If you can hold these positions for 30 seconds each, you just trained your core in under 5 minutes. High plank Low plank Side plank right and left Reverse plank or reverse tabletop V sit This hits your core from every angle. Front, sides, and back. Planks train core stability by teaching your trunk to resist movement, not create it. That matters because the core’s main job is to transfer force and protect the spine, not just flex like a crunch. Research shows isometric core work like planks incr