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.
You step forward with one leg, bending until your thigh is parallel to the floor and your back knee almost touches the floor. Then you stand up and lunge with the other leg. The specific muscles are transverse abdominus, gluteus maximus, gluteus medius/minimus, quadriceps, hamstrings and obliques.