Athletic shoe stores have been carrying so-called “toning shoes” for some time now. These sneakers feature a curved, unstable sole. Walking requires more effort, as the shoes are said to mimic the effort of walking barefoot on a beach, for example. Proponents of this technology claim that the instability created by the shape of the sole forces wearers to use muscles that would otherwise not be used, helps improve posture, relieves certain joints and even burns more calories. But is there any evidence to support these claims?
Many studies have been conducted on the subject, all with very few volunteers and most financed by toning shoe manufacturers. A doctor decided to study these shoes and recruited a group of female students. The students walked on a treadmill for 10 minutes, once with toning shoes, and once with regular sneakers. Sensors were attached to the participants’ legs to measure the electrical impulses generated as their muscles contracted. The researchers also measured the women’s oxygen consumption in order to evaluate how much energy they burned. The results showed that muscle activation and oxygen consumption were almost identical in the two groups.
The longest study on these shoes was conducted at the University of Calgary. Volunteers wore toning shoes during the day for six weeks. At first, the participants wobbled a bit in their shoes, activating and strengthening the small and often underused stabilizer muscles in the feet and ankles. But after six weeks, the swaying had diminished and those muscles were no longer being exercised as much. In other words, for a limited time toning shoes do in fact help strengthen a few muscles in the feet and ankles, but not the big muscles in the calves and buttocks.
Independent studies performed to date do not support manufacturers’ claims that these shoes increase the intensity of the effort, thereby helping burn more calories and toning big muscles such as the thighs and calves. There is therefore no reason to buy these shoes if those are your goals. However, some people like the sensation of walking in toning shoes. If such is your case, there is not contraindication to using them!