A guy would have to be pretty insecure about his masculinity to deny that Dwayne “The Rock” Johnson has some pretty fabulous pectoral muscles.

And yet, are they strong enough that Johnson could bounce a berry off one of them in such a way that it would travel some distance? I doubt it.

If that sounds to you like a strange way to start a column, then you really need to read this column more often. Also, you probably haven’t seen the trailer for Johnson’s new 3-D movie “Journey 2: The Mysterious Island,” which opens nationwide on Friday.

In it, Johnson informs a young man seeking romantic advice that most, if not all, women are impressed by something he dubs “the ‘pec pop’ of love,” which is the rhythmic flexing of one’s (presumably) enormous pectorals. And then, by way of demonstration, he bounces a berry off his left pectoral with the force of a shuttlecock bouncing off a badminton racquet.

Given that the berry in the film is clearly computer-generated, we are forced ruefully to concede that Johnson’s pectorals would probably be incapable of a dazzling rally of volleys in a game of berry badminton. It’s not as if we needed more proof that today’s action heroes are less manly than the action heroes of old. Why, it seems like just yesterday that Chuck Norris was bouncing watermelons off his pectorals and Bruce Lee was doing the same to spiny bitter gourd without even getting scratched.

In truth, I know next to nothing about fruit-based displays of masculinity. What I do know is that this “pec pop” of Johnson’s is both the oddest use of 3-D and the worst romantic advice ever.

There’s a lot that is odd about “Journey 2: The Mysterious Island.” It is both a sequel to the 2008 big-screen version of Jules Verne’s “Journey to the Center of the Earth” and an adaptation of Verne’s book “The Mysterious Island.”

Because the plot of “Journey 2: The Mysterious Island” does not involve a trip to the center of the earth, Warner Bros. couldn’t very well call it “Journey to the Center of the Earth 2.” So the studio took the calculated risk of naming it “Journey 2” with the knowledge that at least a few moviegoers would confuse it with what Steve Perry’s rock band called itself after he left it for good in 1997.

As if this all weren’t perplexing enough, Verne’s original “The Mysterious Island” is a sequel, not to his “Journey to the Center of the Earth,” but to his “20,000 Leagues Under the Sea.”

Rumor has it that Captain Nemo and the Nautilus (the protagonist and submarine, respectively, from “20,000 Leagues”) both loom large in the plot of “Journey 2: The Mysterious Island,” as do elements culled from Robert Louis Stevenson’s “Treasure Island” and Jonathan Swift’s “Gulliver’s Travels.”

Clearly, Warner Bros. is hoping that youthful viewers of “Journey 2: The Mysterious Island” will go back and discover for themselves the thrill of adventure books – the thrill of visiting faraway lands; of encountering exotic creatures; and of learning that adventure books published before 1923 in the United States are considered in the public domain and can therefore be used with impunity and without remuneration by movie studios.

Whatever happens with big-screen adaptations of adventure books going forward, it is important for movie studios to keep one thing in mind: More than two-thirds of moviegoers surveyed in my imagination say they have a strong interest in seeing Captain Nemo “pec pop” a giant squid.