MOVIE REVIEW : ‘THRASHIN’ ’: BREEZY TRIP TO NOWHERE

“Thrashin’ ” (citywide) is another fatally split movie--entertaining on the technological level, vacuous on the human one.

When it’s just roaring along through a kaleidoscope of Los Angeles locations, the camera perched behind, above or below the skateboarding heroes and villains, the movie can be fun. It’s shot in an extravagant, try-anything, music-video style. It’s rattlingly paced, vibrant and splashy.

Then we get to the story. Stop me if you’ve heard this one: Boy meets girl; boy loses girl; boy gets girl. Sound familiar? Try this for extra spice. Two warring teen-age gangs clash--the free-and-breezy Valley Guy “Ramp Locals” and the swaggering, black leather, bone-in-the-nose “Daggers.”

The Ramps are led by clean-cut hero Corey Webster (Josh Brolin), the Daggers by scowling Tommy Hook (Robert Rusler). Hook’s sister is heroine Chrissy (Pamela Gidley). Eventually, they rumble.

Then they have a cross-country skateboard race, shot from helicopters. Corey, his arm broken in the rumble, and Hook are the main contenders. Meanwhile, Chrissy--about to give up on everybody because they were behaving so badly (who can blame her?)--changes her mind. We get one more movie championship-or-race, with the heroine charging back to lend support and the hero bucking 100 to 1 odds in a hearts-and-guts try for last-minute victory. Does anyone want to take those odds?

Perhaps sensitive to charges of unoriginality, the “Thrashin’ ” press book explains that producer-writer Alan Sacks and co-writer Paul Brown laboriously constructed this tale from extensive investigations into the skateboarding milieu--during which they actually hopped on boards themselves--and took copious notes, scribbling down voluminous scraps of conversation (“Bizotic!” “Full Wilson!”).

Suddenly, to their complete amazement, they realized that this neo-realistically slanted research was turning into “West Side Story” on skateboards. Even more amazingly, the director of the film eventually turned out to be David Winters--who played “West Side Story’s” Arab on both stage and screen. Who says real life isn’t full of astonishing twists and coincidences?

Sacks’ last movie was the inventive, grimy little sleazoid “du-BEAT-e-o,” which had offbeat touches. But however this screenplay evolved--whether from real life, or TV, or if it was originally scribbled down on a cocktail napkin--it’s awful. If skateboarders really talk like this, they’ve been spending too much time looking at bad movies and not enough time skateboarding.

There are some saving graces, including most of the scenes that don’t depend on dialogue (about half the movie). Skateboarding is a genuinely photogenic sport--as Noel Black proved two decades ago in the more leisurely “Skaterdater”--and Winters frequently catches its fire and spirit. The movie often has a good, rapid, ragged, rip-along pace. Josh Richman--as a wisecracking crony of the hero--is amusing. As Chrissy, Gidley is cute.

As for Sacks and Brown, you only hope they didn’t get writer’s cramp while pulling air up there on their boards. Though it might have been better if they had, and their zesty young cast had just winged the entire movie.