so i'm trying to figure out how to do the 'power rush' moves without stars.  here's what i keep running into:  
 
 Easy power rush attack:
-----------------------
Use a six button controller and perform one of the following actions for the corresponding power 
rush attack level without
collecting the appropriate number of stars.
Character Level 1 Level 2 Level 3 
Axel X, Toward, Toward X, Down, Toward X, Back, Down, Toward
Blaze X, Toward, Toward X, Toward, Up X, Down, Toward, Up
Skate X, Toward, Toward X, Toward, Down X, Up, Toward, Back
Zan X, Toward, Toward X, Back, Up X, Up, Back, Toward     
 
the PS3 equivalent to X is L1.  but no matter how fast i hit L1, forward, forward, axel won't do it.  what's the deal?  it's weird that you'd press an 'action' button before a movement button.  

Maybe it's redundant posting in this thread, given how long it's been since anyone posted in it, but this might be of use to other people who come along. Ah well.
 
Maybe the problem was that you pressed the buttons too quickly? 
Anyway, as I recall, after you press the X button, your character remains still for a few seconds until you either enter the command accurately, or the effect wears off.

The maximum version of Axel's is just that button + fireball motion.  Make sure that you've actually got the x button assigned.  I have the game on 360 and I remember there being something odd about having to assign it. 
 
Also, you can't combo any of them.  If you're attacking someone and trying to bust out that super move in the middle of it, it won't work.