One of the easiest ways to pick up a running injury is by running in shoes which are past their effective life. But running shoes are expensive, and if your mileage is high, the cost (and environmental impact) of constantly replacing them quickly adds up.
So what, I hear you ask, is the best way to tell when to replace your shoes to maximise their mileage and minimise your risk of injury? Step into my office, dear runner…
The starting point for assessing the lifestage of a shoe will always be the amount of mileage it’s done. If you use a tracker app like Strava or Garmin Connect, it’s well worth making use of their gear tracking features so you can know exactly how many miles any pair of shoes has run.
Manufacturers will have a recommended maximum mileage for any given shoe, which is usually 400 or 500 miles, but these should be taken with a pinch of salt as there are so many other factors at play.
In interpreting the mileage a shoe has done, you should consider the type of terrain it’s been used on. 400 miles on a running track or treadmill are unlikely to fatigue a shoe as much as 400 miles on cross country trails.
Although we don’t recommend waiting for your feet to tell you when your shoes are end-of-life, as your shoe enters its higher mileage twilight years you should become extra attuned to small pains and niggles. These could be early warning signs that your shoe is no longer doing its job of keeping your joints and muscles as protected as it should.
Particular injuries which could appear might include shin splints, knee pain or plantar fasciitis – though given the interconnectedness of the body’s mechanics, old running shoes could be responsible for pretty much any running injury.
If you’re familiar with the ‘new shoe bounce’, you may have met its cousin the ‘old shoe plod’. As a shoe deteriorates, its shock absorbancy diminishes, making running feel more sluggish. If you think you can feel every single impact in the feet, hips or knees, or you’re having to work harder to maintain a certain pace, this may be a sign that your shoes need replacing.
One of the easiest ways to evaluate a shoe’s remaining shelf life is to look for physical signs of degradation. In particular, you should look at:
The most visible sign of a worn out shoe is worn out treads on the sole. If they are worn down to the extent that significant parts have become smooth, then this is a definitive sign of a shoe being ready for replacement.
You can use the wear patterns on your treads to evaluate your gait – if the treads on your shoes wear out very unevenly (i.e. more in one place than another), then this indicates some imbalance in your running style. You may want to take your shoes to a shop or physio/podiatrist to get their opinion on whether you are wearing the right pair or if you should do strengthening exercises to improve your technique and avoid injury. For example, if the front of the shoe wears out particularly fast, this is a sign of overpronation.
Check out our guide to buying running shoes.
Another sign that a shoe needs replacing is when the main shock-absorbing part of the shoe – the spongy base beneath the heel – is beginning to become permanently squashed. This means that the shoe will have less natural bounce, reducing injury protection and increasing the amount of energy you can ‘bounce’ out of the ground after impact.
This is a sign that the previously soft insole is getting pressed down to the harder base, reducing shock absorption.
Overall, there are many ways to tell when a shoe needs replacing – and it could be any of the above points. The good news is, with so many indicators, you don’t need to blindly follow the manufacturers’ recommendations to the mile. By eeking out a bit more mileage in certain circumstances, you can help your bank balance and the planet.