T Nation

Why Winning Athletes Are Getting Bigger



ScienceDaily (July 19, 2009) â?? While watching swimmers line up during the 2008 Olympic Games in Beijing, former Olympic swimmer and NBC Sports commentator Rowdy Gaines quipped that swimmers keep getting bigger, with the shortest one in the current race towering over the average spectator.

What may have been seen as an off-hand remark turns out to illustrate a trend in human development -- elite athletes are getting bigger and bigger.

What Gaines did not know was that a new theory by Duke University engineers has indeed showed that not only have Olympic swimmers and sprinters gotten bigger and faster over the past 100 years, but they have grown at a much faster rate than the normal population.

Furthermore, the researchers said, this pattern of growth can be predicted by the constructal theory, a Duke-inspired theory of design in nature that explains such diverse phenomena as river basin formation and the capillary structure of tree branches and roots.

In a new analysis, Jordan Charles, an engineering student who graduated this spring, collected the heights and weights of the fastest swimmers (100 meters) and sprinters (100 meters) for world record winners since 1900. He then correlated the size growth of these athletes with their winning times.

"The trends revealed by our analysis suggest that speed records will continue to be dominated by heavier and taller athletes," said Charles, who worked with senior author Adrian Bejan, engineering professor who came up with the constructal theory 13 years ago. The results of their analysis were published online in the Journal of Experimental Biology. "We believe that this is due to the constructal rules of animal locomotion and not the contemporary increase in the average size of humans."

Specifically, while the average human has gained about 1.9 inches in height since 1900, Charles' research showed that the fastest swimmers have grown 4.5 inches and the swiftest runners have grown 6.4 inches.

The theoretical rules of animal locomotion generally state that larger animals should move faster than smaller animals. In his contructal theory, Bejan linked all three forms of animal locomotion -- running, swimming and flying. Bejan argues that the three forms of locomotion involve two basic forces: lifting weight vertically and overcoming drag horizontally. Therefore, they can be described by the same mathematical formulas.

Using these insights, the researchers can predict running speeds during the Greek or Roman empires, for example. In those days, obviously, time was not kept.

"In antiquity, body weights were roughly 70 percent less than they are today," Charles said. "Using our theory, a 100-meter dash that is won in 13 seconds would have taken about 14 seconds back then."

Charles, a varsity breaststroke swimmer during his time at Duke, said this new way of looking at locomotion and size validates a particular practice in swim training, though for a different reason. Swimmers are urged by their coaches to raise their body as far as they can out of the water with each stroke as a means of increasing their speed.

"It was thought that the swimmer would experience less friction drag in the air than in the water," Charles said. "However, when the body is higher above the water, it falls faster and more forward when it hits the water. The larger wave that occurs is faster and propels the body forward. A larger swimmer would get a heightened effect. Right advice, wrong reason."

In an almost whimsical corollary, the authors suggest that if athletes of all sizes are to compete in these kinds of events, weight classes might be needed.

"In the future, the fastest athletes can be predicted to be heavier and taller," Bejan said. "If the winners' podium is to include athletes of all sizes, then speed competitions might have to be divided into weight categories. Larger athletes lift, push and punch harder than smaller athletes, and this led to the establishment of weight classes in certain sports, like boxing, wrestling or weight-lifting.


Makes sense. Bigger people will have the advantage of longer limbs but have the disadvantage of a lower strength to weight ratio. With the improvements in strength training, I could see the disadvantage being reduced somewhat and a new taller "sweet spot" of heights were people tend to be fastest.


Don't agree fully.

I believe there is going to be sweet spots for speed. There are tall fast and short sprinters, but most of them are actually short. With the sprinters the longer limbed guys have a disadvantage of not being able to have as quick "turnover" as the shorter guys, but the shorter guys have to have quicker "turnover" than the taller guys to win. It balances out, still shorter sprinters are winning. Also the weights are in the range of 165-210lbs. 180-200 lbs would be a 6 ft guy where 165-185 would be a 5'9" guy which is a common height.

If your too heavy your not going to be as fast, and there is a "too much" bulk issue at some point.

On swimming I can't comment. I would tend to believe its going to be boyancy vs drag, and also power is going to make a difference.

Have any of you thought of this?

What if the running forms, or ball throwing forms that are "optimal" today - can be exceeded by a large margin by a "strange" form, like Michael Johnson blowing out the 200m world record by a huge margin with a "strange" and "inefficient" form according to all the old models.

I personally believe each body type has a optimal running form, however if you mentally have to focus on it at the expense of power and speed your going to be slower.

Just some tangents to discuss on this thread.


Where were all these super fast short guys in the olympics?


so now there will be height/weight classes in gymnastics too? sheez, when will we all finally accept that we arent all able to be the best at everything...




I'm not sure what you disagree with? The study is merely reporting facts about the average height of sprinters. What can you disagree with?


