The most popular sport in the world is soccer, although it is known in virtually every other country other than America, as football. Like any sport, soccer has its rules, and sometimes those rules need to be updated or revised to reflect the reality of the play of the game. For instance, a two-footed lunging challenge on another player is basically a red-card offense, because of the inherent danger that could occur should either of these feet hit with impact against another's players leg. If you watch soccer, often enough, you will notice that a significant portion of the game is actually played up in the air, to which the player that is able to control an aerial ball with his head can help his teammates or create a goal for his team. While contact in the sport of soccer is expected, what occurs way too often in soccer games, is contact between one player's elbow or arm and another player's face. As these are great athletes that are both young and strong, an errant elbow to the face can break a cheekbone, break a nose, knock a player unconscious, or take away another player's courage.
Too many times during the play of the game the incidents with an errant elbow or arm striking an opponent happens, to which sometimes it is clearly a foul, sometimes it appears incidental, and other times it isn't really clear at all. The thing is there should be a rule applied that you should not be allowed to jump and attempt to head the ball in such a way that you are using your arms and/or elbows to shield another player away or to possibly harm them. The easiest way to effect that change is to mandate that a player's arms must be kept to his sides in a normal natural motion and that while jumping, that the player's arm cannot be extended out at a height higher than mid-chest level. For players complaining that need to extend arms to get aerial lift or to shield the ball, they will have to make do with this modified rule with arm usage and subsequently to widen their legs so as to control their space better.
Those that have taken an errant or deliberate elbow know the power and damage an elbow or arm can do to their face when it is left unprotected. It is far better to change the rules of soccer so that rather than put the referee in the position as to adjudge whether an arm or elbow is inadvertent or deliberate, the rules will simply allow the referee to apply it as necessary as well as for the protection of the players.
Without players, no sport would exist, and to know any player's intention on a given play is something that is not actually knowable, whereas a rule equally applied to all, is fair to all, and will not noticeably affect the game of soccer at all, except to cut down on unnecessary injuries and damage that errant elbows and arms create. For instance, inside the 18-yard box, defenders are known for not making stupid tackles on the opposing players, as well as typically keeping their arms behind their backs so as to not incur a penalty. The game does not suffer for having them do so, nor will it suffer for the non-usage of elbows and arms.