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

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.

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^-1 (trained) or 18 km·h^-1 (national-level). Running economy (RE) was assessed using a portable gas analyzer (MetaMax 3B-R2); spatiotemporal gait variables were recorded with shoe-mounted sensors (RunScribe^TM); and participants rated comfort, cushioning, and perceived performance on a 10-point Likert scale.

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 VO₂ findings. For gait parameters, stride length and step frequency were unchanged across conditions in both groups. Whereas contact time in the national-level group was longer in Dragonfly1 than in Dragonfly2 and Victory1, whereas Dragonfly2 and Victory1 did not differ; in the trained group, contact time was unchanged across spikes. Subjectively, across all participants, foam-only spikes were rated more comfortable and more cushioned, whereas perceived performance did not differ between models.

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.