It's understandable that "The Smashing Machine," a new movie by Benny Safdie, might put you in mind of Darren Aronofsky's great 2008 film, "The Wrestler." Unfortunately, what it most strongly recalls about that movie is its rich emotional glow, and especially its poignant lead performance by Mickey Rourke. Compared to that earlier picture, this new one, also set in the world of professional grappling, feels skimpy and routine.

Which is not to say it has no heart of its own. Its star, Dwayne Johnson — the Hollywood action-comedy titan and onetime pro wrestler himself — has an appealing sweetness (he's even capable of a brief bout of weeping here); but he doesn't quite have the emotional range to draw us all the way into the movie. Part of the problem is the script, which was written by Benny Safdie with no input from his brother Josh (who codirected their breakout films "Good Time" and "Uncut Gems") or Ronald Bronstein (who cowrote both of those pictures). Despite the movie's genesis — it's a biopic based on the life of mixed martial arts champion Mark Kerr as laid out in a 2002 HBO documentary — the story is too anecdotal to generate sustained narrative energy.

It opens with a bang, though — with Kerr in the ring delivering a brutal knee to the face of an opponent, before proceeding to beat the man bloody (after which a referee moves in to ask, "Do you know who you are?"). We're back in the 1990s here — in the early days of (virtually) no-holds-barred "extreme wrestling," the sensational blend of wrestling, boxing, judo, jiu-jitsu and MuayThai (the kicks and leg sweeps of traditional Thai boxing) that has already spawned the Ultimate Fighting Championship circuit. The audience for this freewheeling combat is largely confined to Japan and Brazil, and Kerr, with his super-being physique (and un-Rock-like black hairpiece), is one of the sport's rising stars.

The need to pump air into this story takes us to Arizona to visit the desert home Mark shares with his gum-chewing girlfriend, Dawn Staples (Emily Blunt), and then to meet Mark "The Hammer" Coleman (personable MMA fighter Ryan Bader), his career-long wrestling pal. Blunt generates a believable blue-collar air as she navigates the increasing number of annoyances in her relationship with Kerr, who is irritated that she doesn't make his protein shakes quite right and isn't sufficiently attentive to his potted saguaro cactus (he wants it to look like the ones in the old Road Runner/Wile E. Coyote cartoons).

Mark and Dawn's squabbling ebbs and flows — we never get all the way down to the kernel of conflict in their union. We see at one point that Mark has a drug problem (painkillers, unsurprisingly), and at another that Dawn likes to party with her friends (margaritas) while Mark is struggling to straighten out. Can this soon-to-be marriage be saved?

Director Safdie has made some unusual choices in creating a movie about professional mayhem. A lot of the ring action is shot outside of the ropes (as opposed to right up in the battered faces of the contenders, in the manner of "Raging Bull"). And the score, by Belgian jazz composer Nala Sinephro (who briefly appears in one scene playing the national anthem on a pedal harp), is counterintuitively light and airy (and possibly, you may find, worth a download).

The movie naturally follows Kerr's pursuit of an MMA championship, but two hours is more time than it needs to tell that story. Especially at such an underpowered pace.

Photos courtesy of A24