As Harris pointed out – this is a complicated question. My quick answer to your question (as I read it)is yes – a balanced exercise program that includes strength training and aerobic conditioning should definitely improve your overall body shape – including your legs. This is also assuming that you’re eating a healthy diet & not over-consuming calories – which will increase your amount of body fat (even around your knees!)if you are. But if you’re asking if there’s a particular exercise to target the fat that seems to have accumulated around your knees, my answer is no. That’s known as “spot reduction” and unfortunately, that doesn’t work (excluding surgery). To make a long story longer, I’m with the others – if you want those great legs back, get the help of a qualified trainer to help you devise the proper exercise program. You also want to look into your diet & eating habits. Good luck Sybil, with the right plan, those legs will be back before you know it!