The Biomechanics of Competitive Male Runners in Three Marathon Racing Shoes: A Randomized Crossover Study
We have shown that a prototype marathon racing shoe reduced the metabolic cost of running for all 18 participants in our sample by an average of 4%, compared to two well-established racing shoes. Gross measures of biomechanics showed minor differences and could not explain the metabolic savings.
To explain the metabolic savings by comparing the mechanics of the shoes, leg, and foot joints during the stance phase of running.
Ten male competitive runners, who habitually rearfoot strike ran three 5-min trials in prototype shoes (NP) and two established marathon shoes, the Nike Zoom Streak 6 (NS) and the adidas adizero Adios BOOST 2 (AB), at 16 km/h. We measured ground reaction forces and 3D kinematics of the lower limbs.
Hip and knee joint mechanics were similar between the shoes, but peak ankle extensor moment was smaller in NP versus AB shoes. Negative and positive work rates at the ankle were lower in NP shoes versus the other shoes. Dorsiflexion and negative work at the metatarsophalangeal (MTP) joint were reduced in the NP shoes versus the other shoes. Substantial mechanical energy was stored/returned in compressing the NP midsole foam, but not in bending the carbon-fiber plate.
The metabolic savings of the NP shoes appear to be due to: (1) superior energy storage in the midsole foam, (2) the clever lever effects of the carbon-fiber plate on the ankle joint mechanics, and (3) the stiffening effects of the plate on the MTP joint.
We thank Jesse H. Frank and Claire Denny for help with data collection, Owen N. Beck and Stephen Allen for help with data analysis, Geng Luo and Emily M. Farina for fruitful discussions and providing the mechanical testing data, and the runners for their participation.
Compliance with Ethical Standards
This study was performed in accordance with the ethical standards of the Declaration of Helsinki. Ethics approval was obtained from the University of Colorado Institutional Review Board (Protocol# 15-0114).
Informed consent was obtained from all individual participants included in the study.
The running shoes used for this study were provided by Nike, Inc.
Conflict of Interest
Wouter Hoogkamer and Shalaya Kipp have no conflicts of interest relevant to the content of this article. Rodger Kram is a paid consultant to Nike, Inc.
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