Effects of longitudinal bending stiffness and midsole foam on running energetics

Background Advanced footwear technology has become common place in the competitive running world. However, a systematic exploration of the benefits of each of the primary components has not yet been presented. Purpose To quantify running economy and step parameters in four different shoe conditions: PEBA shoes with plate, PEBA shoes without plate, EVA shoes with plate and EVA shoes without plate. Methods Participants ran at 14 km/h (n = 8 males) or 12 km/h (n = 6 females). The shoe order was randomly assigned for the four shoe conditions, where the participants wore each shoe twice in a mirrored order. Results There was a significant effect of the presence of the plate (-1.0%) as well as a significant effect of foam type (-1.0%). However, there was no significant interaction between presence of plate and foam type. Adding a plate significantly improved running economy for EVA (-1.3%) but not for PEBA (-0.6%). PEBA foam improved running economy, this was significant for the shoes without a plate (-1.3%), but not for the shoes with a plate (-0.6%). Step frequency and contact time were similar between shoes and not correlated to running economy improvements. Conclusions Starting from a baseline condition with traditional foam without a plate, either adding a plate or using PEBA foam improved running economy with a similar amount (1.3%). Adding the alternate second feature non-significantly improved running economy with an additional 0.6%. The benefit of both technologies combined (1.9%) was smaller than the sum of its parts (1.3% each). Key points ### Competing Interest Statement Herlandt Lino and Montgomery Bertschy have no conflicts of interest relevant to the content of this article. Wouter Hoogkamer has received research grants from Wolverine Inc (Saucony) and Puma SE. Damion Perry is an employee of Puma SE. No footwear company had any influence on the conceptualization of this study or results presented in this publication