Effect of weight on speed



P

paul

Guest
Having trouble googling for this but I presume someone has done a study.

Is there a documented relationship between your running speed and your weight, all other variables
remaining the same? i.e. if you magically lost 2kg of fat overnight, how much faster would you be
the day after? I imagine that just attaching a rucksack with different weights doesn't accurately
represent the same thing but it might be interesting nevertheless.

Paul
 
On 12 Feb 2004 16:52:29 GMT, [email protected] wrote:

> I imagine that just attaching a rucksack with different weights doesn't accurately represent the
> same thing but it might be interesting nevertheless.

Y'think? I'd imagine it to be a complete waste of scarce research funds.
 
In article <[email protected]>, [email protected] wrote:
> Having trouble googling for this but I presume someone has done a study.
>
> Is there a documented relationship between your running speed and your weight, all other variables
> remaining the same? i.e. if you magically lost 2kg of fat overnight, how much faster would you be
> the day after? I imagine that just attaching a rucksack with different weights doesn't accurately
> represent the same thing but it might be interesting nevertheless.

There is a prevailing viewpoint that energy cost of running is approximately linear function of
bodyweight. If this is true, then losing x% of your weight in fat should result in dropping x% from
your racing time.

Unfortunately, I couldn't find anything that confirms this online. You can get to journal articles
that measured effect of added weights on energy cost of running on jap.physiology.edu. There are
studies that have measured this. Unfortunfortunately, they're not freely available on the web.

Cheers,
--
Donovan Rebbechi http://pegasus.rutgers.edu/~elflord/
 
Well, obviously if you are lighter you will run faster...to a point. There are two "minimum
weights" many people encounter. One is the "indeal racing weight" and the other the "ideal training
weight". The training weight is higher...during training (especially for marathons) the body is
under great stress and in a constant state of recovery and repair. The body must have adequate
resources to complete these tasks. If one is too light, their body will be under an additional
stress and not recover as quickly. The ideal racing weight is lower. This is typically the lowest a
person can weight and not feel weak or start losing a lot of muscle. In preparation for a race,
mileage is typically lowered, removing stress from the body and allowing the loss of a few
additional pounds below ideal training weight. But there is still a minimum. Many runners fall
victim to anorexic-like tendancies, thinking that lower is always better. Using myself for an
example, my ideal training weight is about 147-150. Any heavier and I notice it slows me down; any
lighter and I have recovery problems. My ideal racing weight is 145; however I can rarely reach
that for marathons since I can't lose weight during a taper and still recover. I normally only
reach 145 for a goal 10K or half. Andy Hass
 
<[email protected]> wrote in message
news:[email protected]...
> Having trouble googling for this but I presume someone has done a study.
>
> Is there a documented relationship between your running speed and your weight, all other variables
> remaining the same? i.e. if you magically lost 2kg of fat overnight, how much faster would you be
> the day after? I imagine that just attaching a rucksack with different weights doesn't accurately
> represent the same thing but it might be interesting nevertheless.

You might reference a thread from a few months prior on this newsgroup, available on Google at http://www.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&threadm=13360-
3FB13 88A-136%40storefull-2338.public.lawson.webtv.net&rnum=1&prev=/groups%3Fhl%3D en%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8%26selm%3D13360-3FB1388A-
136%2540storefu ll-2338.public.lawson.webtv.net. The post by Kerry Wilson contains a link to a site
that I found interesting in this regard. The site (http://zhurnal.net/ww/zw?HandicapJogging)
mentions a traditional belief that a pound of excess weight corresponds to roughly a 2-sec/mi
handicap. He does not, unfortunately, offer any research to back that up, but it seems within the
realm of reason.

Another rule of thumb I've seen, equally undocumented, is that you can expect a similar percentage
gain in performance as the percentage of body mass decrease. So, if you lose about 10% of your body
mass, you can expect about a 10% increase in speed.

The question, of course (if you're close to a reasonable weight) is, where does "excess" weight end
and "necessary" weight begin?
 
