This is one of my favorite exercises for women because it dramatically strengthens and tones the glutes and hamstrings. For best fat-burning results, be sure to choose a weight that challenges your muscles. If you feel like you could easily do more than 10 reps, you need to use heavier dumbbells.
How to do it: Grab a pair of dumbbells with an overhand grip and hold them at arm's length in front of your thighs. Stand with your feet hip-width apart and your knees slightly bent. Without changing the bend in your knees, bend at your hips and lower your torso until it's almost parallel to the floor (keep the weights as close to your body as possible). Pause, then return to standing. Your back should stay naturally arched during the entire movement.
Do 10 reps with a challenging weight (15 to 40lbs depending on your fitness ability).