Have you noticed that the average podiatrist will prescribe custom arch supports regardless of arch height? Doesn’t that strike you as a bit peculiar? If you’re going to shell out $300-500 for a set of custom foot orthotics wouldn’t you like to fully understand why you should expect them to help you to walk better, to stronger, healthier feet, to less pain or whatever your need is?
The Purpose of the Foot Arch
The arch is the natural shock absorber of the feet. When flexing, it allows the foot and ankle to pronate – lean inward. This motion unlocks the bones of the feet so they are packed loosely to absorb the shock of the heel hitting the ground when you walk and run. Clearly, if the foot doesn’t lock again, packing the bones more closely when you try to push off, you will be pushing off with a bag of bones instead of a stiff lever arm. This mechanism is controlled by your hips.
Through gait, your hips drive your feet into pronation (ankle rolling in) and toward supination (ankle rolling out). Without this mechanism, your gait will lose some fluidity, softness and strength. When your foot is forward of your body ready to strike the heel, your hip on the same side is forward rotated, internally rotating the leg and releasing the foot to pronate freely. That reduces the impact of your heel strike and cushions the full loading of the foot. As your foot moves through the gait, the heel lifts and you’re ready to push off, the hip rotation has reversed, externally rotating your leg, supinating and locking your foot. That packs the bones closely in your foot, makes it more rigid to act as a strong push-off lever.
There is No “Normal” Arch Height
There is no standard for the height of the medial foot arch. Most people have a “normal” low to medium height arch. Some people may have no arch at all when they stand, and a good number of people display high arches. This is usually not a structural problem. Your arches are controlled by muscles that can either be too elongated or weak trending toward over-pronation and a lower arch or shortened and hyper activated trending toward a high arch and supination. Most often we are dealing with a subconscious neuromuscular response to a structural propensity to over-pronate. Even people who have flexible flat feet can display a supinated gait. It is a common subconscious compensation pattern.
The outliers are the ultra-high peaked arch “Cavus Feet” and the no arch feet “Pes Planus”. While ultra- high arches are more prone to cause severe problems, flat feet can be trouble free.
The most important fact here is that the feet need an ability to pronate and that arch height during stance and gait is primarily a neuromuscular behavioral issue.
Roots Biomechanics and Arch Supports
Dr. Merton Root, DPM developed the mechanical model podiatrists use today to assess your foot function. One of his basic tenets is that most people have “fallen arches”, a condition that needs to be prevented to achieve better foot mechanics and avoid pain. He prescribed the use of arch supports by specifically placing the foot in it’s optimal static position and cast a proper arch support to maintain that position. This is the basic component that is included in virtually 100% of custom foot orthotics and is sold over the internet and in running stores by the millions because people have been told all their lives by doctor and advertising that their feet have to be supported. How many articles do you find on the web that discourage the use of arch supports?
What happens when you introduce your feet to arch supports?
Go out and pound a 2x4 into every coil in your car’s suspension. You’ll get a stressful, hard ride for sure. After a while parts of the car will start to break down because of the lacking suspension. In your body this action is amplified, because the motion of your ankles, knees, hips, back and neck all depends on what your feet are doing. If rigid arch supports could actually lock your feet from heel strike to toe off they would create havoc with your body. Fortunately, the arch support itself is only able to restrict motion of your feet when your feet are flat on the ground and for many that is bad enough.
As your foot approaches heel strike, the arch support has limited impact because it’s only supported by your shoe, so you still retain most of your impact protection. That’s good news. Then as the ball of your feet reaches the ground, your feet should be able to pronate but if it’s a hard arch support, it will shock your kinetic chain, ankles, knees and hips by locking your feet. This is both uncomfortable and it creates a lot of pressure under the arch on the navicular bone which is why most arch supports have changed to a more flexible design. There is however a trade-off here. As the arch support becomes more flexible, your foot is allowed to pronate more so you get away from the optimal foot posture suggested by Roots Biomechanics. You may have a difficult time with the pressure under your Navicular bone, but the idea is that you’ll get used to it.
Next your heel rises and your “fallen arch” is no longer supported by the arch support. As described above, the external rotation of your leg tries to supinate your foot, but if you are structurally set up for over-pronation, which most people are, its game over! Your arch is going to drop, your foot pronate and your push off collapse.
So arch supports are really only doing their job when you are standing still with your feet flat on the ground. At any other time they have little impact, and if the arch supports are flexible, the standing impact is reduced according to their softness all the way to nothing.
