The principle behind the floor press is simple, and right there in the name: You're moving from the bench to the floor. In doing so, you'll be doing more than just shifting your position.

Doing a flat bench press is probably better, so lie flat on the bench and let your feet rest gently on the floor – it will just keep the pressure off the lower back and increase range of motion.” ...

Dumbbell Bench Press The dumbbell bench press primarily ... Lay flat on a bench (or the floor) with dumbbells in your hands (palms facing away from you) and feet planted firmly on the floor.