Everyone with an opinion on toning shoes is jumping on the bandwagon of them not working or working depending on which side of the fence you are on. Toning shoes do work for some things and do not work for others, so to make a blanket, they do not work claim is as nonsensical as making a blanket claim that they do work! Of course, everyone making the claims are (armchair) experts.
Toning shoes are a sector of the footwear market that have design features to make them unstable. This instability will theoretically make the muscles work harder, giving the alleged additional ‘tone up‘ when using them. The marketing of these shoes was certainly hyped, often in infomercials on late night television and celebrity endorsements (Kim Kardashian). There were many health gains claimed to be associated with the tone up that could allegedly be gained from the shoes ranging from getting rid of cellulite to improving the circulation to improving the posture and even headaches! As the evidence supporting the claims did not exist and what did exist showed that there was not a tone up, there were a number of legal issues and two companies (Skechers & Reebok) had to settle with the Federal Trade Commission for many millions of dollars. As the shoes are unstable, there is also an increased risk for falls and accidents while wearing these shoes, so there are a number of class action suits filed against the manufacturers as a result of injuries sustained from accidents and falls while wearing them.
Yet despite that, there are plenty of anecdotes and testimonials about how great the toning shoes are. However, on the other hand, there is evidence that you do not get the tone up that was claimed from the extra muscle activity from the unstable design features on the shoe.
So what are toning shoes good for? As they do alter muscle activity and alter the posture or alignment, this can be of potential benefit. The rocker sole design used by many of the toning shoes will mean the big toe joint does not need to bend as much when walking, which has potential therapeutic implications for those with osteoarthritis of this joint. The change in postural alignment will help some people with postural problems; they may also hurt other people with postural problems. The problem is that the research derived clinical guidelines as to who will really best benefit from these toning shoes and who will not just do not exist yet.
Despite the legal trouble of recent years affecting the toning shoes sector, do not write them off. They do have uses and can be potentially very useful for some clinical conditions. We just need more work to determine who should be in them and who should not be. Pretty much all the research in recent years on toning shoes are here.
What about toning shoes for runners? There is no evidence one way or the other, but it is plausible that they will have some benefits. Using muscles differently for short period of time will have some theoretical benefits. I wear my toning shoes to work one day a week. No harm in that.
I go where the evidence takes me until convinced otherwise.