A push in the back is a free kick awarded in Australian rules football against a player who illegally tackles or interferes with a player from behind. The rule is applied in two different circumstances: tackles and marking contests.
A tackler, loosely speaking, is not allowed to push an opposition player in the back during a tackle. By the strictest definition of a push, any contact from behind could be considered a push in the back, so the rule is usually enforced under only the following three circumstances:
While the second and third circumstances are objectively applied by umpires, there is some subjectivity concerning the first interpretation. This arises because a bent-over player can be easily knocked over by incidental contact, forcing the umpire to make a judgement call regarding whether or not be considers the push to be sufficiently substantial to warrant penalty. Furthermore, it is not uncommon to see a player "take a dive" when he feels contact from behind, and umpires will not pay a free kick if they believe this to be the case. Nevertheless, it is relatively easy for fans to predict when these free kicks are going to be paid. Umpires are much less lenient if a player pushes another near the boundary line, due to the increased danger of crashing into the fence.
One of the rules introduced by the VFL when they split from the VFA 1897 was the protection of a player who jumped for a mark from being put off balance by a player pushing him from behind. Pushes in the back are usually paid under the following three circumstances.
Free kicks under the first circumstance are easy to spot and are always paid, because a player already in the air cannot take a dive when pushed. However, under the other two circumstances, making judgement calls can be very difficult: it is easy for a player to take a dive in these circumstances; a sprinting player who is pushed may, in the act of trying to fall safely, take an unnatural leap which inadvertently makes the play look like a deliberate dive. As such, paying free kicks for pushes in the back in marking contests has always been contentious.
However, these pushes are all caused by the arms. Players in marking contests are allowed to push their opponents out of the contest with their bodies, within reason; so, a subtle nudge with the shoulder would not be penalised, but a full-blooded bump in the back would be penalised.
In 2007, the AFL introduced an interpretation of the push in the back in marking contests, referred to as hands in the back. Under the rule, any player who placed his hands upon an opponent's back in a marking contest, whether there was a visible push or not, would be penalised.