Rule 6.4 Checking from Behind
(a) A minor penalty and a Game Misconduct or a Major penalty and a Game Misconduct at the discretion of the referee based on the degree of violence of the impoact; shall be assessed any player who pushes, bodychecks, or hit an opposing player from behind, anywhere on the ice.
If the player is injured, a Major penalty and a Game Misconduct must be assessed. A Match penalty could also be assessed under this rule.
(b) Where a player is high-sticked, cross-checked, bodychecked, pushed, hit or propelled in any manner from behind into the boards or net, in such a way that the player is unable to protect or defend herself, a Match penalty shall be assessed.
Note: Referees are instructed not to substitute other penalties when a player is checked from behind in any manner. This rule must be strictly enforced.