Hold on to either end of a resistance band and step onto the middle of it with both feet so your ankles are directly underneath your hips. Lean forward slightly, bending at your hips. It's OK if your knees are slightly bent.
Bend your elbows straight back, focusing on pulling your shoulder blades together. Holding onto the band, slowly straighten your arms behind you, palms facing up.
Slowly return your arms to the bent-elbow position to complete one rep. If you don't have a resistance band, use dumbbells instead.