Load barbell with small plates (e.g., 5-10lbs) allowing it to roll.

Kneel on floor, grip barbell overhand, shoulder-width.

Engage core, keep back straight (slight arch okay, avoid rounding).

Slowly roll barbell forward, extending arms and hips, lowering torso.

Roll out as far as possible maintaining control and straight back.

Pause briefly.

Engage abs and lats forcefully to pull barbell back towards knees, returning to start.

Repeat. (Advanced: start from standing).