did some googling and it turns out I'm a rare example of someone being wrong on the internet...
http://www.criticalbench.com/training-abs.htmThe quoted bits that follow come from a guy who's neck's wider than his head, so I'm not inclined to argue. He debates:
> 4 - Depending on your goals, you can work them first or last. If your focus is abs then train them first. Weaknesses should be trained early on in the session when you are fresh
vs...
> 6- Do them last after your larger muscle groups as sacrificing core strength at the beginning of the workout can compromise safety and strength.
and concludes:
> Why would you fatigue your abs before doing any muscles that require your core as a primary stabilize?
> obvious that if you train your abs first, you won't have the core strength necessary to do certain leg exercises that require a fair amount of core strength. If your abs and core are fatigued from previous exercises, it can cause weakness on subsequent exercises and increase the risk of lower back injury...never sacrifice core strength and safety simply to get your ab training out of the way early even if it's your weakest body part.
(So I'm wrong, at least from a body building perspective but I'm not sure I want to change this aspect of my workout. I don't want to abandon a set of 90 jackkinfe situps, which I'd not be able to do, and woruld do with even shitter form at the end of my workout, perhaps injuring something, and I don't do heavy leg stuff any more. Anyway that's enough bodybuilding sites to keep me going for a while
)