Day 26 spends the entire two minutes on your side. The circuit is a straight-arm side plank on each side, followed by a side elbow plank on each side - 30 seconds per position, four positions, no front support anywhere. It is the most specialised card in the program, and the obliques have nowhere to pass the work along to.
The two variations differ in height and in what they demand. The straight-arm side plank stacks you on one hand with the top arm reaching up to the ceiling, which lifts the hips higher, opens the chest and puts a real balance and shoulder-stability demand into the position alongside the core work. Dropping onto the forearm for the second pair lowers the whole body, shortens the base and shifts the load off the shoulder and squarely into the side of your trunk. Running them in that order means the harder balance comes first while you are fresh, and the deeper oblique work comes second when there is no shoulder left to hide behind.
In the straight-arm holds, stack the supporting hand directly under the shoulder, push the floor away and lift the underneath hip so the body forms one clean diagonal from heels to head. Keep the top arm straight and the chest turned open rather than rolling forward. In the elbow versions, the same rules apply with the forearm flat and pointing straight ahead. Look forward rather than down in all four, and if the hips start sinking, reset rather than sag through the remaining seconds.
Two minutes spent entirely on one edge of your body, then the other.
Make it Harder: Lift the top leg away from the bottom one in both straight-arm side planks and hold it there.
Make it Easier: Take the first two panels down onto your forearm as well, so all four are side elbow planks.
