Plank: Start with a forearm plank by resting your weight on your forearms and toes, keeping your body in a straight line.
Russian Twists: Sit on the floor with your knees bent and feet flat. Lean back slightly and lift your feet off the ground.
Bicycle Crunches: Lie on your back with your hands behind your head. Bring your knees toward your chest and lift your shoulder blades off the ground.
Standing Side Crunches: Stand with your feet hip-width apart and arms extended overhead.
Leg Raises: Lie on your back with your hands under your hips for support. Lift your legs off the ground, keeping them straight, until they are perpendicular to the floor.
Mountain Climbers: Start in a plank position with your hands directly under your shoulders and your body in a straight line.