thank you! But, I sure dont have strong knees, not anymore!! That's why I said to be careful of the joints. Right now I am putting off decisions to have knee replacement, hip replacement, and major back surgery . I can hardly walk because of spinal stenosis that has caused numbness from the knee down on one leg ,and both feet. And it hurts. Not complaining, although it sure gets old, at least I can still walk, just slow and waddle like the Happy Penguim!!