Perceptual and biomechanical variables for running in identical shoe constructions with varying midsole hardness

OBJECTIVE: Perceptual ratings of mechanical variables were compared with biomechanical variables that are related to running injuries. DESIGN: Eight identical running shoes with a relatively close range of midsole hardness were used. Ground reaction force (GRF), in-shoe pressure distribution and rearfoot motion were measured during running. Perceptual ratings were obtained after the running trials. BACKGROUND: Previous studies reported high correlations between cushioning perception and biomechanical variables for shoes that featured large differences in midsole hardness. METHODS: A 15-point categorical rating scale was used to judge impact severity, pressure magnitude and rearfoot motion in running. Rating scores were compared with biomechanical variables (GRF, pressure distribution and pronation values) using regression analyses. RESULTS: Regression analyses revealed high relations between different biomechanical variables and the perception scores. The best relation to perception was analysed for the median power frequency of the vertical GRF (r(2) = 0.97). A negative correlation (r(2) = 0.54) between the first impact of GRF and the perception of impact severity could be revealed. CONCLUSION: The present study suggests that the body's sensory system seems to differentiate well between impacts of different frequency content. Based on perceptual abilities, subjects adapt their running style to avoid high heel impacts.