Motion-induced fatigue in offshore workers
For people who work at sea, movement from the ship can cause a phenomenon called motion-induced fatigue (MIF). Research has shown that even a short duration of motion effects human performance, potentially leading to MIF. Add to that the physical and mental effort involved in offshore jobs and there’s potential for errors and compromised safety.
There’s very little research, however, on the effects of long-term motion. Given that work shifts in many offshore industries are often long, kinesiology master’s student Greg Pearcey wondered what affect that would have. Mr. Pearcey wanted to determine the extent to which long duration motion affects human performance and put a time line on it. In other words, how long would it take to recover?
“A regular shiftwork schedule for seafarers in the offshore industry typically consists of a six hours on, six hours off rotation,” said Mr. Pearcey. “An increased understanding of how people learn and fatigue in motion environments would be valuable information when creating work and training schedules for employees in this industry in terms of productivity and safety. It might also help us create simulation techniques to combat motion-induced fatigue and decrease learning times when the workers are immersed in a motion environment.”
The study included two sessions: one hour of motion on a ship motion simulator in the Faculty of Engineering, and one of control (no motion). Participants performed several tests that allowed researchers to examine maximal elbow force production, reaction time and visuomotor (the integration of a motor task and vision) accuracy tracking, which Mr. Pearcey describes as someone performing a task that matches what they see on a screen.
“In this case, we were measuring their ability to pull on a strap, which produced a line representing the amount of force applied, and match it to a line that represented various fluctuations amounts of force over a 30 second time frame.”
What he found was that reaction times were significantly slowed, a result he attributes to the extra attention needed to operate in this environment. “When in motion, people are constantly aware of the motion and how they can possibly fall down. Because this requires resources from the brain, there are fewer resources available to perform motor tasks to the same extent as when they are not in motion.”
Mr. Pearcey explains that these results could affect any task that involves reading and reacting to a stimulus or performing any task at a working interface. “For example, there may be more errors when a captain is trying to steer toward certain coordinates or following a sailing path in rough seas. In emergency situations, the ability of people to react to hazardous events will likely also be compromised slightly and, essentially, any computer task will be affected.”
A portion of the study results have been presented at the International Applied Human Factors and Ergonomics conference in Krakow, Poland and the entire study is currently being prepared for publication in a peer-reviewed journal.
Mr. Pearcey, who was supervised by Drs. Duane Button and Scott MacKinnon, received a provincial government Special Scholarship for Students to Pursue Graduate Studies Related to Resource Development, funds from the Natural Sciences and Engineering Research Council of Canada and an Atlantic Canada Opportunities Agency grant.