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.
The basics: It's important to do lunges properly so you don't put unwanted strain on your joints. Here's how to perfect your form: Keep your upper body straight, with your shoulders back and relaxed and chin up (pick a point to stare at in front of you so you don't keep looking down). Always engage your core.