OK, I'll try this one more time in the hope that you have a genuine interest. But, in all seriousness, this can be easily solved if you just go to your local skate park and ask any kid there to pump a transition for you. Obviously no amount of video or anecdotal evidence is sufficient on this forum. Go see it for yourself. I am amazed that anyone needs to be "convinced" of this, it is second nature to any kid with a skateboard, bmx bike or pair of inline skates.
Here is how it works, as you approach a transition you crouch down, then extend your legs as you hit the upslope. Not only will you maintain your speed but you will gain speed. This is easy to prove by seeing how high you go with a neutral stance, then how much higher you go with the pump. The same effect is true of down transitions and horizontal ones. many skaters also swing their arms for extra momentum, but it is not required.
Here is the video FOM thinks is so suspicious. The skater starts on the flat and initially steps up the wall to start his motion, Then he uses his legs to pump the transitions on the way up and down. Within a couple of passes he has gained enough speed to get about 16 feet of vert with air. Although he does swing his arms as well, the main impetus is coming from the pumping action of his legs. Very specifically his speed increases up the wall, it has to or he couldn't climb the wall. Forgive the eighties porn music!
I'm just editing this to say that there is no perfect video out there that isolates that one move. It's too easy to claim that there is some other influence there, like he gains all his speed on the down slope and not the up. I don't know if it is visually possible to tell the difference between maintaining or gaining speed in this environment, but you can see the timing of the leg action. Again, hate to be repetitive, but just go see it, then all arguments are moot.
Edited by MrGolfAnalogy - 9/11/13 at 12:15am