Saw this on the myfitnesspal blog. Could really help with knee strength for skating and sit spins!
https://blog.myfitnesspal.com/the-28-day-squat-challenge-youll-want-to-start-now/
Cool, thanks! I think I'd have to start slow, though... I did squats as part of the 7 minute workout for a while (30 seconds, about 10-12 squats) and after a month of that had twinges in my knees so I cut way back.