Lie face up, with your back flat on an exercise mat, the soles of your feet firmly on the floor and a long resistance band under your upper back. Loop each end of the resistance band round the palm of your hand. Then proceed to hold a dumbbell firmly in each hand with an overhand grip and your arms extended directly above you, at a 90 degree angle to your torso. Hold the dumbbells fairly close together with the palms of your hands facing away from you. This is the start position. Inhale as you bend at the elbows, driving them out and lowering the dumbbells towards the floor. You should feel a stretch in your chest at the bottom of the movement. Pause at the bottom when your elbows touch the floor. Then exhale as you reverse the movement and drive the dumbbells back overhead. Squeeze your chest muscles as you do so. Repeat for the required number of reps (or time).