Day 17 attaches the hold to every rep. Three items at 3, 4 or 5 sets with two minutes of rest: 8 combos of a decline sit-up followed by a 5-count hold, then 10 crunch kicks and 8 reverse crunches.
The hold has been sitting at the end of the sit-ups since Day 5; here it moves inside them. You sit up, hold the top for five counts, lower all the way back down the decline, and go again. Eight combos is forty counts of holding per set - four times what the old standalone 10-count delivered - and none of it arrives fresh, because every count follows a rep. That is the gap between an isometric you perform once and one you keep returning to while steadily more tired. Behind it the reverse crunches have grown from six reps to eight, so the back half of the round got heavier at the same moment.
Start counting only once you are fully up, and hold with the torso genuinely upright instead of resting back against the pads. Elbows stay wide, hands behind the head, breathing continuous - holding your breath through five counts eight times over will find you out. Lower under control every time, because the descent on a decline is a rep in its own right. Reverse crunches keep the long slow lowering they had six days ago.
Forty counts hidden inside eight reps - the arithmetic of this session is worse than it looks.
Make it Harder: Move the hold to the bottom instead, five counts in the stretched position before each rise.
Make it Easier: Hold for 3 counts rather than 5 and keep all 8 combos.
