL ABSTRACT Background: High injury rates and costs associated with occupational falls make them an important prevention target. Purpose: The goal of this study was to examine the impact of experiencing a slip on the peak required coefficient of friction during subsequent gait trials in which subjects were informed that the floor was no longer slippery. Methods: Twenty-seven young (20–31 years) and 25 older adults (50–65 years) walked across a dry floor (baseline dry) then experienced an unexpected slip. Following this, 15 dry trials (recovery dry) and a second unexpected slip were completed. Required coefficient of friction and general spatiotemporal gait parameters were derived during walking on dry surfaces. Results: Young adults initially reduced their peak required coefficient of friction on the left (previously slipped) foot but, after being informed that the floor was no longer slippery, eventually returned to within baseline levels of peak required coefficient of friction and walked with faster gait and longer steps. Young adults exhibited a second slip of similar magnitude to their first slip. Older adults continued walking more cautiously, with a decreased peak required coefficient of friction and other gait adaptations, after experiencing a slip, even though there was no threat of a subsequent slip. With this cautious gait, older adults experienced over a 40% decrease in peak slip velocity in the second slip event. Conclusions: The age-related differences found after experiencing an unexpected slip provide valuable information that should be considered when designing slip paradigms, slip-prevention measures, and the workplace. The possibility of generating more than one unexpected slip would allow researchers to further investigate this unique event to prevent falls in the workplace. It is important to understand how frictional requirements and other gait adaptations are impacted by experiencing a slip, to ensure that ergonomic interventions, such as shoe–floor design, slip-prevention training, and warning systems, can be effective. Safety warning systems should also be a focus of slip prevention in the workplace, since experiencing a slip alone may not have a long-lasting effect on gait adaptations that could minimize future slip risk, especially in young adults.