Runescape : Momentum needs no ability bar

Momentum, a accurate ability which allowed you to resist from other ability damages from your opponent as well as cause more damage without using any ability, it was introduced in evolution of combat, now it won’t need ability restoration anymore, previously it took full bar. Here’s the screenshot of the ability.

 
So you can fight the NPCs, if you want to leave your desk for a few minutes, and you will be still hitting high during the combat.