Carefully hold a light dumbbell (3 to 5 pounds) between your feet or, for greater safety, use ankle weights. Lie facedown with your forehead resting on your hands, palms down, elbows pointing out to the sides, and legs extended. Press your hips into the floor and bend your knees until your calves are perpendicular to your thighs. (Be sure to squeeze feet together so as not to drop the dumbbell.) Next, tighten your glutes and lift your knees off the floor as high as comfortably possible (not shown). Hold for 3 seconds, then return to start.
