Keenberg
First Post
TRAMPLE Centaur racial power
You stamp your hooves down and try to crush a nearby enemy.
Encounter
Standard Action Melee 1
Target: One enemy
Attack: Strength, Dexterity, or Wisdom vs. Reflex, this is an unarmed weapon attack and benefits from anything that would affect such attacks.
Hit: 1[W] + the chosen ability modifier damage, and the target is knocked prone.
I'd think a Trample is something that would have to be used as a charge/bullrush attack. Standing still and doing this would be more akin to a stomp. Perhaps if you included the clause that it must be made as a charge/bullrush attack, the character could continue moving away from the enemy without triggering OA's from that enemy.