The Effect of Nike ZoomX Vaporfly Next% 2 on Running Economy in Trained Distance Runners During a 20-km Run.

PURPOSE: This study aimed to examine the effect of Nike ZoomX Vaporfly Next% 2 (VF) on running economy (RE) in trained to highly trained long-distance runners during a prolonged treadmill run (20 km), and whether VF could maintain the RE benefits over time compared with a conventional training shoe (TS). METHODS: Fourteen trained to highly trained runners participated in 2 test sessions, completing a 20-km treadmill run in VF on one day and TS on another. Oxygen uptake, respiratory exchange ratio, and heart rate were measured throughout the run, and RE was calculated from the final 2 minutes of each stage (0, 5, 10, 15, and 20 km). Shoe order was randomized. RESULTS: Ten participants completed both test days. RE was consistently lower in VF compared with TS throughout the running protocol, accompanied by lower oxygen consumption. No significant shoe × distance interaction was observed, indicating that the difference between shoe conditions remained stable over the 20-km run. Both shoes showed a nonsignificant tendency toward deteriorating RE over time. CONCLUSIONS: VF demonstrated lower metabolic cost and superior RE compared with TS during prolonged treadmill running. However, the progression of RE over time did not differ between shoe conditions, suggesting that VF provided a stable metabolic advantage rather than reducing the rate of RE deterioration.