MONTREAL - Dave Williams is a sole man -- at least when it comes to his feet.

And a team of researchers from the University of Guelph can thank the retired Canadian astronaut for his foot fixation.

During a 1998 trip into space aboard the Space Shuttle Columbia, Williams noticed a tingly sensation in the soles of his feet.

That sensation has prompted researchers to take a closer look at the sudden changes in skin sensitivity experienced by some astronauts in space.

Nicknamed "Project Hypersole," the researchers will keeping an eye on the feet of eight crew members on the remaining U.S. shuttle flights. The space ferries have three missions left before they're scheduled to retire this year.

Several astronauts who blasted off last week aboard Space Shuttle Atlantis are already taking part in what's described as "the ultimate tickle test."

Williams says he noticed a "funny tingly sensation" during his first space flight, when he pushed his feet against a locker.

He says the foot research now being carried out in space may help people on the ground, starting with seniors.

"There is a wide range of individuals on Earth who have altered sensations in their extremities, primarily due to diseases like diabetes. And that altered sensation in their feet may affect their gait and their balance, which could actually predispose them to fall," Williams said in an interview.

Researcher Leah Bent said skin sensitivity is a particularly important issue for seniors.

"We certainly know that as individuals get older the amount of information that they get from their skin is certainly diminished, so they have very severe decrease in skin sensitivity," she said.

Bent says the soles of astronauts' feet seem to help them maintain their balance in space.

"They actually have less information in their inner ear so that sensory information is decreased, (and) the body naturally compensates by increasing other sensory inputs," she said.

"We believe it's the body naturally turning up the volume or increasing the sensitivity of the skin to compensate for this lack of information from the inner ear."

Bent is testing the changes in skin sensitivity on the bottom of astronauts' feet, before and after flight, to determine which balance receptors are more active when the body is in zero gravity.

She says some researchers think they can help seniors with "an increased sort of noise in their insoles," adding that it may be possible to create a vibrating corrective shoe for seniors.

"It's way down the line, and certainly our main interest is just looking at the basic science behind it. But that's certainly an opportunity," she said.

Bent hopes the research now underway will eventually help seniors who fall down because of balance problems.

"That's the hope in the long run," she said.

Williams says research carried out during the space program has already had an impact on Earth.

"One of the most exciting has been the adaptation of the Canadian robotics technology that's used in the Canadarm to a new field of surgical robotics," he said.

"I would say the whole application of robotics to surgery is a very important spinoff."