Serratus Anterior excercise

This muscle, located on the side of your chest along your ribs, attaches to and allows you to rotate your shoulder blade (a.k.a. scapula). It plays a vital role when you raise your shoulder to flex your arm and move it away from your body.

Test it: Do a pushup without wearing a shirt and have someone look at your back during the move. If you have a winged scapula, your shoulder blade will stick out; this means your serratus is weak. A strong one suctions your scapula in during the movement, eliminating the winged look.

Improve it: Standard pushups strengthen the muscle, but doing pushup variations is the quickest way to correct a weakness. Use a power rack to perform incline pushups on a barbell. Start with your body at the lowest incline that doesn't allow your shoulders to wing—which means placing the bar relatively high. Perform 3 sets of 8 to 12 repetitions. As you become stronger and learn to control your scapular motion, work your way down the rack until you're doing regular pushups with perfect body alignment.


From Men's Health Magazine

Mom's Note: It looks as if you can do this exercise using a counter (like the bathroom sink counter top).