Point-Counterpoint: Can Toning Shoes Have A Legitimate Impact?

David Y.S. Yee, DPM, FACFAOM, and Eric Fuller, DPM

   There are also claims of anterior rocker soles being a form of toning shoes. This type of shoe has equal thickness of the midsole in the posterior 60 to 80 percent of the shoe and tapers to essentially zero thickness at the very tip of the shoe. This type of shoe has been in use for a long time to reduce the pressure on the forefoot in the treatment of plantar ulcers. The rocker effect happens when the person tries to put weight on the forefoot. The shoe cannot push back but it can roll forward. What this does is shorten the lever arm of ground reaction force at the ankle. In other words, there is less resistance for the ankle plantarflexors. Therefore, this type of shoe will not act as a toning shoe at all. On the other hand, it would be good for someone with Achilles tendonitis.

   A third type of shoe is unstable in the frontal plane. One type of this shoe has a partial sphere or spheres on the bottom of the sole. The effect is the same as balancing on a narrow stick that is parallel with the length of the foot. Just as with the sagittally unbalanced shoe, the shoe wearer has to make some conscious or unconscious decisions on how to stand in the shoe. The shoe wearer can choose to either invert or evert the foot so the sole contacts at the edge and the bottom of the spheres to create a relatively more stable platform or an attempt to balance on that “stick.” The muscles that would have increased activity would be the invertors or the evertors. These muscles are relatively small and are not going to burn a significant amount of calories to qualify this shoe as a shoe that will tone the calf, thighs and buttocks.

   As with the other aforementioned shoe types, there has to be some concern about problems that may surface. To balance on a narrow base of support, the invertors and evertors will be working constantly. Feet that are prone to either posterior tibial or peroneal tendonpathy will be at risk with this increased activity of the muscles. If the shoe wearer chooses to stand highly inverted or everted, there is further chance for strain on various anatomical structures. In gait, these shoes could also be increasing the risk for ankle sprains in feet that are already laterally unstable.

   A final category of toning shoes is the heelless shoe. These shoes have a platform under the forefoot and the heel is suspended in the air. To stand in these shoes, patients will constantly need to contract the gastroc soleus muscle group. Obviously, patients will be using the gastroc soleus muscles in these shoes more than other shoes in general. Would patients then be using these muscles too much? Another question is how much work patients need to do to increase muscle strength. Do they really need to be constantly contracting their triceps muscles to increase strength?

   This question is also relevant for all the other types of toning shoes. If you look at weightlifting as a way of increasing strength, experts suggest anywhere from six to 20 repetitions of lifting a weight is sufficient, noting that patients do not need to have constant contraction of a muscle to increase strength.

What Recent Studies Reveal About Toning Shoes

To test the effectiveness of the shoes and evaluate the claims behind them, Porcari and colleagues designed a pair of studies.1 One study evaluated patients’ exercise responses to walking in traditional athletic shoes versus toning shoes. The second study focused on patients’ muscle activation in regular athletic shoes in comparison to toning shoes.

   For the first exercise response study, researchers evaluated 12 physically active female volunteers, ranging in age from 19 to 24.1 All patients completed a dozen five-minute exercise trials in which they walked on a treadmill for five minutes wearing a traditional running shoe (New Balance) and a toning shoe. The shoe order was randomized as patients walked at 3.0 mph with a 0 percent grade hill; at 3.5 mph/0 percent grade; and at 3.5 mph/5.0 percent grade. The authors also monitored patients’ oxygen consumption, heart rate, ratings of perceived exertion and expenditure of calories.

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