Popsugar Fitness Workouts Best Exercises For Arm Day The 16 Best Exercises For Arm Day December 20, 2017 by Jenny Sugar View On One Page Photo 9 of 16 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 9 Up-Down Plank Begin in a full plank. Lower your right elbow to the mat and then your left, coming into an elbow plank. Put your right hand on the mat, and straighten your right elbow. Do the same on the left to return to a full plank. This counts as one rep. Complete three sets of five reps. Previous Next Start Slideshow WorkoutsStrength TrainingArm Exercises