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

Abstract

ABSTRACT “Super-shoes” are designed to improve endurance running performance by reducing the metabolic demands of running. Although the research on “super-shoes” is still developing and has mostly been studied in male runners, it is not clear how possible mediating factors, such as foot strike pattern, influence the metabolic cost and joint mechanics in competitive female runners. Purpose The objective of this study is 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. Methods Eighteen competitive female runners ran four 5-min bouts on a force instrumented treadmill at 12.9 km·h−1 in 1) Nike Vaporfly Next% 2™ (SUPER) and 2) Nike Pegasus 38™ (CON) in a randomized and mirrored order. Results Metabolic power was improved by 4.2% (P < 0.001; d = 0.43) and metatarsophalangeal (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 with CON. There was no correlation between foot strike pattern and the between-shoe (CON to SUPER) percentage change for metabolic power (r = 0.093, P = 0.715). Conclusions 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.