A really neat feature in the app is that you can get rewarded with activity badges. 

Activity badges will reward you for things such as meeting a certain target duration, the number of friends you've made, how many times you've liked your friends' posts, and whether you are on a streak. 

To get to badges, click on the activity tab and then scroll down to see which badges you've already been awarded.

If a badge is colored in, it means you've been awarded that badge.

If the badge is gray, it means you've yet to unlock that badge.