While shoe-wearing doesn’t change the musculature of the fore-foot, it does change the pliability of the fore-foot, resulting in lower pliability for people who wear shoes. Modern shoes have a narrow toe box and medial arch supports, leading to decreased natural function of the foot. Your toes cannot spread as they do when barefoot, so the muscles of your feet don’t get the relaxation they need on a regular basis.
This also affects the absorptive properties of your foot, which are jammed into a smaller surface area and directed through narrowed (though thicker) channels of tissue. This combination of lack of movement and focused force results in strain on the structures of the foot and leads to symptoms like plantar fasciitis (Kadambande, et al., 2007).
Most running shoes create very real sensory deprivation. Aboriginal barefooters pick up specific information about their environment from their feet. Your skin absorbs all kinds of elements from the environment around it. Contact with the earth provides not only information about temperature and texture but also information about soil health, which is directly related to your own health.
A different paper’s bottom line says that the use of footwear seems to lead to an increase in the appearance of what is called “hallux valgus.” That means that the tip of the big toe points away from the midline of the body, toward the outside of the foot - especially when the footwear in question is ill-fitting (too small, too tight, inflexible, etc.).
Over time, this situation leads to the formation of bunions (which is when the bone around the toe reforms to match the new angle of strain). The paper finds that, “a hallux that already exhibits valgus deviation often tends to straighten when footwear allows spreading of the toes” (Barnett, C.H., “The normal orientation of the human hallux and the effect of footwear”, pg. 493, 1962).”
Hallux Valgus
So, if your shoes are the cause of hallux valgus (and they may not be, there may be other bio-mechanical issues your body is dealing with), switching to a shoe that allows your toes to spread will help reverse the process. Barnett’s findings above have been supported over the years, notably and recently, by Zipfel and Berger (2007).
Not only is the information above not new it shouldn’t be surprising! Part of the reason for hallux valgus, as pointed out by Barnett, is the weakening of the muscle that controls the movement of the big toe away from the other toes - the abductor hallucis. This leads to a discussion about why some people who don’t wear restrictive footwear exhibit hallux valgus and foot deformations. These are the “biomechanical issues” mentioned in the parentheses above.
The body is a long “kinetic chain,” where the forces from any part of the body extend to every other part in some way shape or form. There is no part of your body (or brain) that is not connected directly to every other part. The distinctions we make between body parts are useful in learning anatomy and physiology, and in focusing on particular areas, but they are also misleading if we forget to reconnect the parts with the whole.
If you have a postural deviation (such as rounded shoulders and a forward head position, also known as “upper crossed syndrome”) that deviation extends down the entire body to the feet. Your entire body will attempt to compensate to keep you upright, and to keep your head on top of your body, with your eyes pointing straight ahead, so that you’re able to see your environment.
Those deviations at the top will cause you to put more pressure on the inside of your foot than across the entire surface. That pressure will lead to a turning out of the entire foot (valgus, again), as well as a turning-out of the big toe. Voila! Hallux Valgus!
