I would describe none of the solo work we do as isometrics.
Of course internal drills are very, very different from isometric exercises that you would be prescribed by a physical therapist, for instance, but any drill where there is no outside body movement neatly falls into the category of "isometric". The strict definition is met by the standing and partial squat drills done by every internal training group I have seen, for instance. My point is that Tomiki must have thought himself quite clever in selecting this explanation. It was the kind of statement that is both quite accurate and gives away nothing, and is therefore very typical of conversation on the topic.