The Influence of "Super-Shoes" and Foot Strike Pattern on Metabolic Cost and Joint Mechanics in Competitive Female Runners.

Abstract

To assess the influence of "super-shoes" on metabolic cost and joint mechanics in competitive female runners, and to understand how foot strike pattern may influence the footwear effects. Eighteen competitive female runners ran four 5-minute bouts on a force instrumented treadmill at 12.9 km·h-1 in: 1) Nike Vaporfly Next% 2TM (SUPER) and 2) Nike Pegasus 38TM (CON) in a randomized and mirrored order. Metabolic power was improved by 4.2% (p < 0.001; d = 0.43) and MTP negative work (p < 0.001; d = 1.22), ankle negative work (p = 0.001; d = 0.67), and ankle positive work (p < 0.001; d = 0.97) were all smaller when running in SUPER compared to CON. There was no correlation between foot strike pattern and the between-shoe (CON to SUPER) percent change for metabolic power (r = 0.093, p = 0.715). Metabolic power improved by 4.2% in "super-shoes" (but only by ~3.2% if controlling for shoe mass differences) in this cohort of competitive female runners which is a smaller improvement than previously observed in men. The reduced mechanical demand at the MTP and ankle in "super-shoes" are consistent with previous literature and may explain or contribute to the metabolic improvements observed in "super-shoes", however foot strike pattern was not a moderating factor for the metabolic improvements of "super-shoes". Future studies should directly compare the metabolic response among different types of "super-shoes" between men and women.