Running Shoes…Another Look

Happy Spring! Or does Spring + Winter = SPRINTER? Or maybe Winter + Spring makes WIN[N]ING! Here we are in southwest Montana and it’s April. Even though I’m sometimes a joker (but not a smoker or a midnight toker), this post contains no fooling around. Looking out my window this morning, the world is covered in snow and the thermometer reads 11 degrees Farenheit, but’s going to be a beautiful, fabulous day. And I think of Spring, as winter’s grip lessens its hold on us, and we are beginning to emerge from our real or imagined dens and start to recreate, exercise, and just MOVE more outdoors. This of course brings us to footwear, and specifically running shoes.

As most of you know, I’ve been a shoe geek for a long time. Probably just an overall geek, really, but I’m interested in how shoes work, or don’t work, for us. I’ve had some stints in running shoe research and design, wear testing, sales, and footwear prescription, and I’ve always found it intriguing. I wrote a few posts several years ago by first asking “Are we born to run?” and then by taking a closer look at the subject of barefoot running. These laid the foundation for a diatribe on running shoes and some specific advice on footwear selection. This was followed by a revisit to maximalist shoes as research indicated some controversy with this shoe style. A little time has passed and I have some new observations to share. I like where the running shoe industry is heading, and I’m pleased to see our collective views becoming more rational.

Up first is the issue of humans existing with feet in shoes for generations. The contention here is that not only could our feet be weaker and more shoe-dependent from a lifetime of shoe use, but that we may be downgrading our genetic code with respect to foot functionality. The rapidly-evolving field of epigenetics would suggest that we may be gradually turning off gene expression for foot durability/stability, and passing that condition down from generation to generation. In other words, on average, a 2018 foot may not be quite as versatile as a 1694 foot may have been. I don’t know about you, but this certainly gives me pause (paws?) for thought. While we all may be a little more shoe-dependent than our ancestors, there is still a place for going barefoot and strengthening our feet, we just have to be sensible.

Foot shape, and ultimately shoe shape, is another great topic. We humans have a general similarity, in that almost all human feet look like human feet (as opposed to an elk hoof), but within that classification there are a few differences. Some feet are narrow, some are wide. Some are thick, some are thin. Some have high arches, some have low. And the list goes on. It’s nice to see the variety of shoe shapes, based on the lasts or templates that manufactures use to create footwear. Across brands, and sometimes even within brands, you can get a shoe that matches your particular foot shape. And let’s add to this that many shoe makers are finally starting to create lasts that look like a bare footprint, instead of the opposite. I’m referring to the old trend of creating running shoes with wide heels and pointy toes. I’ve never seen a human foot that looked like that. Look down at your wet footprint when you step out of the shower and you’ll observe the toes to be wider than the heels. We are seeing wider and roomier toeboxes in shoes that allow for a more natural and less stressful fit to the foot. There is even a mild amount of forefoot splay that happens in the stance phase of the gait cycle and we benefit from shoes that encourage this function.

And speaking of function, our feet perform a variety of actions when they are on the ground during each stride cycle. Perhaps the function that most people get excited about, and often somewhat confused about…is pronation. Put simply, pronation is that natural relaxing downward and inward that our feet do as they conform to the ground. It’s a component of how we adapt to our support surface and absorb shock. It gets a bit amusing when a person, usually well-meaning but slightly misinformed, states “I pronate.” Resisting the urge to be snarky, I comment that very close to 100% of the population pronates to some extent. And as with almost all things biologic, pronatory function exists in a normal distribution under a bell-shaped curve. You actually want and need some of it, just not too much, which is more appropriately called overpronation. And too little pronation falls into the classification of underpronation, which is usually less than ideal as well. That bell-shaped curve, with most (68%) of the bell representing one standard deviation on either side of the mean, represents the Goldilocks principle in pronatory function. There are going to be differences, and we probably want most people functioning near the mean, but some will exist on the stable side of the mean, some will hang out on the mobile side of the mean, and we might not be able to change that very much. With respect to this topic, some runners do benefit from stabilizing features within the shoe, but the perspective that all pronation must be aggressively limited and that this is the sole responsibility of the shoe, has relaxed a bit.

