Comparative analysis of foam-only versus carbon-plated advanced footwear technology spikes in distance runners.

Background: Advanced footwear technology (AFT) spikes are commonly offered in two configurations: foam only and foam combined with a carbon fiber plate. Whether the plate provides additional metabolic or performance benefits over foam-only designs remains uncertain. Therefore, this study compared physiological, biomechanical, and perceptual responses to two commercially available AFT spikes (Nike ZoomX Dragonfly, foam only; Nike Air Zoom Victory, foam plus carbon plate) in trained and national-level distance runners. Methods: Thirteen male middle- and long-distance runners (trained, n = 6; national-level, n = 7) completed three randomized 1600-m submaximal trials on an outdoor track at 16 km·h Results: In the national-level group, both foam-only spikes (Dragonfly1, Dragonfly2) produced better RE than the carbon-plated model (Victory1), with no difference between the two foam-only versions. In the trained group, RE did not differ across spikes. Energetic cost paralleled the VO Conclusion: At long-distance race paces, foam-only AFT spikes improved RE and were perceived as more comfortable than a plate-integrated spike in national-level athletes. Adding a carbon plate did not guarantee a metabolic benefit and may increase energetic cost when shoe stiffness exceeds an athlete-specific optimum. Spike selection, particularly for track events, should demystify carbon plates and prioritize the individualized selection of shoe stiffness and geometry matched to event distance, running speed, and athlete-specific biomechanics.