I sense another reality show on the horizon…
The correct answer is no. You cannot do it.
Your best bet is to pick an event you like and start training for the senior olympics.
Can you name one? Because according to Wikipedia, a sport has to be played in 35 countries to be considered for competition by women and 50 countries for competition by men.
According to this site, there definitely is:
(Spelling errors are apparently not penalized.)
Do you thus believe that nearly any fairly fit person could win a medal? How then to account for the fact that in each Olympics only three do? Were the other competitors less than fairly fit? Did they typically practice for less than 5 years?
It seems valid to argue that a reasonably obscure sport like modern pentathlon offers a somewhat better chance. But not that a person of anything like average ability could realistically hope to win a medal (or even qualify to compete).
Or crash your car on purpose and try for the paralympics.
Only new sports, many old ones are grandfathered in.
Justin Irwin. His Observer Sport Monthly article about his quest and failure is online.
Does anyone know of a list of at the athletes at the most recent Winter and Summer Olympics and their ages? I’d be interested in knowing which are the sports for which being over age 50 isn’t a prohibitive bar to success. Three that I know of are shooting, equestrian, and curling, but there may be others (archery? fencing?)
Of course, even for these sports, I doubt that you can take them up at an advanced age and compete at an Olympic level, since you’d have the advantage of neither youth nor experience. I know for a fact that it’s damnably difficult to start curling in your forties.
“Normal” competitors are limited by money and time. Training for five events is both time-consuming and expensive, and presumably the “normals” have lives and obligations (family, jobs, school) unless they are lucky enough to score a sponsor somehow. It would be extremely rare to train for this sport since childhood unless you are quite wealthy. As I have repeatedly said, there is a chance it could be done, and success for the OP is dependent on unlimited funds and full-time training.
“Many successful pentathletes were late developers in sport and started with humble abilities in only one of the five disciplines. Time and persistence are often superior to talent alone and modern pentathlon rewards those who are prepared to stick to a goal.”
http://www.pentathlon.org.au/info/criteria.php
Wayne Channon just became somewhat famous in the dressage world. He bought a bunch of top of the line horses and trained with a very expensive big name trainer. He rode six horses a day every day with constant instruction for 6 years and I think he could qualify for the Olympics now. You only have four years and you would probably need four million dollars just for the horse flesh, that wouldn’t include any living/training expenses. Of course, you have to make it to the right shows at the right time with the right scores to qualify. But you might have a glimmer of hope in dressage if you have a TON of cash, a love of horses and a lot of Anti Monkey Butt Powder. http://www.antimonkeybutt.com/ 
But note that your quote is from a site whose aim is to increase MP participation in Australia - a much broader goal than training Olympic medalists (of which it appears Australia has never produced any). Thus “successful” does not here equate to “Olympic.”
Again, though I don’t know for sure I’m going to guess that the number of humans over 50 that have won an Olympic medal in MP - or any other sport - after just a few years of training is close to zero.
Can you name one? I’ve been looking at the Wikipedia list of Olympic sports, and I don’t see anything very obscure, although BMX biking might qualify, and nothing that appears to be grandfathered in. If they were going to grandfather anything, surely it would be croquet or tug-of-war, but they managed to eliminate both of those.
Or you could take an IQ text, deliberately botch the answers, and go for the Special Olympics.
Seriously, if the OP is willing to wait for the Winter Games, there’s the chance at getting a curling medal. Still, Olympic curlers aren’t the fat guys seen on Canadian television on Saturday afternoons; they’re usually young and quite athletic themselves, and many have been sliding granite since they were in kindergarten. You could try to change your citizenship to that of a country where there are curling facilities, but the number of active curlers is in the low hundreds or even tens; Australia, Israel, South Africa, and so on.
If the OP was quite small perhaps he could be a coxwain for a rowing team. AFAIK being a cox doesn’t require much physical aptitude (other than saying “stroke”).
Obviously it requires rowing know-how, but that could probably be picked up in 5 years.
The oldest medalist was 72 (shooting)
Brian
The two that I thought of were Team Handball and Field Hockey. Maybe they’re played in enough places, but at one time they were few nations that competed.
I have a guy working for me who is training for the winter Olympics. He’s ranked 17th ( I think) in the world for his particular sport, which happens to be one of the more crazy ones, and number 3 or 4 for the US team. He has some good experience and training.
He’s early 20’s, in great shape, very intelligent, and has one of those determined personalities. Good guy, good employee.
I’ll end up sponsoring him at some point, I am sure.
But how frickin’ cool is that?
Someone a couple posts up beat me to it, but I would also guess that your best - and perhaps only - chance would be as a coxswain. You don’t have to row, you just have to be light and have a voice that can carry a good twenty feet or so.
I’ve had several friends go to the winter and summer Olympics, one even won a silver. In many ways they are like all of the rest of us. But put them in their specialty and they just go to a different level. It’s scary how much better they are then us amateurs. When skiing, jumping, paddling with the rest of us they make it look effortless.
I still think that anyone who spent 10 hours a day, every day, for 4 years, practicing shooting, they would be an olympic caliber shooter. I dont think the question then is really, can a middle ager win a medal if they started training now, but can he dedicate himself so entirely to that purpose for 4 years. If you can, then that would make you a)more dedicated than the average shooting olympian, and therefore b) certainly capable of winning a medal.
So your thesis is that talent and aptitude have little to do with skill - all that really matters is practice (and presumably coaching).
It’s possible, but IMO unlikely. I used to be a fairly serious about pistol competition, and it was common to meet dedicated, long-time participants who had “plateaued” - they weren’t all that great, and never got better despite their (in some cases extensive) practice. My experience in other forms of competition bears this out - practice is important, but has only a limited ability to make up for a lack of talent.