The opposite of pronation, in biomechanical terms, is supination. Our feet naturally progress from pronation toward supination during every stance phase. If, as we reviewed above, the foot pronates to adapt to the support surface and absorb shock, it supinates to stiffen and become a rigid lever for push-off. So, again, some folks will say “I supinate,” and we must refrain from saying “Woop dee doo, you and me too!” A true supinatory gait pattern is extremely rare, often associated with pathology such as neurologic disease, and occurs essentially when the foot strikes the ground and rolls outward, not pronating at all. This is dysfunctional and highly undesirable. An underpronator may live life a little more on the supinatory side of the mean, and thus may have greater needs for shock absorption and less for stability. And thankfully, both the shoe industry and many runners have begun to recognize that components of running form such as footstrike, knee flexion angle, and quadriceps activation can actually decrease ground reaction forces more than a shoe midsole.

So as we continue to see shoes classified as stability-enhancing or neutral/cushioned, and there is a place for these shoes, the perspective that the shoe has to do everything for the runner’s gait and performance has thankfully lessened a bit. And, even though this seems as an aside, I want to briefly discuss orthotics, but I’ll bring the discussion back around quickly. As a PT, coach and trainer, working with runners for over 3 decades, my estimate is that I’ve manufactured and/or sold nearly 2,000 pairs of orthotics. That’s my full disclosure and while it may seem like a conflict of interest making this statement, I’ve never been an “orthotics pusher.” I’ve always viewed orthotics as a tool to use, in most cases temporarily, to offload injured tissue and help with healing from lower extremity problems. I have consistently and still do encourage runners to be patient with injury recovery, progress training intelligently, fix their form, strengthen their bodies, and be reasonable with expectations. But this has backfired many times. When an orthotic helped to reduce or eliminate pain, the runner often unfortunately became “addicted” to the device and bypassed all those other corrective principles. I’ve seen people come into the clinic with these monstrosities (that they got elsewhere) of plastic, wedges, duct-tape and you-name-it, and share “religious experiences” about their orthotics. If I suggested they didn’t need them anymore, or needed a less aggressive device, they usually reacted emotionally and adamantly stated they require their orthotics for life. No manure here, I’ve even had a few people who slept with their orthotics strapped to their feet while in bed! I once actually grabbed one of these “fecalfrankensteins” and whipped it up against the wall! Unfortunately I was unable to shatter it (not my most shining professional moment). I won’t belabor this subject and will save it for a separate post, but whether we are talking about shoes or orthotics, maybe we shouldn’t expect them to do everything for us. And maybe there are other things we can “fix” so that our running performance and experience is enhanced while using less, not more, footwear.

Runners come in all shapes and sizes. Their stride patterns, footstrikes, limb length, vertical displacement, arm swing, trunk rotation, and many other descriptors can vary a bit. Some runners run lots of mileage, others very little. Some run only on 1 surface or terrain, others on every one imaginable. We have runners who perform most of their locomotion at very fast paces, and also those who prefer a much lesser velocity. And let’s not forget about fashion, as sometimes the need for something flashy is superseded by a call for a more demure presentation. And this is where the shoe industry has made outstanding progress. When I took my first official run in gym class, I wore high-top Converse Chuck Taylor’s. Several years later my parents drove 70 miles to a sporting goods store (the running shop hadn’t been born yet) to take me to get a pair of Tigers, which came in blue or red with white stripes. I wanted the blue ones but they only had the red ones in my size. Flash forward a few decades, and we have great choices for every running application and fashion statement one would care to make.

However, we must remember that the shoe industry is indeed a business. Profits drive sales, and the primary goal of the shoe maker is to sell shoes. That stated, marketing, i.e. determining what the consumer will buy and promoting that product, sometimes trumps research when it comes to organizational budgets.Think back to the late 2000’s when minimalist shoes became so popular. Every manufacturer had several in their product line and for a short time these shoes dominated the total sales. Then a few years went by, maximalist shoes came out, and suddenly every major shoe brand now emphasized these models and the minimalist shoes had almost vanished. As someone who studies the research in this area, I can tell you that there was never a general consensus in the data that either type of shoe, or any shoe for that matter, was necessarily the end-all, do-all, or be-all. But popular demand drove the industry in a powerful manner. We just have to use our common sense, along with our fashion sense.

