The fallacy of extrapolating from professional athletes

The fallacy of extrapolating observations from professional atheletes to make observations about populations / individuals in general seems to be very common, including here on the Dope. It’s a subset of the general fallacy of extrapolation, but it’s a subset that seems to catch a lot of people out.
These are some recent examples:

  1. Weightlifting is not good for building muscle mass because champion weight-lifters look chubby
  2. A woman is very unlikely to beat a man at tennis; the Venus sisters lost a doubles game to the 245th ranked men’s team!
  3. A chess player is unlikely to increase in rating after age 30; most of the greatest players peaked in their 20s
  4. There’s no way you can run further than that guy; he’s from East Africa!

Of the four examples, I think most people would reject (4), partly because it would ping their racist-dar. But many people would agree with the logic in the others.

I think the critical difference that people don’t get is that, at the semi-pro level and below, the degree to which someone has practiced / studied is often the deciding factor.
At the professional level though, you need to “max out” all the factors, certainly the thousands of hours of practice, and then on top of that even something which only gives a 1% advantage suddenly becomes crucial.
For the bodybuilding one specifically, some degree of “padding” seems to give some advantage when lifting ultra heavy weights (seems jury is still out on exactly why). But there’s no doubt that weight training in general will help to build muscle mass while not increasing bodyfat.

NB: 1 and 2 are paraphrased from the Dope, 3 and 4 were seen elsewhere

It is a fallacy of hasty generalization to say that such extrapolation is very common based on two (unlinked) posts in the SDMB and two “elsewhere” examples.

There is a saying that, if you are learning the game of golf and trying to construct your personal approach to the game, you should NOT watch the pros for pointers. In my personal experience, I have found that to be very true.

Pros can do things that “weekend warriors” can’t. For example, they hit very long drives in the neighborhood of 300 yards with regularity, and they have the skill to get altitude and bite on long irons, so they can shoot for greens in two, an approach that someone like me would be foolhardy to emulate.

So, for example, on a par 5, if I “extrapolate” from the pros and go for broke, I can easily “blow up” the hole and shoot an 8. On the other hand, if I hit a solid drive (250), two fairway woods, and a short iron I can get some altitude and backspin on, I have a chance to be near the hole and two-put for a bogie 6.

If I had said that they were the *only *examples that would be a fair comment. But I didn’t, in fact I said recent examples, implying this is just a sample.

I ain’t touching nbr. 4 with a 10 foot pole, and I know next to nothing about chess, so I will leave those alone.

#2 - People don’t think women can’t beat men because the Williams sisters lost to the 203-ranked man in straight sets. They think women can’t beat men because, well, women almost never beat men in tennis. That’s not an extrapolation from pro sports; it is an observation from ordinary experience. The point of the Williams anecdote is to show that the difference is extreme - even female players who are close to being all-time greats can be beat by men who are nowhere near being all-time greats. That goes all the way down from the super-elite down to the club level - any woman at any level is going to have hundreds of men who can beat her.

#1 - Bodybuilding != Olympic lifting != powerlifting. Heavyweight and superheavyweight lifters have higher fat levels, especially for supers (men and women). That’s because there is no weight limit, and therefore no need to experience the nearly inescapable loss of muscle mass that comes with fat loss. It is nearly impossible to lose only fat. Lifters, power- or Olympic, at the lower classes are a lot more lean than the supers.

I have never heard from anyone who doubted that weight training in general will not build muscle mass.

If you gain weight, weight training will maximize the amount of muscle mass that you gain, although gaining at least some fat is almost inevitable. Bodybuilders tend to gain weight (muscle and some fat) in the off-season, and then diet down (thus losing fat and some muscle) while continuing to lift to maximize one and minimize the other. Plus the top bodybuilders tend to be extreme mesomorphs - they are high in muscle mass by nature. They also take a lot of anabolics, which affects muscle metabolism.


I think the reason people extrapolate from professional sports is largely because they are visible, easily-cited examples. Millions of people watch the Olympics, Super Bowl, NBA Finals, Wimbledon, etc. The videos are on YouTube, the sports outcomes are all readily accessible on Google, etc. So if someone wants to argue that women can’t cut it with men in tennis or that black athletes run naturally faster than white athletes, they can just say, “Well, look at (the Super Bowl, Venus losing to a 245-th ranked man, Usain Bolt,)” etc.

