Spasticity is a condition of muscles that is a velocity resistance to stretch. What that means to a child and to a parent is that if you move the limb slowly, you have a difference than if you move that limb fast. Spasticity restricts movement and it creates a break on the system. It's as if they're trying to move, but they're held back. By treating spasticity, you may improve the range of motion or the action of the movement.