Could the surface I stand on make that much difference?

"Based on industrial studies, it could, said Dr. Mark Redfern, professor of bioengineering at the University of Pittsburgh, though the physiological reasons are not clear. Redfern, who studies human movement and ergonomics, published research in 1995 about people who stand to work for long periods of time.

In both the laboratory and on the assembly line, different kinds of floors and floor covering were rated based on the subjects' reports of discomfort, joint pain and fatigue.

The results varied, Redfern said, but the bottom line was that the harder the floor, the more discomfort people felt. However, if the surface was too soft, people also experienced pain, apparently because of the energy required to pick up the feet and move around."