I really don't think there's such a thing as a "static attack" because the human structure is always moving. Not only the muscles involved in breathing but the opposing groups which keep the body pointed in (more-or-less) the desired direction, etc.
There must be some degree of energy committed to the attack or it's just "holding hands" and there is no need for aikido.
Possibly some people are not taught to use the energy or ignore it in order to create their own energy that's supposed to overwhelm the uke ... I dont' understand the concept of a static attack. I'm not even considering the worth of an attack that some use where uke gives their partner lots of momentum to use for whatever they want by just running at their partner with the intent to be thrown down.
Of course there are varying degrees of force that should be applied depending on the skill level of the person you're with.
All attacks are essentially ki no nagare. There's just differing amounts of force, speed, and movement depending on the intent of the training.