pounds per mile

why do you think the relationship is linear?

i remember reading someone saying how each pound over slows them down x amount, im just trying to work out what my 18min 5km will translate to when i lose the 5lb of flubber!

fa22y wrote:

does anyone know the formula for how much your pace slows down per mile for each pound you are overweight??

does anyone know why this topic will never be discussed on a running message board in kenya?

Somebody will know; I've heard it before but can't remember. I would guess about 30 sec.

fa22y wrote:

does anyone know the formula for how much your pace slows down per mile for each pound you are overweight??

I've heard tell that you can estimate the potential time savings by first converting your performance level to a certain VO2Max( or VDOT, if you've got Daniel's book handy), then multiplying it by the ratio of your current weight to your new weight. So for example, if I'm 6 feet tall and weigh 200lbs, and my VDOT is 50, which equates to a 20min. 5k, my VDOT at 150lbs will be (200/150)*50, or about 67, which then equates to a 15:30 5k.

Of course, this assumes that all of the weight lost is 'unnecessary,' such that only the bottom half of the power to weight ratio is changing, which is an oversimplification. It's probably not all that unrealistic though, since 150 is a generally a healthy weight for 6'. Also, the extra muscle and bodyfat being lost not only reduces the effects of gravity, but frees up more blood supply, lowering the demands on your heart and allowing more blood to be sent to your legs, not to mention less bodyfat means less pressure on your lungs and easier breathing.

Also, I believe as a rule of thumb, you can knock off around 2 seconds per mile for each lb of 'unnecessary' weight lost, or about 1 minute in the marathon for each lb, so it's pretty significant.

2 seconds per pound per mile,

So if I can get up to 230 and still run a sub 20 5k, then by dropping my weight down to 130 I could break the world record. I am not making fun of fat people any more....they are all potential record holders....

Mandingo wrote:

Somebody will know; I've heard it before but can't remember. I would guess about 30 sec.

i am currently about 170 lbs and a 20 minute 5k'er.

i was about 150 lbs 1 year ago, so i need to lose a few pounds. assuming i do that, my new 5k time will be:

10 minutes.

that's not the way it works,in your example:170-150= 20

pounds.So 20x2secs.x3.1 miles=124 seconds.You could expect

about a 2 min. improvement,provide the training is there

b as in b, s as in s wrote:

So if I can get up to 230 and still run a sub 20 5k, then by dropping my weight down to 130 I could break the world record. I am not making fun of fat people any more....they are all potential record holders....

Yeah, the formula is going to break down a little at the extremes, there'll be diminishing returns, and it'll be a little different for each athlete. I think this particular counter-example is unrealistic though. An athlete who weighs 230 and can run sub 20 is not going to have an optimum weight of 130, or anywhere close to that.

Here's a calculator:

http://academic.udayton.edu/PaulVanderburgh/weight_age_grading_calculator.htm

Mostly for fun, of course, but since I added 15 lbs of muscle, my 5K time has slowed exactly what it says it should (my 400 is better, 800/1500 are the same)

A quote from an earlier thread where a very knowledgeable source, that is jtupper, said

"I typically calculate 2.7 sec per mile per pound of unnecessary tissue that you lose. It will vary with your ability level, but you have the idea -- (1) multiply your VDOT times your body weight in kg (pounds X .454 = Kg). (2) This will give your an absolute value for estimated VDOT (3) subtact the anticipated weight loss from current weight and (4) divide the new (lighter) weight into the Absolute VDOT value that you got in #2 above. This will give you a new VDOT to use for calculating performances. Naturally, the catch is that you must be getting rid of body mass that is not useful to your running. If you try to lose too much to make these mathematics look even better, you will start to lose muscle mass and the absolute VDOT value will decrease as fast or faster than the body mass is reduced and VDOT used for determining performances will not be to your liking"

Iberian Tiger wrote:

Here's a calculator:

http://academic.udayton.edu/PaulVanderburgh/weight_age_grading_calculator.htm

Mostly for fun, of course, but since I added 15 lbs of muscle, my 5K time has slowed exactly what it says it should (my 400 is better, 800/1500 are the same)

One problem with this: it doesn't use your height at all. I am a 5'9" female at 123lbs, which is very close to the lower limit in terms of BMI (I don't think I could lose more than a pound or two and not look scary) and it's telling me I could drop 40 seconds in my 5K by getting to 110lbs. I'd be in the hospital at that weight!!!

So I guess it might work if you're a 5'4" female or 5'9" male (the averages), but not if you're significantly taller or shorter.