By Libby Bergman PT, DPT, OCS, FAAOMPT
Still my favorite racing shoe... the long extinct KSwiss Kwicky Blade
I fell in love with running during my early college days. Growing up as a swimmer, running was somewhat of a punishment when we were over trained in the pool, our shoulders were overloaded or when our coaches wanted to accelerate early season fitness gains. But in college, running was freedom. It was outside, it was free and we had a fantastic running community in Madison, Wisconsin. I was soon immersed in running culture and working at a locally owned running specialty store where I learned to match runners of all levels with “appropriate” shoes based on their individual comfort and gait tendencies. The only problem was, the more I was taught about pronation and supination of the foot, and how to fit a runner in a shoe based on what I observed, the less it made sense. Understanding ankle and foot biomechanics has been an over 20-year endeavor in my career, and led me to PT school and eventually into my current PhD program.
My own interest in this topic happened to coincide with the rise of many prominent biomechanical researchers, most notably Irene Davis from Harvard who was the first to look at barefoot versus shod (or “shoed”) running. Devotees of Dr. Davis’ work and the book Born to Run (a true story about an indigenous culture who ran nearly barefoot) brought the trend of minimalist shoes into popular culture and the running shoe world has never been the same. Shoe makers and runners began to question the structure of a traditional running shoe and whether it was necessary to have the amount of support that was built into them. Then the next question came- why have we always made shoes with a 10-12 mm drop from heel to toe?
Enter the zero-drop “fad.” When this fad hit over the past 5-10 years, entire shoe lines made their shoes “zero-drop.” The problem is, if you are an American, its highly likely that every athletic shoe you’ve owned since childhood (save the converse Chuck Taylor era shoes) likely has had 10-12 mm of drop from heel to toe- and your foot and ankle biomechanics and achilles tendons have adapted to that over years of use. A sudden change from 10-12mm to 0mm of drop even in the occasional runner can wreak havoc on foot and ankle biomechanics and create significantly more load through the achilles tendon.
Should I switch to a zero drop or minimalist shoe?
Here’s the deal, 15 years and volumes of research later, we STILL don’t have a great consensus matching running shoes to runners. The only consensus in the literature is that if it feels good, wear it. In general, running shoes have a spectrum of stiffness in the midfoot which prevent pronation, or rolling in of the arch. Pronation was once the worst of all evils when it came to running injuries. Preventing it was the panacea, the cure to every runner’s aches and pains. Like most biomechanical concepts, this was far too simple and, frankly, untrue. Researchers and clinicians were left with a void of knowledge and into that void moved an astounding variety of new running shoe concepts.
When evaluating a running shoe, the first thing to look at is how much midsole stiffness (or pronation prevention) it has. The heavy-duty pronation preventers are deemed “motion control shoes.” If you pick one of these up and try to twist it like you’re wringing out a towel, you won’t get far. The midsole is stiff and often various shades of gray indicating the material is of higher density. This shoe is a great choice for larger framed runners and runners who know they have some type of midfoot laxity (see your PT if you don’t know this!). They may also help runners with a hip or knee weakness compensate for their injury or allow for a long-standing structural issue to be managed in a more mature runner.
As we move down the stability spectrum, the middle of the road are stability shoes which offer some amount of midsole stiffness, but less than the motion control shoe. Finally, you reach the neutral shoes. These are the ones that have next to no midfoot stiffness and you can wring out like a towel if you try to twist it from toe to heel. These tend to be more “minimalist” and have less support.
There is an argument for moving down this spectrum of stability over your years progressing as a runner. Clinically, we tend to think that as runner’s get stronger and adapt to mileage over years of training, there is some benefit to having a slow (years long) progression towards less support over time. We are demanding more of the foot musculature and lower kinetic chain muscles over time so less support helps to support the strength and load adaptation that has been built over years of training. Less support also means less weight (in ounces) of the shoe so as runners move towards goals of improving their performance, there is often a desire to move down the spectrum of stability.
The same concept applies to moving from a standard shoe (10 mm drop) towards a lesser drop shoe (4-6 mm) to a zero-drop shoe (0 mm drop from heel to toe). If you are looking to make this change, do so slowly. Consider starting with the more minimal shoe during midseason speed workouts and increasing your volume in the more minimalist shoe as your race fitness comes into view. Think of working towards the less supportive, less drop shoe as a process that occurs over several seasons rather than switching all at once. And before you make the decision to move to a less supportive shoe, consider your goals.
● Are you content with your current footwear? Do you have a long and good history with a certain type of shoe?
● Why do you want to change shoe type and what are your running goals?
● Are you looking to progress in your running career, particularly in distances under marathon length?
● What’s your injury history and how would a switch impact your injury risk versus the benefits that may be gained in speed and form?
Running shoes have become an unnecessarily complicated topic for consumers over the past 10 years. Check out this “minimalist index” calculator to help you quantify changes in a shoe you are considering: https://therunningclinic.com/minimalist-index/#calculate
And don’t be afraid to consult one of our PT’s for a foot and ankle biomechanical analysis, running gait analysis or for a friendly discussion on how footwear changes may interact with your injury history.