Zenyatta vs. Rachel Alexandra

Inky, I wouldn't worry about anything nearly that dramatic. At least not more than is normal with horses. They'e brilliant at hurting themselves, although you're right they prefer to do it whenever the connections have some kind of plan -- that's the same whether you're talking about a big race or a weekend trail ride.
But you can get a vet scratch for something far from life or career threatening. With runners at this level, all either of the girls has to do, quite literally, is leave a few more grains of feed in the bottom of her tub.
Neither filly's connections want to run her if there's any chance she's less than perfect. And getting two top horses perfect on the same day involves some mystical alignment of the stars.

 

Oh, I know. I won't believe they're both running until I see them both in the gate.