Women cyclists competing at the top level are noticeably slower than the top men (rule-proving exception noted), but damm, some of those women on my favourite bike route brush me aside like I wasn’t there. Sadly these are exactly the type of women I would like to impress :frowning:

You said this extrapolation “seems to be very common.” It certainly happens but I question how common it is.

Can you link to #1? I missed that post and I’m betting that’s not what was said at all.

You’re taking #2 out of context:

The second statement in #3 may be a fact supporting the first statement, but the first statement may have been made independently of the second part. It may have been said because there is evidence that a chess player is unlikely to increase in rating after age 30 (assuming the person making the claim was speaking of players that took up the game much earlier than 30). Your fourth statement isn’t even regarding professional athletes.

Without cites, how can we be sure this is a common fallacy?

I’m not sure if I’ve ever heard that, but I have heard people incorrectly say if you stop lifting weights, the muscle will turn to fat. But most regular people do weightlifting for aesthetic reasons anyway. They want to look good by having the muscles show, so they also want to minimize their body fat so their muscles aren’t hidden. It is challenging to lose fat while lifting weights. You need to eat enough calories and nutrition to support muscle development, but not so much that it gets converted to fat.

I guess they are fallacies if you use them that way. I’m not sure that I’ve ever heard anyone say #1, but if they have I guess it’s a fallacy.

#2 is generally worded more like ‘Men are better than women in tennis.’ and that’s true as a whole. I don’t think that anyone is under the illusion that Stephen Hawking-God(or lack thereof) rest his soul could have beaten Serena Williams at tennis simply by nature of his gender, but it’s more like saying that if I am the 1 billionth best male tennis player in the world, I will beat the 1 billionth best female tennis player in the world. It’s also a recognition that it’s not really a fair competition for random man to play random woman in most sports. It’s not saying that every man would beat every woman. An example is that my son runs middle school cross country. His time is fine, he ran about the 20th best sixth grade boy’s time at his last meet, but he would beat every sixth grade girl but two and there are more girl runners than boy runners, so it’s not an issue of girls not running. The fastest girl’s time (and she was smoking the other girls) would have come in 10th in the boy’s race. In a similar vein, in my son’s soccer club, there is a girl that is very skilled and can easily keep up with him. The other 20 girls are not even close (well, one of them is close. There’s a big drop off after her.) There are plenty of boys that can keep up with him though. There’s a fundamental fairness imbalance that gets even more pronounced after puberty and it’s one that needs to be addressed (typically by having boys compete against boys and girls against girls). There’s a reason that boys vs girls sports exhibitions are rare. They just aren’t fun for anyone due to real strength and speed imbalances.

Number 3 I’m not sure about. I think that we all know that our absolute peak is in our twenties, but I think that we also know that most of us weren’t performing at our peak then, nor are we now. I know that no matter how hard I train, I’ll never be as good as I possibly could have been when I was 23. This body and brain don’t work that way anymore. To be honest, I’m not entirely sure that even with training I could ever beat my 23 year old self, but I do know that I can get better than I am now. I think that’s not really due to looking at top players, but just feeling our bodies and brains and remembering what they used to do.

Number 4 is I think something said more in jest. I think that most people recognize that not all East Africans are long distance runners (really, they only tend to come from Nandi in Kenya and a few provinces in Ethiopia.) I do think though that if you are entering a marathon and a bunch of East Africans are in it too, you’re probably screwed. Genetics do mean something and their training regimen is usually off the charts. If they’re racing in the west, it means they aren’t schlubs, so you should probably just assume you’ve lost.

I can only speak to #1, and I have to say that I’ve never heard anyone say that.

Now, people may think other things related to that, like “bodybuilders aren’t strong, their muscles are just for show,” but that’s a different issue. Strength is not the primary goal in bodybuilding- muscle size, symmetry, low body fat and appearance are. But the top pros are way stronger than most people. Just look at Ronnie Coleman doing dumbbell chest presses with 200 lbs. in each hand. But, if he wanted to be a champion powerlifter, he could (probably) be stronger than he was as a bodybuilder.

One that bothers me is “BMI is an invalid measure, because muscles weigh more than fat.” Sure, if you’re that Ronnie Coleman guy (180cm, 130kg) with a BMI of 40, it is pretty meaningless. I can guarantee that 99%+ of people with a BMI of 40 have a BMI that high because they are carrying 150 pounds of extra fat. (Yes, BMI isn’t perfect, but it was never meant to be. It is very simple to measure, and is predictive of many health outcomes.)

