1. Risk of injury increases when running on shoes with greater than 350-500 miles.
2. Comfort is key when purchasing a running shoe that works best for you.
3. Rotating between different shoes can help reduce injury.
As I plunge down a rocky slope, I know they just aren’t right. The blocks of wood under my feet hinder my ability to naturally skip from rock to rock, requiring far too much brainpower to maneuver as I descend. Although my jog around the shoe store parking lot indicated that this pair would be the one, I now understand that these shoes will be a disaster while running down a slippery mountain in the dark at the end of a race. Oh well, back to the shoe store...
Although running is a relatively low-equipment sport, what you put on your feet still matters. With all of the different styles and models available, it can be difficult to decide which one will work best for you. Here’s a quick cheat sheet of how to figure out which shoes will allow you to run your desired miles without injury.
When is it time to get a new pair of running shoes?
If you are asking the question, then it’s probably time. While there is some debate over this topic, the general recommendation of replacing your shoes every 350-500 miles has not changed since the late 1990s. Ethyl vinyl acetate (EVA), the material most often used for the midsole (squishy) portion of the shoe, unfortunately, has a shelf life. The honeycomb-like structure that allows for compression with equal rebound will eventually start to crack, leading to breakdown of the material. Without effective EVA, the cushion in your shoes that helps with shock absorption is greatly diminished, therefore, your risk of injury is greatly increased.
Head to a running shoe store
If you have already found your perfect running shoe, then by all means, get that sucker for cheap on the internet. If, however, you are searching for your ideal shoe, heading to a shoe store, excuse me, a SPECIALTY RUNNING shoe store, will end up saving you time, money, and injury in the long run. Pun intended.
Don’t show up empty-handed.
Bring along your old running shoes and, if you wear them, orthotics. Your old running shoes may have some clues including wear patterns and global deformations that can give further information to the running shoe experts. If you wear orthotics, make sure they are in each pair of shoes that you take for a test drive.
Work with a running shoe expert and then don’t always listen.
Make sure that you have a running shoe expert to help you with your shoe search. This salesperson will likely measure your foot length and width, watch you walk, and watch you run to determine which shoe will work best for you. This conventional method of shoe prescription focuses heavily on providing you with a shoe that is matched with your foot type and running style.
More specifically, if you have a high arch and stiff foot causing you to run with lots of supination (ankle rolls to the outside of the foot), you will generally be prescribed a cushioned shoe. If you have a more mobile foot that tends to collapse into too much pronation (ankle rolls to the inside or arch of the foot) as you run, you will likely be given a motion control shoe.
While there is some research that demonstrates that motion control shoes can alter running form by controlling your foot and your lower leg, the change does not appear to have an effect on injury. When looking at a military population, 3 different studies all determined that matching runner foot types with running shoe types did not result in any difference in injury rate. An additional study came to the same conclusion that shoe type had no influence on the rate of injury or pain in female runners. This is likely due to the fact that as this prospective study with a large sample size (i.e. well-done study) demonstrates, foot type is not associated with injury risk.
The best part about all of this confusing and counterintuitive data is that when it comes to selecting a shoe that will reduce your likelihood of injury, comfort is key. I, therefore, recommend that you listen to the shoe expert and try out the recommended shoes, then you go a little wild and try a wide variety of different styles. Whatever pair of shoes feels best for you is likely going to keep you running your best without injury.
More isn’t always better
I caution you to not fall into the trap of thinking that a soft and cushiony shoe is going to prevent you from sustaining an injury. Recent research indicates that more highly cushioned shoes may actually increase your impact force as your leg naturally stiffens more in a softer shoe when it hits the ground. Although this may seem counterintuitive, imagine jumping up and down as high as you can on a concrete sidewalk. Now imagine the same thing on a trampoline. On the concrete, your knees will need to bend a ton as you land in order to absorb the shock. On the trampoline, however, your knees will stay relatively straight. This is because your body actually anticipates what is required by your joints based on the surface below and will naturally stiffen up. The same thing happens with the amount of cushion in your shoes when you run. With increased stiffness in your legs due to the softer surface below, you actually have a higher impact force through your body when you run with highly cushioned shoes versus less cushioned shoes.
Assess and reassess
Before finalizing your purchase, check to make sure that the running store has a decent return policy. While the shoe may fool you during a quick jog around the parking lot, it won’t be able to do so after a few real runs. If the shoe doesn’t feel right to you for any reason, don’t hesitate to take it back and continue with your hunt.
If you like two pairs, buy them both!
Some interesting research indicates that rotating shoes can actually help reduce injury rates by 39%. The authors hypothesize that when you spread your miles across multiple pairs of shoes, different forces are applied to your body resulting in less repetitive strain. As a trail runner who also does a lot of road running, I naturally switch between different pairs of shoes on a regular basis. If you, however, stick to a single type of terrain, using a different shoe for speed vs recovery days or good weather vs bad weather days can help you rotate your shoes to keep yourself injury-free.
While finding the best pair of running shoes can be a time-consuming process, it is worth the effort to get shoes that won’t contribute to your risk of injury. If you have any questions about your shoe wear or want to learn more, feel free to contact us here.