I like this one to change up the standard boring old plank. I would recommend that you have enough core strength and are already able to do the basic plank with ease before doing this exercise. This is a great one to do with a partner and see who can go the longest, it makes for some fun competition.
To begin set up some small plates, I would suggest using 5lbs-10lbs. If you are first trying this then start with just a few plates, maybe 3-4 and then as you get better you can use 5-6 plates and more weight ( 10lb plates). Put the plates right next to your hands, and then get yourself into a plank position making sure you keep your abs tight, and elbows under your shoulders. Now lift your left arm and grab one of the plates and then return to the plank position before passing it to your right hand and then placing it on the opposite side. Check the video below for a better idea of this one. Your goal should be to pass the plates back and forth ass many times as you can. Moving from the left to the right side equals one pass. This exercise all will work the shoulder and some rear delts.
