Patrick de Block
Even if you were only summarizing the last paragraph, your summary isn't entirely correct as it leaves out essential information. I think you need the whole quote to get an idea of dual opposing spirals, at least, I don't know what to drop from it.
I think I understand what you mean. And I don't disagree with it. But we have to start somewhere. I'm not saying that this is all there is to it, but we have to get an initial idea of what is meant by the the term.
Saying that they are muscle groups, is a very general place to start, we can begin to flush out as we go. The problem I see with these discussions, is the lack of desire to get to a beginning place and go from there. This isn't the end of the conversation, it's only the very very beginning. If we can start with something simple, like "The duel opposing spirals are muscular pairs in the body, that can be used to great effect", we have something simple to start from. If we have a huge paragraph, we'll just confuse ourselves as we get further into it.
If "The duel opposing spirals are muscular pairs in the body, that can be used to great effect" is not correct, then we should fix that now, and find something that everyone can agree is the basic building block of our conversation. If we can't find something that everyone agrees on, then we're probably not all talking about the same thing.