The 3-6-9-12 Ab Routine
This routine features three exercises that you do in a ladder sequence, meaning you start out with smaller reps, work your way up to the highest number, then work back down to the small reps again. Do each of the following exercises three, six, nine, 12, nine, six, and three times, as described on Colleen's website. Try to do them without stopping, but take short breaks if you need:
- Pilates pumps left and right (a cross between the single-leg stretch and a crunch)
- Rocking elbow planks
- Pikes (similar to these ball pike planks, but on your elbows without the ball)
Colleen said this should take you about five minutes.