the "physical pushing match" theory is one where the battle would rely on the valour of the men in the front line, whilst those in the rear maintained forward pressure on the front ranks with their shields, and the whole formation would consistently press forward trying to break the enemy formation. this is the most widely accepted interpretation of the ancient sources thus when two phalanx formations engaged, the struggle essentially became a pushing match. historians such as victor davis hanson point out that it is difficult to account for exceptionally deep phalanx formations unless they were necessary to facilitate the physical pushing depicted by this theory, as those behind the first two ranks could not take part in the actual spear thrusting.