Few exercises look as simple as a plank – until you do it! The plank works your core and arms, but if you think you’re too advanced for a normal plank, we challenge you to try this variation.
Try planking with an arm circle!
Step One: Lie in a plank position, reach your left arm back and then circle it overhead, bringing your palm back to the floor; repeat on the other side. This counts as one rep.
Step Two: Complete five to eight reps, keeping your core stable and belly button pulled up toward the spine.
Step Three: The wider apart your feet are, the more stable you will be. Do not let your pelvis drift toward the ceiling.
Source: POPSUGAR. Image: Blackfitness101.com