>Having trouble googling for this but I presume someone has done a study.
>
>Is there a documented relationship between your running speed and your weight, all other variables
>remaining the same? i.e. if you magically lost 2kg of fat overnight, how much faster would you be
>the day after? I imagine that just attaching a rucksack with different weights doesn't accurately
>represent the same thing but it might be interesting nevertheless.
>
>Paul
>
Below are Jack Daniels' "Oxygen Power" equations:

pct_max= 0.8 + 0.1894393 * exp(-0.012778 * time ) + 0.2989558 * exp(-0.1932605 * time) vo2 = -
4.60 + 0.182258 * velocity + 0.000104 * velocity^2

vo2max = vo2/pct_max

Where velocity is in meters/minute for a particular race distance and time is time in minutes for a
particular race distance. Relative VO2max is in units of ml*kg^-1*min^-1.

The equations do not include weight. However, you can take a particular race time, such as a 40
minute 10K, and scale the relative VO2max for a change in relative VO2max due to weight. You can
adjust for whatever weight you want. For a 160 lb male starting with a 40 min 10K time, the
projected improvement just from reducing weight would come to roughly 13 seconds per pound, which is
relatively close to some rules of thumb.

However, as Andy noted, there is an ideal training/racing weight for each individual and improvement
beyond this point will not result in improved results.

Lyndon

"Speed Kills...It kills those that don't have it!" --US Olympic Track Coach Brooks Johnson
 
<[email protected]> wrote in message
news:[email protected]...
>
> Well, obviously if you are lighter you will run faster...to a point. There are two "minimum
> weights" many people encounter. One is the "indeal racing weight" and the other the "ideal
> training weight". The training weight is higher...during training (especially for marathons)
> the body is under great stress and in a constant state of recovery and repair. The body must
> have adequate resources to complete these tasks. If one is too light, their body will be under
> an additional stress and not recover as quickly.

This is a great point. I'm about 10 lb. heavier this year than I was about a year ago, when I ran a
marathon. Just now, I'm beginning to run at speeds comparable to what I was doing back then (in
speed and/or tempo workouts). I feel stronger now than I did then, and I can tell my body recovers
faster. I still have some fat I'd like to lose, especially around the middle, but I bet some of that
"extra" 10 lb. is muscle (my body fat % is about the same it was last year), so your comment about
ideal training weight has be thinking I shouldn't fret so much. It would be nice not to be lugging
it around during a race or long run, though :).

<snip>
--
ø¤º°`°º¤ø,,,,ø¤º°`°º¤ø,,,,ø¤º°`°º¤ø,,,,ø¤º°`°º¤ø¤º°`°º¤ø,,,,ø¤º
eNo
"If you can't go fast, go long."
ø¤º°`°º¤ø,,,,ø¤º°`°º¤ø,,,,ø¤º°`°º¤ø,,,,ø¤º°`°º¤ø¤º°`°º¤ø,,,,ø¤º
 
<[email protected]> wrote in message
>
> Well, obviously if you are lighter you will run faster...to a point. There are two "minimum
> weights" many people encounter. One is the "indeal racing weight" and the other the "ideal
> training weight". The training weight is higher...during training (especially for marathons)
> the body is under great stress and in a constant state of recovery and repair. The body must
> have adequate resources to complete these tasks. If one is too light, their body will be under
> an additional stress and not recover as quickly. The ideal racing weight is lower. This is
> typically the lowest a person can weight and not feel weak or start losing a lot of muscle. In
> preparation for a race, mileage is typically lowered, removing stress from the body and
> allowing the loss of a few additional pounds below ideal training weight. But there is still a
> minimum. Many runners fall victim to anorexic-like tendancies, thinking that lower is always
> better. Using myself for an example, my ideal training weight is about 147-150. Any heavier and
> I notice it slows me down; any lighter and I have recovery problems. My ideal racing weight is
> 145; however I can rarely reach that for marathons since I can't lose weight during a taper and
> still recover. I normally only reach 145 for a goal 10K or half. Andy Hass

Yes, I agree with all of this. My training weight is about 134 - 136lbs, and I like to race in the
130 - 132 range. I've tried dipping slightly below 130lbs and that's when the negative effects you
mentioned start to occur.

