Back when the original "Rocky" was released in 1976, Sylvester Stallone himself probably never thought he'd be playing the character 30 years later. "Requiem for a Heavyweight" and "Million Dollar Baby" aside, not too many movies about heavyweight boxers star senior citizens. But at least "Rocky Balboa" is about the fact that the sexagenarian Italian Stallion may well be too old to step back into the ring. Given Hollywood history, it wouldn't have been surprising if the sequel had completely skirted the issue of Stallone's age.

The issue of time is a fluid one in film franchises. While it may take years for a I to stretch into a II and beyond, the story being told rarely keeps step with production time. In character-based series like "Spider-Man," the characters are supposed to stay roughly the same age, while in something like "Harry Potter," the maturation of the protagonist is an integral part of the story. Einstein's theory of relativity has its place in movie franchises.

"Harry Potter" is unique in that at this point, the films practically piggyback J.K. Rowling's books, and the seventh installment is slated to be the final chapter of the young sorcerer's tale. Since the books follow through the school years and the movies come so quickly, the actors are able to remain age-appropriate to their characters. It's likely that at this point even Rowling herself sees the films' Harry, Daniel Radcliffe, as she's pounding at the keys.

But youth is adaptable, and even if it takes years to get the final "Harry Potter" film onscreen, many actors in their 20s can convincingly play both teens and more mature roles. As an actor passes through middle age, however, the suspension of disbelief can start to strain. Harrison Ford was in his late 30s when he first strapped on the whip and fedora to play Indiana Jones in 1981's "Raiders of the Lost Ark," which is the perfect age for the well-traveled yet spry archaeologist. It remained easy to buy Indy's derring-do in the film's two sequels, which were released over the next eight years, but the prospect of a 64-year-old Ford returning to the role in the long-delayed fourth installment is pushing it a bit. It's probably no coincidence that one of the film's working titles is "Indiana Jones and the Ravages of Time."

But what about when a character doesn't age, as in, say, James Bond? In Ian Fleming's original 1953 novel, "Casino Royale" (someone should make a movie out of that), the fledgling superspy is described as being in his mid-30s. Today, despite a more than 40-year history of films that outlasted the Cold War, 007 should still be about the same age. Of the six actors who have played the character in the series, George Lazenby was the youngest at 28. But "On Her Majesty's Secret Service" (1969) was his only stab at the role, so we never got to see him age into the character. Conversely, Bond number three, Roger Moore, was already 45 when he stepped into the role in 1973's "Live and Let Die." Moore would stick with the character for another six films, making him 58 when his final outing, "A View to a Kill," came out in 1985.

Obviously, Bond the character is not closing in on 60 in the film. But movie magic can only go so far, and Moore seems in need of more than just the usual Q gadgets to keep going. You can practically hear Bond's lumbago acting up as he battles Max Zorin (Christopher Walken) atop the Golden Gate Bridge. And faced with Stacey Sutton (Tanya Roberts), perhaps the least appealing Bond girl of them all, you have to wonder how 007 kept his reputation in those pre-Viagra days.

But James Bond the icon is bigger than any actor (even Sean Connery) who's played him. We can accept new faces behind the Walther PPK. But what happens when characters become so identified with their portrayers that their fans could never go for a replacement, no matter how long in the tooth the actors got?

What happens is "Star Trek V: The Final Frontier." The 1989 entry in the series (directed by Captain Kirk himself, William Shatner) finds the Enterprise hijacked by Spock's half brother, Sybok (Laurence Luckinbill), in order to breach an energy field known as "The Great Barrier" and reach the planet Sha Ka Ree, the home of ... wait for it ... God! In fact, "God" turns out to be an evil presence imprisoned on Sha Ka Ree eons ago, but maybe it would've been better if the crew of the Enterprise had met their maker in this awkward, embarrassing flick.

The movie is filled with ill-advised humor at the expense of the crew, almost all of whom were pushing or past retirement age by then. They creak through the movie under the constraints of girdles, wigs, caps and layers of wrinkle-concealing makeup. A mountain-climbing Kirk sports a T-shirt under his Starfleet uniform that says -- we kid you not -- "Go Climb a Rock," proving that Spencer Gifts still exists in the 23rd century. An overweight, doddering Scotty (James Doohan) actually bangs his head on a doorway and knocks himself out. Even the Enterprise itself, despite being a newly commissioned ship (to replace the one Kirk destroyed at the end of "Star Trek III: The Search for Spock") is buggy and clunky, perhaps an unintentional metaphor for the entire series?

The film was pilloried by the press (as well as the typically more forgiving fans) and the next film, "Star Trek VI: The Undiscovered Country" (1991), wisely brought a decommission to the original full crew of the Starship Enterprise. And yet it seems as if it took nothing less than the deaths of Doohan and DeForest Kelley (Dr. McCoy) to finally permit Paramount to recast the original characters in the upcoming reboot helmed by "Lost" creator J.J. Abrams.

Still, Hollywood is so youth-obsessed that there's probably some karmic balance in the fact that Steven Seagal, at a jowly 55, is still kicking butt and sporting ponytail in action films like this year's "Attack Force." OK, so it's a horrible, straight-to-video piece of product that doesn't add anything to the cultural landfill, but at least he's not a drain on society!

And there is something reassuring in the idea of Stallone returning to the role that made him a respected artist -- remember, "Rocky" won the Oscar for Best Picture -- even if that status was fleeting. It's easier to believe that Rocky Balboa could step back into the ring in his 60s than to believe that 23-year-old Kate Bosworth's Lois Lane is an established Pulitzer Prize-winning journalist with a 4-year-old kid in "Superman Returns." Just goes to show you, there are times when older is better.

Check out everything we've got on "Rocky Balboa."

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