Narrow push-up on exercise ball

Place the stability ball on the ground and position yourself in a push-up position with your hands on the ball, slightly narrower than shoulder-width apart. Engage your core and keep your body in a straight line from head to toe. Lower your chest towards the ball by bending your elbows, keeping them close to your body. Pause for a moment at the bottom, then push yourself back up to the starting position by straightening your arms. Repeat for the desired number of repetitions.