Up and down plank takes the ladder: from a straight-arm plank you lower onto one forearm, then the other, then press back up one hand at a time - continuously, for 10 seconds with 10 of rest, 20 with 20, and 30 with a full minute after. One ladder, one set; 3 to 5 sets by level.
This is the day the plank learns to move vertically. Every descent and press-up is a single-arm moment - three points of support while the fourth travels - so the trunk has to cancel the twist that each transition invites. The triceps and chest do the visible lifting, but the real work is rotational: a torso that stays square through thirty seconds of up-and-down has earned every bit of the minute-long rest that follows.
Go down forearm by forearm and come up hand by hand, placing each exactly where it started - no crawling forward across the floor. Fight the hip wobble, and remember that wider feet give it less to fight with. Alternate which arm leads so both sides share the pressing, and keep the head neutral with your eyes on the floor just ahead of your hands.
Up, down, up, down - the simplest instructions in the program and some of the hardest to follow well.
Make it Harder: Lead every transition with your weaker arm and let it set the pace.
Make it Easier: Run the whole ladder from your knees and keep the transitions strict.
