Sunday, March 26, 2017

The Amazing Human Foot

"The human foot is a masterpiece of engineering and a work of art." - Leonardo Di Vinci

As a topic often misunderstood by medical professionals and laypeople alike, I'll be talking about feet (and healthy shoes) for the next several blog posts.  This can be a touchy subject in the running/athletic and medical communities primarily because people's livelihoods are involved in the myths surrounding footwear. I'm still going there anyway because if there is one thing that gets my blood boiling, it's bad information that ultimately leads to pain, disability, and unnecessary surgeries.

And unfortunately the fact today is that advertising has inundated the population with myths and marketing regarding what needs to be worn on the foot to move properly, safely, sustainably, etc.  It's as though you need a special degree to understand how to use and take care of your own feet.  If we slow down for a moment to think about this issue we might realize how ridiculous this topic has become; how many of you need a PhD to use your hands properly?





What's my theory?  In general, bad shoes create nearly all of our foot problems (75% of Americans will encounter foot problems in their lifetime; most of us have foot deformities caused by bad shoes).  It is eerily similar to how processed junk food has helped create a health crisis in our country.  The medical machine awaits your foot problems with injections, surgery, more expensive shoes...oh yeah, and a cane or walker.  I hope to bring a few important concepts about feet to light in this article.






Did you know that your feet house a quarter of all the bones in your body and 250,000 sweat glands?  Each foot has 33 joints, 107 ligaments, and 19 muscles/tendons that support it.  Clearly as a point of anatomy, your feet are designed to be flexible and mold to the uneven terrain we find in nature.  By molding to the world, your feet send the brain important feedback that's used for balance and leg control.  Think of your feet and your ankles like the maestro for the rest of the body.  They lead the orchestra of muscle activation based on what they report (or what they don't report) to the brain.






When we are babies, in general, our toes line up perfectly with the metatarsals of our feet.  In other words, the widest part of our foot is at the end of our toes, not our metatarsal heads.  Nearly every foot I see today is deformed from its natural state due to a tapered toe box.  We can look at architecture and clearly see that the base of every arch must be stable for the arch to be strong.  By narrowing the toes we destabilize the base of our arch, meaning we lose the strength and proper functioning of the arch.  Most people who think they need arch support are actually lacking proper alignment of their toes due to years or decades of bad shoes.  You can look to a study published in the Journal of Bone and Joint Surgery in 1905 by Hoffman to see what healthy and unhealthy feet look like.  This is a must-read for anyone interested in foot health.  It's been over 100-yrs since this article was published and yet most of the public is not familiar with how our feet should look and function.






This narrowing of the toes and lack of arch stability ultimately leads to the need for pronation control.  Our arches are designed to store and release energy via pronation yet most shoe companies and salespeople will suggest that pronation is something the shoe technology needs to block or control.  The reality is that pronation is a normal motion of the foot and not being able to pronate can actually lead to stress fractures and other problems.  The flexibility of the arch allows us to pronate and store free energy in our arches.  Like a spring mechanism, we get free energy upon the release of this tension.  So controlled pronation is normal, it's great, it's supposed to be there.  You only need non-deformed toes and muscle control to allow the arch to work properly.  Throw in arch support and you block pronation, aka the storing and releasing of free energy (The Foot's Arch and The Energetics of Human Locomotion. Sci Rep. 2016; 6: 19403).

Or you can avoid surgery by not wearing stupid shoes.

While basic foot mechanics are quite fascinating, brain science is even more so.  Most people in our modern society stuff their feet into shoes from the time they wake up to the time they go to bed and never think twice about it.  But what would happen to your hands if you were to cast them nearly every waking hour?  Talk to any occupational therapist and they would tell you how quickly you would lose coordination, hand awareness, muscle strength, etc.  Try brushing your teeth with your non-dominant hand and if you're like me you feel quite clumsy.  This is not because my left hand is a poorly designed body part and I need to protect it, it's simply because I never use it for that task.  Our brains store maps of our body parts and the more we use an area the more detailed the map becomes.  Similarly, our maps become fuzzy with body parts we use less often and coordination becomes more difficult.  Fortunately our maps are malleable.


Let's consider a few other examples.  Did you know a woman from Arizona named Jessica Cox was born without arms and learned to fly a fixed-wing plane using only her feet?  Amputees may experience phantom limb pain for a period of time because their brain has not yet remapped itself as "not having the limb."  There are countless examples of brain mapping in action.  When we never take our feet out of shoes, we naturally lose foot control and coordination.  You can be the scientist here and hypothesize what sort of problems might arise from a lack of body awareness.



While the debate about footwear will likely rage on, the science actually demonstrates little true debate about the function of the human foot.  If bad shoes deform our feet, change our mechanics, cause weakness and compensations, and cause us to lose body awareness, then the answer must be healthier footwear as well as time spent out of shoes altogether.

My next post will dive a little deeper into what characteristics make up a healthy shoe. Stay tuned!

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