Stand with your legs just slightly wider than hip-width apart. Your arms should be raised to shoulder height with your elbows bent, holding weights by your ears with your palms facing in.
Looking straight ahead, bend at the hips and knees. Make sure your knees don't go past your toes, and keep your core pulled in toward your spine and your chest lifted.
Drive through your heels to return to standing, while simultaneously pressing the dumbbells overhead. Turn your wrists as you press, so your palms face outward at the top of the movement.
With control, lower the dumbbells to your ears as you return to the starting position.
This counts as one rep. Complete as many reps as you can with proper form in 20 seconds.