Momentum is a cardio circuit shaped like its namesake: it starts from a dead stop, gathers speed exercise by exercise, and then brings everything to a halt. A 10-count plank hold opens the set, climbers get you moving, slow butt kicks and butt kicks shift you up through the gears, split jacks and high knees hit full tempo, and a second 10-count plank hold ends it - motionless, exactly where you began. No equipment, one small patch of floor, and a set that behaves like a physics lesson.

The sequencing is an acceleration curve. The opening hold is zero velocity - your core braced, everything still. Climbers introduce movement while you are still horizontal, so the transition from stillness to speed happens under load. Then the standing block ramps deliberately: slow butt kicks and butt kicks are the same exercise at two speeds, run back to back, which is the workout teaching your legs to accelerate a pattern they already own rather than learning a new one. Split jacks add distance and arm drive, high knees bring peak turnover - and then the second plank hold slams the brakes. Stopping cleanly at full fatigue is its own skill: your heart is pounding, your breathing is loud, and your job is to hold a perfect line anyway.

Hold both planks with hips level, glutes on, and a straight line from head to heels - the second one counts double because everything in you wants to sag. Keep your hips low and steady in the climbers. In the slow butt kicks, make each heel-to-glute contact deliberate and full; when the fast version arrives, keep the same complete range at the higher tempo instead of shortening the kick to buy speed. Land the split jacks with soft knees, switching legs cleanly mid-air, and run the high knees tall - knees to hip height, no leaning back.

An object in motion stays in motion - the trick this workout teaches is starting from nothing and stopping on command.

Make it Harder: Extend both plank holds to a 20-count.

Make it Easier: Drop the split jacks to alternating reverse lunges at the same count.