A Test of the Metabolic Cost of Cushioning Hypothesis in Shod and Unshod Running

摘要

Previous studies that controlled foot/shoe mass indicate that cushioning provides energetic advantages over running barefoot. Further, running in lightweight shoes has a comparable metabolic cost as running barefoot, suggesting that positive effects of shoe cushioning may counteract negative mass effects. We hypothesized: 1) unshod running would have comparable metabolic costs as running shod and 2) cushioning will lower the metabolic cost of unshod running. Eleven participants ran at 3.35 m/s with mid-foot strike patterns unshod and shod (Nike Free 3.0; ~211 g /shoe) on a rigid treadmill. Subjects also ran unshod on 10 mm and 20 mm thick slabs of ethylene-vinyl acetate (EVA) foam (same as most running shoe midsoles) mounted on the belt. Oxygen consumption and carbon dioxide production volumes quantified metabolic power. Our findings demonstrate that cushioning reduces the metabolic cost of running, and suggest an ideal amount of cushioning (e.g. u3c 20mm) beyond which metabolic benefits diminish.