How do they do that?

Quick 1-hr doing the Cherokee Loop, going pretty hard the whole way on the C'dale. Two, no, Four observations of note:

• felt good. went hard. coming home via Millvale I had to back off. I was overheated. took my helmet off the last couple miles to cool down.
• gosh, the weather sure is nice- 65F, sunny and a clean wind
• came up behind rider a couple times towards Maple. After crossing Maple he shot off like a rocket. I saw him two more times at the bottom, but way ahead.
• I got in the way of a rider on the north side of the creek near Grey Fox. He was cool about it but then he shot off like a rocket too. That section always gives me probs, with lots of ups-n-downs, roots and rocks. I did better than usual today, but as I watched the Specialized rider up the trail I don't really understand how to ride that section that fast. Impressive!