Planks engage your core, especially your abdominal muscles. Start with a 30-second forearm plank and increase strength by adding time.
To increase the difficulty, you can perform dynamic plank variants or side planks.
Bicycle crunches work the upper, lower, and oblique abs. Lying on your back with your hands behind your head, bring one knee to your chest and rotate
your body to connect the opposing elbow to the knee. Bicycling with your core engaged, alternate sides.
Sit on the floor, knees bent, feet flat. Lean back slightly and balance on your sit bones.
Touch the floor with each hand while you rotate your body. Hold a weight or medicine ball to make twisting harder.
Mountain climbers train your abs and cardio. High plank with hands beneath shoulders. Run while bringing one knee to your chest. Maintain your core and speed.
Lean back and bend your knees 90 degrees. Hands on the floor to stabilize. Raise your hips and knees to your chest by contracting your abs. Repeat hip-lowering.