Advice on when to replace your Running Shoes?
There can be several tell-tale signs to look for when assessing to see whether your running shoes are worn out. Understanding these can help you decide when you need to drop your hard earned cash on a brand new pair. More importantly having a good idea how long your running shoes tend to last, although this can vary between brand to brand and even models within brands, will ensure you are getting the maximum injury prevention benefits from your shoes.
First of all it is important to understand that the mid-sole running shoes have a running life span of approximately 600 to 800 kms. Some individuals will wear a lot earlier and some will swear they last longer. Remember time spent walking around in them also counts and needs to be taken into consideration in terms of overall wear.
the mid-sole running shoes have a running life span of approximately 600 to 800 kms. #performbetter @pogophysio Click To TweetThe main reason why there is a life span of running shoes is that the foam (Ethylene vinyl acetate the most common) in the mid-sole is designed to have a balance between being soft enough to provide cushioning yet firm enough that they are responsive under foot and have decent memory to rebound close to the original shape for some distance. The last thing an average runner wants to do is have to replace their runners every couple of weeks. Each shoe brand also uses slightly different materials in their mid-sole and this may have an impact on how long the shoes last. Without naming names I am sure you have experienced different brand models that feel fantastic out of the box and then just don’t seem to have that same feel only after a few hundred kms in them? While some others that maybe didn’t feel as fantastic out of the box seemed to be more consistent well into the 500 to 600km mark?
I have found when assessing the life span of a running shoe in clinic the actual time they last can also depend on an individual’s stature, foot strike pattern and foot function. For example a heavier individual is going to compress the foam more on each foot strike when compared to a lighter runner if they are running in exactly the same shoe. Think a 90kg runner versus a 60 kg runner.
A runner who is a true forefoot striker for example is going to be compressing the front of the shoe more often as they are using it for both impact and propulsion. This may also be compounded by the fact that traditional running shoes are made specifically to absorb shock at the heel and have different more responsive material at the front to aid in propulsion. So if a runner is forefoot striking in a traditional running shoe then there could be the potential for faster wear.
Excessive movement with either pronation (feet rolling in) or supination (feet rolling out) during the different foot contact phases of gait could potentially lead to different areas of your shoes wearing faster than others. For example if an individual excessively pronates and is loading the medial side of the shoe more often this could lead to quicker wear in this area. Vice versa if they are excessively rolling out. A good test for this is to place your running shoes on a desk or bench and see if it is leaning towards one side? If it is then it could very well be getting close to being worn out.
Another consideration is what the running shoe is designed for. For example you can’t expect a racing shoe to last as long as a high mileage training shoe because it doesn’t have as much “meat” underneath the foot and the materials in the racer are designed to be as light as possible making them in most cases less durable.
Wear patterns in the outer sole, which is usually made out of blown rubber can give an indication that your shoes are worn out or wearing unevenly. Typically if it has begun to wear through to the midsole layer and it is flat then most likely the rest of the shoe is worn out. Although mainly anecdotal and not necessarily something to put all of your concerns into is excessive wear of certain areas of the outer sole sometimes giving practitioners an indication or clue into certain mechanical inefficiencies. For example excessive wear of the medial part of the forefoot can indicate excessive pronation or more specifically the failure of the foot to re-supinate (roll out) in time for when the heel lifts off the ground. This mechanical inefficiency may or may not be contributing to problems elsewhere in the body but it is important to be aware of at least as a practitioner and assessed as part of the whole running patient picture.
Lastly a common misconceived worry with running patients is that their running shoes are wearing at the lateral heel. This is where our foot first contacts the ground (if we are heel striking) in an inverted position so that our foot can start to pronate as we load to become that adaptable, shock absorbing structure. Unless the wear is drastically different from side to side this is normal. If there is a drastic difference on one side then this could be an indication for example of potential tightness in the calves and/or ankle joint leading to an inversion compensation of the foot during the swing phase. Again this may more importantly give a practitioner a potential clue to reasons for a pathology if one does exist. To be clear if there is excessive wear on one side this does not necessarily mean you will end up with a problem either.
On that note if you are unsure if your running shoes are worn out or if you are concerned about potential abnormal wear then it is best to get in and see a sports Podiatrist who will better be able to assess your shoes as well as look at your overall running patient picture.
Aleks Baruksopulo
SportsMed Podiatrist
BSc (Biomed), BHlthSc (Pod)
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