Abstract

Background A sub 2-hr marathon requires an average velocity that is 2.5% faster than the world record at the time of this study of 2:02:57 and could be accomplished with a 2.7% reduction in the rate of oxygen uptake (VO2) during running. Both Nike and Adidas have developed shoes to help runners break the 2 hr marathon barrier. Purpose To determine if, and to what extent these new shoes reduce VO2 compared with established marathon racing shoes. Methods 28 elite and 14 recreational runners (15 elite men, 13 elite women, 4 recreational men, and 10 recreational women), ran five 5-min trials in Nike Vaporfly, Adidas Sub2, and Adidas adios 3 marathon shoes in a randomized counterbalanced design, followed by a max aerobic capacity test. Elite men ran at 16 km.h-1, elite women at 15 km.h-1, and all recreational runners at 11 km.h-1. We measured the subjects’ VO2 and biomechanical stride characteristics (contact time, stride length, and stride rate). Results The NVF shoe improved running economy by 2.8  1.5% on average compared to ADI and 2.4  1.5% compared to SUB2 in elite runners and 2.9  2.6% on average compared to ADI and 2.2  2.1% compared to SUB2 in recreational runners. Among the 28 elite subjects, the difference in running economy between the NVF and ADI shoes ranged from -0.24 to -5.86% and from -0.19 to -6.39% for NVF versus SUB2. Of the 14 recreational subjects, the difference in running economy between the NVF and ADI shoes ranged from +1.14 to -9.31% and from +2.34 to -6.25% for NVF versus SUB2. Correlations between changes in running economy and changes in biomechanical variables were either trivial or small but unclear. Conclusion Wearing the NVF shoes during submaximal running resulted in significant improvements in running economy compared to ADI and SUB2 in all groups excluding recreational men, likely due to small sample size.