Sore feet, Biomechanics, and Orthotics...

 

 I am a big believer in biomechanics. That belief is rooted in my personal experience with physical therapists and sports podiatrists.  That experience all started about 25 years ago.  At that time I had been cycling 150-200 miles per week for over a decade, speedskating, and doing resistance training. That all sounds like a high level of activity and it is.  But what is hidden in all that activity is the effect of biomechanics.

Cycling involves a flexed position at the hips and mainlining that position for hours at a time. The result is significant strengthening of lower leg flexors, hip extensors, and some hip flexor strengthening if you actively pull up on the pedals.  These patterns are recognizable in the hypertrophy pattern in the legs of cyclists.  At the same time, not a lot of energy is expended in muscles needed to maintain antigravity posture.  As a result cycling is one of the few exercises where energy expenditure can nearly match cardiac output – since not much additional energy is used for postural muscles.

Skating is a more strenuous combination of energy required for maintaining a flexed posture while translating lateral falling movements to forward propulsion and maintaining an unnatural posture. That also involves external to internal hip rotation under pressure as you move from the outside edge of a flat ground skate blade to the inside edge and then pushing off that inside edge.  Another critical point during skating is the hip hinge – a maneuver that I was never taught - to maintain the lumbosacral spine in a flat rather than flexed position when the spine is in a flexed skating position.  All of these movements combined with tight fitting skates, gravity, and centripetal forces while cornering puts tremendous pressure on the feet.

It only took a few years of this level of exercise to create a significant amount of foot pain. I remember deciding to try to walk off the pain one day at work. At the time I was employed by a large medical center.  Walking around the complex was probably about ½ mile.  On my first few attempts I could barely make it due to severe foot pain and back pain.  I could skate 10 miles or bike 150 miles but I could not walk around the block.

My first attempt at addressing this problem was to see a sports podiatrist right at the medical center where I worked.  I also had Haglund’s deformity of the calcaneus bones on both feet and was concerned about possible hallux valgus or bunion formation on the right. The podiatrist examined my feet, took the history and determined he needed to make a pair of orthotics.  After wearing them for 1 day – my foot pain was nearly gone and it resolved completely over the next week.  The orthotics were expensive so I had to transfer them from shoe to shoe.  That could not be done with my custom molded skates but they did fit in my cycling shoes.  I wore them successfully for at least 10 years before they started to fall apart.  I did not develop a bunion and the Haglund’s deformity did not get any worse and improved with just the orthotics. When I called the sports podiatrist's office again, I was advised they no longer did custom orthotics because of inadequate reimbursement. They had no ideas about where I could get another pair.

The theory of orthotics is that they restore the normal arch anatomy of the foot.  I was presented today with the additional theory that they also condition the intrinsic muscles of the foot to maintain those arches.  Both of those theories are somewhat controversial probably because of the diverse methodologies used to study the biomechanics of the foot. The main arches of the foot are shown in the diagram below as the medial longitudinal arch (MLA), lateral longitudinal arch (LLA), anterior transverse arch, and posterior transverse arch.  The bones that make up the MLA are colored pink and the bones that make up the LLA are colored green.

Over the past 10 years my exercise routine has changed to focus more on treadmill workouts. I use typical Bruce protocol parameters to vary the workouts from 3 -12 METS and typically do 90-120 minutes per day with additional weight training. The feet have become a serious problem again with soreness at the insertion of the right Achilles tendon around the entire perimeter, sharp shooting pains through the right arch, and excessive pressure and callus formation of the second toe on both feet.  I have Morton’s toe – a condition that occurs due to a short first metatarsal so the second toe is longer than the first.  At first I thought that this could be remedied by buying longer shoes. Even though I had worn 10.5 for 50 years – I went up to a size 11.  The problem was unchanged.  I tried running shoes that felt spongier than my typically runners.  Things were worse and I got some additional knee pain. I tried several weeks of not elevating the angle on my treadmill and that was also not helpful.

I finally went into an orthotics store today to get new orthotics. There was no medical staff around. The person who assisted me identified himself as a mechanical engineer who decided to change professions after he experienced significant relief from the orthotics he was currently selling. He had a measurement system used to estimate force distribution around the feet that produced the image at the top of this post.  He explained the orthotic system consisting of three different shoe inserts and demonstrated how this system resulted in a different weight distribution than standard shoes.  He had a checklist of other points such as pain in the back or at various joints that he said would be useful for follow up. He educated me in how long I could expose my feet to the three different orthotics and how it needed to be titrated over time. He said that none of what I purchased could be refunded – but I could get a different fitting in the next 60 days and he would call me from time to time to see how things were going. I walked out wearing the orthotics that I could use 24/7 and was reassured that I could use them starting today.

