The running economy and biomechanics of competitive distance runners wearing advanced footwear technology spikes

Abstract Purpose The aim of this study was to investigate the running economy and biomechanics of runners wearing Advanced Footwear Technology (AFT) spiked shoes (spikes) and AFT shoes relative to traditional spikes. Methods 17 (7 female & 10 male) competitive distance runners completed two sessions of eight (four shoes × two replicates), five-minute trials at 15 km*hr −1 (females) or 17 km*hr −1 (males) wearing Nike ZoomX Dragonfly (NDF) and On Cloudspike 10,000 m (OCS) AFT spikes, Nike Vaporfly Next % 2 (NVN) AFT shoes, and Nike Zoom Victory 3 (NZV) traditional spikes. We measured metabolic rates and ground reaction forces and compared average running economy (W*kg −1 ) and biomechanical variables from four trials per shoe per runner. Results When runners wore NDF and OCS AFT spikes and NVN AFT shoes, running economy improved by 2.1%, 2.3%, and 1.9%, respectively, compared to NZV traditional spikes (p < 0.001). These improvements coincided with 6.1%, 4.5%, and 8.9% increases in leg stiffness and 1.5%, 2.2%, and 2.3% increases in ground contact time for the NDF, OCS, and NVN, respectively, compared to NZV traditional spikes (p < 0.002). Conclusion Running economy improved by 2.1% for athletes wearing compliant AFT spikes and shoes compared to traditional spikes. Future generations of AFT spikes that are designed with further increases in midsole compliance and energy return could improve race performance by eliciting potentially favorable biomechanical changes, such as increased leg stiffness and/or ground contact time.