Cochrane Library researchers have reported that past studies on shoe insoles don't substantiate claims that insoles can prevent back pain. The researchers said that there is some support for the idea that insoles may reduce back pain if the pain is relatively mild to start with.
"The systematic review included six previous randomized controlled studies. The studies all compared treatment of customized and non-customized insoles to placebo, no intervention, or other interventions. Some studies reviewed the ability of insoles to prevent back pain in people that spent a lot of time on their feet (walking or standing). Other studies reviewed the effect the insoles had on the pain level of people with current back pain. Some studies reviewed both prevention and pain management."
The best way to prevent back pain, according to experts, is by wearing shoes that are of good quality and that fit well, and by strengthening weak muscles.