Zac Efron between The Rock and a hard place in 'Baywatch'

Renewable resources: Solar, wind, and Dwayne Johnson making fun of Zac Efron.

Baywatch operates on the assumption that we will never tire of hearing Johnson, atop his towering wall of weathered masculinity, belittle the pint-size Efron and his ab-obsessed vanity.

The assumption proves valid. A running joke calls for Johnson to refer to Efron as a boy band or boy toy (N Sync, One Dimension, Bieber) and it works virtually every time.

Efron is a good sport to put up with all of this, although most of the jokes actually come at the expense of Olympic swimming champ and nitwit Ryan Lochte, an obvious model for Efron’s character here.

Efron plays Matt, a narcissistic numbskull and disgraced gold-medal hotshot awarded a spot on the California lifeguard station run by Mitch (Johnson), who’s under orders to accept the new recruit on the grounds that the publicity will help with desperately needed fund-raising.

Their banter is the crux of this lazy but sometimes likable comedy, one with elbow room for supporting players – Jon Bass as a chubby nerd lifeguard and mercy hire who has a stuttering crush on an out-of-his league colleague (swimsuit model Kelly Rohrbach), and Hannibal Buress as a tech nerd.

No use making fun of the plot – it’s meant to be ridiculous, in the spirit of the TV show. An evil businesswoman (former Miss World Priyanka Chopra) is flooding the beach with drugs in order to drive down property values and facilitate her plan to privatize the bay and consolidate it under her ownership.

Nine writers have been credited with updating Baywatch for the 21st century, which in this case means making it raunchy. Baywatch, for all of its jiggle-show appeal, was a tame program, and too often this adaptation assumes that adding vulgarity for contrast is can’t-miss stuff. No matter how many times it misses.

Nobody here seems to know what to do with a PG joke. There’s a scene that calls for the Yoda-like appearance of original cast member David Hasselhoff, and you can feel the audience primed for a big laugh. You can also feel the disappointment when it becomes obvious the scene has been underimagined. Here’s the sort of scene that defines Baywatch: Efron in a morgue looking for evidence on a dead body and leaving no area unexamined. There is full frontal corpse nudity, which I mention in case you were thinking of making this a family outing.

Families have been a core constituency for Johnson and have fed into his good-guy image – so much so that one recent poll had him ranked ahead of other potential candidates in a 2020 presidential poll.

I don’t know about that, but as the man in charge of poking fun at millennial leading bros, hail to the chief.

MOVIE REVIEW

Baywatch

Directed by Seth Gordon. With Dwayne Johnson, Zac Efron, Priyanka Chopra, Kelly Rohrbach, Hannibal Buress. Distributed by Paramount.

Running time: 1 hour, 46 mins.

Parent's guide: R (nudity, language, crudeness).

Playing at: Area theaters.