Women with flat feet more prone to back pain22 Nov 2013
The study, conducted at the Institute for Aging Research at Hebrew SeniorLife in Boston, recruited 1930 men and women with pronated feet (feet that tend to roll inwards when a person walks).
Women in the study were in their 60s, on average. About 38 percent overall reported having low back pain.
Senior author Marian Hannan said the study showed that feet are important – particularly in women – when it comes to preventing back pain.
The study showed that women with flat feet when they walk were more likely to suffer lower back pain.
Past research has hinted that low back pain, which affects roughly one in five people worldwide, could be related to the shape of the foot's arch in the standing position.
The new study, published in Rheumatology, focused on the arch while a person walked.
For their study, Hannan and her colleagues measured each person's arch in the standing position. Then participants walked across a mat with embedded sensors to measure pressure from the heel to the tip of the foot while walking.
Hannan said the body may use other muscles to help make up for flat feet when a person walks, which could explain the link to back pain.
Standing and walking use the foot in different ways. Both a flat foot in standing position and a pronated foot walking could be something to consider during a doctor's visit, Hannan said.
She and her team suggested reasons why women could be more affected by flat feet while walking than men.
For example, women's pelvic bones are wider and not as flexible as men's. In general, women rotate their hips more than men while walking. Women also move their upper bodies more than men when they walk.
"Women probably don't know if their foot function contributes to low back pain, but they can find out about it," Hannan told Reuters Health.
She suggested people with low back pain visit a doctor or physical therapist.
One simple trick to strengthen muscles in the feet is to lay a towel on a flat surface and then scrunch the toes together in order to pick up the towel and lower it back down. Foot orthotics are another option.
Dr Stephen Pinney, an orthopedic surgeon at St. Mary's Medical Centre in San Francisco, called the size of the study "impressive."
He told Reuters Health future studies should follow participants with different arches forward in time to confirm these findings. Research should also determine what effect, if any, interventions such as orthotics might have on who develops back pain.
"We've known that putting a patient in a foot cast after surgery, for example, can lead to lower back pain because this creates asymmetric forces on the back," said Pinney, who didn't participate in the new research.
"Once you have back pain, you'll want to do core muscle exercises and perhaps take anti-inflammatory medication, but anything that is contributing to asymmetry - you will also want to address that," Pinney said.
"There are a bunch of different reasons for getting low back pain, and this adds another category for people to consider."