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Journal of Ergonomics

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A laboratory experiment evaluated the effect of motorcycle clutch design on the electromyography (EMG) activity of the primary agonist finger flexor muscle in the forearm. The goal was to compare muscle fatigue resulting from operation of two different motorcycle clutches in simulated traffic. EMG activity from the flexor digitorum superficialis (FDS) muscle of 12 female and 11 males were recorded while each participant operated an existing motorcycle clutch (requiring 98 N peak force) as well as an alternate design (requiring 36 N peak force) during 60-minute simulations. Muscle fatigue was quantified by measuring the decrease in median frequency of the EMG signals. Compared to operating the existing clutch, male participants experienced a significant decrease in muscle fatigue between 14 to 31% when operating the alternate clutch. Females experienced a decrease of 27 to 49%. In addition to reduced muscle fatigue, the alternate clutch was overwhelmingly preferred by participants and was rated superior for ease of use and comfort. Results provide a better understanding of the effect of clutch design on riders’ muscular loading and implications for design improvements.


Published version. Journal of Ergonomics (2014): S4:006. DOI. © 2014 Conrad MO, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.