(CNN) — If you want a resilient core, strengthening your six-pack is just the start. Your obliques — the muscles that run along the sides of your waist — may not get the same attention as your ...

Lately, my core routine has felt staler than week-old sourdough bread. Sure, classic moves like crunches, Russian twists, and planks are great (and effective!), but in order to reap the gains of ...