The advertisements are vague but alluring: Wear insoles and you will be relaxed and stand with proper posture.
You will be comfortable, even blissful — all day. However, when researchers actually probed scientific studies, they found no evidence that shoe insoles prevent or treat back pain.
“Doctors and other health professionals should not recommend insoles for prevention of back pain or even for back pain treatment,” said Tali Sahar, Ph.D., lead author of a new systematic review. “Insoles might be beneficial for prevention or treatment of other disorders, but this was not the topic of our review,” said Sahar, with the department of family medicine at Hebrew University in Jerusalem
The review appears in the current issue of The Cochrane Library , a publication of The Cochrane Collaboration, an international organization that evaluates research in all aspects of health care. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing trials on a topic.
The new review looked at three studies involving 2,061 participants, which focused on the use of customized and standard insoles versus either no treatment or sham inserts for back pain prevention. Another three studies comprising 256 participants examined the use of insoles for either prevention or treatment of existing back pain.
The three larger studies looked at back pain prevention among male military recruits in Israel, Denmark and South Africa. The interventions lasted five to 14 weeks — and data showed no significant difference in the prevention of back pain between the participants using insoles and those who did not.
The smaller studies focused on civilians. One comprised 96 women, all of whom worked in laboratories or in patient reception and were required to stand for 75 percent of their working hours. Back pain decreased with insole use, the original study reported. However, Sahar and her colleagues wrote that analysis of the data was inadequate.
Still another study focused on 100 nursing students “standing three days a week for eight hours a day.” In that case, some back pain sufferers wearing insoles reported that the pain shifted to lower extremity pain.
The final study involved 60 postal workers, all of whom experienced back pain and were required to walk long distances. In that study, 81 percent preferred the real insoles to placebo insoles. However, the study itself had a “major methodological flaw,” Cochrane reviewers found, and while participants reported a decrease in pain with real insoles, the results were not clinically significant, the team said.
Researchers encountered several obstacles while studying insoles, including participants complaining of discomfort. In a study involving 404 Israeli recruits wearing standard military footgear — boots with leather uppers and rubber soles — about half of the men dropped out. In another study, 25 of 96 women refused to participate because the insoles felt unpleasant and tight.