Armor Training (Ex)
Starting at 3rd level, a fighter learns to be more maneuverable while wearing armor. Whenever he is wearing armor, he reduces the armor check penalty by 1 (to a minimum of 0) and increases the maximum Dexterity bonus allowed by his armor by 1. Every four levels thereafter (7th, 11th, and 15th), these bonuses increase by +1 each time, to a maximum –4 reduction of the armor check penalty and a +4 increase of the maximum Dexterity bonus allowed.
In addition, a fighter can also move at his normal speed while wearing medium armor. At 7th level, a fighter can move at his normal speed while wearing heavy armor