Begin with your feet slightly wider than hip-width apart and toes pointed slightly outward. Your arms should be by your sides and your core pulled in toward your spine.
Looking straight ahead, bend at the hips and knees, while simultaneously raising your arms overhead. 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 lowering your arms to your sides.
This counts as one rep. Complete as many reps as you can with proper form in 20 seconds.