Gotta be the tights
Rode the road bike in to work this morning. Spectacular sunny morning, crisp but where you know it is going to be warm later. There were even swarms of bugs by the fields forcing you to breathe through your nose and keep your lips pursed tight. Legs felt amazingly good. Not sure if it is just being on the road bike after being on the cross bike yesterday or what. But the legs were just ticking over as Phil says.
I think it is the tights. I love these things and wish I'd worn them at the race. They are super thin Lemond training tights, that were dirt cheap. The kind of thin stretchy material that countours to the quad muscles and makes you stand duck footed in front of the mirror to pose.
(Ouch that hurt to flex like that)