LOWER BODY OR BACK ISSUES? YOUR SHOES (PROBABLY) AREN'T HELPING

BUY SOME ERGONOMIC SHOES

(AND DITCH THE OTHERS)

American adults average between 5,000-6,000 steps a day. Adults in western Australian average around 9,700 steps a day, and Amish men and women average between 14,000 and 18,000 steps a day! I even knew one girl who regularly registered more than 30,000 steps over the course of her workday! [42-44]


Spread out over the course of a year, those 5,000 to 18,000 steps a day become 1.8 to 6.5 MILLION steps. The type of shoe your foot is in during each of those foot strikes will play a major role in the health and function of your feet (which in turn heavily impact the knees, which impact the hips, which impact the lower back, and on up the kinetic chain).



Regularly wearing shoes that encourage more natural foot and ankle functioning is an important step (pun intended) in alleviating lower body pain and dysfunction and helps to ensure that lower body pain and dysfunction related to poor foot biomechanics won’t occur in the future. So what makes for a good shoe? I recommend looking at 8 criteria…


FOOT-SHAPED DESIGN

We buy gloves shaped like hands, so how much sense does it make to buy shoes that aren’t generally shaped like our feet?! A foot-shaped design generally has a significantly wider toe box (among other distinctives) when compared to traditional shoes.



"ZERO DROP"

The “drop” of a shoe is the difference in sole thickness between the heel compared to the forefoot (where the ball of the foot will be). A "zero drop" (0mm drop) encourages a more natural foot strike, whereas an elevated heel tends to encourage a more prominent heel strike, which can decondition the muscles, tendons and ligaments of the foot while also increasing the amount of shock and impact force travelling through the foot, ankle and lower extremities.



FLAT SOLE

You might think that a “zero drop” shoe would, by nature, have a flat sole, but you’d be wrong (I’ve made the same mistake myself, which is why I mention it here). The flat sole mimics a flat ground surface, encouraging a more natural foot strike.


APPROPRIATE "STACK HEIGHT" (SOLE THICKNESS)

Stack height is the sole height- basically the distance from the bottom of your foot to the floor. If the stack height is too low and you're walking (or running) on hard surfaces (concrete, asphalt, etc.) for significant lengths of time (or if you’re significantly overweight), your foot will likely ache from the effect of repeated impact (I speak in part from personal experience). If the stack height is too high, you may feel unbalanced, which can increase the risk of falling (or rolling/twisting your ankle). For me, the “sweet spot” stack height (not too low, not too high) for a general training, work or recreational shoe is usually somewhere between 15-25mm.


OTHER SHOE QUALITIES TO CONSIDER

Lightweight: Think about the average number of daily steps again (5,000-18,000). Every additional ounce a shoe weighs works against a natural movement pattern in the foot and lower leg. A lightweight shoe with a decent stack height will likely be in the 5-7oz range (larger sizes will obviously weigh more, and smaller will weigh less).


Good Fit: While I believe the 5 factors above are central in choosing a health-promoting shoe, there are other design factors that will play into how the shoe feels on your foot. These factors add to the overall feel and fit of the shoe. What we’re aiming for here is a fit that’s not too tight/constrictive (which may adversely affect toe splay and the natural functioning of the foot and ankle) but that comfortably secures the foot (so the foot doesn’t slip/slide when performing physical activity). Consistency in sizing should also be considered.


Good Traction: What you want here will depend on the types of activities you're doing and surfaces you're doing them on. For me personally, I usually prefer a shoe with a lug (or lugged) sole. A lug sole includes moderate to deep indentations and/or grooves which provide added grip and traction. One of my life goals is to avoid slipping or falling down as much as possible, and the lug sole helps with that.


Durable: How long the shoe maintains its integrity (i.e. durability) should also be considered. One of the more common criticisms I've seen with shoe companies that are relatively small in size (as is the case with many of the companies that produce the kinds of shoes we’re discussing here) is that the durability of their product is sometimes lacking when compared to shoes produced by larger manufacturers (ex. Nike, Adidas, etc.).

A common question that pops up when discussing shoe durability is “How often should I replace my running or athletic shoes?” The specific answer depends on several factors, but the general advice is to replace every 300-600 miles, or 3-6 months. [45]


Reasonably Priced: Since my introduction to “foot-shaped, zero-drop, moderate-stack-height” shoes in early 2012, I’ve seen discounted pairs for as low as $50, while other models go for as high as $200. A median price point seems to be around $100 a pair.


Positive User Reviews: If you're anything like me, you probably find value in reading the reviews of others before purchasing a product. While amazon.com is an option, with shoes I find that runrepeat.com gives me insights that Amazon doesn't.


Reputable (and Fast) Vendor: While I order a lot of things from Amazon, with shoes I've also had good experiences ordering from Zappos.com, Backcountry.com, Runningwarehouse.com and REI.com, among others.


