Needs review
Source: Player's Handbook

Description: You are skilled at knocking down opponents.

Prerequisites: STR 13, Power Attack

When you attempt to overrun an opponent, the target may not choose to avoid you. You also gain a +4 bonus on your Strength check to knock down your opponent.

Special

A fighter may select Improved Overrun as one of his fighter bonus feats.

Normal

Without this feat, the target of an overrun can choose to avoid you or to block you.