My Grandma turned 89 in February. A couple months ago we went shopping for a new pair of slippers. She balanced on one foot while untying her shoe, slid her foot out of her shoe and into the slipper. She may have held my hand through the process, but her balance was impeccable. And this is a woman who had polio as a child. Her legs are two different lengths. There was a point in her life when all her leg muscles had atrophied after spending months strapped to a wooden board, immobilized.