The game will feature three difficulty settings, the hardest one will require a ton of motion control from the user while the other two will be less realistic but easier. It's an interesting concept but it remains to be seen whether it will catch on with gamers.
All these sensors mean that for the game's more basic manoeuvres, you will control your character in exactly the same way you'd control a real skateboard. Turn left and you'll turn left. Rock to the right and you'll lean to the right. Whip around 180 degrees and, yes, it'll respond, and your avatar will turn around.
For the more complex stuff, like flip tricks and grabs, you'll have to move or hold your hands/feet over the sensors. Which will mean a lot of work, particularly if you've never mastered the coordination to handle a real skateboard.