This is the best exercise to build chest volume. It builds up your torso by expanding your chest.
Lie down on a horizontal bench.
Grasp the dumbbell with both hands. Your hands hold it under the inner plate of the dumbbell firmly, and hold it straight at one level with your eyes. This is your starting position.
The dumbbell handle should be between your thumbs and index fingers of both hands.
As you inhale, lower the dumbbell over your head, expanding the chest, while bending your elbows slightly.
Pause for 1-2 seconds at the top and as you exhale bring the dumbbell back to the starting position.
Do not use a heavy dumbbell to avoid injury to your joints and triceps.
Always start this exercise off with a deep inhale.
During the exercise, your spine will arch naturally and lower back will separate from the bench. People with lower back problems should be careful.