The last Active Plank circuit: climbers, plank leg raises, plank crunches and plank arm raises, fifteen seconds each, one unbroken minute per set with a minute of rest - 3, 4 or 5 sets by level.
Plank crunches are today's addition: from a full plank, each knee drives in toward the elbow and returns, a slow-motion climber that trades speed for a deliberate fold through the midsection. The circuit alternates its demands cleverly - a sprint, then stability with a moving leg, then the crunch fold, then stability with a moving arm - so no fifteen-second block repeats the challenge of the one before it. It is the busiest floor minute in the program, and the most complete.
In plank crunches, bring the knee all the way in - a half fold is a stomp, not a crunch - and keep the hips from lifting as it travels. Leg raises and arm raises keep their old rule: the torso stays so still that the moving limb looks like it belongs to someone else. Open the climbers at a pace you can still respect by the fourth exercise.
Four plank variations, zero seconds of standing up - the floor is where this program does its quietest damage.
Make it Harder: Slow every plank crunch down until the knee genuinely touches the elbow.
Make it Easier: Run the circuit at Level I and add an extra 30 seconds of rest between sets.
