Crunches and leg raises won’t build a strong core. They may build visible abs, but they don’t train what the core is designed to do, resist movement. If you want real core strength, you need to focus on anti-movement training. Anti-extension (resist lower-back arching) \t•\tPlanks \t•\tHollow body holds \t•\tAb rollouts \t•\tDragon flags Anti-lateral flexion (resist side bending) \t•\tSingle-arm farmer’s carries \t•\tSide planks \t•\tLateral back extension holds \t•\tHuman flag (and variations)