American Football is somewhat unique in its format, which makes " Contact " heavier and more frequent by design.  The intention is to deliberately play the man and NOT the ball, even if the man being " taken out " doesn't even have the ball.  If you notice at " kick offs, " the front line " of the team in possession is deliberately charged by the front line of the opposing team; who have the sole intention of taking out the player in possession of the ball.  His team mates intention is to " Block " all opposing players, in their attempt to get at the player with the ball. So, these tactics would incur several infringements in English / UK Rugby from obstruction to dangerous tackling........never mind forward passing.......which is actually part of the US game.