Border Collies are bred to herd sheep. Gotta be quick and agile. They're high energy dogs, and generally aren't well suited to be house dogs. I gotta give the guy on the bike props! I would have crashed multiple times at half that speed.
I used to have a retractable leash attached to my moutain bike frame and my German Shepherd would run ahead of me. She'd do 10 miles easily. Called her my up hill power assist!
I remember doing some stupid stuff on my bikes when I was a kid but the only suspension we had back then were the wheel spokes and the air in the tires.
One time the neighbors dog ran out beside me and somehow managed to get hung up under the pedals. Don't ask me how but I was able to get stopped without ever actually running over the poor thing with a tire. Neither of us was hurt much and I'm not sure who was more scared, me or the dog. :grin: