Branch Warren in “Generation Iron.” (The Vladar Company)

Bodybuilders are a peculiar bunch. They’re extraordinary physical specimens, driven to sculpt their legs, biceps, shoulders and glutes into chiseled masses of impenetrable muscle. Point a camera at them, though — as writer-director Vlad Yudin does for the engaging documentary “Generation Iron” — and these intimidating mountains of taut flesh reveal themselves to be charismatic, funny, passionate and totally aware of the unusual nature of their chosen lifestyles. As narrator Mickey Rourke puts it, “They’re in a freak show, with no circus tent to hide away in.”

Yudin’s film is a direct relative of the 1977 hit “Pumping Iron,” which introduced mainstream audiences to the Mr. Olympia bodybuilding competition and helped transform Arnold Schwarzenegger into a household name. The former “Governator” is one of many professionals — from competitors and trainers to judges — profiled by Yudin as he captures the pain and gain associated with bodybuilding in 2013.

Not much has changed. The science behind rigorous weight training has advanced over the years. Controversial supplements and steroids, which are candidly discussed in Yudin’s film, play a larger part in the development of competitive bodybuilders.

But the men showcased in “Generation Iron” still mirror the aggressive, athletic protagonists we’re accustomed to seeing in fictional and nonfiction sports features. They are relentless competitors, consumed by their desire to succeed at their chosen sport. They accept no shortcuts. That’s why they are the best of the best at what they do.

That’s also why “Generation Iron” succeeds where other rote sports docs often struggle. Instead of clinging to clichés, Yudin wisely uses the inherent eccentricities of the bodybuilding community to help distance his film from convention. These are colorful characters populating the gyms and global competitions filmed for “Iron,” and they have fascinating stories.

Phil Heath, nicknamed “The Gift,” is a self-confident competitor who understands the show-business aspects of this industry. Kai Greene, meanwhile, comes from an underprivileged background, and his constant personal battles outside the bodybuilding competition have made him hungry for success. And then there’s Sibil Peeters, a senior trainer whose various nicknames include “Grandma” and “The Trainer From Hell.” ESPN Films ought to greenlight a “30 for 30” documentary dedicated to her story as soon as possible.

Ironically, there is fat to trim from Yudin’s enlightening doc. By choosing to focus on seven men in the 2012 Mr. Olympia competition, “Iron” occasionally repeats its points; these men take similar steps down the path to victory. But “Iron” opens a window to an exclusive club and gives valuable insight into a small, dedicated and proudly unique community. Now excuse me while I push away from this laptop and head to the gym.

O’Connel is a freelance writer.


PG-13. At AMC Hoffman Center 22. Contains thematic material and brief strong language.
106 minutes.