Re: Body Average Density Measurement Correction

[Guest guest]

From my previous message,

> " body density (mass density/volume) "

Sorry but after rereading this, it occurred to me that this could be

slighlty confusing to some. What I meant was,

" body density (mass/volume) "

a=z

[Guest guest]

Yargg - almost wish I hadn't done this experiment. Anyway

(a=z) ~ 77.9 Liters to 80.194 Liters of stuff

I won't mention what the Brozek and Siri formulas predict for my %BF,

but based upon my past readings when I was 10/15 lbs lighter, am

guessing the values are very close to reality.

Also as an aside there is about 4.7 more gallons of me than when I

ran the 100 in 10.2 sec at age 17. No wonder I'm not so spry

anymore. Anyway this finding is a real kick in the pants and I am

like totally skipping dinner tonight. (I may get drunk on red wine

instead) So this bear a=z is going back into hibernation for now -

maybe I'll be lighter tomorrow.

a=z

> >

> > From my previous message,

> >

> > > " body density (mass density/volume) "

> >

> > Sorry but after rereading this, it occurred to me that this could

be

> > slighlty confusing to some. What I meant was,

> >

> > " body density (mass/volume) "

> >

> > a=z

> >

>

[Guest guest]

Rodney,

I think that your calculations are about twice what they should be.

E.g., at 12.2%BF the density is 1.07140 kg/liter.

A 150 lb person weighs 68 kg (150/2.2). Dividing the weight by the

density gives a volume of 68/1.0714 = 63 liters. This means that you

need 5 liters (68 - 63) for flotation since the density of water is 1

kg/liter. This is slightly bigger than a one-gallon jug.

Tony

> >

> > From my previous message,

> >

> > > " body density (mass density/volume) "

> >

> > Sorry but after rereading this, it occurred to me that this could be

> > slighlty confusing to some. What I meant was,

> >

> > " body density (mass/volume) "

> >

> > a=z

> >

>

[Guest guest]

Hi Tony:

Thank you. You are right! I mixed up metric with imperial

measurements. DUH! Please cancel that thought about the danger of

drowning : ^ )))

I hope the following table is a lot more accurate:

The following applies for the number of liters of flotation required

given BF% for someone weighing 150 pounds (68.04 kg):

BF% Density Liters

------- ---------- ---------

23.0 1.04610 ~3

15.9 1.06250 ~4

~8.9 1.07930 ~5

~2.0 1.09670 ~6

So the above table (if I got it right this time! and if you know very

approximately what you BF% is) will tell you how much flotation you

will need when you do the experiment at the pool.

Perhaps Tony would be kind enough to make sure I have it right this

time : ^ )))

Rodney.

>

> Rodney,

>

> I think that your calculations are about twice what they should be.

> E.g., at 12.2%BF the density is 1.07140 kg/liter.

> A 150 lb person weighs 68 kg (150/2.2). Dividing the weight by the

> density gives a volume of 68/1.0714 = 63 liters. This means that

you

> need 5 liters (68 - 63) for flotation since the density of water

is 1

> kg/liter. This is slightly bigger than a one-gallon jug.

>

> Tony

>

>

> --- In , " Rodney " <perspect1111@>

wrote:

> >

> > Hi Aequalsz:

> >

> > GOOD stuff. Thank you!

> >

> > It seems to me from that article that the following applies for

the

> > number of liters of flotation required according to BF% for

someone

> > weighing 150 pounds:

> >

> > BF% Density Liters

> > ---- ------- ------

> > 18.5 1.05630 ~8

> > 15.4 1.06380 ~9

> > 12.2 1.07140 ~10

> > 9.0 1.07910 ~11

> > 5.5 1.08700 ~12

> > 2.6 1.09490 ~13

> >

> > That is a lot more flotation than I would have expected would be

> > required to keep someone afloat!

> >

> > Has anyone ever considered an increased drowning risk for people

on

> > CRON? ;; ^ )))

> >

> > Rodney.

> >

> > PS: I hope I got my calculations right!

> >

> > --- In , " aequalsz " <aequalsz@>

wrote:

> > >

> > > From my previous message,

> > >

> > > > " body density (mass density/volume) "

> > >

> > > Sorry but after rereading this, it occurred to me that this

could be

> > > slighlty confusing to some. What I meant was,

> > >

> > > " body density (mass/volume) "

> > >

> > > a=z

[Guest guest]

Hi Tony:

I now see that while we are a lot closer than we were previously, we

are still not exactly in agreement.

So this is what I did:

I took the case where someone weighing 68.04 kg needs five liters of

flotation, and concluded that:

his density is 68.04÷(68.04-5) = 1.0793

According to the equations that translates to a BF% (averaged) of 8.9%

-------------

Taking the case of a 68.04kg person needing four litres of flotation:

his density is 68.04÷(68.04-4) = 1.0625

Which gives an average BF% of 15.9%

-------------

Does this make sense to you? Or am I out to lunch ........ again?

Rodney.

> > > >

> > > > From my previous message,

> > > >

> > > > > " body density (mass density/volume) "

> > > >

> > > > Sorry but after rereading this, it occurred to me that this

> could be

> > > > slighlty confusing to some. What I meant was,

> > > >

> > > > " body density (mass/volume) "

> > > >

> > > > a=z

>