Tone Your Shoulders in Just 15 Minutes

Move 3: Straight-Arm Kick-Back

With a weight in each hand, position your feet hip-distance apart, slightly bending the knees. Hinge forward from your hips, keeping your back flat and allowing your arms to hang straight down with palms facing each other (shown, near right). 

Lift your arms up and back, keeping them straight, until they are slightly above hip level (far right). Lower your arms back to the starting position and do 10 to 15 reps. Repeat the set two more times, resting for 60 to 90 seconds between each round.