Sprinting physiology: male vs female
August 9, 2011 10:24 AM   Subscribe

Why do male sprinters seem to tend towards quite a lot of upper body muscle while female sprinters tend towards being leaner?

Watching athletics with my SO and she suggested this was the case but neither of us could see a definitive reason why so thought I would ask the collective. Biology, advantage, fashion, vanity, other? (Yup, I was reminded by the current MeFi FPP.)
posted by biffa to Health & Fitness (13 answers total) 1 user marked this as a favorite
Do you mean why male sprinters carry more muscle mass? "Lean" usually implies body fat percentage--male sprinters have a very low body fat percentage, lower than their female counterparts.

Male sprinters carry more muscle mass than female sprinters because men have more testosterone then women, and thus build strength and muscle mass more readily. If you compared an average female sprinter to an average non-athletic woman, she'd be more muscular than her. But she's not going to have more muscularity than her sprinting male counterpart because she doesn't have the capacity to build that level of muscle mass without chemical assistance.
posted by schroedinger at 10:30 AM on August 9, 2011

Sexual dimorphism. Men tend to have, on average, 40-50% more upper body muscle mass than women.
posted by valkyryn at 10:34 AM on August 9, 2011

I can tell you from the female sprinters I've known at the college championship level that it is NOT fashion or vanity! I'm not sure if you've seen a female sprinter in person, but they are much, much more muscular than the female "ideal" or fashion. While they occasionally complained about finding cute clothes that fit right, they didn't build or not build muscle based on looks.
posted by the young rope-rider at 10:35 AM on August 9, 2011

Yup, I did mean more muscle mass. Obviously all are in good shape physically, but men seemed much more bulky. Do sprinters stay in the same ratio for muscle mass (ie the 40-50% mentioned above) as for the average person? If not, why not?
posted by biffa at 10:43 AM on August 9, 2011

It's easier for men to pack on muscle mass anywhere, including the upper body, over women. Elite women sprinters have more upper body muscle mass than elite women long distance runners.
posted by QuarterlyProphet at 10:50 AM on August 9, 2011

Psychological warfare. It really is not necessary to look like a bodybuilder above the waistline. But if you think it is important, and it looks good, than it becomes important. Sport is mind, as much as physical ability. Before a big final, the athletes have to be forty minutes in each other's company, waiting in the call room, before they are allowed on the track. You probably can win the race before it is run, by looking like nobody has anything on you.

The fastest sprinter of a non-west-African genetic background right now, the Frenchman Christophe Lemaitre, looks skinny though.

The American Calvin Smith, who once was a world record holder on the 100 meter, even was tiny and skinny.
posted by ijsbrand at 10:51 AM on August 9, 2011

When you overstress the big muscles they trigger your body to go into a muscle growth mode. When this happens, your body doesn't just grow the stressed muscles, it grows all of them. In other words, intense leg exercises can result in bigger arms and shoulders, moreso for men.
posted by rocket88 at 11:58 AM on August 9, 2011

If they are cheating, the drugs that build leg muscles coincidently build upper body muscle, wanted or not. In addition, sprinters use their arms to swing to help build momentum, so they are actively being used.
posted by procrastination at 12:40 PM on August 9, 2011

Here is a woman deadlifting 330lbs. Here is a man deadlifting 330lbs.

Although they are of comparable strength, you'll notice that the woman is far, far less bulky.

In general, women have to go to incredible effort to put on any kind of bulk, whereas a lot of guys can bulk up by blinking, or at least by training hard at running, as rocket88 mentions.

In addition, women usually have a larger differential between their upper body strength and their lower body strength. That is, the man from the above video is likely to have a better bench press than the woman, even though their deadlifts are comparable.
posted by emilyw at 1:19 PM on August 9, 2011

Just to clarify for some of the people who are responding under a different assumption, upper body strength is advantageous for sprinters, so they build it in the gym by lifting weights. They don't get that jacked from swinging their arms while running.

