Abstract
Humans tend to increase their step frequency in barefoot walking, as compared to shod walking at the same speed. Based on prior studies and the energy minimization hypothesis we predicted that people make this adjustment to minimize metabolic cost. We performed an experiment quantifying barefoot walking metabolic rate at different step frequencies, specifically comparing preferred barefoot to preferred shod step frequency. We found that subjects increased their preferred frequency when walking barefoot at 1.4 m/s (~123 vs. ~117 steps/min shod, P = 2e-5). However, average barefoot walking metabolic rates at the preferred barefoot and shod step frequencies were not significantly different (P = 0.40). Instead, we observed subject-specific trends: five subjects consistently reduced (−8% average), and three subjects consistently increased (+10% average) their metabolic rate at preferred barefoot vs. preferred shod frequency. Thus, it does not appear that people ubiquitously select a barefoot step frequency that minimizes metabolic rate. We concluded that preferred barefoot step frequency is influenced by factors beyond minimizing metabolic rate, such as shoe properties and/or perceived comfort. Our results highlight the subject-specific nature of locomotor adaptations and how averaging data across subjects may obscure meaningful trends. Alternative experimental designs may be needed to better understand individual adaptations.
Highlights
Humans value economy of locomotion, and prior studies suggest that people tend to adopt a step frequency that minimizes metabolic rate at a given walking speed[1,2,3,4,5,6]
On average, we found that the metabolic rate during barefoot walking at the barefoot SS step frequency was not significantly different from the metabolic rate during barefoot walking at the shod SS frequency (P = 0.40, N = 10, Fig. 1)
Minimization of metabolic energy is often assumed to be the primary factor governing preferred step frequency during human walking and running[10,13,15,16]. This assumption is derived from empirical observations of shod gait, which suggest that people choose a step frequency close to the metabolic minimum during level-ground, forward walking[1,2,3,4,5,6] and during walking conditions when biomechanical demands are altered[11,12]
Summary
Humans value economy of locomotion, and prior studies suggest that people tend to adopt a step frequency that minimizes metabolic rate at a given walking speed[1,2,3,4,5,6]. This energy minimization hypothesis related to step frequency is based on the study of shod walking. One potential reason for the increase in barefoot step frequency (relative to shod) is that removing the shoes changes the gait optimization (e.g., because the mass, length or other properties of the shoe no longer have an effect), shifting the frequency at which minimum metabolic energy is expended for a given speed. Barefoot & Shod rate of walking barefoot at different step frequencies, and to compare the metabolic rate when walking barefoot at an individual’s preferred barefoot step frequency vs. their preferred shod step frequency
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
