It takes guts for mature people of the female persuasion to begin an exercise routine in advanced age. there is a huge difference between fat on your body like flabby thighs and but and atrophy. Because of the aging process, you lose both muscle mass and bone density over time, so you have to work hard to counter the natural effects of years passing. If you overused your leg like running long distance can put strain and pressure on the legs and can cause flabby skin especially in the thigh areas. Legs can look flabby due to excess fat and lack of muscle tone. If you have one or the other in your thigh or calf areas, it can leave you feeling too self-conscious to wear clothes that reveal your legs.