The Piston Row.
1. Holding dumbbells, stand with your feet shoulder-width apart. Adopt a golf address position and hold your arms are at 90 degrees to your spine, palms facing each other (not shown in image but the movement is the same). Pull the weights to the sides of your chest. This is the starting position.
2. Keeping your right arm as still as possible, lower the weight in your left hand until your arm is straight. Lift the dumbbell back up to the side of your chest, then lower your right hand.