The technology and material behind running shoes has never been more advanced, just look at Nike’s latest shoe the Zoom Vaporfly.
The shoe that was used in Nike’s breaking2 project, includes a full-length carbon fibre plate and an advanced midsole foam that claims to offer 13 percent better energy return.
Putting the advancements in shoe technology aside, running shoes are still man-made products with a limited lifespan and as the mileage builds up, your shoes will lose stability, cushioning, become worn, and prolonged running in shoes in this condition can leave you sidelined.
To minimise the risk injury, it’s advisable to replace your shoes at the right time. But when is the right time? To help you make an informed decision here below are few key guidelines.
1. The outsole tread is worn
One of the main intended uses of a running shoe is to provide traction when we run, and over time the rubber on the bottom outsole will wear away. Depending on how your foot strikes the ground one part of the shoe might wear away more quickly.
The worn part on your shoe can also highlight your gait pattern, and if there is considerable wear on one side and minimal wear on the other, it could indicate a biomechanics imbalance issue. If this is left unaddressed you increase the chance of an injury developing over time.
2. The mileage on your shoes is high
An old rule of thumb among runners is to replace your running shoes every 250-350 miles, depending on your running style, weight, and the surface on which you run.
Where you run also determines how soon you’ll have to replace your shoes. If you run on rough roads or trails, you’ll need to replace your shoes sooner than if you primarily run on grass. If you take good care of your running shoes, you may be able to get away with the higher end of the mileage range.
3. Aches and pains
Your body can be quick to tell you when it’s time to invest in a new pair of running shoes. Sore hips, feet and knees can be indications that the stability, support and cushioning built into the shoe has worn down to the point that it’s counterproductive to continue running in them.
4. You only have one pair
All runners have a favourite pair of shoes that they trust for any run, regardless of the weather or terrain. However, when you only wear the one favourite pair it can increase your risk of injury. Why is that? It is because with every run the midsole foam (the part of the shoe that gives your legs that “springy” feeling with each step) becomes compressed, and for it to return to its original shape it needs time, usually longer than 24 hours.
When the midsole foam of your shoe isn’t allowed to return to its original shape it’s more compressed, and running in shoes in this state increases the strain on your feet and lower limbs.
If you feel you over-reliant on one pair of shoes, it is recommended that you invest in a second pair. Once you have that second pair, alternate every few days to give the midsole foam a chance to return to its original shape. This will also help prolong the life of your shoes.
And there is science to back it up. In a recent Scandinavian research project, researchers looked at runners who changed between models of shoes over a 22 week period. They found that 39 percent had a lower risk of injuries compared to runners who ran continuously in the same pair of shoes. It was concluded that because the leg muscles are having to work differently in each pair of shoes, less stress is repeatedly applied to the same muscles.