The news that Arnold Schwarzenegger has signed up for a new action movie after completing a role in the second Expendables brings one very obvious question to the fore: When does someone get too old to be an action-movie star?

Schwarzenegger's signed on for Black Sands, a movie in which he plays a loner (of course) who makes a stand against a "ruthless weapons manufacturer," according to Deadline Hollywood (I'd ask if there is any other kind of weapons manufacturer, but then I remember that there is, but they all become Iron Man in the end), which will begin shooting in April next year - at which point, he'll be 64 years old. Of course, he's not alone in this: Sylvester Stallone is 65, and he managed to sell his role in the original Expendables without too much trouble.

(Bruce Willis has also signed on for another Die Hard, but he's a baby compared with these two, at 56 years old. He's got at least another eight or nine years of wondering how the same [expletive deleted] can happen to the same guy five, six or seven times depending on how successful the next movie is.)

Even so, there's something slightly worrying about the idea of men at the age of retirement being the ones saving the world from corrupt businessmen, crime lords and whatever other dangers populate the underworld these days; I'll be the first to admit that either Stallone or Schwarzenegger could crush me without breaking a sweat - possibly without even noticing, for that matter; I know how small and breakable I am - but still... Shouldn't they be at the very most making the cameo appearances to get the fanboys all excited while other, younger people do most of the heavy lifting?

I admit, I kind of thought that was the point of the original Expendables; have Stallone be there, but give the majority of the action to Jason Statham, Jet Li, Steve Austen et al in some kind of subtle passing of the torch moment. But seeing Arnold take the lead in this new movie just seems... depressing, almost, in all manner of ways. I get that he wants to keep making movies, but is there really no other kind of movie he could go for at his age? No-one wants to see Twins 2: Quadruplets? No Kindergarten Cop 2: College Days? I know that action movies aren't the most logical of beasts in the first place, but it'll really seem ridiculous to see a man in his mid-60s continually get the better of guys half his age with the only reason seemingly "being evil makes you slower and weaker."

Not only that, but Schwarzenegger and Stallone doing these movies - and even the younger-but-not-that-much-younger Willis, for that matter - just feels cruel to the Stathams or Vin Diesels of the world; it's as if it's a reminder that, even twenty years on, cinema hasn't managed to produce any bigger action stars, and so these guys just have to come back to save the day. It's unfair, considering that the focus of action movies has shifted from the personality to the gimmick, the stunt or the catchy tagline; Arnold, Sly and the like may still seem bigger today, but it's because, when they were around, the movies were just so much smaller around them and they had to shoulder more of the weight.

Maybe I'm alone in this; perhaps everyone else in the world wants to see men in their mid-60s shoot everything that moves, kick butt and grimace in between delivering one-liners carefully designed for maximum repetition by fans for years afterwards, as if that somehow makes everyone watching feel more secure in their own aging and less worried about their own mortality. But, for me, it just seems... undignified, perhaps? Or perhaps just kind of sad. I understand that not everyone is built to grow old gracefully, but I find myself wishing that some people could at least do it a little less explosively.