Kettle Bell Swing
A dumbbell can be substituted (hold onto one end). Assume a squat position and grasp the weight between your legs. Stand up, keep arms straight, and swing the weight up to shoulder height, using your lower body and the momentum of the weight. Let it swing between your legs as you go into a deep squat, hinging at the hips with knees bent.
Reps: 30 sec of continuous swinging, rest 60 sec, repeat 30 sec