The Process: Side Planks
The side plank is a core exercise. Brigette Williams with Living Balanced says it helps strengthen the pelvic floor and the entire core unit, especially the deep core muscles.
It’s an advanced version of a regular plank and can also strengthen the arms, hips, and legs.
She recommends starting with a variation on your knees and working your way up, doing about 10 reps on each side.