Day 5 kicks first and lifts second. The circuit is 20 butt kicks, 20 high knees, 20 butt kicks and 20 split jacks - four exercises straight through, 2 minutes rest, 3, 5 or 7 sets by level. It reverses the emphasis of Day 2: butt kicks on the outside, high knees in the middle, and a new jack to finish.
Butt kicks - running in place with the heels flicking up toward the glutes - open and return, giving the hamstrings 40 reps in a set with the high knees between them driving the knees up in front for 20. The two are the same run seen from opposite ends of the leg, and alternating them keeps the pace up while spreading the load. Split jacks are the newcomer: from a stance with one foot forward and one back, jump and switch the legs so the other foot lands in front, the opposite arm reaching up as each foot lands forward - a scissoring jump front to back rather than side to side. Twenty split jacks is 10 landings on each side, and they ask the legs for a bigger effort per rep than anything else in this circuit, which is why they sit last.
Butt kicks stay light and quick, heels high, upper body relaxed. High knees drive to hip height with the arms pumping. On split jacks, land with both knees soft and the front knee over the ankle, not past the toes; the reach overhead should be full and the switch should be a real jump, not a shuffle - if the split is getting shorter as the reps climb, slow down and lengthen it.
Kick, knee, kick, split - the legs ran the whole circuit and finished with a jump that made them prove it.
Make it Harder: Sink lower into every split jack landing so the front thigh approaches parallel before you switch.
Make it Easier: Do the split jacks as alternating reverse lunges - step back instead of jumping - and keep the running blocks as written.
