This article is going to show how u can do weight watchers for free, but first off, lets see why weight watchers is so successful. The 4 pillars of success; Food, exercise, behavior & support.
1 Hip muscles. Lunges work all of the gluteal muscles in the hips, primarily the gluteus maximus that is used to extend your hips. Taking large steps during a lunge can further engage this muscle. The gluteus minimus and gluteus medius are also used to stabilize your body throughout the lunge.  Thigh muscles.
A rear lunge works the same muscles but with more emphasis on the quadriceps. The secondary target area is glutes in the buttocks and the muscles in the front and rear of the calf. You do a rear lunge much like a forward lunge, except you step to the rear rather than front.