The Single-Arm Plank is a challenging variation of the basic High Plank. Begin in the High Plank position, lift your left arm straight out in front of you and hold for 30 seconds before switching sides. You might have to widen your feet a bit to achieve the Single-Arm Plank.
25 Plank Variations for a Shredded, Stable Core
These 25 plank variations will add some variety to your workouts while you shred your core.