Hi ​@Sarah Mesnil, what kind of device are you using? It seems that the GPS is struggling - that usually happens for example when:

• running in places with obstructed view of the skies (such as: tunnels, very tall buildings, forest with heavy foliage overhead, bad weather day with very thick clouds)
• using a device with less reliable GPS (in general, a sports watch performs much better than a phone)
• having some kind of power-saving mode enabled on your device (meaning that the GPS location may be checked less frequently)

If you could specify the device you're using, also the app (are you recording with the Strava app or are you only importing the activity to Strava afterwards?), environment (tall buildings etc), and someone with a similar experience may have a good recommendation on how to solve this. 

Bonjour, 

J'enregistre directement avec Strava, je n'ai pas de montre pour suivre mon activité.

Je cours en général en campagne ou ville avec un ciel dégagé.

So it's the Strava app on your phone, correct?

Make sure that your phone is not in low power (power-saving) mode when you go for a run, as that may negatively impact the app's ability to check the gps location often enough. Also, don't keep the phone deep in your backpack or so.

A watch would likely be much more accurate, but the phone app should be usable too, hopefully your next run with the phone will be recorded at least a bit better