(For an entire program filled with core-shredding movements, check out THE 21-DAY METASHRED. One guy lost 25 pounds of fat in 6 weeks!)
Focus on driving your forearms through the bench upon landing in a plank. This ensures more scapular protraction—or separation of the shoulder blades—which engages key shoulder stabilizer muscles called the serratus anterior.
They’re the muscles that resemble shark gills along the side of your rib cage.
Try it: You can plug the exercise into a circuit as your core movement. Or you can perform the move for 20 seconds, followed by a 10-second rest for 5 to 10 rounds.