Just how costly is 10lbs to performance?

554 wrote:

The rule of thumb is that each pound of "extra" body weight over your ideal number adds 70 seconds/mile.

I think you mean 7 seconds. So anyway, my 16 flat 5k at 6-1 /180 could be 14:50 if I had the will power to lose 10 pounds. That would be nice!

According to Bob Glover, losing 1 percent of your weight will improve performance by 1 percent. So I weight 140. If I lose 1.4 lbs., then my 7 minute pace should improve by 4.2 seconds (420 seconds per mile *.01).

From my own experience, this is about right. However, once I drop below 135 lbs., then I don't see any improvement at all. I'm 5'7" and 51 yrs. old.

Penelope Pitstop wrote:

Ackley wrote:

The rule of thumb is 2 seconds per mile per pound. I believe this is attributed to Tom Osler and that Jack Daniels studied it and it was about right.

I have also heard one minute per pound over a marathon. (Slightly more benefit than the rule of thumb.)

I don't see how this can be accurate. I weigh about 185 (older runner) and can do about a 17:00 5k now. My ideal running weight is about 150 - so that is 35 pounds. So you are telling me I should subtract 70 seconds per mile or about 3 min and 30 seconds for a 5k? So, that would give me about a 13:30?

Yeah...older runners who are 35 lbs overweight do not run 17:00. But if you really could run 17:00 while being 35lbs overweight, you could definitely run sub-14:00 at your ideal weight.

Edgarr wrote:

Six feet, 150 pounds. Personal best for 3k is 8:30. Now, let's say I drop 10 pounds by next winter. Aside from the gains in fitness from training, let's assume that my fitness remains idle, but I drop 10 pounds. From what I have read and heard over the years, is that the cost per pound of fat per mile is 2 seconds. 10lbs x 2s = 20 seconds per mile. Over 3k, would this indicate a 38 second improvement over 3k with weight reduction alone?

Assuming you were completely healthy at 140lbs...which is a pretty big assumption...and all other things equal...being 10lbs lighter should save you ~14secs per mile...at least by the charts I have.

The weight loss will increase your speed by a certain percentage. So a runner who is twice as slow as you could lose 10lbs and save 28secs per mile...if that makes sense.

That's why the you can't really say you save so many secs per pound...cause it depends on how fast you are.

It also depends on the percentage of your weight that you lose. A 200lb person who loses 10lbs will not save as much time as a 150lb person who loses 10lbs...assuming they currently race at the same speed...because the 150lb person lost a greater percentage of their weight.

All that said...I have a feeling that going to 140lbs will be too hard for you and will compromise your heath...in which case everything is out the window. But I don't know you or your make-up...so it's only a hunch.

Losing weight only helps till the point where your body stops being able to properly recover from workout and you begin to have energy system problems. I used to be under weight and used to always get dizzy since I had no reserves of energy. I have gained only 2 or 3 more pounds and my times have improved a lot

kod3200 wrote:

I disagree that losing weight makes you faster. Obviously if you were 5'10/200+ pounds then dropped to 150 pounds that would make you quite a bit faster, but if I lose 3 pounds I'm gonna chip off 10 seconds per mile? I could take off my jersey, shorts, socks, shoes, and watch and that'd be close to 3 pounds. Does that mean if I run my mile literally bare ass naked I'm gonna PR 10 seconds?

I weigh 142 pounds and am 6'0 (same as Ryan Hall in high school, I must be the next prodigy marathoner). My 5K is 15:47 which is 5:05 pace. If I dropped weight and came back 120 pounds, that's a 22 pound difference. 22 lbs X 3-5 seconds would be between 66-110 seconds per mile off my PR. Thats roughly 3:15 pace, or a 10 minute 5K.

Please stop making up non-sense about losing weight=exponential speed growth, some kids gonna starve and die.

Yeah please stop making up nonsense. Physics doesn't really exist! Science is a lie!!!

PTF wrote:

Yeah...older runners who are 35 lbs overweight do not run 17:00. But if you really could run 17:00 while being 35lbs overweight, you could definitely run sub-14:00 at your ideal weight.

They sometimes run mid 17, though.

It does not depend on percentage.

Yes...definitely...plenty guys in their 50's run faster than that...just not when they are 35lbs overweight...

Here is an article discussing weight and running (Osler is mentioned):http://www.joehenderson.com/runnersworld/319.html

Penelope Pitstop wrote:

Ackley wrote:

The rule of thumb is 2 seconds per mile per pound. I believe this is attributed to Tom Osler and that Jack Daniels studied it and it was about right.

I have also heard one minute per pound over a marathon. (Slightly more benefit than the rule of thumb.)

I don't see how this can be accurate. I weigh about 185 (older runner) and can do about a 17:00 5k now. My ideal running weight is about 150 - so that is 35 pounds. So you are telling me I should subtract 70 seconds per mile or about 3 min and 30 seconds for a 5k? So, that would give me about a 13:30?

I cannot believe you guys are taking this so literally, if you lose weight from your ideal weight (different for everyone) it makes sense that you would run faster and maybe 2 sec per mile is a fair assessment. If you lose too much weight then it would have a negative effect (factoring muscle loss, nutrition etc..) Dont be so stupid as to think at an older age and 185 pounds that if you lose weight you will run in mid 13s, the time off is just an average per runner. Its people like you who post dumb shit that real runners no longer come to read posts on this website.

Old Time in seconds * ((New Weight/Old Weight) ^ (1/3)) = New time in seconds

5:00 current mile. Drop in weight from 150 to 145 while maintaining same power, etc. New time =

300 * ((145/150) ^(1/3)) = 4:56.63

Before everyone starts putting their fingers down their throat after breakfast, there is an optimal weight range below which you will under-perform.

Ask Kevin tschirhart

I've had a yo-yo weight my whole life. I can attest from personal experience that the 2 second rule is about right.

Ackley wrote:

The rule of thumb is 2 seconds per mile per pound. I believe this is attributed to Tom Osler and that Jack Daniels studied it and it was about right.

I have also heard one minute per pound over a marathon. (Slightly more benefit than the rule of thumb.)

You are correct….the improvement would not be linear, however if you were to get down to 160, in a healthy sort of way, you probably could run close to 1:18 given what you have told us….now for the big question….is it worth it to you?

The cost is very dependent on the type of meat that is being purchased. A fine cut of steak will be significantly more expense than a non-lean pound of hamburger. You may wish to go with meat-like substances such as spam and these will not be as expensive and will have a longer shelf life.

Your wellcome.

Dr. Pepper wrote:

Old Time in seconds * ((New Weight/Old Weight) ^ (1/3)) = New time in seconds

5:00 current mile. Drop in weight from 150 to 145 while maintaining same power, etc. New time =

300 * ((145/150) ^(1/3)) = 4:56.63

By that formula I'd only cut 32 seconds off my 5k by losing 15 pounds of overweightness. Not buying it.

1:26 while 5'1" and at 195 is actually quite impressive and shows talent. If you could get down to 160 healthily (I think that weight is perfectly healthy for that height but dropping 60 pounds to get there isn't as healthy) then I see no reason why you couldn't come close to 1:13