I don't know a ton about sprinting but I would throw my hat in the ring with those who say it's just biology. I know plenty of women who are very strong in their upper bodies (and have worked hard to achieve that) but don't look as big as male sprinters do.
posted by telegraph at 1:20 PM on August 9, 2011

In my Track and Field program, our sprinting coach made us spend two days a week doing upper-body strength training, because he said, basically, you can only run as fast as you can swing your arms. There's more to it, but there is a connection, so professional sprinters do upper-body work as well.

Then there's the sexual dimorphism — women generally just don't build as much muscle in their upper bodies unless they're really trying.
posted by General Malaise at 1:21 PM on August 9, 2011

All these answers seem like half-rights, so I'll just add my half-right, too!

I think it's mostly to do with sexual dimorphism, women just on average have less of an upper body build. The upper bodies are built up though - in both sexes from the exercises they do w/weights, most likely in the off season. We're talking about Oly lifts, Squats, Deadlifts, Clean and Jerk, Snatch, etc, etc, etc - that sort of stuff. ALL are incredible lifts to develop power - and all required you to use your upper body.

I think only a unaware sprinter is looking - specifically to gain mass. Most likely, they're trying to gain as much sprinting speed and power ,while still weighing as little as possible. Why? Basic physics. You can have tremendous power without looking like you're competing in a body building competition - the gym time and strategies are completely different. But there's a sweet spot which is different for everybody (and this is why you see a little discrepancy in body builds, even in the same sex) of how fast you can sprint, given how much bulk you put on. It's the same reason I can outpace anybody in my old '86 Celica with a manual transmission at a stoplight - for the first 50 feet. Then, that 2 ton truck is going to be able to pass me.

Also - if you're intelligent with your training program, you understand that there's more to sprinting then your legs. Your legs are attached to your mid section, so that needs to be strong and it needs to take on the force and stresses you put on it. Your arms are another piece of that puzzle. Everything needs to be fucking incredible form for a 100 meter sprint - you need to think of your body as a whole.

If you look at a marathon runner, that balance of strength and weight time of the event is completely different, since actually going for 2+ hours means people who have more bulk (which is inevitable if you want to be stronger) have a serious disadvantage - it takes *more* power, in the long run for a marathoner who weighs 20lbs more than one that does not. Those wispy marathoners aren't strong - they'll never win a one rep max over a sprinter, but if you think strength over time (ie POWER) they'll destroy anyone bigger than they are.

It's false that lifting weights will affect your muscle mass in your entire body - if you don't believe me, look at a Tour de France T-Rex-massed hill climber: well-developed legs, tiny little arms. There *is* generally support for the idea that if you work out just your left side of your body - you'll get *some* benefit of the strength training on your right side, *specific to that exercise*. There's also truth in that most exercises, unless you're really consciously isolating the muscle (which has little benefit for most athletic pursuits), will work more than that one muscle you're "targeting". I can do a pushup and still work like, my calves and certainly my midsection, even though in my mind I'm thinking "this is good for my shoulders!".

I think also that this (working one side, gaining mass on the other) has to do with how specific your hormones are in targeting what gets what message. But again, you can work out just your right arm, without having it completely transfer in terms of strength or mass to your left.

And anyone that thinks that dudes can just gain muscle like nothing, I'm happy to meet you to prove you otherwise :) Yes, I eat enough.
posted by alex_skazat at 4:09 PM on August 9, 2011

Here are pictures of the male and female 100 meter world record holders. Here is a photo of Ben Johnson, one of the bulkier sprinters of the past known for his steroid scandal. I don't really see the gender-specific differences you see. Perhaps part of the upper body muscle is due to vanity and devoting unnecessary time to working out the upper body, or just the genetics of effect of being a naturally gifted lean muscle builder, which goes a long way to being a world-class sprinter.

As a former sprinter I can tell you however that the upper body and core strength is almost as critical to sprinting as lower body strength is. Sprint speed isn't all about explosive power and propulsion off the track. It also depends on using your entire body in concert to build forward momentum, stride length, and rapid turnover. Try this experiment: go sprinting with your upper arms completely limp.
posted by drpynchon at 5:16 PM on August 9, 2011 [1 favorite]

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