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

are you talking 10 lbs of extra muscle or of fat?

fat...maybe a little muscle since you can't really lose fat without shedding some muscle.

The rule of thumb is 2 seconds per pound of fat per mile. So for a 5K, that's 6 seconds for every extra pound of fat.

10 pounds of extra fat will slow you down about a minute for a 5k.

gira wrote:

The rule of thumb is 2 seconds per pound of fat per mile. So for a 5K, that's 6 seconds for every extra pound of fat.

10 pounds of extra fat will slow you down about a minute for a 5k.

That rule overestimates, IMHO. I've found it to be more like 1 - 1.5 sec/lb/mile at most. Over the years my weight has varied a lot and I have struggled with my weight, so I have a lot of experience with this.

I think the higher estimate is due to people being out of shape, coming back and losing weight. So much of the estimate is not the effect of weight loss, but of improved fitness. The effect of just weight loss is nearer half that estimate.

any other porkers wanna weigh in?

Most likely not a linear relationship. Don,t know, but conjecturing, first 5, negligible, 5-10 1-1.5 sec, 10-15 2sec, 15-20 2-3, 20-25 3 25-30 5, ...etc

In my practical experience, it is at least 2.7 seconds/pound/mile, based on a range of 10K times, spread across 16 pounds (and more like 4.5 seconds/pound/mile for the next 15 pound range). Using my most conservative rate, and extrapolating linearly, if I get down to 110 pounds, I can run a 26:21 10K.

But (as Pantman observed) my higher estimate is likely due to the combination of weight loss derived from improved fitness. Sorry I can not separate the two, based on my own personal observations.

Could you test this by running a 5K with a 10 pound bag of sugar and comparing the time to a previous time on the same course?

I really think that carrying a 10# sack of sugar would slow me down more than 10 seconds per mile - that would be exhausting! My arms would cramp up, my stride would be shortened....

I think a better test would be with some sort of weight vest to evenly distribute 10# over the torso, at least.

I've often heard 1 second per mile for every # of fat.

physics says it woud be ~

ratio of weights^0.5

lets try it :

a) say you are a 5'00 miler & weigh 150 with 10 pounds of blubber -> 5'00 * ( 140/150 )^0.5 =

4'49.9

or 10s/mile or 1s/pound/mile

b) say you are a 4'00 miler & weigh 140 with 10 pounds of blubber -> 4'00 * ( 130/140 )^0.5 =

3'51.3

or 9s/mile or again near enough 1s/pound/mile

and what reasoning led you to this end result?

The rule of thumb that works well for me is: each 3% loss of weight improves time over a given distance by 2%.

So, if I weigh 166.7 lbs, a 5lb weight loss (3%) would lead me to expect to improve my 5K time by 2%.

Losing another 5lbs (from 161.7 -> 156.7, a 3.09% decrease) would lead me to expect about a 2.06% decrease in 5K time.

YMMV

For each 1% loss of fat by weight, you should realistically be aiming for a 1% improvement in pace. If you don't achieve this then you are doing something wrong.

ventolin^3 wrote:

physics says it woud be ~

ratio of weights^0.5

lets try it :

a) say you are a 5'00 miler & weigh 150 with 10 pounds of blubber -> 5'00 * ( 140/150 )^0.5 =

4'49.9

or 10s/mile or 1s/pound/mile

b) say you are a 4'00 miler & weigh 140 with 10 pounds of blubber -> 4'00 * ( 130/140 )^0.5 =

3'51.3

or 9s/mile or again near enough 1s/pound/mile

What kind of physics is that?

Any of you have a coach ask you to run around a field carrying a ten pound weight? No? Anybody? Well, if you want your runners to lose weight, that's a good method, as long as they don't tell their parents or school officials.

Here is my experience. By the time I was a senior in HS, I was 5,8 and weighed 125 pounds. My PR ws 17:23. Over the next 2 years, I progressed in my training and made my long runs longer and my intervals faster. and hit the gym everyday and blew up. By the start of my Junior year of college, this year, I ran a 5k on a reputable course in 16:09.

The Everlasting Gaze wrote:

Here is my experience. By the time I was a senior in HS, I was 5,8 and weighed 125 pounds. My PR ws 17:23. Over the next 2 years, I progressed in my training and made my long runs longer and my intervals faster. and hit the gym everyday and blew up. By the start of my Junior year of college, this year, I ran a 5k on a reputable course in 16:09.

the course had a good reputation and/or standard of running fast?

The course was reputable in the sense that it has been used for 10+ years and has measured in at 5000 meters repeatedly and is well known. Many 5k times are illegitimate because of the course on which they were performed.

Interesting question. Of course I could test it, as could anyone else, but I won't.To be meaningful, the 10 pounds of sugar would have to be distributed all over the body, to more accurately represent where the extra fat would be.

Testing 123 wrote:

Could you test this by running a 5K with a 10 pound bag of sugar and comparing the time to a previous time on the same course?