Day 53 is the last of the cardio days to send you to the floor, and it picks the rotation drill to do it with. Four 15-second intervals - high knees, plank rotations, high knees, plank rotations - three to seven sets, one minute of rest.
You met plank rotations on Day 16 as part of an abs session. Here they do a different job: opening the body into a side plank with one arm reaching to the ceiling, then rotating through centre and opening the other way, all while your heart rate is still high from running in place. Rotating under fatigue is where the obliques and the shoulder stabilisers get properly tested, and doing it with your breathing already elevated is a fair simulation of every sport that ever asked you to change direction while tired.
Stack your hips as you open so the body forms one flat plane, and press the supporting hand into the floor rather than collapsing into that shoulder. Control the return through centre instead of dropping. On high knees, keep the cadence high - the interval is short and the rotation will feel slower if you have earned it.
Fast on your feet, then slow and wide on the floor - the last time this program asks for that particular swap.
Make it Harder: Lift the top leg as you rotate open so the side plank is supported on one hand and one foot.
Make it Easier: Rotate from your knees and take the reaching arm only as high as your shoulder allows.
