Feat:Feat K

Knock-down
[General]

Your mighty blows can knock foes off their feet.

Prerequisite: Base attack bonus +2, Improved Trip, Str 15+

Benefit: Whenever you deal 10 or more points of damage to your opponent in melee, you make a trip attack as a free action against the same target.

Sources: Deities and Demigods, Sword and Fist