Bertschy, M.; Rodrigo Carranza, V.; Wilkie, E. W. C.; Healey, L. A.; Noble, J.; Albert, W. J.; Hoogkamer, W.

Background: Quantifying the potential benefits of advanced footwear technology (AFT) track spikes in middle-distance events is challenging, because repeated maximal effort trials (as in sprinting) or aerobic running economy trials (as in long-distance running) are not feasible. Objective: We propose and evaluate a novel approach to assess the benefits of AFT spikes that consists of a series of 200m intervals at self-perceived middle-distance race pace. Methods: We conducted four experiments to evaluate the validity, sensitivity, reproducibility, and utility of this novel method. Results: (1) Participants ran 1.26% slower (p=0.0188) in spikes with 200g added mass than in control spikes, exactly equal to the known effects of shoe mass on running performance. (2) Participants ran significantly faster in AFT prototype spikes than in traditional spikes (p=0.0296). (3) Participants performed our interval-based method to compare two other AFT prototype spikes against traditional spikes, on three separate days. Group-level results were consistent across days, but to evaluate individual responses at least two separate sessions are needed. (4) Participants ran significantly faster in two AFT spike models than in traditional spikes (2.22% and 1.74%). Speed was similar between a third AFT spike model and the traditional spikes. These speed results were mirrored by changes in step length, as participants took significantly longer steps in the two faster AFT spike models (2.31% and 1.92%), while step length was similar between the other spikes. Conclusion: Our novel interval-based approach is a valid and reliable method to quantify differences between spikes at middle-distance running intensity.