Running may be one of the most natural of human functions. Excepting injury and congenital issues that preclude some individuals from participating, humans are mechanically designed to be able to run a little (as in across the street when necessary) to a lot (those inclined toward longer distances). We’re genetically programmed to have running as a function in our quiver of movement patterns, just like squatting and climbing. As natural as running can be, shoes can help a runner to have greater traction, protection, and durability. This is particularly true when we run on asphalt, gravel roads, and sidewalks (thumbs-down). Those are not natural surfaces like grass fields and sandy beaches, and we can usually benefit from an upgrade from the barefoot condition known as a shoe (or two, as in a pair). Shoes help us to optimize the foot-ground interface and are a wonderful invention of modern society. So I’m not here to make the argument, which I don’t find overly defensible, that we don’t benefit from shoes. But the shoe must fit (as in…”if the shoe fits”) in order for that interface to be enhanced and not deteriorated. A poorly fitting shoe will not only cause potential for pinching, hot spots, blisters and other maladies, it will not allow for optimal force transference and dissipation. We need our shoes to be of the right “type” for our feet and gait, our surface, our mileage, our speed, our foot shape, and our fashion preferences. And this is where things are really doing great in the running shoe industry. The choices abound and the industry has done a great job of classifying and describing shoes to assist the consumer. Add to this the evolution of the running shoe store or department and the education and training of footwear sales professionals, and suddenly, now more than ever, finding the right shoe that really fits, is easy.

There are some very positive trends I’ve noticed in running shoe design, and I think we are all benefitting. There are many more of these attributes than the ones I’ll mention, but here are a few:

  • Min/Mod/Max: You can still find minimalist shoes and these models can give you a “close to barefoot, but protected” feeling. If you run on soft surfaces, and/or (like me) don’t run much (a.k.a. a minimal amount of running) these are definitely worth a try for most runners. Moderate shoes, otherwise known as “daily trainers” come in better selections than we’ve ever had and through a little try-on work (or a lot), you can find the one with the best fit and function for your foot. And if you prefer more ample midsoles, maximalist shoes are now offered by most major brands.
  • Zero-drop/mid-drop/more-drop: The drop, or heel-to-forefoot differential, can now be had with great variety. Zero drop shoes are basically flat, and I recommend these for grass training (when not barefoot) and sprinting. If you haven’t used them before, progress slowly. Mid-drop shoes with differentials of 4-6mm are great for road or longer distance running and many people prefer this configuration. More-drop shoes with differentials of 8-12mm are the more (pun) traditional models. I usually don’t recommend these shoes as they can magnify heel striking forces, but there are still a few applications and runners with preferences for these models.
  • Weight: Shoes have gotten lighter. The manufacturers have utilized lighter, stronger, thinner synthetic materials in the uppers and laces, and have pared down outsoles to eliminate unnecessary materials. This gives a feeling of unencumbered running and has been proven in studies to decrease oxygen consumption in some subjects.
  • Durability: Well, this category may have taken a hit, as lighter and lesser shoes tend to wear out a tad sooner. Less substantial uppers and thinner outsoles do indeed blow out or wear through a bit more quickly, but personally, I don’t mind that. I don’t expect the shoe to last forever and it’s nice to get a fashion upgrade once in a while.
  • Midsole Technology: It appears that we have passed the era of gimmicks. The addition of air, gel, and other products continues but perhaps in a more sensible manner. Ethylene vinyl acetate (EVA) technology (this is the foam of which most running shoe midsoles are made) has advanced and we are seeing shoes with improved cushioning to weight/thickness ratios (when we may be seeking that). Also, more recent research shows that midsole durability has increased slightly. Finally, there is new evidence to suggest that midsole compression may not be as critical an indicator for shoe replacement (at least in some runners who are relatively efficient) as once believed.

In closing, I view this post as one of congratulation (to the shoe industry) and not one of condemnation. Running can be great exercise for many of us. If you want to run I want to encourage you to do it intelligently, safely, prudently, and joyously. And rest assured you can find a great shoe to enhance your running experience. But here is a final piece of wisdom, if you’ll allow me to be candid. Let’s look at quality. Try to focus on savoring your running more than just stacking up miles…keep it natural; as in surface, pace, volume…all things. You rock! Thanks!

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