If I was to invent an insole, maybe one with some fancy ‘bells and whistles‘ and then simply made the claim that it strengthens the muscles of the foot, would you believe me? What if I added the word ‘barefoot’ to the products name to make it sound impressive? Would you believe me then? Of course you wouldn’t as you are not that stupid!
That is exactly what a company has done: Barefoot Science, have made an insole that they claim strengthens the muscles of the foot, yet have produced not one shred of evidence to back up the claim. Why does anyone believe them, just because they say its true? The strengthening claim has been widely promoted on their website, on the “As Seen on TV” infomercials, in the marketing for the insole and even in a tweet from them:
If it was a “fact”, then where is the data that says they do, preferably from an independent source? I have searched their website and can find nothing that backs it up, except testimonials and a claim from a ‘Dr’ that it does (which should be red flags). I have no idea if they really do strengthen the small muscles of the foot or not, but if that claim is made, I would expect to see some data. The onus is on those making the claims to produce the data. Most countries have laws against making these sorts of claims in advertising. The Federal Trade Commission in the USA and regulatory authorities in other countries have taken to task many companies for doing exactly this (eg the recent Skechers $40 million settlement with the FTC for making health claims associated with their product that was not supported by any data; and not to mention the potential for class action suits such as the one Vibram are facing).
Looking at design of the insoles and trying them myself, the large ‘dome’ they have would tend to plantarflex the lessor toes, via the mechanism of dorsiflexing the metatarsals. Given that this is the role of the intrinsic muscles that they are claiming the insole strengthens, then if the dome does it, then the muscles do not need to do it, so the muscles would get used less, meaning they get weaker, not stronger. Of course this is still hypothetical yet plausible and I will wait for the company to produce the data before reaching a conclusion. Until I am convinced otherwise, these insoles belong in the snake oil category (the ‘As Seen on TV‘ should have been a red flag).
That tweet is certainly showing an extraordinary ignorance of flat feet! The EMG data on flatfeet show the muscles are very active compared to ‘normal’ arch feet, so the muscles in a flat foot are already strong as they are working harder. Perhaps they could explain what they actually hope to achieve by making them even stronger? We already know that weaker intrinsic muscles of the foot are associated with a higher arch foot (think, the ‘intrinsic minus’ foot that occurs in diabetic motor neuropathy; and the higher arched foot that develops in early CMT when only the small muscles of the foot is affected). So perhaps they could explain the mechanism by which strengthening the small muscles of the foot is the “only viable and reliable solution“, when theoretically, the weaker intrinsic muscles lead to a higher arched foot.
I still can’t work out what the word ‘barefoot‘ has to do with it. You have to be wearing shoes to use the insoles, that is not ‘barefoot‘ … don’t figure! And, of course, they throw in the “natural” fallacy for good measure in the marketing which should be another red flag.
I have no doubt that some people wearing these could get some therapeutic benefit, but there is no data as to if this is a placebo effect, due to the natural history of the problem, psychological perceptions of symptoms or really is a mechanical effect (see: Why Ineffective Treatments Sometimes Work). The mechanical effect, could well be a muscle strength change or could be a totally different mechanism. For example, the design and placement of the dome in the insole will theoretically improve the windlass mechanism of the foot and easily account for any therapeutic benefit claims, which as nothing to do with the strength of the intrinsic muscles of the foot. In the absence of data, I actually think this is a more plausible mechanism for any therapeutic benefits that might occur.
I have nothing against exercises to strengthen the muscles of the foot as they are probably helpful in a number of conditions, I just remain unconvinced that this product does it. We do know from the evidence that traditional types of foot orthotics actually strengthen muscles (2 studies) and does not weaken muscles (1 study) – which is contrary to what Barefoot Science state on their website (why do they ignore the published evidence and effectively, lie?). No study has shown that they weaken muscles. I go where the evidence takes me until convinced otherwise.
POSTSCRIPT: There was a belated reply to the above tweet:
Interesting that the studies are ongoing, but it still a fact that they work ….. don’t figure! How do they know the results of the studies if they have not been finished? How many times have, how many other companies claimed the exact same thing and never produce the studies? (The company behind the Circulation Booster is one that comes to mind! Same marketing techniques; same sorts of unsupported claims;claims made about studies being done and they never produce them; been there ….done that!). I have searched all the clinical trial registries for ‘barefoot science’ and many permutations of that and could find absolutely nothing (let alone 6), so will wait with baited breath to see what it is about.