Day 21 closes the third week with three arm exercises and three floor exercises: 20 W-extensions, 20 elbow clicks, 20 bicep extensions, 12 flutter kicks, 6 windshield wipers and 6 deadbugs, in order, for 3, 4 or 5 sets with up to 2 minutes rest. W-extensions start with the arms bent in a W shape - elbows out, fists up - and extend both arms straight overhead, then return. Elbow clicks start with the arms bent and the fists up and swing the elbows together in front of the face, then open them wide again. Bicep extensions are the Day 9 exercise: fists at the shoulders, arms extended straight forward.
The arm trio works the shoulders and upper back from three directions with the arms tensed as their own resistance: overhead in the W-extensions, in front in the elbow clicks, forward in the bicep extensions. The floor trio then trades speed for control. Flutter kicks return from Day 3. Windshield wipers lie on the back with the arms out wide and both legs raised straight, lower the legs to one side and bring them back up, 6 in total so 3 to each side. Deadbugs lie on the back with the arms reaching up and the knees bent over the hips, extend one arm overhead and the opposite leg out, return, and swap - 6 in total. Both of those are about keeping the trunk still while the limbs move, and 6 slow ones is plenty.
Tense the arms through every rep of the standing exercises and squeeze the shoulder blades on each W-extension. In the elbow clicks, keep the forearms vertical and bring the elbows all the way together. Flutter kicks keep the lower back down. In the windshield wipers, keep the shoulders pinned to the floor and let the legs travel only as far as the shoulders allow. In the deadbug, press the lower back into the floor and stop the extension the moment it tries to lift.
Three weeks done - the arms finish upstairs, the abs finish on the floor, and nothing today asks for speed.
Make it Harder: Slow the windshield wipers to a 3-count in each direction with the shoulders pinned down.
Make it Easier: Keep the knees bent for the windshield wipers and throughout the deadbugs.
