Your attack hinders your foe's movement as much as the roughest terrain.

Encounter   ✦     Primal, Weapon
Standard Action      Melee weapon

Target: One creature

Attack: Strength vs. AC

Hit: 2[W] + Strength modifier damage, and the target is slowed until the end of your next turn.

  Earthstrength: The attack deals extra damage equal to your Constitution modifier.

Published in Primal Power, page(s) 95.