Walking on Water
By Rick Davis
It’s sort of like the walk of an intoxicated person.
That’s how UNO researcher Jeff Kaipust describes the gait of seafarers aboard ship.
“The steps are kind of choppy, they might be longer and they tend to sway from side to side,” says Kaipust, who spent 10 days aboard the Thomas G. Thompson research vessel last April in a first-of-its-kind study looking at the gait of sailors.
“When you’re walking on a boat, you’re kind of at the mercy of the boat. If the boat tilts one way, then you’re just going to go with it.”
Kaipust is the building coordinator at UNO’s internationally recognized Nebraska Biomechanics Research Building — a state-of-the-art center that houses seven research labs dedicated to studying human movement variability.
The research aboard the Thomas G. Thompson — a 274-foot government research ship operated by the University of Washington — came about through collaboration with University of Minnesota researcher Thomas Stoffregen, Ph.D., who has studied sea sickness and standing body posture, or how people control body sway.
It’s no secret — as anyone who’s sailed can attest — that it takes a couple of days aboard ship get your “sea legs,” adapting and adjusting to walking with the constant rocking and rolling over waves.
“But when I started looking into this, it turned out that no scientist had ever done any controlled research on it — period, end of story,” Stoffregen says. “So that was a big open door.”
He contacted Nick Stergiou, Ph.D., professor and director of UNO’s Biomechanics Research Building, and the two decided to collaborate on the research. In April 2013, the research team boarded the Thomas G. Thompson in Honolulu for a 10-day voyage back to its home port in Seattle.
Kaipust brought the equipment necessary to study the sailors’ gait, including portable sensors placed under participating crewmembers’ shoes, one at the toe and one at the heel.
The researchers conducted an initial test while the ship was docked, to get some baseline data, then set sail. It was a rough beginning. The trade winds kicked up, making the sea choppy.
“We all got sick,” Stoffregen recalls. “It was three days before we were all up and about again.”
After that initial setback, the research crew — Stoffregen, two of his students and Kaipust — got back to work. In addition to the four researchers, there were about 25 crew members onboard engaged in the day-to-day operation of the ship. No other scientists were onboard, as the ship was headed back to its homeport.
Stoffregen says the research was “elegantly simple.”
Participating crew members were tested along a large open deck at the rear of the ship, walking back and forth for about eight minutes. Then they were tested walking back and forth for eight minutes along the interior of the ship.
“We were looking at the difference the role of the horizon had on their timing,” Kaipust says.
“If you’re on a cruise, they’ll tell you, ‘If you feel uncomfortable, if you’re worried about sea sickness, if you’re feeling unsteady, get up on deck and look at the horizon,’” adds Stoffregen. “Well, let’s see if that matters.”
They also were tested walking across the long axis of the ship (fore and aft) and the short axis of the ship (port and starboard) to see what differences may occur. (The stepping patterns were more variable along the short axis, as the movements of ship were more pronounced.)
The researchers also studied the walking patterns of the crew members at sea compared to while the ship was docked.
“Dr. Stergiou has a theory that the elderly have walking patterns that are similar to those of a person who is adjusting to walking on a boat,” Kaipust says. “We were trying to see if that theory is true.”
And what did they find? “Yes, in general, they do have kind of a similar movement pattern or variability pattern,” Kaipust says. “Secondly, we’re looking at how these crew members have adapted, and if that could translate into helping elderly individuals.”
Stoffregen also says the research may have some implications for astronauts, who often return from space flight feeling motion sickness. “This phenomenon is almost identical to an ancient phenomenon of travel by sea,” he explains. “There are remarkable similarities. And it’s a whole lot cheaper to study the nautical version.”
Another study, Stoffregen says, is being planned, and he’s excited about the possibilities.
“This research is totally in its infancy,” he says. “We have an amazing opportunity.”