TWO TYPES OF ZERO-DROP, FOOT-SHAPED SHOES:

MINIMALIST & NON-MINIMALIST

Minimalist shoes that are also zero drop and foot shaped tend to be very lightweight and have very low stack heights (sole thickness). In my experience, these kinds of shoes are good for weight training and walking/jogging/running on soft forgiving surfaces (ex. grass fields, certain trails, softer sand). Spending long periods of time or doing high impact activities on hard surfaces in these kinds of shoes tends to cause foot pain for many people. Companies that produce these kinds of shoes include Vibram, Xero and vivobarefoot.


Non-minimalist shoes that are also zero drop and foot shaped may be relatively lightweight or moderate weight or even relatively heavy, and tend to have moderate to high stack heights. These kinds of shoes (depending on specs) tend to be good for cross training and walking/jogging/running on harder and less forgiving surfaces (ex. track surfaces, treadmills, roads, sidewalks, wooden floors, etc.). Because of the built up sole on these types of shoes (>15mm thick), the ball of the foot and the heel are more protected from the impact of the foot strike. However, some stability, balance and proprioception may be loss because of it. Companies that produce these kinds of shoes include Altra and Topo Athletic.


Lems is another company that makes zero drop, foot shaped shoes, and they tend to offer both minimalist and non-minimalist models.


"IS THERE SCIENCE ON THESE KINDS OF SHOES?...

...IF SO, WHAT'S IT SAY?"

Since 2010 there's been a notable increase in the number of published peer reviewed studies looking at the effects of "minimalist shoes." One of the problems I see when glancing at the scientific literature is that most of the authors fail to distinguish between the minimalist shoes I just described above (ex. Vibrams, Xeros, etc.) and the non-minimalist-but-still-zero-drop-and-foot-shaped shoes we just talked about (ex. Altras, Topos). Most of the studies I've looked at so far are comparing the biomechanics of barefoot movement to minimalist shoe movement to conventional shoe movement.


Another problem seems to be ignoring the type of surface the activity is performed upon. Running on hard surfaces like concrete, asphalt or even a track or treadmill in a conventional shoe with 30mm of cushioning will have very different effects on impact forces and the plantar (bottom) area of the foot than will running on these surfaces in a minimalist shoe with a 5mm sole.


Those two important issues aside, what's the data say?


A 2012 article from the U.S. Army Medical Department Journal looked at self reported survey data from more than 2500 adult runners and found that those who wore traditional shoes were 3.4 TIMES more likely to report injuries than experienced runners wearing minimalist footwear (the article also outlines the limitations of self reported survey data). [46]



Another 2012 study, this one of 52 runners, found that "74% of runners experienced a moderate or severe injury each year, but those who habitually rearfoot strike had approximately twice the rate of repetitive stress injuries than individuals who habitually forefoot strike." [47]


A January 2013 study published in the British Journal of Sports Medicine found that running efficiency was superior in barefoot running when compared to running in minimalist shoes. [46]


A May 2015 study in the journal Sports Health found that "both barefoot running and minimalist running shoes produce greater running efficiency... with a greater tendency toward a midfoot or forefoot strike and a shorter ground contact time." [47]


A 2015 study of 35 distance runners found that the rate of rear foot striking (where the heel impacts the ground instead of the midfoot or forefoot) was lowest during barefoot running (59%) followed by non-cushioned minimalist shoes (63%) followed by cushioned minimalist shoes (87%) followed by standard shoes (94%). [48]



A 2017 BMJ study of 35 runners found that "the use of minimalist footwear leads to increased cadence and reduced stride length during treadmill running (when compared to standard running shoes)." [49]


A 2017 review of 20 studies in the journal Sports Medicine- Open found that minimal footwear provided limited benefits for running economy and muscle development. The review also noted the risk of injury during the initial transition period (from conventional to minimalist shoes) due to higher loading rates and plantar pressures, however, the overall injury incidence when wearing minimalist shoes versus conventional shoes was similar. [50]


A 2018 study in the journal Scientific Reports found that those wearing minimalist shoes had higher and stiffer longitudinal arches and larger abductor hallucis and abductor digiti minimi muscles when compared to those wearing conventional shoes. In other words, wearing conventional shoes is associated with weaker foot muscles and may increase the risk of developing flat feet. [51]


A January 2019 study headed by Dr. Sarah T. Ridge found that "Minimalist shoe walking is as effective as foot strengthening exercises in increasing foot muscle size and strength." [52]


A 2020 review of 63 studies found that "Minimalist shoes can improve running economy... but also induce greater loading of the ankle and metatarsophalangeal (big toe) joint." [53]


Some of the main takeaways of this research center around the relative superiority of minimalist shoes versus conventional shoes when it comes to...

  • running economy and efficiency (cadence, stride length, etc.)

  • lower leg muscle activation and strengthening

  • reduced chance of developing flat feet

  • reduced chance of rearfoot/heel striking and

  • reduced risk of injury.


CONSIDER THE SURFACE TYPE TOO!

On that last point (risk of injury), I think it's very important to consider the type of surface the running or physical activity is being performed on. For instance, an inexperienced runner sliding on a pair of minimalist Vibram's and going for an 8 mile jog on concrete is likely a recipe for injury.



