Elite Swimmers Share Same Ideal BMI Across Different Race Distances

For years its has been known that in running, different distances favor different body types. Sprinters are generally more powerfully built and thus have a higher BMI, while distance runners are generally thinner and smaller and have a lower BMI. This is due to the tradeoff between weight and power in land athletes. Stronger athletes generally weigh more due their larger muscle masses, which in turn, requires more strength to move quickly. Larger muscles also require more oxygen transport.

Whether a similar tradeoff exists in swimming has long been unclear. Drag, not weight, is the primary limitation on the speed of swimmers. According to a new study (paywall) published by Christian M. Gagnon, Michael E. Steiper, and Herman Pontzer of CUNY, swimmers face no such tradeoff between body mass index, or BMI, and endurance. The study, published in Proceeding of the Royal Society B, examined swimmers who completed in the London Olympics in 2012. They showed that swimmers competing there did not have statistically different BMIs across a wide range of events, from the 50m to the 10,000m open water competition. The BMIs of most swimmers completing in London fell within a fairly narrow range – 22-24 for the men and 20-22 for the women. The study also looked at the height and weight of swimmers across various distances and found insignificant differences in each for both genders. Runners, in comparison, get significantly smaller and lighter the longer the distance they compete in.

Only freestyle events were considered here, so whether there may be differences in ideal body types for different stokes was not looked at. Also unknown is whether elite swimmers have these body types naturally or whether intense training causes swimmers to naturally converge to a single body type.

BMI is just a ratio of a person’s weight to the square of their height, so does not take into account other body factors such as body fat percentage. It remains to be seen whether sprinters exhibit any other body types differences compared to endurance swimmers. Another recent study (paywall) in the Scandinavian Journal of Medicine & Science in Sports by Bex et. al. showed that endurance swimmers tend to have a higher concentration of slow twitch muscle fibers as compared to sprinters. Unlike BMI, slow-twitch muscle fiber composition is something which is measurable without special equipment and techniques, proton magnetic resonance spectroscopy in this case.

Based off of the study, it certainly isn’t advisable for coaches to pigeonhole swimmers into certain events or distances based on body type alone. Certainly however, much work remains to be done to find what sort of biomechanical or body-type tradeoffs exists for swimming speed vs. endurance.

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CraigH

It’s interesting that the women tended to have lower BMI than the men, although this difference is probably due to increased muscle mass on the men, I’d imagine.

Tarzan

Correct observation craigh!💪🏊‍♂️🏊‍♀️

GSWIMMER

Women typically have higher body fat % over men, maybe thats what you are thinking about. Body mass index is just a height to weight ratio that doesnt consider fat so men should have high due to significantly more muscle

James

It is very interesting. Especially since many unfortunate historical standards have found male swimmers to have a very “idealized” V shape (larger shoulders/chest, small waist) while female swimmers in particular have been stigmatized for having what amounts to a similar type build.

It would also be interesting to compare it to slightly more recent but historical swimmers. For instance, take someone like Caeleb Dressel versus a Matt Biondi. At least visually, Biondi had a much “softer” physique versus what might simply be referred to as the “jacked” physique of Dressel. Perhaps a greater concentration on land and gym based training to supplement to pool work.

anonymous

Breaststrokers tend to be more stocky. Just from what I see, particulary guys.

Similar BMI’s from Biondi and Dressel, however BMI says nothing about body fat vs muscle.
Matt Biondi was 6’6.5″, 209 lbs BMI 23.8
Caeleb Dressel is 6’3″, 190 lbs BMI 23.6

Lpman

Maybe the Olympics are discriminating against athletes with BMIs over 30

AfterShock

That’s why Sumo wrestling isn’t an Olympic sport.

M Palota

It’d be interesting to see the BMI for weight lifters and athletes in the throwing sports. I’d bet their BMI’s are pushing 30.

Male weight lifters in Rio had an average BMI of 29.3, 38% had a BMI greater than 30.
Female weightlifters in Rio had an average BMI of 26.3, 16% had a BMI greater than 30.

beverly drangus

Would be interesting to see the stats when the superheavy weight classes are excluded. The weight classes with a weight maximum tend to look slimmer.

Camp2

Am I the only one who thinks BMI is a useless way to measure a body type?

EX QUAKER

I don’t know how many doctors told me, based on my body type, that I was overweight with my 27.0 BMI… this is while I was training. I’m a stocky guy; 6’2″ 210lb while maintaining a body fat percentage of 7%. Yes, I agree that BMI is useless.

Replyleaver

@EX QUAKER unless you’re a bodybuilder, your fat percentage is probably not 7 and you’re really just chubby..

BMI is useless in discussions of health and ‘weight targets.’ However, when discussing concepts such as the forces of drag and friction exerted upon the human body, as is the case in this study, it is valuable.

Drewbrewsbeer

Negligibly better than useless

BMI’s biggest flaw is not differentiating between weight from fat and muscle. Pretty much anyone who is swimming or running at the Olympics has a really low body fat percentage, so that is kind of a non issue for this data set.

Mr G

Really!

Someone that is 65 inches tall with a BMI of 23 does *not* have the same body type as some that is 75 inches tall with a BMI of 23.

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