Challenges could be so much better by making it simpler and broader, Simple step challenges, 1 Rep max Challenges, Rowing Challenge for distance or time alll would be better than how it is now. Currently you trapped with either completing any cardio or any workout to gain points why not just simply track steps or weight loss and even weights your lifting to gain improvement statistics?

Its a great start and my client do like a challenge but its super restrictive for the stuff other apps have, Like Everfit and even the knew AI Coach app