The bigger they are...

Close Combat Attacks made by models with this special rule always wound on to-wound rolls of 4+ (or better if the model’s Strength allows it). When rolling for Charge Range, if the charged unit contains one or more models of the following Troop Types: Ridden Monsters, Monsters, Monstrous Beast, Monstrous Cavalry or Monstrous Infantry, models with this rule gain Swiftstride for this Charge Range roll. This does not apply to Pursuit moves.