If you're much of a runner, you've experienced that point in your running career where it's time for new shoes. Sometimes it's a "feeling", sometimes its a sign reading "SALE", and other times it's blatantly obvious holes in the toes, heels, or base of the foot that force us to buy a new pair of shoes.
Image by Rachael McIntosh: http://www.rachaelmcintosh.com/yycity
Recently, it was that time for me, when I had to make the trip and the big purchase for new running shoes. I can't remember the last time I bought shoes, but I typically buy once a year when there is a good sale, or when too many holes develop on the heel or toe!
Before you throw those old shoes out and replace them in your closet with the shiny new ones, take a moment to evaluate the wear pattern that has developed over the many kilometres it took you to wear those babies out.
Importantly - evaluate the wear patterns with respect to your current injuries, previous injuries, or your upcoming training plan that you plan on putting the new shoes through!
The purple sole of the shoes in the picture above are my old running shoes that probably got between 15 and 50 kilometres per week on them for one year. The sole of the pink and blue shoes are those of my new shoes. Same shoe, same model, different year. Besides the fact that the purple ones are dirty, you can also start to spot some other differences between the old and new pair - like wear pattern.
Before we dive too deep into what the wear patterns mean - let's take a second to think about what happens when we take a foot fall, in the average human being going for a run.
What happens when we take a foot fall during a running cycle?
To dissect the video above, when humans go through one cycle of a running pattern (heel strike, to toe off), we start externally rotated in the hip (femur relative to pelvis), externally rotated in the shank (lower leg - relative to the knee), and slightly dorsiflexed getting ready to land. The slight dorsiflexion in the ankle might change slightly if someone is more of a forefoot or mid foot striker, or has changed their gate depending on their circumstance for whatever reason. But, for argument's sake - most people follow the typical pattern explained above, and land on their heel before they begin to absorb the force. At our ankle, our foot lands in an inverted and more supinated position.
As our body weight shifts forward and our hips become centered over our mid foot with forward momentum of the running gait, our ankles dorsiflex more to absorb the ground reaction forces, and the rest of our leg begins to shift as well - but not just in the sagittal plane, as one would assume with an untrained eye examining running patterns.
We also move a lot in the transverse plane, as well as in the frontal plane. As body weight shifts forward and our body weight is more distributed through the whole bottom of our foot, our upper leg begins to internal rotate (relative to the pelvis), our lower leg (or shank) begins to internally rotate, and our ankle begins to pronate and evert.
Is that a good thing?
It is literally not a good thing or a bad thing - it is just THE thing that happens when we run! Of course there are thresholds of too little or too much pronation, rotation, or dorsiflexion/plantarflexion, but to keep things simple, all of those things occur with one foot fall.
Starting to analyze your own gait based on shoe wear patterns
I usually don't look at the bottom of my shoes or worry about the wear patterns until it's time to get new shoes (once per year). With clients, I would recommend checking their shoe wear pattern once per year unless they were getting injured or feeling pain when running. In that exception, non-symmetrical wear pattern would be something I expect to see, or a symmetrical one that has an unconventional pattern.
Upon examining my old shoes and comparing them to my new shoes, they looked pretty good. I want to see most of the wear through the middle of the heel and the middle of the upper foot, as well as the same side-to-side pattern in the right and left shoes. Too much wear and tear at the tip of the heel could indicate too much heel strike. Too much wear away from the middle of the rear and fore-foot could indicate a compensation pattern in the running mechanics of the shoe owner!
How can you find out if your gait is problematic or may potentially lead to injuries?
Currently, you might think the answer to finding out what type of shoe you need is to go into a running store, take off your shoes, and have a "shoe expert" in the store watch you walk up and down the store a few times so they can evaluate your running pattern, while walking. Wait, what?
You heard me right. They evaluate your walking gait and based on that, they tell you what kind of a runner you are. Not only does that make no sense, and is comparing apples to oranges, it is also common, since being a runner for over 10 years, for them to only watch you in a one-dimensional plane. As I discussed above, each step you take during your run, causes motion in 3-D, not 2D. This means that motion happens in the frontal, saggital, and transverse plane.
This is also problematic because walking in a slow, controlled fashion with shoes off on a flat slippery surface of a running store's flooring, is nothing like wearing shoes, jogging or running at speed, wearing support on your foot and ankle, and adapting with every step to the changing surface of the ground outside (assuming you're running outside!).
The best way to evaluate your running in 3-D is having a coach video you and analyst your motion in 3-D. For a pretty penny you can get a 3-D gait analysis done, or for a little less, a coach like myself can watch you, film you using a program like "Coach's Eye", and then we can slow the video down in all three planes of motion and figure out what is going on.
So how can I find the best shoe for my foot?
Currently, you might think the answer to finding out what type of shoe you need is to go into a running store, but research shows otherwise. The literature tells us that the best shoe for your fit, is likely the one you chose while not thinking about it. Most times, it is the shoe we choose that is most comfortable - that is also the best fit and form for our running style.
My best advice:
My best advice for analyzing your gait pattern is to go see a professional who take a multi-dimensional approach. The best coaches will evaluate your training history, your training plan, your current strengths and weaknesses, and your likely causes for future injury. If you hire them for the long run, they will also continue to test and monitor the things that matter, in a detailed manner.