She is five feet, 3 inches, weighs 112lbs, she wears a size 6 on the top but a size 12 on the bottom. She doesn’t have a great sense of balance so she finds lunges challenging, and her knees tend to get painful after a couple of sessions of squats, lunges etc. Her fitness levels are not great either and I am cautious about getting her heart rate up with bike intervals. I am at loss on how to help her achieve her goals. Any suggestions?