So-called "zero-drop" running shoes have become a recent buzz in the running and fitness communities. The last decade or so has seen some interesting experimentation when it comes to footwear. Most of us have seen Vibram's quite popular offering to the minimalist footwear world with the Vibram Five Finger shoe. These glove-like, nearly barefoot shoes, give a very intimate feel and range of motion when walking or running but they offer so little cushion that they seem impossibly uncomfortable. Merrell, Nike, Adidas and many others have also jumped on the barefoot bandwagon that was started, in part, by the Altra brand.
Altra Zero-Drop shoes. Notice they are heavily cushioned with no drop from heel to toe
The race for the best minimalist shoe started when Altra creators, Golden Harper and friends, began to butcher their running shoes to cut off excess padding in the heel to create an even cushion platform which they postulated may help to reduce injury associated with the foot rolling too much (It was just a hypothesis). Word began to spread that these shoes were just as comfortable as their over-plush counterparts and they were lighter and lent themselves to a more conscious and healthy running style which included what is known as a "forefoot strike". This concept simply conveys that runners have different styles of allowing their following foot to hit the ground. Most runners will strike the ground with their heel first then roll into the ball of their foot and push on by rolling over the big toe; this is how kids run naturally but human physiology wasn't always like that. A minority of runners use a mid-foot strike which essentially allows the following foot to strike the ground almost flat or slightly forward of the arch: historically how ancient human beings probably ran. And an even smaller group of runners strike the ground with the front of the foot first, landing on the ball of the foot and flexing the calf slightly to roll onto the big toe, propelling them forward; this style requires a lot of conscious effort to maintain form for most runners. Each of these styles of running is acceptable, though it is generally advised to adopt a more thoughtful style of foot-strike depending on your physiology. Those with poor knees to begin with, for example, should try to adopt a mid-foot or fore-foot strike style in order to shorten their stride, lessen knee and ankle flexion and provide better stability and less impact on the joints. This injury avoidance rationale is widely accepted for learning and adapting a new style of running or walking but shoes alone will not provide that protection. Avoiding or lessening the impact of injury is absolutely paramount in athletic endeavor and one can understand why Altra runners were trying their damnedest to benefit the running community with new footwear to compliment better running techniques.
This project however, took on a life of its own. Soon Altra, the boutique outlet for running shoes, had customers lining up to see and try their new "zero-drop" design. Word continued to spread and other manufacturers began producing this new design in their own likenesses. With this new spark of interest in minimal footwear, consumers flocked to buy everything that seemed "minimalist" or was branded "zero-drop", not really understanding what they were buying into.
The truth about minimalist footwear is that not only is it a trendy look and feel for the average consumer, but they also create a new physiological demand on the body of anyone that wears them, whether they know it or not. From the first day you begin to wear this different type of shoe, your muscles and joints are working in a different way than they ever had before. Since the day you could walk, your parents probably supplied you with modern, cushioned footwear with a slightly raised heel. This design allows your physiology to comfortably strike the ground with the heel when walking and stand up with straight posture without your knees locking out. The raised heel of a cushioned running shoe does indeed have such an important purpose as keeping you comfortably upright all day. The lack of a raised heel and adequate cushioning on so-called "minimalist" or "zero-drop" shoes can actually improve muscular imbalances caused by heavy stress while wearing typical footwear, however, they may also create similar but opposite imbalances over time!
While the raised heel of generic footwear can overwork our hamstrings, the lower heel of minimalist footwear can overwork our quads! Both situations lead to knee and hip pain, both of which I can personally attest to. This article is prompted by my own discovery of minimalist footwear and how they have affected my overall athletic health over the three years that I have used them. Anecdotally, my experience with minimalist shoes is that they can be very comfortable once you adjust to a slightly different stride. That being said, this adjustment may never happen for some people. Even with a conscious effort to make the change, sometimes our bodies just don't have the ability to safely make a transition like this (after all, we grew into and acclimated our current bodies using typical footwear!). Personally, it took a few months for my quads and knee stabilizer muscles to adjust and I felt great after that! My lower back became less tense, my knees felt better and I could run longer! Though, bear in mind, all of this could be attributed simply to the fact that I had to change my running style to match my new shoes, not to credit the shoes themselves!
After choosing two pairs of progressively more minimal shoes to help adjust, I wore the more cushioned pair everyday and only ran in the more barefoot feeling shoes. The Merrell All-Out Fuse then the Merrell Trail Glove 3 were my progressive choices to ease into the semi-barefoot running style. All things considered, my transition period took more than a year but I finally got used to walking and running a little bit differently and I felt better after running!
Merrell All Out Fuse - Cushioned but zero-drop
Merrell Trail Glove 3 - No cushion, zero-drop
Fast forward three years and I'm still wearing the Trail Glove 3 almost every day. However, my knees are way worse for the wear! It turns out between wearing these minimal shoes all day, every day, and climbing my little heart out at a high level, my hamstrings have been sorely neglected and my quads are over-developed! This led to some extreme stresses on my knees, especially doing high-tension climbing moves like heel-hooks. Now I am relegated to two weeks of sedentary rest to keep my joints healthy and allow my quads to relax so that I can get to strengthening my hammies on the next training round. I noticed that this had become a problem when my knees couldn't help but lock when standing and my lower back and hamstrings always felt tight! When I started to wear more typical running shoes again, my hamstrings got worked and sore and my knees, hips and lower back felt so much better. I had really over-worked my quads and shin structures, so my hamstrings and calves needed some tender love and care!
I suppose this should only serve as an anecdotal cautionary tale to those of you who are in the midst of the minimalist footwear trend or are thinking about using minimal footwear for running or every day use. Keep in mind that the designs of these shoes have not really been vetted and that time is showing that they may cause more harm than good in some cases. Also understand that the original "zero-drop" footwear from Altra does have plenty of cushion! They simply reduced the cushion in the heel for stability. Other manufacturers ran with the minimal footwear idea and deviated heavily from Altra's original intention. So keep in mind that the less cushion your shoe provides, the more work your joints and muscles have to do in order to keep you comfortable! This means an alteration of your walking or running stride to accommodate potentially higher stresses on important leg structures. Stay safe out there and always put some research into your training!