Suppose I created a challenge that runs for 30 days and has 10 other athletes participating. I get 10 push notifications for each of the 10 other participants joining - and 10 notifications per day (!) when they complete the training.
For this little challenge with only 10 other athletes, I get a total of 310 notifications… and makes me want to disable push notifications for the app altogether.
I think that should be reduced. For example by sending a summary each day like “7 athletes completed…” or one should be able to opt-out of those notifications.
Edit: There is another notification per day reminding me to complete my own workout - if I haven’t done so before like 6pm!? 
Thanks & Cheers
Freddy