When should you change your running shoes?

For every pair of shoes covering the same distances, there are a number of factors that affect their lifetime. Between two runners on a similar training regime, here are all the wear factors that come into play:

The load placed on the sole of a running shoe is 5 to 8 times greater than the weight of the runner. It's not difficult to see that, depending on the person, the load on the shoe can vary by several hundred kilos. The more weight is placed on the sole, the quicker it will pack down and lose its shock absorbing properties.

The choice of shoe also comes into play:

- a training shoe with lots of cushioning and a dense sole (lots of material) will last a long time.
- a more lightweight running shoe with less material or a less dense material will wear more quickly.

The price does not affect the type of shoe. Rather, it is the quantity and density of the material in the sole that determines the wear.

For the same distance covered, if you complete a single 3-hour run, your shoes will wear more quickly than if you did three 1-hour runs. The way in which foam packs down over a prolonged period reduces its capacity to recover its density when you stop running.

Still based on the same number of kilometres, the frequency of your runs will affect the way in which the sole packs down. The more frequent your runs, the less the sole will be able to return to its original shape in the meantime.

Each runner has a different running stride: some will wear out the heel more quickly, while for others, it will be the forefoot area that wears more quickly, etc. In general, running shoes will wear more quickly if the runner has a vertical stride (greater vertical amplitude) than a more economical horizontal running stride.

NB: the vertical amplitude is the distance covered on the vertical axis by your centre of gravity with each stride. The greater the amplitude, the bigger the load placed on your soles, thereby causing the cushioning to wear (packing down of the sole).

The materials of running shoes wear out over the years, even when you don't use them. When you leave a pair of shoes, that are new or in good condition, in a cupboard, they will not have the same durability and cushioning quality as a similar pair of shoes which have just been bought from the store.

Maintenance has a significant effect on the lifetime of running shoes: we recommend that you do not put them in the washing machine and tumble dryer. It is preferable to hand wash them on a regular basis, and give them a thorough rinse when necessary. Then, do not dry them in full sunlight or near to a heat source, as this will cause premature damage to your shoes.

If you use your running shoes to practise other sports or for everyday use, they will wear out more quickly. Given the high frequency and time spent in this activity, even if the shoes seem to be in good condition, the packed-down sole will force you to change your shoes.

Do your shoes look as if they are in good condition? It isn't enough to guess the general level of wear. Apart from any holes or a damaged piece of mesh, there are several visual signs that you need to change your shoes:

1. Visual condition of the sole: unusual wear on certain sections and a sole that has become smooth over time.
2. Packing down of the sole:  visually, the sole seems to have wrinkles, and there is less of a drop and less cushioning than before.
3. Feel: When you feel the bumps under your forefoot, it's time to change of shoes. 
4. Discomfort and pain: if you have not changed your pace or volume of training, and you are starting to feel discomfort, or even pain, it may be a sign that you need to change your running shoes.

A word of advice: don't wait until you feel pain in your feet, joints and muscles to change your shoes. To avoid the risk of injury, the best is to calculate the average capacity of your shoes in kilometres, so that you can replace them at the right time. Read on for all the information you need.

The running shoe brands have different estimates of the lifetime of the trainers" 500 kilometres on the clock, change them every year, etc. It isn't always easy to distinguish between the true and the false, but the fact remains that for the same shoe, the wear will depend on your activity (trail, road or track), the regularity with which you run, the type of terrain on which you run and all the factors set out at the beginning of this article.

Check out how to calculate your personal distance if you always run with the same shoes or if you want to compare two different pairs of shoes:

- The best solution is to multiply the number of kilometres that you do per week by the number of weeks between the purchase date and the day, on which your shoes were totally worn out, if you train regularly.
- If you aren't regular, get some help from the app you use to track your training sessions (Strava, Garmin Connect, Suunto, etc.) in order to calculate the number of kilometres completed since the date you purchased your new pair.

You need to be attentive to the warning signs indicating that your shoe is reaching the end of its life the first time that you do the calculation. Later on, you will easily be able to identify the right time to change your trainers before they are put through the mill.

Whether it is for racing or training, you should choose your own running shoes, according to your stride, how often you run and the terrain on which you will run.
Here are the criteria you should focus on when choosing your new running shoes:

Whether it is for the road, trail, track or hybrid, the choice of running shoes starts with your discipline and hence, the type of terrain you will be running on. You can then select the best shoe according to the criteria that are specific to each type of run.

Use the cushioning, stability, weight, energy response, flexibility and drop of the shoe as reference points when comparing different models. By doing a quick equation between your discipline, how the shoe feels and the criteria of the shoe, you can quickly focus your search a bit more precisely on the model you need.

For example, for training shoes that are very comfortable, focus particular attention on the cushioning and drop of the shoe. You will like the comfort and durability of these shoes that are more lightweight, yet more sturdy than racing shoes.

Conversely, if you are looking for dynamic training shoes, you can compromise a little bit on the cushioning in order to have more energy response and flexibility. These models are great for training sessions when you are looking for a similar level of performance to your running pace in racing conditions.

How do you choose your running shoes when you are beginner?

It's not always easy to find your way around, especially if you are a beginner runner. In this situation, make comfort a priority because, when you are learning to run, your feet and joints should not be suffering. For your initial runs and training sessions, choose some running shoes with some good cushioning and a fit that isn't too tight, even if it means choosing a shoe that is 1 or 2 sizes above your usual size.

And if your motivation has dropped, we would encourage you to continue running for the sake of your well-being!

As we mentioned before, weight is a factor that will affect the wear of the shoes, particularly the packing down of the sole. The heavier the runner, the more the sole will pack down when pressure is placed on it. In this situation, it's important to prioritise the cushioning and stability of the shoe.

A lighter runner will be able to get away with more flexible shoes that have less cushioning.

Remember that it is important to prioritise comfort when changing your shoes. Over time, you will feel less pain in the joints because of the running impacts, and it will even reduce injuries.

There are three types of strides, which correspond to the way the foot hits the ground:

- pronator where the foot rolls inwards on striking the ground;
- neutral (or universal) where the centre of the foot strikes the ground;
- supinator where the foot rolls outwards on striking the ground. This is relatively rare.

Some models are more or less suited to your stride. To find out what category you're in, look at the sole of one of your old shoes which will be more or less worn on the inside, outside or centre of the sole.