IOS – iPad: app stops when screen is locked

Basically I have a problem with apps stopping when the screen is locked. I have first encountered this issue when I started using Strava.

I would normally start recording on Strava, lock the screen and put the iPad into my backpack, after I finish the ride, I would unlock the screen just to find out that the app is not running.

I initially though that this is Strava specific issue, but I have since tried Endomondo and it exhibits exactly the same behavior.

Few details:

• If I start the recording, then lock the screen, then unlock it within the short period of time (~ 1 minute or less) – the app is still running. Which means it does not stop immediately after the screen lock
• If I don't lock the screen, but just put the iPad into my backpack, the screen locks automatically in 5 minutes. In this case, no matter how long I ride, the app will keep running and will be still active when I unlock the screen. This is a workaround but not prefered solution

I would like to know why does iPad stop apps after the screen lock and how do I change that behavior.

I am using iPad mini and iOS 8.2

UPDATE:

based on the comments and answers from other users, few more details:

• Location Services are enabled for these apps and set to "Always on"
• Background refresh is enabled in the system and for these apps