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The Definitive Plantar Fasciitis Explanation: The Cause & The Cure [Short Version]

Samuel G Oltman, ND, RMSK

Plantar fasciitis is a foot weakness problem. It’s not a lack-of-support problem or a not-enough-stretching problem. There are many misguided and unexamined assumptions in foot health that persist today adding to the confusion for patients suffering with this debilitating condition. These ideas need to be corrected and that is what I set out to do here from beginning to end. The following is a comprehensive, detailed, and definitive explanation of the cause and cure for plantar fasciitis.

The Claim: The foot is designed to support itself. It is only through deformity and loss of strength (structurally and functionally) that the plantar fascia undergoes injury, inflammation, and degeneration.

The Solution: Restore and maintain evolved intrinsic support and strength mechanisms through proper alignment and progressive load.

Fasciitis vs Fasciosis

Most people refer to plantar fascia injury as “plantar fasciitis” but this term indicates an acute inflammatory response. Most people with this condition have had it for many months and years, meaning it’s in a chronic state of both inflammation and degeneration. The proper term for this is “plantar fasciosis”. The difference simply indicates acute vs chronic and inflammatory vs degenerative.

See this article for the full explanation. For the sake of clarity we’ll be using the term “plantar fasciitis/-iosis” for the remainder of the article to recognize and include both meanings of this distinction.

Evidence Base

In the absence of perfect evidence, we can rely on a few basic, concrete principles:

  • Form is function: The human foot has arches for a reason: arches are extraordinarily strong structures. The arch form must be indicating something about foot function.

  • Muscle physiology: Progressive loading is how we gain strength. Length-tension relationship directly dictates the amount of force a muscle can produce. Use it or lose it.

  • Evolutionary Biology: Three hundred thousand years of Homo sapiens adaptation to bipedal movement with nothing but intrinsic support.

  • Anthropology: Natural experiments provided by people in various cultures with different shoe-wearing habits to our own show us the counterfactuals.

  • Fashion: Modern shoes distort and deform the intrinsic support mechanisms of the foot for explicitly aesthetic and historical reasons.

  • Logic: There is no arch in the world that we “support” by propping it up from underneath. There is no other part of the body we treat by causing its progressive weakening. Both of these violate basic principles, our embodied intelligence, and are antithetical to logic.

The Plantar Fascia

The plantar fascia is a fan-shaped sheet of collagen fibers that span from the bottom of the heel bone to the flexor tendons and toes of each of the 5 digits. Its normal function is to act as a tie-rod between the 3 corners of the tripod-arch anatomy of the foot (more on this later), stabilizing and stiffening the arches as force is applied through its very high tensile strength.

plantar fascia

How Arches Work

Arches derive their strength directly from their shape.

There is no arch in the world, in any domain, that is supported by propping up material underneath it. This defeats the entire purpose of an arch.

foot arch

The human foot does not just have one arch– it has 3, oriented with each other in a tripod fashion.

foot arch

foot arch

The key connection between arches and muscular strength is: the muscles do not need to support the feet/arches through brute strength. They just need to exert enough force to maintain the arch form because the arch itself is so strong by virtue of its shape. When the arch form is distorted its weaker and requires excessive strain from the muscles and fascia to maintain its shape and will eventually fail. Plantar fasciitis/-iosis is a foot weakness problem.

plantar muscles

How Muscles Work

Muscle physiology 101:

  1. Muscles become stronger with progressively increased demand.

  2. Muscle force is directly related to its starting length.

Progressive load and regular use is how muscles become and stay strong. Atrophy occurs in overly supportive shoes: the muscles shrink in size and strength from lack of use. They then cannot produce an adequate amount of force.

The starting position length of a muscle has a direct relationship to the amount of force it can produce in a contraction. This is referred to as the “length-tension relationship”.

foot muscles

By using overly supportive external devices, the muscles have less demand on them, which leads to weakness over time. By putting the foot in a bad position, the muscles are elongated and weak. Both of these interconnected phenomena lead to excess strain on the plantar fascia because the musculature cannot support/buttress the arch forces adequately. Plantar fasciitis/-iosis is a foot weakness problem.

Big Toe Alignment

Your big toe is a big part of your intrinsic arch support.

Arch shape/alignment and muscle strength depend crucially on the position of the big toe. Big toe position influences muscle force generation, structural integrity of the bony arch, and blood flow to the bottom of the foot.

Try this yourself by rolling your ankle back and forth with your toes squeezed together, then do the same thing with your big toe abducted into good alignment. (VIDEO DEMO HERE)

feet shaped like shoes

Many of the arch muscles are connected directly to the big toe. When we distort the big toe through adduction and dorsiflexion (the position it gets put into when in most shoes), all of these muscles get stretched and weaker by virtue of the length-tension relationship. This weak positioning (caused by shoes) creates more movement in the arch, meaning more force and strain on the fascia.

high heel foot health

arch muscles plantar fascia

Big toe position also influences blood flow to the plantar fascia, which when we’re talking about a degenerative fasciosis, blood flow is critical for healing.

