You can definitely feel these moves working your waist and your hip flexor. The 3 moves progress in difficulty and are definitely harder than they look. The first move isn’t that bad, I think the fact that ankle weights aren’t included in these moves makes them easier. For the second move you may have to adjust your position to get your balance right and you’ll really feel the move in the waist/hip of the supporting leg. I actually quite like balancing on the ball, I like the balance aspect and the ball is quite comfy. The last move is SO difficult! I probably spent an extra 10 minutes just chasing the ball around the room whenever it launched off the back of my legs. I found this move SO hard, I could only do a few reps while the ball worked itself further away from the back of my knee and towards my foot, if anyone has any tips for keeping the ball in place please let me know.