THE PLANK Works all abdominal muscles, lower back, shoulders, glutes Kneel on the floor. Bend elbows and place forearms on ground, clasping hands and forming a small triangle with hands and elbows. Straighten legs and balance on forearms and toes, feet six inches apart. Once balanced, make sure tush is level with the rest of body, forming a straight line from the top of your head to heels (as shown). Keep abs engaged to prevent back from sagging. Hold for six counts, building up to 30 counts (counts sound like "1-1000, 2-1000, 3-1000"). If this is too challenging, keep your knees on the ground and shift forward so you¿re balancing your weight just above your knees.