Pro-skater does the IMPOSSIBLE - ft Rodney Mullen

I’d call it a physical reason. And seeing as you are Physics Girl I would have hoped you realized it was only a mathematical reason DUE to the physics. 

Also Rodney Mullen is to skateboarding as I myself am to scootering. All of my scootin friends used to be hitting QPs and doing tailwhips and the like, whereas I was the one manualing like 300ft and coming up with my own special moves… like the one handed x-up manual.. where I would manual, then take a hand off, usually my left, and then whilst still manualing take the right hand and rotate the handlebars to 180 degrees, basically so the front wheel, and whole steering situation on the razor scooter, would be facing backwards (technically not a big deal but everyone knows the Razor logo faces front..) then before I ran out of strength or room, I’d quickly rotate it back before landing the front wheel. 

I DID try to come up with something where I would land the manual with my left hand off it and right hand still in the what I’m calling x-up position… then roll up on an incline and hope to do a half tailwhip 180 in the opposite direction as the original x-up and land straight going back down the original incline, that transformed thru my relative motion into a decline :) anybody understand??