I even thought of adding "Consider Activities On A More Forgiving Surface" as another step to fixing your feet, but realized that topics like the type of shoe and type of surface (and the kind of physical activity) are usually wrapped up in each other.


As far as studies that compare the effects of running on different types of surfaces go, I didn't find as much research as I did comparing shoe types, but there are some studies.


A 2010 study of 44 runners in the Journal of Science & Medicine in Sport (JSAMS) found that peak foot pressures were higher in all areas of the foot measured (central, lateral rearfoot, lateral forefoot) when running on asphalt versus natural grass. In other words, running on grass provokes lighter loads on the rearfoot and forefoot when compared to asphalt. [54]


A 2012 study in the Journal of Sports Sciences looked at impact forces when running on asphalt, concrete, rubber and natural grass. Running on grass produced peak pressures 5-17% lower than running on other surfaces. The study authors concluded that "running on grass may reduce the total stress on the musculoskeletal system compared with... running on more rigid surfaces." [55]


Another 2012 study, this one from Research in Sports Medicine, found that "running on natural grass showed a lower magnitude of maximum plantar pressure at the total foot, lateral midfoot, central forefoot and lateral forefoot" when compared to running on either rubber (a track) or concrete. [56]


While the above 3 studies look at 4 surface types (grass, rubber track, asphalt and concrete), there are several other surface types that are commonly run on, including artificial turf, sand (ex. beach running, beach/sand volleyball), dirt or woodchip trails, clay (ex. some tennis courts), hardwood floors (ex. basketball, indoor volleyball), treadmills and tennis hardcourts.


BAREFEET VS MINIMALIST VS

MODERATE STACK VS MAXIMALIST

My general rule of thumb is, the more forgiving the surface, the less sole thickness you're going to need.


So for barefoot movement, I'm normally comfortable running/moving on artificial turf and some softer sand surfaces. I mentioned the risk of hookworm infection when doing barefoot activities on grass, so I'd probably be a little more leery of that.


For slightly less forgiving surfaces such as hard sand, dirt or woodchip trails and most track surfaces (which tend to be synthetic rubber), I'd probably be comfortable in a minimalist shoe like Vibrams or another zero drop, foot shaped shoe with a stack height under 15mm.


For harder surfaces like hardwood floors, treadmills and tennis hardcourts I'd want a shoe with moderate stack height (ex. 15-30mm). As an aside, these are the kinds of shoes I also prefer as my "daily wear" shoes. Altra's Lone Peak, Superior and Escalante models are some of my favorites.


And for the hardest surfaces (ex. asphalt, concrete) I might even want a "maximalist" shoe with a stack height over 30mm, especially if A) I'm carrying more body weight and/or B) I'm doing longer distances. For zero drop and foot shaped options here, Altra's Olympus 4 has a stack height in the mid 30s (while they're not zero drop or foot shaped, the Hoka brand also makes several models in the 30-40mm stack height range).

SOURCES

42 www.verywell.com/whats-typical-for-average-daily-steps-3435736

43 www.livescience.com/43956-walking-10000-steps-healthy.html

44 www.businessinsider.com/heres-how-much-the-average-american-walks-every-day-2015-7

45 https://well.blogs.nytimes.com/2013/02/18/when-to-retire-a-running-shoe/

46 https://pubmed.ncbi.nlm.nih.gov/23007933/ (results of 2012 online survey of >2500 adult runners; self reported data indicated traditional shoe wearers were 3.41X more likely to report injuries than experienced minimalist shoe wearers)

47 https://pubmed.ncbi.nlm.nih.gov/22217561/ (2012 study of 52 runners found that rearfoot strikers have nearly twice the rate of stress injuries as forefoot strikers)

46 https://bjsm.bmj.com/content/47/6/387.info (2013 study comparing barefoot to minimalist shoe running efficiency)

47 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4482302/ (2015 study on barefoot vs minimalist vs conventional shoes)

48 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4444250/ (2015 study of 35 runners comparing heel strike rates among barefoot, minimalist, cushioned minimalist and standard shoes)

49 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5530131/ (2017 study showing increased cadence and reduced stride length in minimalist running shoes)

50 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5602809/ (2017 review of 20 studies on minimalist footwear)

51 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5829167/ (2018 study on minimalist shoes & conventional shoes and effects on intrinsic foot muscles and arches)

52 https://pubmed.ncbi.nlm.nih.gov/30113521/ (2019 study of 57 runners found that minimalist shoe walking is as effective as foot strengthening exercises in increasing foot strength)

53 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7039038/ (2020 review of 63 shoe studies)

54 https://www.jsams.org/article/S1440-2440(08)00155-2/fulltext (Jan 2010 study of 44 adult runners found peak foot pressures higher when running on asphalt versus natural grass)

55 https://pubmed.ncbi.nlm.nih.gov/22897427/ (2012 study comparing impact forces when running on asphalt, concrete, rubber and natural grass)

56 https://pubmed.ncbi.nlm.nih.gov/22458825/ (2012 study comparing max plantar pressures when running on concrete, rubber and grass)