Energy Storage And Return From Footwear And Biological Structures While Running

Abstract

Energy Storage and Return from Footwear and Biological Structures While Running Extraordinary performances have been achieved by runners using advanced footwear. Previous research has found energetically favorable changes in biological joint kinetics while running in such footwear. However, there is limited research that also quantifies footwear kinetics during running. PURPOSE: To compare energy storage and return from footwear and biological structures while running in shoes of varying constructions. METHODS: Fifteen male runners ran in a motion analysis lab while kinematics and ground reaction forces were collected. Three footwear conditions of varying construction were evaluated (Shoe A, B, C). Shoe A had the greatest midsole compliance and longitudinal bending stiffness. Hip, knee, and ankle joint powers were computed using inverse dynamics to evaluate the mechanical work at biological joints. Distal rearfoot power was computed to evaluate the net mechanical work from the biological foot and footwear structures (Foot + Footwear). Kruskal-Wallis and Wilcoxon signed-rank tests were used for between footwear comparisons. RESULTS: Negative Foot + Footwear work (energy storage) was significantly greater in Shoe A (0.29 ± 0.07 J/kg) than Shoe B (0.21 ± 0.06 J/kg, p < 0.001), but not Shoe C (0.26 ± 0.08 J/kg, p = 0.055). Positive Foot + Footwear work (energy return) was significantly greater in Shoe A (0.30 ± 0.09 J/kg) than both other shoes (Shoe B: 0.19 ± 0.08 J/kg, p = 0.001; Shoe C: 0.15 ± 0.07 J/kg, p < 0.001). Positive ankle work was significantly lower in Shoe A (0.61 ± 0.08 J/kg) than both other shoes (Shoe B: 0.68 ± 0.09 J/kg, p < 0.001; Shoe C: 0.67 ± 0.06 J/kg, p = 0.003). Hip and knee work were not significantly different between shoe conditions (p > 0.05). CONCLUSION: Understanding how advanced footwear stores and returns energy during running may explain the reduction in work required by biological structures and resulting increased performance. Supported by Li-Ning.