Adjust the smith machine to a decline position. Lie down on the bench with your feet secured under the foot pads. Grasp the barbell with a close grip, slightly narrower than shoulder-width apart. Unrack the barbell and lower it slowly towards your chest, keeping your elbows tucked in. Pause for a moment at the bottom, then push the barbell back up to the starting position. Repeat for the desired number of repetitions.
GIF