I will post how this goes over the next few months.  I am hopeful that I will get the same amount of relief that I got from my original orthotics 25 years ago.  I am also hopeful that it will correct additional biomechanical problems like my right foot inverting (rolling out) as I walk and an associated clunking sensation in the right knee as well as hip soreness and clicking during exercise.  I will be very pleased if the right Achilles pain resolves because it has become a chronic problem that I experience 20% of the time.  I decided some time ago to exercise through that pain and it does work.

So far, the cost is high.  Each of the orthotics costs three times what I paid for the originals 25 years ago.  That seems like a lot but considering inflation that is about right.  The only difference is the recommended three different sets.  There is no guarantee and all sales are final.  If they do work, this business keeps all of your specifications on record and service is possible at any of their stores.  I can’t help thinking about the economics of this situation and what it implies for health care in the United States. Orthotics have become a commercial product that you can purchase at a strip mall. I don’t know the range of sizes available or how that is determined, but I know they were not custom fit like the first pair I got from a sports podiatrist.  The retail procedure is much more expensive. At the same time, the podiatrist I was seeing could no longer afford to make them because of inadequate reimbursement.  I guess this is one way we contain health care costs in the US.  Making it retail for much higher reimbursement as opposed to rationing it at the expense of licensed health care providers.  It took me a long time to figure out that American capitalism is not about superior products.  Most of the time it is just about making money and how you can get advantages to do that.  The true test will be in the results that I will revisit over the next several months.

 

George Dawson, MD, DFAPA

Supplementary 1:  A biomechanics approach is also useful because pain can be addressed without any additional measures like medications or injections. At least that is the best case scenario.  It makes little sense to take over-the-counter pain medications when orthotics or physical therapy work for the pain. The previous orthotics I used corrected my foot and ankle pain and low back pain.  It also resulted in improved posture.  All of that from subtle (1-2 mm) changes in the position of my feet.  If these orthotics also work for strengthening the intrinsic muscles of the foot that is also an advantage over having to do specific exercises for those muscles along with wearing the orthotics.  I never found the exercises for the intrinsic muscles of the foot to be very effective.  

Supplementary 2:  Practically all of the running and athletic shoes these days have an insert in the bottom of the shoe.  This appears to provide some arch support - but it does not.  The staff person I was assisted by referred to it as a sock liner.  By definition it is typically a foam layer that your foot rests on and it is not designed to provide much support. There can be a very uncomfortable coarsely finished inner shoe surface below the sock liner.  An insole by definition is designed to provide support and an orthotic is a specifically designed insole to provide more support.  Numerous examples are available on any Internet search.    

References:

1:  Venkadesan M, Yawar A, Eng CM, Dias MA, Singh DK, Tommasini SM, Haims AH, Bandi MM, Mandre S. Stiffness of the human foot and evolution of the transverse arch. Nature. 2020 Mar;579(7797):97-100. doi: 10.1038/s41586-020-2053-y.

2:  Asghar A, Naaz S. The transverse arch in the human feet: A narrative review of its evolution, anatomy, biomechanics and clinical implications. Morphologie. 2022 Dec;106(355):225-234. doi: 10.1016/j.morpho.2021.07.005.

3:  Wang H, Wu Y, Liu J, Zhu X. Investigation of the Mechanical Response of the Foot Structure Considering Push-Off Angles in Speed Skating. Bioengineering (Basel). 2023 Oct 18;10(10):1218. doi: 10.3390/bioengineering10101218.

4:  Chauhan HM, Taqi M. Anatomy, Bony Pelvis and Lower Limb: Arches of the Foot. [Updated 2022 Nov 9]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK587361/

5:  Collier R. Orthotics work in mysterious ways. CMAJ. 2011 Mar 8;183(4):416-7. doi: 10.1503/cmaj.109-3802. Epub 2011 Feb 14. 

 

Image credit:

1:  Foot impressions at the top are from the retail store and are from my feet done today 3/29/2025.

2:  Anatomical images of arches are from reference 4 – reproduced here without alteration per the CC license as follows:  This book is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ), which permits others to distribute the work, provided that the article is not altered or used commercially. You are not required to obtain permission to distribute this article, provided that you credit the author and journal.