Exercise #1: The dreaded plank. Keeping your arms directly under your shoulders, hold this pose for at least 30 seconds, until it gets to be too much.
For a modification, try putting your forearms on the ground. You'll still feel the stretch along your arms (not to mention torso and legs).
But if you want to take your plank to the next level, try holding one leg up in the air, then switching it with the other foot halfway through however long you plan on holding your plank.
Exercise #2: Side planks. In addition to feeling this along your obliques, both arms should feel activated when holding the pose.
As a modification, rest your lower forearm on the ground and place your top foot out in front of the bottom one. To keep feeling the pose, keep that top arm extended up.
Exercise #8: Reverse plank. By this point, your back is likely in need of some reverse strengthening poses, so lift up into a forearm plank with your body facing toward the sky.
Exercise #9: Downward Facing Dog. If all else fails, this yoga pose will work all the arm muscles you might need strengthened. Because we work our biceps in most everyday activities, Moffat said that there's not much need to work them individually, though if you want, weights are a great way to work them.