I agree with this article and this especially relates to hockey and even more to hockey goaltenders. Even look at a recent draft where Zach Parise who was rated to be a top 10 player was drafted 17th overall, with no other reason then he was undersized. NHL goaltenders are also getting bigger and bigger and the days of a goalie under 5'10 are starting to disappear, even though somebody as accomplished as Jeff Lerg (5'6) might have played great all his career he still won't likely get a sniff in the show because of his height.

In 2000 the average NHL goaltender height of the draft was 72.58, in 2004 it was 73.32 and this year it was around 74 inches, it took 132 picks for the first goaltender to get selected under 6' and no goaltender was selected under 5'11. You don't need to be tall to be good at any sport, but it sure does help.


From swimming at a national level I can say that this is true to some extent. This primarily applies to sprinters, but even then there are some exceptions. One of the most well known swimmers that i swam with was around 6'5 and under 190lbs easily.Broke couple records in age group as well as the high school sectional.

Technique plays a huge role, but when you come to a level of the sport, like the olympics, in the finals, everyone's technique is so perfect they dont look to fix their technique but rather to find new ways of getting faster. At that point everything matters, especially the human body. That being said big guys will have a definite advantage, but I do not think that it will become so distinct that there will be a need for weight classes.

Swimming strokes like butterfly and breastroke especially have only been around for some time so the advances in the stroke have been tremendous. Also Freestyle, there are different ways to sprint now, "aussie crawl" or straight arm, the list goes on.


"Airtruth" - Usain Bolt at what 6'6" was an anomoly. They are mostly under 6' and this has been the way it always has been. I'm over 6', so under 6' I'd call "short".


holy shit, bejan made it onto T-Nation. lol this is great, i'm getting a huge kick out of this.

this guy is going crazy applying constructal theory to everything in nature and engineering. although i find his enthusiasm amusing, the theory is very interesting. www.constructal.org is his outlet for all papers constructal.

also, for anyone interested in nature and engineering, shape and structure, from engineering to nature is a pretty thought provoking book. definitely inspired me enough to jump into the ME PhD program with an idea.


here's the actual paper, instead of the hand-wavy press release:


actually the paper is also pretty hand-wavy. also, i don't like too many correlations coefficients and fitted lines on principle. it's an entertaining paper at the least.

they found the "slenderness" and "mass" of record holding athletes are slowly increasing over time. they tried to make a correlation between mass and slenderness that would imply more massive swimmers are less slender and more massive sprinters more slender, but admitted the correlation was not significant. they also took the body density to be constant, which doesn't account for body comp. who knows if it would make a difference.


So as athletics becomes more competitive, the bigger, stronger athletes are the ones winning??





Anomalies in this sense(an outlier but not some freakishly different one, like a midget or something) become trends in elite levels of athletics.


Growth hormone is a helluva drug.


I completely agree, it makes sense that a larger person has the ability to move faster. Think of a giant, say 100 feet tall, there is little chance that youll be faster than he is. Now continue that analogy down to say 10 feet tall, he should still have an advantage and a large one at that. Now continue that down to say comparing a guy 5'6" to a guy 6'6", the taller guy, imo will have an advantage. I think the reason it is only presenting itself recently is because of the advances in strength training to get the taller athlete to have the same body shape as the short stalkier guy. Naturally the shorter guys often have better leverage and naturally carry more muscle, but now that we can get the taller person to the same level they have the advantage.


When it comes to locomotion, tall people have BETTER leverages. Short people have better leverages for lifting heavy weights but it has the opposite effect for running.

The problem is that tall (or more accurately large) people will not be as strong relative to their mass as smaller people. Keep in mind that strong is not necessarily the same as lifting a heavy weight. A stronger person with bad levers (for powerlifting, which likely mean good levers for moving around) may lift less than a weaker person with good levers.

This site gives a good explaination:
search for "Scaling Problems".

The short story is that if you increase an animals size by a factor of 2, the mass increases by 2^3 or by a factor of 8 (the relationship is cubic) but the cross-sectional area of the muscles increases only by a factor of 2^2 or 4. Thus, while absolute strength increases, strength to weight decreases. Its also why large animals like horses cannot have a leg amputated while a smaller animal like a dog can. The horse's mass is much greater relative to the cross sectional area of its bones and thus needs every leg to support its mass. Its also why ants can carry 40x their body weight. If they were the size of people, they wouldn't be any stronger than we are (and in fact likely MUCH weaker).

The strength to weight ratio has always offset the advantage a taller person gets from the longer limbs. This is true for every species where there is a happy "sweet spot" were the best performance is obtained. However, with improvements to strength training, I could see how this sweet spot could move in favour of taller people.


Umm...6'5" Usain Bolt?


Michael Johnson would have to have better turnover than him due to shorter "levers" for example. The other factor mentioned was strength to weight. a 5'10" 190 lb sprinter is going to have more muscle and power than a 6'4" 190lb sprinter for example.

Most obvious thing that "T-Nation" has reinforced to me is any argument can be won no matter if its wrong.