I don't worry as much about weight as the race distance increases; as I think I need a little more
weight for that... for a marathon I think I'd race best at about 134... around my lowest ideal
'training' weight. But yeah, I like racing 5k's in a slightly 'hungry' state for sure.

cheers,
--
David (in Hamilton, ON) www.allfalldown.org
 
SwStudio wrote:

> <[email protected]> wrote in message
>>
>> Well, obviously if you are lighter you will run faster...to a point. There are two "minimum
>> weights" many people encounter. One is the "indeal racing weight" and the other the "ideal
>> training weight". The training weight is higher...during training (especially for marathons)
>> the body is under great stress and in a constant state of recovery and repair. The body must
>> have adequate resources to complete these tasks. If one is too light, their body will be under
>> an additional stress and not recover as quickly. The ideal racing weight is lower. This is
>> typically the lowest a person can weight and not feel weak or start losing a lot of muscle. In
>> preparation for a race, mileage is typically lowered, removing stress from the body and
>> allowing the loss of a few additional pounds below ideal training weight. But there is still a
>> minimum. Many runners fall victim to anorexic-like tendancies, thinking that lower is always
>> better. Using myself for an example, my ideal training weight is about 147-150. Any heavier
>> and I notice it slows me down; any lighter and I have recovery problems. My ideal racing
>> weight is 145; however I can rarely reach that for marathons since I can't lose weight during
>> a taper and still recover. I normally only reach 145 for a goal 10K or half. Andy Hass
>
> Yes, I agree with all of this. My training weight is about 134 - 136lbs, and I like to race in the
> 130 - 132 range. I've tried dipping slightly below 130lbs and that's when the negative effects you
> mentioned start to occur.
>
> I don't worry as much about weight as the race distance increases; as I think I need a little more
> weight for that... for a marathon I think I'd race best at about 134... around my lowest ideal
> 'training' weight. But yeah, I like racing 5k's in a slightly 'hungry' state for sure.
>
> cheers,

I seem to be the opposite to you and Andy, my racing weight is always higher than my training
weight. I'm usually in the 146 - 149 range but when I taper and carbo load I normally rise to
149 - 151.

--
Brian Wakem
 
"Brian Wakem" <[email protected]> wrote in message
> I seem to be the opposite to you and Andy, my racing weight is always
higher
> than my training weight. I'm usually in the 146 - 149 range but when I taper and carbo load I
> normally rise to 149 - 151.

Interesting.... is this your usual plan for a 5k? I could see your point of view in a ½ marathon or
even 10 miler. Don't you find you're a little less sluggish in the shorter road race distances when
a little lighter?

cheers,
--
David (in Hamilton, ON) www.allfalldown.org
 
"DrLith" <[email protected]> wrote in message news:<[email protected]>...

> (http://zhurnal.net/ww/zw?HandicapJogging) mentions a traditional belief that a pound of excess
> weight corresponds to roughly a 2-sec/mi handicap. He does not, unfortunately, offer any research
> to back that up, but it seems within the realm of reason.

The French "VO2max" site has at least a cool set of charts on how much the loss of one kg of excess
body weight would improve the 10K, HM or M finish time for a runner of a certain weight and
previous time.

http://www.vo2max.com.fr/parole/poids1.htm

Anders
 
"SwStudio" <[email protected]> wrote in message
news:[email protected]...
> "Brian Wakem" <[email protected]> wrote in message
> > I seem to be the opposite to you and Andy, my racing weight is always
> higher
> > than my training weight. I'm usually in the 146 - 149 range but when I taper and carbo load I
> > normally rise to 149 - 151.
>
>
> Interesting.... is this your usual plan for a 5k? I could see your point of view in a ½ marathon
> or even 10 miler. Don't you find you're a little less sluggish in the shorter road race distances
> when a little lighter?
>

I wouldn't carbo load for a 5k, but if I reduced my mileage in the week preceeding it I would gain
weight. Maybe I just eat a lot.

