You're right on this. The explosive power of a Q horse is such that nothing can keep up with it's surge. Sometimes the rider has difficulty staying on.

We've got a couple in our gang and on cool mornings, when I let them out of the barn, it is a treat to see them blast off, kicking up and farting, ha.
The staying power, however, of the T-bred is a wonder to behold. When they thunder down into the first turn and are traveling 40 mph, you can literally feel the impact of the hooves in your chest, even with 160,000 people screaming. They keep this up for a mile and a quarter at the Derby. Preakness is one mile, but the "hoss" is the Belmont where they go for 1 1/2 miles. And there is only two weeks rest between each race so the grueling task is all the more amazing. For the last six or seven years, they have pulled the Ky Derby winner out of the Preakness because it is so demanding. I heard yesterday that they are doing the same with Sovereignty.
Then, as in 1973, you get a complete freak of nature, like Secretariat who not only wins the first two races in record times, but then goes out and runs the Belmont and wins by 31 lengths!!!. It defies everything we think we know about horse endurance.
Sorry for rambling on here. Just a fascinating subject for me.......