Start with your feet slightly wider than shoulder-width apart, holding dumbbells with palms facing in. Without rounding your lower back, push your hips back and slightly bend your knees, letting the dumbbells hang just below knee height.
In one movement, stand up, leading with your elbows, thrusting your hips forward, and pulling the dumbbells all the way up to your shoulders, elbows going out to your sides.
Reverse the movement to return to your starting position for one rep.
Keep going for a total of 40 seconds, then rest for 20 seconds.
Repeat the above two moves two more times, then take a one-minute rest.