I deliberately chose not to link the other threads because I didn’t want this thread to be primarily arguing over the other threads, I wanted to discuss the fallacy itself.
If you’re skeptical that this kind of thing is a common phenomenon, fine. And bet away about whether #1 was real.

How so? It’s a thread about the likelihood of a woman / women beating a man in some game in general, and that can and does happen a lot.
I’ve seen it many times, for example, in badminton. Yes the top male badminton players will destroy the top female players. But below the professional level you’ll often see a more experienced woman face off against a man and win.

That claim would be false however. At the amateur level, chess ability is almost entirely a function of how much chess a person has studied. As long as you keep studying, you’ll keep improving.
Otherwise, what are we saying? That a player taking up the game for the first time at age 40, getting a rating of 800 cannot improve from there?

It doesn’t work like that at the professional level because every little advantage counts. Being young does seem to give some advantage, so the top players receive expert tuition to basically know everything humans know about chess while still in their infancy and then take a run at Grandmaster in their teens.

Many top marathon runners are from East Africa. It’s a similar (bad) extrapolation as the others.

  1. What does being chubby have to do with muscle mass? they are unrelated?

  2. Women are generally worse than men at athletics. That is why female world records tend to lag behind male records in a wide range of sports.

  3. No idea.

  4. It isn’t all east africans. It is a subset of Kenyans who produce a lot of high quality runners. I’m not sure as to the reasons why though, but there is something there.

Unrelated, but waist to height ratio is a way to measure the health effects of obesity that take into account muscle mass.

A waist 50% or less the size of your height is ideal (so a 72" man should have a 36" or smaller waist), and muscle mass isn’t really going to alter your waist size the way fat mass will.

From what I’ve seen this is a superior measure to BMI, but it is ever so slightly more difficult to measure, and waist circumference is not collected on most studies that aren’t specifically investigating obesity, while height and weight are collected for almost everything.

Back to the OP. These fallacies seem to generalize to the fallacy of extrapolating the tales of a distribution to the rest of the distribution. Even if a disproportionate number of the very best long distance runners are East African (for whatever reason), that doesn’t provide much information when comparing some random East African to some random non-East African.

Similarly with men versus women, but there is a big enough difference in mean strength that more than just the tails of the distribution of performance are shifted for strength related sports. I’m a pretty good skier. I might be better than 50% of the men (excluding beginners) and better than 60% of the women, but that still leaves lots and lots of women who are better skiers than I am.

To claim though that men are on average better athletes than women isn’t false.

This is probably a mix of both nature and nurture. Male sex hormones produce muscle mass for example. And men are rewarded for sports more than women (men make more money in sports, and get more status/sexual rewards than women for being great athletes).

Granted there are lots of women who are better athletes than men, but when looking at world records or professional sports, they usually have to segregate by gender and the male gender records are better than the female gender records.

Saying all men are better athletes than all women, or saying all east Africans are better runners than everyone else are false.

Saying that, on average, men are better athletes than women, or saying that on average the Kalenjin in Kenya are better runners than other groups are true.

It really comes down to nuances. I really don’t know anyone who is saying all men are automatically better at all sports than women. But on average, men are better athletes.

And women are, on average, better at obtaining education than men. Women earn 3 bachelor degrees for every 2 earned by men. That doesn’t mean all women are better educated than all men. But on average, women are better educated. Women also have higher voter turnout than men (about 53% of voters in the US are women). Again, doesn’t mean all women have higher voter turnout than all men.

I’m not sure you fully read the OP. I’m not claiming these observations are wrong WRT professionals, I am saying that extrapolating from professionals and making inferences about everyday situations is often flawed.

For example, let’s say you tell me about two people, Anne and Bob, who both compete professionally in competitive long-distance running. In this case, it’s very safe to guess that Bob is significantly quicker than Anne because at the top level there is indeed a gap between men and women.

But what about if you now tell me about Claire and David, who just run casually to stay slim? It’s still more likely that David is faster, of course, but I would not be willing to put much more money on it, as at the casual level there is considerable overlap between men and women. I recently took part in a 6km race, and the fastest woman ran it in 24 minutes, while the slowest man’s time was 55 minutes (FYI my time was 29 minutes, so I was soundly beaten by several women).
Extrapolating facts from Anne-Bob to Claire-David is what this thread is about.

I agree with your conclusions but I disagree it’s particularly common, at least among intelligent people. It’s simply a bad argument, as you say.