Was Dr. Root right about “Fallen Arches”
Partially, in that fallen arches and over-pronation is a real problem, but what looks like a fallen arch is in fact an elevated first metatarsal. This can be easily demonstrated using the same concept suggested by Dr. Roots for measuring the height of the “custom” arch support. It is called placing the foot in its “Subtalar Neutral Position”. There are several ways to determine this position, but it is essentially rolling your ankle outward until your heel bone is at a straight angle to the floor, so your ankle is neither pronated or supinated. In that position Dr. Brian Rothbart, DPM discovered that the first metatarsal head, the big toe joint, was not on the ground and properly weight bearing. It looks like the arch is falling because in order to become weight bearing, the first metatarsal head has to travel downward to reach the ground. It is the far end of the arch that is “falling”. The arch maintains its shape until the first metatarsal is weight bearing after which the arch flexes as it should. Dr. Rothbart discovered an entirely different mechanical connection to the “fallen arch” which does not require support to correct.
The Neuromuscular Connection
Your metatarsal bones and toes are vital in balance and propulsion. For balance they individually push back against the ground with the force required to maintain the body posture. You can do this consciously, or it happens subconsciously when the metatarsal heads become weight bearing. The signal to activate the muscles is partially generated by the pressure sensed under the metatarsal heads, so it follows that if the first metatarsal head is elevated, it does not get the signal to contract the muscles that brings it hard to the ground until the arch has dropped sufficiently for weight bearing to be registered. A study (McPoil) of healthy college students documented that the first metatarsal did not become fully weight bearing until 80-88% of the weight bearing gait cycle was completed. Adding arch supports in your shoes tends to make this problem worse by lifting the metatarsal head further off the ground. You can check if you have an elevated first metatarsal by following the self-test on our mortonsfoot.com website.
Follow this link: Self-Assessment.
So, why do arch supports work for some?
We think because it provides a pressure stimulus to the navicular that causes a neuromuscular response. Initially, the pressure of the arch support is unnatural and causes discomfort triggering a natural pain avoidance response. This activates the muscles preventing you from going fully weight bearing on the arch support thereby moving the foot to a less pronated posture. After a while, if you can tolerate the pressure, the arch becomes desensitized from the excessive pressure which is possibly why arch support orthotics work long term for some people, but can also be the reason for the original symptoms returning. Keep in mind that our feet are all variations on a common design so arch support used conservatively for specific reasons can resolve foot pain, but since our feet have significant impact on the entire body, it isn't uncommon for orthotics to cause new symptoms, sometimes elsewhere in the body. Certainly, if you want to try arch supports, you’ll be better off trying an over-the-counter set first to determine how you respond.
Good Intensions based on Incomplete Analysis
The concept of “supporting the feet” with a one-sided cast that prevents the feet from properly moving isn’t considering the neuromuscular system and the natural responses of the human body. Dr. Dudley Morton, DPM, 70 years ago tried to educate his peers on proper function of the first metatarsal and the resulting problems that arose when it was not on the ground and supporting twice as much weight as the other metatarsals. Our customers at mortonsfoot.com, repeatedly tell us that when they mention Morton’s Toe or Morton’s Foot to their podiatrists, they just blow it off as inconsequential and unimportant. We know, because they are our customers, that a wide array of non- interventional practitioners in the field of physical medicine worldwide, are learning that restoring proper function to the first metatarsal is a basic foundation for body-wide healing from musculoskeletal disease and pain.
Gloves Off Series – We’ve had it with Podiatry dogma
After 20 years of working with people in pain and with responsible and caring professionals who care for people experiencing chronic musculoskeletal pain, we have had it with conventional thinking when it comes to your feet and your structural body. We may be risking the wrath of both the podiatry and footwear industries, but so be it. There simply is no rational reason for millions of people worldwide to suffer from chronic musculoskeletal pain. In this series we will cover better alternatives (not only shoes and insoles) to many ailments originating with malfunctioning of the feet. If you are interested in learning more from a clinically experienced engineer’s perspective on chronic pain in your feet and body, sign up for the blog at mortonsfoot.com and stay tuned.
About the Author:
Bjorn Svae is the owner of GRD BioTech, Inc. dba Posture Dynamics founded in 1998. Bjorn holds degrees in electrical engineering and business and has enjoyed a career in design, marketing and sales of diagnostic medical equipment as well as business consulting and entrepreneurship. In 1997, nine years after having undergone bilateral fractured meniscus knee surgery, he met Dr Rothbart and was fitted with an early edition of the forerunner to the ProKinetics Insoles. The pain which had reappeared in the left knee immediately went away and has never come back.