How much does 10 lbs of extra weight slow you down??

logic wrote:

What kind of physics is that?

So if I am a 17 year old girl, I'm 5'2, and weigh 113lbs...how much should I weigh? I know that's a little overweight...well not overweight, but it's definitely solid.

I don't know, and frankly, as a rule and lesson learned, I'm scared to give any weight advice to any woman (or girl).113 pounds doesn't seem all that heavy to me, even if 5'2" is slightly short. (Honestly honey, you don't look fat. You look just fine in that dress.)I think Bekele and Geb's weight and height aren't too different than that, so you can't be too far from optimal.Sorry if it seems unfair, but one major difference between men and women, is that women require a much higher minimum of bodyfat to maintain a normal, healthy body. Something like 16% for women and 4% for men (I don't know exactly).I won't give you any more specific advice, than to eat right and exercise. If you exercise more, you need to eat more carbs, to replace energy, and protein to repair muscles.Matt Fitzgerald just wrote a book about "Racing Weight", where his advice for the optimal racing weight: the weight you have when you set PRs.

IHAVEAQUESTIONNNN wrote:

So if I am a 17 year old girl, I'm 5'2, and weigh 113lbs...how much should I weigh? I know that's a little overweight...well not overweight, but it's definitely solid.

wow, according to all these formulas, if chris solinsky lost 20 lbs he could be beating the africans!!!!!!!!!!!!!!!!!!! seriously, eat up, eat healthy, run, and dont worry about it!

Forget Solinsky -- I already said, at 110 pounds, *I* can beat all the Africans.It's one thing to compare improvements when dropping from 180 pounds to 150. It's fun to make linear assumptions, and fantasize, but at some point, when weight loss involves losing muscle, or losing more fat than is healthy, or necessary for correct functioning of organs, and basic survival, times start increasing again.Unfortunately for some, genetics also factor largely, for things like determining body type, distribution of muscle mass, and ability to lose weight.Therefore I like the pragmatic, yet seemingly circular, advice, to eat right, and exercise, and lose as much weight as allows you to run personal bests, but not more.

3218 wrote:

wow, according to all these formulas, if chris solinsky lost 20 lbs he could be beating the africans!!!!!!!!!!!!!!!!!!! seriously, eat up, eat healthy, run, and dont worry about it!

rekrunner wrote:

Perhaps "ventolin^3" relies on this basic formula for energy (from any standard first year physics):

E = (1/2)*m*v^2

You could assume that "all things being equal" and "same level of fitness" means the same energy is required for the two different masses:

(1/2)*m1*(v1)^2 = (1/2)*m2*(v2)^2

Solving for v2 gives:

v2 = v1*(m1/m2)^(0.5)

a tad skeptic wrote:

and what reasoning led you to this end result?

You learn't this in your first year at Loughborough didn't you Gary?

Fat people have stronger muscles to move that extra weight around. A 10 lb. decrease on weight will add about 2-3 seconds per mile.

Gravy wrote:

Fat people have stronger muscles to move that extra weight around. A 10 lb. decrease on weight will add about 2-3 seconds per mile.

+1

Fat people are also more motivated to run to lose their fat. That can also add another 2-3 seconds, meaning a fat person can run 6 seconds faster per mile or over 18 seconds faster in a 5K if they can complete it without getting out of breath or nipping into KFC.

I ran 6 miles with a weight vest once ... 12pounds... brutal.

I was running 8-9 minute miles it was awful.

I was in 2:30 marathon shape...

I don't know how much... but I would say try running a few miles at marathon pace with no weight...

then repeat with 2-5 pounds.... I can only imagine effort would go through the roof...

repeat another 2 mile without weight.

I think 5 pounds lighter...feels like about 10 seconds per mile when I'm super fit.

This is about 2 seconds per pound. I can only imagine late in a marathon it is even more.

If someone handed me a 5 pound weight with 10k to go...I'd be walking.

Missing so far from this discussion is optimal weight. Almost all marathon champs, men and women, have a BMI of 19 or 20. Same for other distance events. Believe it or not, 800m is still a distance event and optimal BMI is still very low, near 20.

Sprinters tend to have BMI of 23. Light enough to be fast but much more muscle.

So, losing weight won't help if you are already optimal. I suspect the relationship is nonlinear... the farther above BMI=20, the more the extra weight hurts you. So going from BMI 25 to BMI 26 is worse than going from 20 to 21.

I will run my own numbers and see what I find. I have good data over a 15 pound range...all considerably above "optimal" (ie... I'm fat!). I'll also adjust for course and heat and age. I am losing about 0.7% per year in speed due to aging. I've had similar running fitness so I don't have the data problem of multi-collinearity of weight and fitness.

BTW... the average NFL linebacker has a BMI of 31 which is considered "obese" by the US government. I dare you to call one "fat@$$"

I ran my marathon PR at a BMI of 21 exactly.

Which, as a 5'7 man, is not an easy feat for someone of bigger-than-average build. That comes down to 133 lbs.

At my heaviest, I have been 187 lbs and "normal" weight is about 155 lbs, even at 60 mpw. To get to a BMI of 21 requires several months of dedicated, calorie-counting, every-day, effort.

Happy times when you could call out fatties

10 lbs of muscle will slow you down more than 10 lbs of fat because even if those 10 lbs of muscle are not "needed" for running they will consume blood, oxygen from your bloodstream and energy (carbohydrates) ... of course your joints can't tell the difference between fat or muscles, they just have to carry that weight.

of course if the extra wt 10lbs is all fat....then you slow down more. I have found that losing 10 pounds, my 5k drops by at least 20 secons. Definitely, extra mass has the impact

After a decade of a sedentary lifestyle, I got back into running. I weighed 190, and was running a 5K in about 28 minutes. I trained for a couple of years, and lost 20 pounds, and dropped 5 minutes on my 5K. The real question is how do you know if the weight droppage contributed to more or less than half of the time droppage. I would guess it was probably close to 1/3 of the difference, because the training was far more than I was doing beforehand.

I guess I am saying this to say this would be hard to accurately measure, without some way of distributing the weight over the body to replicate where the weight was before.

I was actually think about this problem this morning. I am currently 12 pounds heavier than I was at this time last year. Fortunately the weight is muscle not fat but no matter how hard Ive tried to drop weight for my upcoming marathon I cant. Been stuck at 5'9" 160# for last month. Just hit 1000 miles for 2024 this week and Im decently fit and God willing should break 3 but man it would have been nice to race this at 148#s instead

This was a really interesting, thoughtful, reasoned, and sincere discussion with commenters being forthright about what they know and don’t know.

*13 years ago

Very little of this anymore.