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.
It can be performed with free weights or with body weight only. Because its primary goal is increased muscle strength through the use of weight, the lunge is a weight resistance exercise, not a cardiovascular one, and should be incorporated into a routine as such.