Day 29 is the last abs day: 18 knee-to-elbow. That is the set. Rest 2 minutes, then repeat for 3, 4 or 5 sets by level.
Hands behind the head, elbows wide, one knee lifting up and out to the side to meet the same-side elbow, then the other side, alternating - 18 means nine per side. The abs days ran 12, 14, 16 and now 18: one exercise, four visits, six more reps than when it started. Nine per side is a real set now, and the standard is the same as it was on Day 6 - which is what makes the extra reps count.
Lift the knee sideways rather than forward, and fold from the waist so elbow and knee meet in the middle. Stand fully tall between reps. Keep the pace steady, and slow down rather than shorten the fold if the balance goes late in the set.
Eighteen standing reps and the abs days are done - one exercise, honestly practised, took your middle from twelve to eighteen.
Make it Harder: Do 24 instead of 18.
Make it Easier: Do 12 instead of 18.
