I have never read a Batman comic. Everything I know about him is from movies, cartoons and online culture.
Disregarding his ability to recover in the long term from injuries that would probably cripple a person, how plausible is his athletic prowess? I don’t care what continuity, edition, or media is involved.
I’m not really a big reader of the comics, but I’ll just say this: What is presented in Batman Begins (and to a lesser extent, Dark Night) is said by fans to be one of the most realistic he’s ever been portrayed.
I’ll leave the real fans to decide if this is based on fact, and to what degree.
Someone actually wrote an entire book addressing this specific question. Look up Becoming Batman: The Possibility of a Superhero by E. Paul Zehr.
Well, ignoring the injury aspect is what makes it unrealistic in the first place. Look at pro wrestling. That is completely choreographed, and yet the pain pill dependency, head injuries and other results of such daily physical abuse lead to an incredibly diminished life expectancy.
Now imagine doing that for real. I don’t care how great a shape you are in, or how trained a fighter you are. After a couple of years, you would be physically broken.
There are two questions: short term and long term.
Short term: The more restrained portrayals seem credible for a peak-conditioned and trained athlete.
Long term: As noted above, injuries and pushing one’s limits add up over time.
Same with professional sports athletes, like those in (American) football. Retired by their late thirties, bad knees, bad back, etc. And they wear pads.
He’s not wearing hockey pads!
Who? Batman? No, I don’t think he is… 
Justin’s riffing on a line from Dark Knight.
Sometimes Batman is portrayed realistically in terms of physical capabilities, often times… less so. Just like every action hero ever.
Ah. I’m so easy to woosh. Is there a support group for people like me?
Another thing to keep in mind is he’s had to train to build his strength, endurance, dexterity, etc, as well as learn to fight, and all his other skills.
Including his mental skills - he’s the world’s greatest detective, an expert on damn near everything, an expert strategist and tactician…
And, depending which writer you ask, he started either in his late teens or mid-20s, and has only been going at it for ~10 years.
So, it defies all definitions of realism, just by the ‘where the HELL does he get the time’ angle.
So nobody else sees a giant cartoon “POW!” when they hit a guy?
Just me, then… great.
I’d say he’s a mutant, but Marvel’s lawyers might come after me.
I would say the most unrealistic thing he does is swing around. I just don’t see that happening in a real physics world.
Batman is armored (depending on continuity) and generally fights with surprise and against people much less skilled than him. I don’t have too much problem with his ability to one-shot thugs. I’m sure if Muhammed Ali (in his prime) rounded a corner as I was walking down the street he could knock me out without much fuss.
Aside from the swinging, the most unrealistic thing I can think of is his ability to dodge. I don’t doubt you can make yourself a hard target, use the shadows, etc. But eventually if a thousand guys take a shot at you, one is gonna connect by random chance.
I am only considering short term, as the long term ramifications seem clear.
I think the Watsonian answer for this is that his suit is bulletproof and more advanced than anything we have.
One of my favorite lines from “The Dark Knight Returns” comes as Batman is shot in the dead center of the yellow logo on his chest. He thinks to himself:
…MAGNUM load has to be – Hits me like a freight train…
…Why do you think I wear a target on my chest – Can’t armor my HEAD…
For that matter, Batman’s about the only superhero I can think of for whom there’s a really excuse for wearing a cape. The bad guys tend to aim at the center of the cape, which is usually billowing away from his body.
The defensive purposes of a cape are also discussed in Watchmen. When he’s starting out, Nite Owl wears a cape because he’s seen fictional superheros (The Shadow, I think?) use it to throw off the aim of people shooting at them. He can’t do that trick himself and he decides the cape is slowing him down, so he stops using it. Of course there’s also a sort of amateur superhero who gets shot to death during a bank heist when his cape gets caught in a revolving door. So there’s one fictional superhero who thinks capes only work in fiction. I won’t go into The Incredibles.
A disillusioned Captain America (a) briefly called it quits in the wake of Watergate, but of course (b) couldn’t actually bring himself to stop fighting crime and saving lives even in 1974, and so tried to rebrand himself as a Batman-style vigilante relying on sheer damn athleticism; he promptly tripped over the cape while trying to bust a couple of crooks. So never mind whether that fictional superhero thinks they work; consider the fictional villain who saw it happen: “He tripped over his cape! I always knew I’d see someone do that someday!”
The Mythbusters did some tests and proved that it is physically impossible for a human being to dodge a bullet. And that’s just one bullet!
He used to do this thing where he’d be in freefall, whip out a Batarang with a nylon cord attached, and throw it hard enough to snag a building ledge to continue swinging. So, not very.
Properly written, there should be almost no fantasy elements in Batman. Of course, there are several now: the flying Batmobile, a functioning UFO and a tesseract to Pluto in the Batcave. His physical prowess is just one more unbelievable thing.