 Many defensive players have complained that the league is being too strict in their interpretation of what constitutes an "illegal hit", and that it forces them to behave significantly different than how they were taught to play the game.Another concern is the league's instructions to game officials to err on the side of caution, since questionable calls late in close games significantly affect their outcome.However, the medical community has supported the move, believing that it will help reduce concussions and other head injuries.