To strengthen the muscles in your upper back and rear delts (those muscles in the back of your shoulders), try this simple move. It’s ideal after hours of sitting in front of a computer or driving. Pulling your elbows behind you engages your upper back, which helps relieve tension in your chest, neck and upper trapezius muscles.
1. Place the center of a resistance band or stretch tubing under your right foot. Grasp the ends of the band in each hand. Bend your right knee and lean your torso forward with your arms hanging below your shoulders. Keep your abdominals pulled in to support your spine.
2. On an exhale, point your elbows back and gradually stretch the band as you move your hands toward your hip bones. Be sure to keep the tops of your shoulders pressed down away from your ears. Pause for two seconds with your hands near your hips. Lower to the start position and repeat 12 to 16 times.
Source : Los Angeles Times