Chest press- alternative arms with dumbbells

Lie face up on a bench holding a pair dumbbells at your shoulders with an overhand grip.
Keep your feet on the floor and your hips and shoulders on the bench, arch your thoracic spine.
Press one dumbbell straight up over your shoulders.
Lower the dumbbell, keeping your elbow close to the body until your upper arm just break parallel to the ground.
Repeat with opposite arm.