I am 64 year old female with serious left knee issues. As I can no long jump about I thought I would give this a try. I finished the gradual version and started again. I only do the 15 minute versions as I find the longer ones too much of the same thing for too long. Elements is great for making you think about how you are doing what you are doing (like in Pilates). I have discovered a few muscles I never had control of before. Calling the movements by animal names makes them easier to remember and my overall coordination has improved a lot.