Your shield bash throws your enemies off balance.

Prerequisite(s): Improved Shield Bash, Shield Focus, Stumbling Bash, base attack bonus +11 or fighter level 8th.

Benefit(s): As a swift action when you hit a creature with a shield bash, you can attempt a trip combat maneuver against that creature at a –5 penalty. This does not provoke an attack of opportunity, and if your attempt fails by 10 or more, you are not knocked prone.