Fair catch catch is called a "mark"; see mark (rugby) and mark (Australian football) for more information (however in Australian Rules Football the player is not protected from the opposition team while attempting a mark). Fair catches featured in some extinct forms of football, and they have been abolished in other modern codes. In Rugby league the defensive player attempting to catch the ball cannot be tackled whilst in the air, though the attacking players can contest the ball by attempting to catch it themselves. A player who successfully catches the ball is able to be tackled only once they have landed
Comparison of American football and rugby union can play equally well in a variety of positions and most will play in the same position from youth. Every position in rugby has its own unique name (except for number 8) and associated skill base. In most club and schoolhouse American Football, the majority of players play both offense and defense, only being substituted for injury. Substitutes in American football can return to the game at any stoppage in play. In rugby union, any player substituted off for any reason, except for a 'blood' injury, is prohibited from returning to the field of play (with the possible exception of