--
Brian Wakem
 
"Donovan Rebbechi" <[email protected]> wrote in message
news:[email protected]...
> In article <[email protected]>, [email protected]
wrote:
> > Having trouble googling for this but I presume someone has done a study.
> >
> > Is there a documented relationship between your running speed and your weight, all other
> > variables remaining the same? i.e. if you magically lost 2kg of fat overnight, how much faster
> > would you be the day after? I imagine that just attaching a rucksack with different weights
> > doesn't accurately represent the same thing but it might be interesting nevertheless.
>
> There is a prevailing viewpoint that energy cost of running is
approximately
> linear function of bodyweight. If this is true, then losing x% of your
weight
> in fat should result in dropping x% from your racing time.

I would say it can't be linear in the same sense that the energy spent is also tied to the energy
stored, and this stored energy must be carried as a load (weight). For instance, you could say an
automobile spends less energy to travel the same distance when it is lighter and that it could go
faster the lighter it is; but if you achieve a light carry-load by emptying out the gas tank... I'm
sure you get the point. :)

--
ø¤º°`°º¤ø,,,,ø¤º°`°º¤ø,,,,ø¤º°`°º¤ø,,,,ø¤º°`°º¤ø¤º°`°º¤ø,,,,ø¤º
eNo
"If you can't go fast, go long."
ø¤º°`°º¤ø,,,,ø¤º°`°º¤ø,,,,ø¤º°`°º¤ø,,,,ø¤º°`°º¤ø¤º°`°º¤ø,,,,ø¤º
 
In article <[email protected]>, Lyndon wrote:

>Paul wrote:

>>Is there a documented relationship between your running speed and your weight, all other variables
>>remaining the same?

> pct_max= 0.8 + 0.1894393 * exp(-0.012778 * time ) + 0.2989558 * exp(-0.1932605 * time) vo2 =
> -4.60 + 0.182258 * velocity + 0.000104 * velocity^2

Thanks for all the replies. I doubt I would've guessed some of the answers like the above :)

I've lost 8kg and am aiming to lose another 5 whilst keeping the same lean body mass and should end
up with a body fat % of around 10%. If I get any faster, I'll report back here...

Paul
 
In article <[email protected]>, eNo wrote:
> "Donovan Rebbechi" <[email protected]> wrote in message news:[email protected]...
>> In article <[email protected]>, [email protected]
> wrote:
>> > Having trouble googling for this but I presume someone has done a study.
>> >
>> > Is there a documented relationship between your running speed and your weight, all other
>> > variables remaining the same? i.e. if you magically lost 2kg of fat overnight, how much faster
>> > would you be the day after? I imagine that just attaching a rucksack with different weights
>> > doesn't accurately represent the same thing but it might be interesting nevertheless.
>>
>> There is a prevailing viewpoint that energy cost of running is
> approximately
>> linear function of bodyweight. If this is true, then losing x% of your
> weight
>> in fat should result in dropping x% from your racing time.
>
>
> I would say it can't be linear in the same sense that the energy spent is also tied to the energy
> stored, and this stored energy must be carried as a load (weight). For instance, you could say an
> automobile spends less energy to travel the same distance when it is lighter and that it could go
> faster the lighter it is; but if you achieve a light carry-load by emptying out the gas tank...
> I'm sure you get the point. :)

People seldom lose enough fat to "empty out the gas tank", but this is an issue with glycogen stores
(but that's not what I was talking about). The difficulty with fat is that it's hard to maintain
extremely low body fat levels, and doing so requires a diet that isn't optimal for endurance
training (e.g. a bodybuilders pre-contest diet).

Cheers,
--
Donovan Rebbechi http://pegasus.rutgers.edu/~elflord/
 
I lose 2 kilograms of weight every morning. I don't seem to jog any faster because of it.....unless
I really really have to go.
 
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