Set bar (Smith machine/rack) or suspension straps at waist height.

Position yourself underneath, facing up.

Grasp bar/handles, overhand grip, slightly wider than shoulders.

Extend legs, body straight head to heels (easier: knees bent). Engage core.

Pull chest towards bar/handles, retracting shoulder blades, bending elbows.

Pause briefly.

Slowly lower back to start.

Repeat.