When using her powerful blow rage power, the barbarian can forgo the normal bonus to damage (including any bleed damage granted by the bleeding blow rage power or similar boosts to the damage of the powerful blow rage power) and instead deals 1 point of ability damage to the target's Strength or Dexterity score for every four class levels the barbarian has attained. The target can attempt a Fortitude saving throw (DC 10 + 1/2 the barbarian's level + the barbarian's Strength modifier) to halve this ability damage. A barbarian must have the powerful blow rage power and be at least 8th level before selecting this rage power.