To summarize, when the big toe is in a bad position, (adducted and dorsiflexed) the foot becomes weaker 1) through loss of structural arch alignment that counteracts pronation and arch flattening forces, and 2) through over-extended musculature not able to produce adequate buttressing force simply by virtue of their starting position. Plantar fasciitis/-iosis is a foot weakness problem.

The Foot Is Designed To Support Itself

Taken all together, the human foot has a tripod-arch tensegrity anatomy; muscles to buttress the forces through the arches; the big toe providing structural stability and muscle leverage; and a plantar fascia to tie and buttress the arch ends. With all of these elegant and synergistic support strategies, how do we end up with the foot weakness that causes plantar fasciitis/-iosis?

Fashion Footwear

All three intrinsic foot support/strength dynamics (Arch form, muscular strength, and big toe alignment) are disrupted by 4 features of conventional fashion footwear:

  • Tapered toe box that squeezes the toes together putting the big toe into adduction.

  • Raised heel that dorsiflexes the toes and over-stretches the arch musculature and fascia.

  • Toe spring that further dorsiflexes the toes, lowers force generation, and increases arch movement.

  • External arch supports propping up the foot and weakening the muscles through lowered demand/activation.

Why are shoes like this?

Modern shoe designs are a remnant of 15th century European status symbols. We can trace the advent of narrow toe shoes and heels to specific points in history as they conveyed specific things about someone’s status in society.

Your athletic shoes are not different from high heels: They have all the same features, just less.

plantar fascia shoes
Left: Not shaped like a foot. Right: Shaped like a foot.

The counterfactual is also in plain sight: we can observe the feet of people in societies that don’t wear modern shoes. This provides a natural experiment where we don’t see toe deformity, we see exceedingly rare heel pain despite no external support, and these people tend to be far more active than most people in Western countries. This is how the foot is supposed to function.

We uniquely burden the feet with body-deforming fashion.

Arch Supports

There has never been a study showing long term benefit from orthotic arch supports. It doesn’t exist for plantar fasciitis/-iosis or any other condition. There are many studies and meta-analyses showing the absence of long term benefit, here and here and here.

The use of arch supports could be justified if: 1) it made sense logically, or 2) had studies showing long term benefit. Neither of these criteria are met with orthotic arch support.

They are illogical because there is not another arch structure in the world that is “supported” by being propped up from underneath. It defeats the entire purpose of an arch. Arch supports do not make sense from an engineering standpoint or from a muscle physiology standpoint.

This illogical approach could be accepted as simply counter-intuitive if there were studies showing long term benefit of arch supports. However, there is not a single study showing long term benefit of arch supports.

There are studies with the headlines “orthotics show long term benefits…” but when you read the study there is symptom relief at 6 weeks and no difference by 12 weeks (and variations of this pattern, as seen here and here and here). There are multiple large meta-analyses concluding there is no evidence to support the use of orthotic arch supports over the long term– only that they decrease pain in the short term. Even a study showing no benefit compared to sham device. This study shows improved arch form and larger muscles with LESS orthotic use. Yet they persist as a long term strategy, ignoring shoe-induced deformity, degrading foot health, and promoting plantar fascia injury.

We uniquely weaken the feet when they have pain unlike any other part of the body.

If you put the foot in a bad position and the arch falls, it doesn’t prove that it needs arch support. It proves that it needs better positioning.

Summary Of The Cause

The human foot has amazingly elegant foot support/strength strategies that we have developed over many hundreds of thousands of years. When these strategies are disrupted, we see excess strain put onto the plantar fascia.


If you hear yourself saying "Yeah, but...", see the long version for your questions and objections answered.

A Definitive Diagnosis

Ultrasound imaging provides a definitive diagnosis. An ultrasound can image the plantar fascia completely and provide a complete qualitative and quantitative analysis. I do all this in-office during your visit for a fraction of the cost of an MRI– which is not as sensitive in determining the diagnosis. This is another area of expertise for me and what my RMSK credential signifies. Most podiatrists don’t have ultrasound in their office. It all starts with the correct diagnosis and often the patients I see haven’t even had that part done correctly.

The Cure

Now, how do I treat a patient with a confirmed case of plantar fasciitis/-iosis?

1) We reverse engineer all of the above causes to restore natural foot function. The changes in function, biomechanics, and exposure to stress need to be incremental and progressive. The emphasis for different people is different depending on anatomy and history.

