You can decrease damage taken by a third during bonus play in God of War 3 for PS3, all you need to do is find Hercules’ Shoulder Guards which are located in the water where you find him floating.. simply swim down beneath him to find his soulder guards.
Note that this is a bonus item and can only be used during bonus play, which can be enabled once you beat the game at least once. Turning on bonus play automatically disables trophies.