Title

Load carrying with flexible bamboo poles: Optimization of a coupled oscillator system

Document Type

Journal Article

Publication Title

Journal of Experimental Biology

Publisher

Company of Biologists

School

School of Medical and Health Sciences

RAS ID

31380

Funders

Edith Cowan University, Collaboration Enhancement Scheme.

Further funding information available at: https://doi.org/10.1242/jeb.203760

Comments

Schroeder, R. T., Bertram, J. E., Nguyen, V. S., Hac, V. V., & Croft, J. L. (2019). Load carrying with flexible bamboo poles: Optimization of a coupled oscillator system. Journal of Experimental Biology, 222(23). Available here

The author's accepted manuscript of this article is Available as chapter 4 of Gait entrainment in coupled oscillator systems: Clarifying the role of energy optimization in human walking. https://ro.ecu.edu.au/theses/2281/

Abstract

In Asia, flexible bamboo poles are routinely used to carry substantial loads on the shoulder. Various advantages have been attributed to this load-carrying strategy (e.g. reduced energy consumption), but experimental evidence remains inconsistent – possibly because carriers in previous studies were inexperienced. Theoretical models typically neglect the individual’s capacity to optimize interactions with the oscillating load, leaving the complete dynamics underexplored. This study used a trajectory optimization model to predict gait adaptations that minimize work-based costs associated with carrying compliant loads and compared the outcomes with naturally selected gait adaptations of experienced pole carriers. Gait parameters and load interactions (e.g. relative amplitude and frequency, phase) were measured in rural farmworkers in Vietnam. Participants carried a range of loads with compliant and rigid poles and the energetic consequences of step frequency adjustments were evaluated using the model. When carrying large loads, the empirical step frequency changes associated with pole type (compliant versus rigid) were largely consistent with model predictions, in terms of direction (increase or decrease) and magnitude (by how much). Work-minimizing strategies explain changes in leg compliance, harmonic frequency oscillations and fluctuations in energetic cost associated with carrying loads on a compliant bamboo pole.

DOI

10.1242/jeb.203760

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