The curious case for walking barefoot
Wearing shoes when we walk changes how our feet interact with the ground below us, according to a novel new study in the journal Nature.
The study, which echoes some of the research that first popularized barefoot running, finds that walkers move differently when they are barefoot or shod and have differing sensitivity to the ground, potentially affecting balance and joint loading.
The study results intimate that there could be advantages to perambulating with naked feet, not the least of which, surprisingly, involves developing calluses.
Today, many of us might consider such calluses unsightly and disagreeable. But Daniel Lieberman, an evolutionary biologist at Harvard University who, with various colleagues, conducted much of the early research into barefoot running, began to wonder recently whether those calluses might have a hidden utility and beauty.
To learn more, he and a team of collaborators compared how a group of people in Kenya walked (with shoes and without) and compared that with a group in Boston.
When male and female volunteers strolled on treadmills at Lieberman’s lab in Boston while barefoot, they struck the ground in about the same way as the unshod walkers in Kenya had. But when those same volunteers donned average, cushioned sneakers, their walking subtly altered. They began striking the ground a little more lightly at first but the impacts from each stride lingered longer than when they were barefoot.
Such persistent impacts tend to move up and dissipate through our leg bones, ankles and knee joints, whereas the shorter, sharper jolts created when we walk barefoot are more likely to rise through our soft muscles and tendons, Lieberman said.
What these findings suggest, in aggregate, is that what we wear on our feet shapes the way that we walk and that nature would make a fine footwear engineer, Lieberman said. Shoes protect our feet and sop up some of the slight pounding during a walk, he said, but they also alter our strides and could, over time, increase the pressure and wear on our leg joints.
Meanwhile, calluses (created by walking without shoes) shield us from some of the discomforts and pointy objects we encounter while barefoot but do not reduce our contact with and feel for the ground.
So, the message of the study would seem to be that people who have concerns about their balance or their knees but not their pedicures might consider sometimes walking barefoot, he said.