A bit of a balancing act of beginners, but this move will really make a difference in your thighs! "Sit up straight on left side of chair's edge with feet together, abs engaged. Bend left knee (calf beside chair, parallel to floor), and place pen behind it. Hold sides of chair, flex left foot, and curl left heel up toward seat. Do 5 reps. Holding curl, press left leg back 5 times; repeat circuit. Switch legs; repeat."