Stand with your feet hip-distance apart and your arms at your sides. Squat until your thighs are parallel to the floor. Keeping your arms straight, bring them forward and up until your upper arms are in line with your ears (A). Return to standing, then lift your right knee to hip height as you sweep your arms down across your body until the back of your left hand is outside your right knee (B). Return to standing and repeat on the other side. That's one rep. Do three sets of 12 to 15 reps, resting for 30 seconds between sets.
HOW TO DO IT: Step to your left and lower your body into a lateral lunge, placing both hands on the floor. Without moving your feet, lift your hands and hips and shift your weight over your right foot, so you end up in a right-side lunge. Alternate back and forth for 30 to 60 seconds. To really kick up the burn, turn this movement into a monkey shuffle by simultaneously loading your hands, lifting your hips and shuffling your feet side-to-side between right and left lunge positions.