Optimum Burn is a low-impact cardio workout tuned for exactly what the name promises - the steady, sustainable intensity where your body burns fuel most efficiently. Jumping jacks return three times as the pacemaker, with side jacks, seal jacks, arm scissors, scissor chops, march steps and butt kicks rotating between them, ninety reps per set and not one of them requiring you to leave your feet for more than an inch.

The structure is built around variety at a constant intensity, and that constancy is the science. The recurring jumping jacks reset the tempo at the start of each row, and every exercise between them shifts the emphasis just enough to keep different muscles cycling without ever letting the heart rate spike or crash. Side jacks and seal jacks are jumping jack dialects - one swinging the arms overhead from the hips, the other clapping them together in front - while arm scissors and scissor chops park the legs and hand the rhythm entirely to the shoulders. March steps and butt kicks close each set with running patterns softened to ground level. Moderate, continuous, varied: the zone where you can keep going, which is precisely the point.

Land every jack variation softly through the balls of your feet with a slight give in the knees. Keep the arm work at shoulder height with full range - as fatigue arrives, the arms will lobby to drop, and the burn lives in refusing them. Drive the march steps to genuine hip height and snap the butt kicks heel to glute, keeping the rhythm brisk enough that the last row still counts as cardio.

Not maximum burn - optimum. The fire that lasts is the one you can feed for every single set.

Make it Harder: Speed up every exercise while keeping the landings soft.

Make it Easier: Step all the jack variations out side to side instead of jumping.