BACKGROUND: Sea travel leads to well-known changes in gait, but these effects have not been evaluated using quantitative data obtained through controlled experiments. We obtained quantitative data on step-timing patterns as experienced maritime crewmembers walked on a ship at sea. METHODS: Using a within-subjects design, crewmembers walked back and forth along straight line paths (11 m long) that were parallel with the ship's long (i.e., fore-aft) and short (i.e., athwart) axes. Using contact switches attached to the feet, we measured temporal parameters of gait, including stride time, the variability of stride time, and the coefficient of variation. We also evaluated the temporal dynamics of stride times using detrended fluctuation analysis. RESULTS: The variability of stride time differed between walking fore-aft (mean = 0.10 s) and walking athwart (mean = 0.28 s). The coefficient of variation also differed between walking fore-aft (mean = 11%) and walking athwart (mean = 43%). CONCLUSIONS: We obtained direct evidence that ship motions in roll and pitch differentially affect the timing of stepping patterns in human gait. This novel finding motivates new research on quantitative parameters of gait at sea.
Bibliographical noteFunding Information:
We extend our thanks to Captain Russell DeVaney and Bill Rall, Port Captain at the University of Washington, for allowing us to conduct our study on the R/V Thomas G. Thompson. In addition, we thank crewmembers of the R/V Thomas G. Thompson who volunteered to participate in our study. The research was supported by a Grant in Aid of Research from the University of Minnesota.
© by the Aerospace Medical Association, Alexandria, VA.
- Motor control
- human performance at sea