Day 6 is the second plank day, and it changes the question. All four positions are straight-arm: a wide plank hold, a standard plank hold, and then a raised leg plank hold on each side. Thirty seconds each, two minutes total, and for half of it you are down to three points of contact.
The card walks you from stable to unstable. The wide plank spreads the feet apart and gives you the broadest base you will get all program, which makes it the gentlest of the four and the right place to set your line. The standard plank then narrows that base and hands the difference straight to your core. The last two panels lift one leg off the floor entirely, and that single change does something specific: with only one foot down, your hips immediately want to rotate and tip toward the lifted side, and the muscles that stop them from doing it are precisely the ones this program is training. Same position, one less support, twice the work.
Set your hands under your shoulders and push the floor away so your upper back stays broad rather than collapsed between the shoulder blades. Squeeze your glutes in all four holds - a plank held with loose glutes sags at the hips. In the raised leg holds, lift the leg only to hip height and keep it straight; the goal is a level pelvis, not a high foot, and if your hips twist as the leg rises, the leg is going too high.
Two of these planks are harder than they look, and you will know which two by the second one.
Make it Harder: In the raised leg plank holds, lift the opposite arm as well - down to two points of contact and nothing left to hide behind.
Make it Easier: Set the lifted foot back on the floor and hold a standard plank for those two panels instead.
