Day 3 is cardio as one continuous run: 10 march steps, 4 butt kicks, 10 march steps, 4 butt kicks, and so on for four rounds - read the list on the card from top to bottom, and the whole list is one set. Rest 2 minutes, then repeat for 3, 5 or 7 sets by level. Two movements, alternating, no stopping between them.
March steps are marching on the spot with the knees lifting high and the arms swinging naturally, one leg at a time. Butt kicks lift a heel toward your glutes behind you, then the other, hands held loosely at chest height. Ten of one, four of the other, four times: the march steps build the rhythm and the butt kicks briefly change the pace, and the switching is what keeps your heart rate from settling. Both are stepped, not jogged - the standing foot stays planted.
Lift the knee to about hip height on each march step and stay tall - no leaning back to hoist it higher. In butt kicks, keep the knees pointing down and bring the heel up as far as it comfortably goes; if it does not reach, that is fine, the movement still works. Keep the arms moving throughout, because they carry the rhythm from one exercise into the next.
Fifty-six steps without a pause and Day 3 has your heart rate exactly where it wants it.
Make it Harder: Run the whole sequence twice back to back before taking your rest.
Make it Easier: Keep the butt kicks low - heel to mid-calf is enough.
