Effects of Highly Cushioned and Resilient Racing Shoes on Running Economy at Slower Running Speeds

Abstract

Purpose: The Nike Vaporfly line of running shoes improves running economy by ∼2.7% to 4.2% at running speeds of 13 to 18 km·h−1. It is unclear whether similar benefits are conferred at slower speeds. Our purpose was to determine the effects of the Nike ZoomX Vaporfly Next% 2 (VFN2) on running economy at 10 and 12 km·h−1 compared with a mass-matched control (CTRL) shoe. Methods: Sixteen runners completed 4 × 5-minute trials at both 10 and 12 km·h−1 on the same day. Each shoe was tested twice at each speed in a counterbalanced, mirrored sequence. Data are displayed as mean (SD). Results: A 2-way repeated-measures analysis of variance showed a significant shoe × speed interaction for oxygen consumption (P = .021). At 12 km·h−1, oxygen consumption (in mL·kg−1·min−1) was lower (−1.4% [1.1%]; P < .001) for VFN2 (35.8 [1.7]) relative to CTRL (36.4 [1.7]). That was greater in magnitude than the differences observed at 10 km·h−1 (−0.9% [1.8%]; P = .065) between VFN2 (29.4 [1.9]) and CTRL (29.6 [1.9]). Conclusions: From these data, it appears that the VFN2 still enhances running economy at 10 and 12 km·h−1; however, these benefits are smaller in magnitude compared with previous research at faster speeds.