However, as long as you have human feet, the common principles of footwear are:

  • Big toe in the correct position, coming straight (or as straight as possible) off the 1st metatarsal bone. This requires wearing a shoe that is shaped like a foot, or wide-toe box. This also requires for most people utilizing a toe spreader like Correct Toes to correct the deformity that has already happened up to this point.

  • Shoes that are flat from heel to toe (“zero drop”) to put the musculature in the optimal resting length position and ensure equal weight/stress distribution from front to back. This also includes reducing toe spring.

  • Removal (or minimizing) extrinsic “arch support” in order to use and activate the foot muscles, improving strength and arch function.

  • Cushion: take it or leave it. You can do all of the above with plenty of cushion under your feet. The goal is not to be barefoot. The goal is pain-free function. We do that by working WITH the body, not against it.

Don’t be scared off by thinking “He’s just going to tell me to be barefoot all the time.” We want strength and alignment. Not a dogmatic belief in an endpoint that might not work for everyone.

There are always going to be fashion and sport specific reasons to wear non-perfect shoes. Exceptions prove the rule. Do the best you can.

What shoes do I recommend?

2) After footwear and toe alignment correction, I move into rehabilitation exercises and various ways to promote more foot strength through using the muscles more. Bigger muscles means less plantar fasciitis/-iosis. Targeted stretching that is aimed at reversing deformity and promoting better biomechanics is also implemented. This takes time but is crucial and in-line with how we treat every other part of the body: strengthen the muscles around the problem area to induce a greater ability to compensate.

Strengthening exercise can also just be walking in Correct Toes without any external support. Barefoot on grass is great for this. We want to promote normal, healthy function. If you haven't done something like this in a long time, you need to go very slowly and incrementally.

3) I also recommend as many things as I can to promote circulation. So we do heat (stop icing your heel!), epsom salt soaks, topical capsaicin, and self-massage. I also often recommend copious amounts of fresh ginger to patients with cold feet and hands.

4) There are injection therapies that can help both the degenerated tissue and the pain. There are pros and cons to each, some are better than others for different people. In the case of any injection, I use ultrasound-guidance so there is no guess work. I also do nerve blocks so the discomfort of the injection is minimal. Neither of these measures are done routinely in other clinics.

PRP can be a great solution for persistent fascia issues that haven’t responded to conservative measures. If you’ve had a cortisone injection that didn’t work for your heel pain, you probably either don’t have a fascia injury (because nobody actually looked at the fascia), the person injecting missed the target because they did it without image guidance, or it got to the right location but you were put right back into the shoes that caused it in the first place. Cortisone can be a great tool in plantar fasciitis/-iosis to give people a break from the pain as they engage in the necessary rehab, alignment, and strengthening. But cortisone is not a solution if you’re not changing the factors outlined above.

Not everyone will achieve “perfect” foot health/alignment/strength. For many, I see them after 6 (or more) decades of their feet being deformed and dysfunctional. But we can still get massive improvements. We do not want to allow perfection to be the enemy of good. These principles exist on a spectrum and we get an enormous amount of improvement without being perfect.

Regardless of how unhealthy you think your feet are, we can resolve the pain of plantar fasciitis/iosis. The final solution may be a mix of rehab exercises, Correct Toes, a foot-shaped shoe with plenty of cushion, and a low arch support with long activity for years (because the muscles can take that long to unlearn a lifetime of bad habits). For others it may be a smooth transition into nothing more than a minimalist shoe and regularly wearing Correct Toes.

While this article focuses on the plantar fascia, these same principles apply to every common foot condition and cause of pain: bunions, neuromas, metatarsalgia, Achilles tendinosis, etc.

Plantar fasciitis/-iosis is a foot weakness problem. Restoring structural stability and muscular strength through alignment is the cure.

At Cascade Regenerative Medicine we utilize first principles thinking; we prioritize health over covering up symptoms; we back up what we do as much as possible with evidence, by actually reading the evidence; we do not do things just because that’s how they’ve been done before; we treat YOU, not an algorithm; we always consider multiple perspectives; we integrate physics, anthropology, evolutionary biology, psychology, philosophy, and are always learning; we value your time and give you the tools to make the best medical decision for yourself; we are constantly looking for better ways to serve you and to help you live a better life.

Do not settle for what constitutes mainstream care today. Nobody has the level of expertise that I do at the intersection of foot health, injection therapy, and ultrasound. If you or someone you know has plantar fasciitis/-iosis, Schedule with us today to see for yourself how much better your feet can feel.

Much of this knowledge, experience, and expertise comes from my years of friendship and tutelage with Dr. Ray McClanahan, DPM. He was inspired by the work of Dr. William Rossi, DPM to invent Correct Toes and pioneer the medical space of natural foot health. Many thanks to Dr. McClanahan and all the wonderful people working in this space.



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