Luckily, I've so far avoided being a victim of much of this kind of thing. I've heard "extend a lot of ki when you do this" occasionally, but that's about it. I don't find this very helpful, because it doesn't say HOW to extend "Ki", but there you have it.
Also luckily, one of my first teachers was an engineer by education, like me. His instruction was that "ki" can be thought of as the knowledge of how to employ physics and mechanics to manipulate a mass, in this case, uke. Center is thus not a metaphysical site of concentrated energy, but the center of gravity which is where a force is most efficiently applied if one wants to move a body. For us less-than-enthusiastic-aikido-as-religion types, "ki" as physics is helpful in seeing through some of the more esoteric stuff.