A growing-pain stage

Innocence is a fleeting thing in the world of teen and preteen pop -- remember how quickly Britney went from book bag to bustier? The Disney organization might try to keep a tighter leash on the process, preserving the wholesomeness of its stable of music and TV stars even as they near the treacherous shoals of young adulthood, but it can be tricky.

Case in point: “High School Musical: The Concert,” which played at the sold-out Honda Center in Anaheim on Friday and comes to Staples Center tonight. If the Disney folks have trouble translating the carefree charm of their popular 2006 TV movie to its stage version, you know it’s something more fragile than it appears.

The raw materials were certainly here. The songs from “High School Musical” form a compendium of throwback pop that perfectly captures the movie’s unreal but welcoming world of East High School, where the game-winning shot and the role-winning audition, not drugs and gang fights, are the issues that matter.

The music, from buoyant sunshine-pop to roof-raising soul celebrations, doesn’t sound calculated for commercial impact in today’s environment of hip-hop and synthetic pop, and the soundtrack CD becoming last year’s biggest-selling album was an encouraging surprise, as when kids select a cereal that’s actually good for them.

Taking it on the road as a concert made sense financially, both as a ticket-selling machine and as a promotional vehicle, but in beefing it up into something bigger than just a live reprise of the songs, something was lost, and “High School Musical” itself took a back seat to big-production showcases for three of the movie’s stars.

If Vanessa Hudgens and Ashley Tisdale were ideal schoolgirls a couple of years ago when the movie was made, they’re now young women, and their grown-up outfits and dance moves -- and the relatively generic nature of their own music -- removed their spotlight segments from the “HSM” spirit.

Corbin Bleu fared a little better, his own antic personality and rhythm-rooted music capturing a youthful exuberance that peaked in a drum corps-assisted blowout from his upcoming album.

One major no-show compounded the problem. Zac Efron, the movie’s leading man, is busy shooting a movie, and no one else could provide his element of upright earnestness. In fact, his replacement, Drew Seeley, looked and sounded a little too old and experienced, suggesting a college dude who hangs out with high-school kids. A little creepy, especially in his romantic duets with Hudgens.

Not that the concert ever became tawdry or unseemly. It just missed the essence of its premise. Tisdale and Hudgens actually seemed more like kids play-acting as adults (the former as a Gwen Stefani wannabe, the latter a Rihanna aspirant) than the real thing, and when they came back to earth from their big productions, they regained their appeal.

Lucas Grabeel, Tisdale’s smarmy brother Ryan in the movie, was the effusive if sometimes long-winded host of the 90-minute show, whose level of discourse was pitched for the littlest ones. The singers delivered declarations of gratitude to the fans for their support, and Grabeel got a loud response when he asked how many people were attending their first concert.

Somewhere between low-rent and Broadway-big, the production values were in line with the typical modern pop concert, with a six-member band giving things some live punch and the troupe of dancers (including cast member Monique Coleman, who also has made a mark on “Dancing With the Stars”) adding energy and spirit.

In any case, there may well be another chance to get it right. At the end, the stage backdrop proclaimed the perhaps inevitable words: “High School Musical 2 ... This summer.”

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‘High School Musical: The Concert’

Where: Staples Center, 1111 S. Figueroa Ave., Los Angeles

When: 7 tonight

Price: $38.50 to $58.50

Contact: (213) 742-7340