This year's go at Burnham Triathlon in two weeks' time is going to be a spectacular ass-pull. I haven't run since winter, haven't swum all year, and all my cycling has been of an entirely different character (super low effort, super long duration); my high-effort cardio fitness is somewhere back with the autumn leaves, I think. The Auld Knee is another factor: it hates torque, and TT riding is torquey spin.
So, some tests before actually racing:
Swim: Can I actually remember how to swim crawl at all? If I can, can I get back to the required 20 lengths without puking up a lung? Get in the pool and JFDI.
Bike: Does riding hard hurt? And more importantly, does the hurt matter? Through LEJOG there was plenty of hurt, but ample ibuprofen meant it shut up an went away; also the first ten miles hurt worst, so a warmup may be indicated. Torque hurts more but if it's just a rubbish signal from complaining gristle, I can pill and tune it out to a degree. Get the road bike fettled and hammer some commutes. Do Science on it.
Run: Can I actually run? Apparently yes I can -- if I can do 20 minutes now, I can do the 30-35 that Burhnam's sandy 5k offers, on race-day when the gumption is high. Cardio effort is extreme though, and my feet and calves are like "wat?". Test passed, though it's going to be ugly.