Day 12's circuit reads like a misprint and isn't: climbers, shoulder taps, climbers again, then plank rotations - fifteen seconds each, a minute of continuous work, a minute of rest, 3 to 5 sets by level.
The doubled climbers are the design. The first interval arrives on fresh arms and feels like cardio; the second arrives after fifteen seconds of shoulder taps have quietly drained your support muscles, and suddenly the same exercise is a shoulder workout with a running problem. Sandwiching the taps between two sprints turns four short intervals into one long argument between your legs, which want to go faster, and your upper body, which would like everyone to stop.
Hold the standard plank shape through everything: shoulders over wrists, hips level, no piking as the fatigue arrives. On shoulder taps, push the floor away and make each touch deliberate - fast sloppy taps rock the hips and waste the exercise. In the second climbers interval, match your first interval's knee drive stride for stride; that comparison is the day's honest measure.
Climbers twice in one circuit is not a misprint - it's the whole point.
Make it Harder: Keep both climber intervals at an identical full sprint, with no slowdown allowed in the second.
Make it Easier: Place your hands on an elevated surface - a step or a sturdy chair - for the whole circuit.
