A Validation of a Novel Running Economy Protocol and Comparison of Two Carbon-Plated Running Shoes in Female Long-Distance Runners

INTRODUCTION Running economy (RE) is the strongest predictor of long-distance running performance in well-trained athletes (1). Carbon-plated running shoes have indicated improvements of 4% in RE when compared to previous generation non-carbon-plated running shoes (2). However, these studies have key methodological limitations; the prescribed intensities didn’t replicate race demands, the influence of fatigue was not considered, and testing was only completed on males. AIM: The primary aim of this study was to develop an appropriate protocol to measure RE in female long-distance runners. The secondary aim was to compare performance and RE of two carbon-plated performance shoes in female long-distance runners. METHODS Seven female endurance athletes (age: 30.7 ± 6.6 y, mass: 59.1 ± 5 kg, VO2max: 55.3 ± 4.1 ml/kg/min) completed a graded exercise test to establish a relative race intensity (90% of lactate threshold). Participants completed two testing sessions during the follicular phase of the menstrual cycle in alternating footwear, which consisted of four 7-minute trials, a 25-minute continuous run, four 7-minute trials, and a 13-minute distance trial. RE was recorded as the oxygen consumption and energetic cost of running from minutes 5-7 of each trial. Shoe preference was recorded midway through the first session and the end of the second session. A linear mixed model was used to compare economy and performance metrics. RESULTS There was no significant difference in RE because of fatigue and no significant difference between shoes. However, large individual variations were evident. Participants reported disagreement between preferred shoe and the shoe that demonstrated greatest RE. CONCLUSION A longer protocol that controlled for the menstrual cycle did not induce fatigue related changes in female participants, supporting a higher resistance to fatigue in females (3). The individual variation between shoes suggests that further analyses should be conducted to inform shoe selection for female long-distance runners.