Redistribution of knee and ankle joint work with different midsole thicknesses in non-rearfoot strikers during running: A cross-sectional study

Purpose To investigate the effects of midsole thickness on non-rearfoot strike runners’ redistributions of knee and ankle joint negative and positive work. Methods Fourteen healthy male runners wore minimalist, traditional, and maximalist shoes and ran in a straight line in each shoe in the laboratory at a speed of 15 km/h, with a ±5% difference being allowed. Whole-body kinematics and ground reaction forces were recorded, and the data of eleven non-rearfoot strikers were used for the analysis. Ankle and knee joint negative and positive work was calculated by integrating each joint's torque power. Friedman test was used for statistical comparisons. Results Minimalist shoes induced significantly greater ankle joint negative and positive work than in other shoes. Maximalist shoes induced significantly lower ankle joint positive work and greater knee joint negative work than in other shoes, and significantly greater knee joint positive work than in minimalist shoes. Conclusions Our results indicated that non-rearfoot strikers redistributed joint negative and positive work from the knee to the ankle when using minimalist shoes or from the ankle to the knee when using maximalist shoes. It is recommended that future research employs more rigorous study designs, such as randomised controlled trials and longitudinal studies, to provide a more accurate assessment of the effect of these shoes on injury rates.