Improved Bull Rush( Player's Handbook v.3.5, p. 82)
[Fighter Bonus Feat, General]
Your Bull Rush is more effective.
Power Attack (PH) , STR 13,
Awesome Blow (MM4) , Awesome Blow (MM3) , Awesome Blow (MM) , Awesome Blow (MM5) , Cometary Collision (PH2) , Hammer's Edge (CW) , Improved Overrun (SF) , Knockback (RS) , Pushback (MH) , Rampaging Bull Rush (RS) , Shock Trooper (CW) , Three Mountains (CW) ,
When you perform a bull rush you do not provoke an attack of opportunity from the defender. You also gain a +4 bonus on the opposed Strength check you make to push back the defender.
A fighter may select Improved Bull Rush as one of his fighter bonus feats.
Performing a bull rush provokes an attack of opportunity.