Four Minute Plank is precisely what its name declares - two hundred and forty seconds of continuous planking, divided among four variations so no single position breaks you before the clock does. Full plank, elbow plank, side elbow plank and uneven plank rotate through timed intervals, and the only equipment is a floor and your refusal to come off it.

The rotation is what makes four minutes survivable, and it is smarter than simply enduring. The full plank and elbow plank trade the load between straight-arm shoulder support and forearm-based core demand - two versions of the same hold that tax subtly different links in the chain. The side elbow planks turn the challenge ninety degrees, handing each oblique chain thirty seconds of solo work while the front of your trunk recovers. The uneven plank - one forearm down, one hand planted - is the sneakiest interval on the card, loading each shoulder asymmetrically and forcing your core to level out a base that refuses to be level. Then the opening pair returns to close the account, meeting muscles that remember them from three minutes ago and are not pleased.

The standard never changes across all six intervals: one straight line from head to heels, glutes tight, hips neither piked toward the ceiling nor sagging toward the floor. In the side plank, stack shoulder over elbow and keep your hips lifted high. In the uneven plank, resist the tilt - the entire exercise lives in keeping your shoulders level when your base is not. Breathe steadily throughout; a held breath makes every second longer.

Four minutes. One position, four dialects. The clock only moves for those who hold still.

Make it Harder: Raise one leg for the final ten seconds of every interval.

Make it Easier: Instead of doing full 4 minutes, count to 10 when holding each pose.