Female caliper tests (3 point?)

[MEB]

I found this website.

http://www.brianmac.demon.co.uk/fatyuhasz.htm

I was wandering if these calculations are accurate?

M

[bombflower]

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DB stands for body density. The numbers are standardized, so you cannot simplify the formula. Just take it slow and if you want me to double check your arithmatic, just let me know! I would be more than happy to.

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I meant, could you make the formula simpler (as in put the correct signs in)? Sorry I'm making this more difficult than it really is...

[Tuf]

[ QUOTE ]
[ QUOTE ]
Here's the three point formula:

For women:

Db = 1.0994921 - (.0009929)(sum of three skin folds) + (.0000023)(sum of three skin folds^2) - (.0001392)(age)


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What's "DB?"

Could you possibly simplify this forumla? I'm really horrible with math, so I'm really confused by all of these numbers.

What does the "^2" mean?

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Bombflower, the "^2" means "raised to the power of two." So you will multiply that number by itself.

I will give you a sample and show you the process you will need to follow to determine your body density:

Skin Fold #1=10 mm
Skin Fold #2=12 mm
Skin Fold #3=14 mm
Sum of 3 measurements=36
Sum of 3^2=1296
Age=18

*So your formula should look like this:

Db = 1.0994921 - (.0009929)(36) + (.0000023)(1296) - (.0001392)(18)
<font color="green">simplified to:</font>
DB = 1.0994921 - .0357444 + .0029808 - .0025056
<font color="green">simplified to:</font>
DB = 1.0582613

*So, you can now plug this in to the BF formula like this:

BF% = [(4.95/Db) - 4.5] x 100
<font color="green">simplified to:</font>
BF% = (4.67748371 - 4.5) x 100
<font color="green">simplified to:</font>
BF% = 17.7


*Does that help you understand?

[bombflower]

Thanks tuf! I think I've got it down now. Off to test my bf and see if I can get it right.

[Tuf]

No problem! [img]/forum/images/graemlins/wink.gif[/img] Feel free to post it up if you want me/us to check your work.

[bombflower]

So for the three-point I would measure the Suprailiac, Thigh, and tricep?

Then add those three together...

So my measurements for those three are

Suprailiac = 9
Thigh = 15
Tricep = 12
Sum = 36
Sum of 36^2 = 1296
Age = 17

However, I have no idea about the rest.

[Tuf]

Lol! If only I had known your age, my sample would have been just what you needed! [img]/forum/images/graemlins/grin.gif[/img]

Just plug in your age where I had the age of 18 in the formulas I showed you above. You should come up with 15%. [img]/forum/images/graemlins/cool.gif[/img]

[a-folov]

Suprailiac = 9
Thigh = 15
Tricep = 12
Sum = 36
Sum of 36^2 = 1296
Age = 17

Db = 1.0994921 – (.0009929)(sum of three skin folds) + (.0000023)(sum of three skin folds^2) – (.0001392)(age)
Db = 1.0994921 - (.0009929)(36) + (.0000023)(1296) - (.0001392)(17)
Db = 1.0994921 - 0.0357444 + 0.0029808 - 0.0023664
Db = 1.0643621

BF% = [(4.95/Db) – 4.5] x 100
BF% = [(4.95/1.0643621) – 4.5] x 100
BF% = 15.067292418623323772990413694738 = 15.067%

[bombflower]

15% seems a little low, because back in April when I was measured I was at 15% and looked lower, and it was the same 3-point test. Hmm. Maybe I was lower and I was just tested inaccuratelty then.

Anyways, thanks for helping me figure it out!