It's pretty common among women that our genetics cause our legs to be bigger than our upper bodies. We can't do anything about our genes, but that doesn't mean that nothing can be done. There are no exercises that will "slim" your legs. When we lose fat we lose it everywhere, regaurdless of what we are doing for exercises for certain body parts. If you focus on losing a little fat your legs will get slimmer, which is great. However, your upper body will look slimmer too, which won't help with the disproportional look.