Hemler SL, Sider JR, Redfern MS, Beschorner KE; Gait kinetics impact shoe tread wear rate; Gait & Posture, vol. 86, pp. 157-161, 2021.

Adequate footwear is an important factor for reducing the risk of slipping; as shoe outsoles wear down, friction decreases, and slip and fall risk increases. Wear theory suggests that gait kinetics may influence rate of tread wear.

Do the kinetics of walking (i.e., the shoe-floor force interactions) affect wear rate?

Fourteen 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. Participants then wore alternating pairs of shoes in the workplace each month for up to 24 months. A pedometer was used to track the distance each pair of shoes was worn and tread loss was measured. The wear rate was calculated as the volumetric tread loss divided by the distance walked in the shoes. Three, mixed linear regression models were used to assess the impact of peak normal force, shear force, and RCOF on wear rate.

Wear rate was positively associated with peak RCOF and with peak shear force, but was not significantly related to peak normal forces.

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.