Shoe cushioning affects lower extremity joint contact forces during running

This study evaluated the effect of running shoes with differing midsole cushioning on ankle, knee and hip contact forces during running. Joint contact forces were estimated in 40 recreational runners (28 female, 12 male) while running over ground in three shoe conditions. Shoes differed only in midsole cushioning (45, 57 and 70 Asker C). Three-dimensional kinetics and kinematics were collected during running and input to a musculoskeletal model to estimate internal axial forces at the ankle, knee and hip. Multivariate ANOVA suggested that more cushioned shoes, relative to less cushioned shoes, reduced peak joint contact forces (p < 0.01) and load rates (p < 0.01). Ankle joint contact force and load rate were reduced with increased cushioning (p < 0.01) with moderate to large effects observed between pairwise comparisons (p ≤ 0.01–0.05, d_z=0.41–1.35). Cushioning effects were also observed for knee joint contact force (p = 0.03) and loading rate (p < 0.01) with load reduction only seen when comparing the soft and hard shoes (p ≤ 0.05, d_z=0.41–0.44). Midsole cushioning had less of an effect on hip contact force (p = 0.31) although hip contact force loading rate was influenced by midsole cushioning (p < 0.01) with lower rates observed for soft versus medium and hard shoe comparisons (p ≤ 0.01, d_z=0.41–0.62). These results suggest that increasing shoe cushioning properties ∼10–20% may benefit individuals susceptible to high loads at the ankle, and to a lesser extent knee and hip, during running.