Here are 20 good exercises for the core muscles:
Plank: Start by getting into a push-up position and then lower yourself down onto your forearms. Hold your body straight and tense your core for 30-60 seconds.
Side Plank: Begin by lying on your side with your elbow directly under your shoulder. Lift your body off the ground and hold for 30-60 seconds. Repeat on the other side.
Dead Bug: Lie on your back with your arms extended towards the ceiling and your legs bent at a 90-degree angle. Slowly lower your right arm and left leg towards the ground while keeping your core tight. Return to the starting position and repeat on the other side.
Russian Twist: Sit on the ground with your knees bent and feet flat. Lean back slightly and hold a weight or medicine ball. Twist your torso to the right and touch the weight to the ground next to you. Repeat on the other side.
Bicycle Crunches: Lie on your back with your hands behind your head and your knees bent. Bring your left elbow towards your right knee while straightening your left leg. Repeat on the other side.
Bird Dog: Begin on your hands and knees. Extend your right arm forward and your left leg back while keeping your core tight. Hold for a few seconds and then repeat on the other side.
Leg Raises: Lie on your back with your hands under your hips. Slowly lift your legs towards the ceiling and then lower them back down without touching the ground.
Superman: Lie face down with your arms and legs extended. Lift your arms, chest, and legs off the ground as high as possible and hold for a few seconds.
Mountain Climbers: Begin in a push-up position. Bring your right knee towards your chest and then quickly switch to your left knee. Continue alternating for 30-60 seconds.
Hollow Body Hold: Lie on your back and lift your arms and legs off the ground. Hold for 30-60 seconds.
Lateral Leg Lifts: Lie on your side and lift your top leg towards the ceiling. Lower it back down and repeat on the other side.
Scissor Kicks: Lie on your back with your hands under your hips. Alternate lifting your legs towards the ceiling while keeping them straight.
Spiderman Plank: Begin in a plank position. Bring your right knee towards your right elbow and then return to the starting position. Repeat on the other side.
Flutter Kicks: Lie on your back with your hands under your hips. Alternate lifting your legs up and down while keeping them straight.
V-Sit: Sit on the ground with your legs extended in front of you. Lean back slightly and lift your legs off the ground while reaching towards your toes.
Russian Twist with Weighted Ball: Sit on the ground with your knees bent and feet flat. Hold a weighted ball and twist your torso to the right and touch the ball to the ground next to you. Repeat on the other side.
Corkscrew: Lie on your back with your arms extended out to the sides. Lift your legs towards the ceiling and then twist them to the right and lower them towards the ground. Return to the starting position and repeat on the other side.
Plank Jacks: Begin in a plank position. Jump your feet out and then back in while keeping your core tight.
Jackknife Sit-Up: Lie on your back with your arms and legs extended. Lift your arms and legs towards the ceiling and then bring them together towards your toes.
Kettlebell Swing: Stand with your feet shoulder-width apart and hold a kettlebell with both hands.