Don’t fancy Russian twists? Try plank windmills instead. They're one of the best plank variations for also strengthening your obliques — the muscles that run along your waist.
To do the windmill plank, you’ll start in a high plank position, lift an arm toward the ceiling, feed the arm underneath your body, complete reps on one side, then move to the other. You can add a set of light dumbbells to increase the intensity or work with your body weight if you’re short on equipment.
