In this range, the butt and thighs will be more rounded and pronounced. The waist size starts to increase and the stomach shows rounding. The amount of lean muscle that you have plays a huge role in determining how you will look. This is the range that most female athletes fall in, and is considered as highly fit. This body fat percentage is not sustainable for most men. There is some definition in the abs, but usually the arms and legs start to lose muscle definition.