Day 21 opens the final third of the program with four exercises you know well. The circuit is high crunches, knee crunches, the dead bug and flutter kicks - 30 seconds each, two minutes, one circuit. Every position on this card has appeared before; what has changed is how they feel arriving three weeks into a daily habit.
The card runs a clean top-to-bottom sweep of the abdominal wall. High crunches curl the shoulders toward legs held vertical, isolating the upper abs by taking the hips out of it. Knee crunches then close the body from both ends at once, hips and shoulders travelling toward each other. The dead bug switches the trunk from producing movement to resisting it, holding the lower back flat while opposite limbs extend away. Flutter kicks finish at the bottom of the range with small alternating kicks and the pelvis held steady against them. Upper, whole, deep, lower - four exercises that between them leave nothing untouched.
In high crunches, keep the legs vertical and still. In knee crunches, meet in the middle rather than doing all the work with your shoulders. In the dead bug, the lower back staying down is the only rule that matters, and everything else adapts to it. In flutter kicks, keep the legs long and the motion small, and lift the whole range higher if your back starts to complain.
Three weeks in, the same two minutes and a body that meets them differently.
Make it Harder: Run the entire circuit without a single pause between exercises - no micro-breaks, straight from one into the next.
Make it Easier: Bend your knees toward the ceiling instead of holding the legs straight in the high crunches.
