Athletic Rock!  That's how they classified themselves.  In fact, they began wearing helmets, and various other sports (hockey, baseball, etc.) gear in concert incorporating them into the playing of their instruments (for instance, elbow pads and hockey masks were used to strike cymbals)  Their music (that is these first 3 albums,were pure speed and power – heavily influencing the genres of speed/thrash metal and power metal (their first US Tour was aptly named the "Kill 'em All for One" tour, with Metallica as THEIR opening act.  Then...they decided to go more 'commercial' with their sound, alienating their hard core fans like us at Robscurities.