Hold a dumbbell in each hand and stand with your feet hips-width distance apart. Keep a slight bend in your knees. Fold your torso forward so your back is almost parallel with the floor and your arms are extended out, in line with your shoulders. Draw your abs in to protect your lower back.
As you exhale, bring your elbows toward your shoulders and close to your side. To get the upper back working, think of sliding your shoulder blades together. As you inhale, slowly lower the dumbbells back to the starting position. This counts as one rep.
With control, perform as many reps as you can in one minute.