Def Leppard's current anthem defines the parameters of the group's musical and esthetic approach--"Rock, Rock, 'Til You Drop." Which is exactly what the group did for and to a capacity crowd at the Capital Centre last night.

In the last year, the young British quintet has emerged as a behemoth in the new generation of hard rockers whose relentless energy and muscular melodic persuasion stops just short of heavy metal's sludgehammer approach. Joe Elliott's raucous vocals and the frenetically entwined guitars of Steve Clark and Pete Willis transformed the band's rockers into unpulled punches that thoroughly delighted the massed Def Lep brigades. If at times the concert seemed an excuse for the massive merchandising campaign holding sway on the Capital Centre concourse, the band thankfully kept things tight and propulsively direct.

Krokus, which preceded and exceeded Def Leppard, hardly lived up to its own miserable expectations with a set that was mercilessly loud, sexist and stupid. A plethora of regurgitated cliche's emerged from a band that obviously dropped out of the Billy Squier school of method rocking right after taking advanced Tina Turner vocalese.

Krokus' concept of dynamics was to plug in, and the only relief seemed to be to go out on the concourse and shop for T-shirts, hats and other rock souvenirs. Maybe that's why the group was on the bill.