Running Shoes: Hazardous to Your Joints?
Study Shows Running Shoes Exert More Stress on Knees and Hips Than Running Barefoot
Jan. 7, 2010 -- Compared to running barefoot, running in
conventional running shoes increases stress on the knee joints up to 38%,
according to a new study.
''There is an increase in joint torque that may be detrimental," says D.
Casey Kerrigan, MD, the lead author of the study, published in PM&R: The
Journal of Injury, Function and Rehabilitation.
Joint torque is a measure of how much a force causes the joint to
But Kerrigan is not advocating that runners take up barefoot running -- just
that her findings may be a reason to redesign running shoes. Kerrigan, formerly
chairwoman and professor of physical medicine and rehabilitation at the
University of Virginia, Charlottesville, now heads JKM Technologies and is
designing a running shoe.
At least one podiatric specialist calls the study finding ''much ado about
Running Shoes Study: Details
Kerrigan's team evaluated 68 runners -- 37 women, average age 31, and 31
men, average age 36 -- who ran at least 15 miles a week. None had
any history of musculoskeletal injury.
Participants ran barefoot on a treadmill and then in a running shoe: the
Kerrigan's team observed how each condition, barefoot and shod, affected the
joints of the hip, knee, and ankle.
Compared to running barefoot, the researchers found running in running
shoes increased stress on the lower extremities. They found a 54%
increase in the hip internal rotation torque and a 36% to 38% increase in knee
torque. Is that increase mild, moderate, worrisome? "We don't know,"
Kerrigan tells WebMD. "We just know it's an increase."
She attributes the increased stress to the characteristic design of the
majority of running shoes, including an elevated heel and increased material in
the midsole arch.
Providing this cushioning in the heel, she suspects, counteracts the body's
natural response to compensate for the torque associated with impact.
The increases found in her current study are higher than when she compared
barefoot walking to walking in high heels. The high-heel shoes increased knee
joint torque by 20% to 26%, she says.
Running Shoes Study: Analysis
Some torque on the knee is normal, of course. "What we are saying is, there
is an increase over what would be experienced just walking around," Kerrigan
Her concern is that the excess stress may contribute to knee osteoarthritis, although the
study did not look at a link between running shoes and injury or running shoes
and the development of arthritis.
She isn't suggesting barefoot running -- a trend that's picked up steam in
the past year or so -- is necessarily better than running in athletic shoes,
Running Shoes Study: Other Opinions
''It's much ado about nothing," says Bruce Williams, DPM, past president of
the American Academy of Podiatric Sports Medicine and a spokesman for the
American Podiatric Medical Association, of the study results.