The Backstreet Boys must be determined to go out with a bang rather than a wimper. Explosions. Rockets. Big blasts of confetti and streamers. The Orlando boy-group sensation laid 'em all on thick for a sold-out crowd of 16,000 at the Molson Amphitheatre yesterday. But no amount of special effects could cover up the fact that the Backstreet Boys' act was wearing thin. Instead, they looked like parlor tricks designed to draw attention away from the show's threadbare musical furnishings. Yesterday's appearances, which included sold-out concerts at 2 p.m. and 8 p.m., marked the Backstreet Boys' fourth visit to Toronto in 18 months. A wildly appreciative response from most of the pre-teen girls in attendance showed that at least the fan appeal of singer-dancers Kevin Richardson, Nick Carter, Brian "B-Rok" Littrel, A.J. McLean and Howie Dorough hasn't faded -- or that they're still in good physical trim. Well, except for A.J., who tore a ligament in his ankle towards the end of the first set and had to sit out the entire evening show. Canada is the biggest BSB market in the world per capita, as the quintet were none too shy to point out mid-set during the afternoon set. That was no excuse for coasting through the show, only flipping out of autopilot for an occasional victory roll or two -- although A.J. did work hard enough to injure himself in the line of duty. The constant, screaming din of the audience -- which the band seemed to feed off in past concerts -- was just another layer of nonsense for the Boys to hide behind. The same gags and lines from the group's January SkyDome show were trotted out in a revue-style snooze-fest that clearly tested the patience of the younger kids in the crowd. This was a band going through the motions, however unintentionally funny those motions might have been. Competing for comic relief prize: The curtain swinging open at the start of the show to reveal the Boys' six-man backing band and ... the road crew, fumbling to clear the set for Nick, Brian, Kevin, Howie and A.J. Birthday-boy Howie being elevated on stage in an open red satin shirt and pants and launching into a striptease that wasn't lurid so much as it was lame. A.J.'s near-felonious shout-out to "all the sexy ladies in tha house." Eek. There were flashes of likability from Brian, who proved himself a trooper after undergoing heart surgery earlier this year. Undisputed star Nick -- once the tiny young one, he's shot up in the last year to become the tallest of the bunch -- chirped out a full-on power ballad. Everything else came off like a two-hour Chippendale's audition. Cut out the obnoxious amount of dramatic pauses, awkward between-song stumblings and constant calls of "Hellooo!!!" and "Wassup Taranto?" and they could have been out of there in 15 minutes.