Sit-ups focus on strength and endurance of the abdominal muscles. The dumbbell press over your head also work with your shoulders.
Lie down on your back. Bend your legs and place your feet firmly on the ground to stabilize your lower body.
Grab a dumbbell in your hands above your chest.
Bend your upper body all the way up to your knees and then press the dumbbell up over your head with straight arms.
Slowly lower yourself back to the starting position.
