1. Plank
The plank is one of the most common core exercises because it works more than just the stomach. It can also help strengthen the shoulders, back, and hips when done with good form. Start on your forearms and toes, keeping your body in a straight line from head to heels. Try not to let your hips drop or rise too high.

Hold the position for a short time at first, even 10 to 20 seconds. Focus on breathing and keeping your body steady. As you improve, you can slowly increase the time. If the full plank feels too difficult, place your knees on the floor and practice that version first.
