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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SwimmerFan99
4 years ago

Sprint Freestylers – Tall and Bulky
Long Distance Freestylers – Tall and Skinny

Sprint Backstrokers – Tall and Lean Muscle
Mid Backstrokers – Tall and Lean Muscle

Sprint Breastrokers – Short and Bulky
Mid Breastrokers – Medium/Tall and Lean Muscle

Sprint Flyers – Tall and Lean Muscle
Mid Flyers – Tons of Height Variation (short legs being a commonality), Lean Muscle

Luigi
4 years ago

Paltrinieri’s BMI is 19.74 😁

Pvdh
4 years ago

Dressel and Michael have the same exact upper body…

AfterShock
4 years ago

Since when is proton magnetic resonance spectroscopy not special equipment?

PNW
Reply to  AfterShock
4 years ago

I think they missed a “not” somewhere in the paragraph

science geek
Reply to  AfterShock
4 years ago

I know proton magnetic resonance spectroscopy isn’t a particle accelerator or zero point energy but I agree that that line was hilarious.

Potato Built Swimmer
4 years ago

Swimming is managed as a sport very differently from running. You don’t have sprinters typically start out in a distance runner group eventually allowing the runner to move over to sprint work because they have succeeded with the distance training. To the running world, this way of managing the sport would sound kind of crazy. Sprinters in the running world show aptitude for sprinting and do sprint training. Is that because of incremental force in running doesn’t have incremental resistance (air) like swimmings effect of drag (water)? Who knows if you can compare the sports but if you gate keep swimming with distance training, you will have a hard time keeping a higher BMI swimmer. Those rare athletes survive in… Read more »

Truth
4 years ago

What’s the average BMI of Coaches? Too high for sure.

Mike
Reply to  Truth
4 years ago

And let’s not even get started on officials.

Swack
Reply to  Truth
4 years ago

WORD

Yozhik
4 years ago

” swimmers face no such tradeoff between body mass index, or BMI, and endurance”
If it is a scientific like article it would be nice if all terms used be clearly defined. What is endurance? Is it a measurable factor? If it is so then what is the way to measure it. Is it the same as measuring tiredness. Or it has nothing to do with the common sense definition and is characterized by concentration of particular substances in the blood: oxygen, lactose or something else.

Admin
Reply to  Yozhik
4 years ago

I think in this case endurance is measured by “length of race competed in.”

JimSwim
Reply to  Yozhik
4 years ago

And it should say freestyle swimmers since the article only analyzed them

Camp2
4 years ago

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

Mr G
Reply to  Camp2
4 years ago

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.

Editor
Reply to  Camp2
4 years ago

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.

Drewbrewsbeer
Reply to  Camp2
4 years ago

Negligibly better than useless

EX QUAKER
Reply to  Camp2
4 years ago

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.

Admin
Reply to  EX QUAKER
4 years ago

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.

Replyleaver
Reply to  EX QUAKER
4 years ago

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