Prone position is an anatomical term for a body position in which an individual lies face down with the head, palmar surface of the hands and arms, stomach, and anterior surface of the legs all making contact with the surface. Prone lying is a good position to help open up your joints, specifically your hips and low back, and improve flexibility by going into an extended position resulting in a relaxation and/or a stretch to the flexor musculature. This position can also help provide a stretch to the trunk muscles and is often utilized in strength training, specifically the posterior chain muscles, due to the resistance from gravity when working in a vertical direction.