If nothing done in the final 10 days will help, and you can't go cold-turkey on training, then what's an endurance athlete to do? This is where experience seems to matter most. There is no perfect race without a perfect taper. I suppose the perfect physical taper maintains your already-peak fitness level while letting your muscles rest and rebuild after the months of breakdown. Experts also say that resting your body by training slow is not the answer -- that just teaches you to race slowly. Thus, this is where I would hope that my live-and-learn experiences come in handy, but my data is mostly limited to two sports, running and swimming. And separately -- not as a single event.
Let's gather the data. In running, the taper method that seems to work best for me is to maintain intensity and reduce mileage drastically in the final two weeks. In swimming... well, let's just say that swim coaches don't believe in tapers. I've been known to have my fastest races after my longest, hardest "warm-up" (in swim coach terms, this special type of warm-up is called: "let's have a 2-hour practice before the meet."). And finally, I've never done a bike race, so I have no taper experience there.
Thus, to avoid a taper disaster, I've decided to read, read, read, attempt to apply other people's knowledge fused with my own, and then listen to my body. And, after my final really "hard" workout yesterday, my body says to rest. Why? Because I'm tired. Will it work? I have no idea. But I KNOW it can't hurt. Another data point.
The wildcard of the taper is the mental part. My mind never handles tapering well. I second guess. I second guess my training. I second guess my nutrition. I second guess my taper. The best I can hope for is that my relaxation techniques will still work. I think I'll go practice that now. And, just in case, I'll pray for disaster relief.