Knock-Down

(Sword and Fist: A Guidebook to Monks and Fighters, page 7, DnD 3.0)

[General]

Your mighty blows can knock foes off their feet.

Prerequisite

Improved Trip, Base attack bonus ++2, 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.