Try this fix if your strava is crashing
Press the "running apps" button (usually the left of the three buttons on the bottom of your phone or long-press the menu button if you only have the one) and lock strava app to prevent it from being automatically killed if your phone starts to run low on RAM.
If your RAM is running low your phone starts to kill running apps and locking an app prevents it from being killed. Strava is quite the memory hog so it's not surprising the phone decides to kill it if it's running out of free RAM.
You can also find an option in "developer settings" in your phone to change the memory optimization to be less aggressive with killing apps to free up RAM.