Help Ford!

[Toby]

Hey Ford, I test my stats with a set of calipers. But they came with a brochure and a table that calculates based on one measurement taken at the suprailiac. I've been doing that, but I want a more accurate measurement. Can you expand on this (http://forum.kungfumagazine.com/forum/showthread.php?s=&threadid=27219) post? Or point me in the direction of where I might find piccies to help? I mean, e.g. you say pectoral, but is it at the nipple, 2" above, 2" to the side, doesn't matter, etc?

[Ka]

As long as you use the same set of calipers(hope they are not plastic cheapos), in the same precise areas along the same axis(vertical,horizontal,diagonal fold) for repeat tests.
Generally the more areas the greater accuracy.The general areas that I was taught are
Biceps,Triceps(right or left is more determined by who you were taught as long as its consistently one side and one area),Suprailiac,Sub Scapula,Chest,Mid Anterior Thigh, Mid Abdominial.Other areas Midaxillary,Medial Calf
Personally I wouldn't rely on one area if you are after a high degree of accuracy.
Chest :Skinfold with its long axis directed at the nipple,(pinch from just infront of armpit(Anterior Axillary Fold) line toward the nipple.)Official measurment area: half the distance between the anterior axillary line and the nipple(men).

It helps to mark the area,and use a system for locating that area(I can post up the "official"locator refference points if you want.)
Remember to take 2 measurements of each area with about 10-15 secs inbetween(if there is variation of more then 10% then your pinch method may need more practise)
Place caliper head about 1-2cm from fingers.
Keep a constant pressure with thumb and forefigure
Give it a couple of seconds before reading measurement after taking pressure off the lever arm of calipers.
Don't do it straight after exericse,or when sweaty.
Practise it.
Yeah I know I'm not Ford but thought I'm chime up
Hope thats of some use

[Toby]

Thanks Ka. Good info in there. Unfortunately they are plastic cheapos - the Accumeasure ones. But I heard/read good reviews of them beforehand and there was no way I was gunna shell out $100's for a good one. I wouldn't mind an expensive one, but there are other things that are higher priority for me. The thing I did hear was that the plastic ones were way more accurate than the resistivity scales for 1/4 the price.

[Ka]

Re: Plastic,I'm sure if you keep in the same area it will produce a good result,just that we are told that there are large differences in the quality of the calipers.(ofcause I'm not sure if that justifies the huge prices)They will be better then those scales for sure.

Could be worth having a quiet word to your Local GP and asking if you can do one measure up(just as a comparsion).But then again Medicares going down isn't it.

[Toby]

Results are generally reproducible with the plastic set. However, the calibrations are crude and the table that I'm supposed to compare against is too coarse. I.e. it makes jumps like 12-13mm == 15.7% b.f., 14-15mm == 17.5% b.f. (somewhat made up numbers). You can get the accuracy of 12-13mm and 14-15mm but I usually use 0.1mm vernier calipers when I'm measuring things so I like a bit more accuracy than 2mm and ~2% increments. Plus the table is only for suprailiac measurements so the purpose of the thread was to get lots of measurement sites to increase accuracy a bit. Oh to afford some Harpenden calipers ...

[Ford Prefect]

Gimme a little bit Toby. I'll see if I have a file that explains it. If I don't, I'll shoot some pictures. Give me a couple days.

[Ford Prefect]

I found a file, but it was password protected. I didn't feel like finding something to rip the password off, so I just took a screen shot. Here you go.

[IronFist]

there was no way I was gunna shell out $100's for a good one.

Try eBay.

[abobo]

I found my old files for the study I mentioned in this (http://forum.kungfumagazine.com/forum/showthread.php?threadid=27599) thread. This time I ran the regression taking out density, height, knee circumference, and ankle circumference. I don't have all of my old work, so I did some things from scratch, hopefully semi-correctly.

This won't be very accurate. If Ford's equation and this equation give the same result, I will be amazed.

Body fat % = -23.3 + (.0635*age) - (.0984*weight) -(.493*neck cirumference) + (.949*abdomen) - (.183*hip) + (.265*thigh) + (.179* biceps circumference (extended)) + (.451* forearm circumference) - (1.54*wrist circumference)

Caliper and circumference measurements should be in cm, weight is in lbs, age is in years.

[Toby]

Thanks guys. I'll give it a shot.

Iron, I tried ebay. The Oz ebay doesn't have any Harpendens. The US one does, an English seller with current bid around US$83. Still too much ...

[Toby]

Help again!

I tried this formula from the thread I linked in my first post:

1) Get your weight in pounds

2) Take caliper measurements (in mm):
-Pectoral/Chest
-Right Tricep
-Right Bicep
-Suprailiac
-Lower Back
-Subscapular
-Umbilicus
-Right Calf
-Right Thigh

3) Add up all the above measurements and plug them into this formula:
(sum of measurements/bodyweight) * 28/100 = bodyfat % for men

But no joy! My sum of measurements was 160mm. My bodyweight tonight was 87kg == 191.4lb. So 160/191.4 * 0.28 = even less b.f. than Iron. What did I do wrong?

[rubthebuddha]

So 160/191.4 * 0.28 = even less b.f. than Iron. What did I do wrong? your not eating enough hungry man dinners, obviously. :p

[Ford Prefect]

If the sum was 160mm, then according to the equation you have 23.4% BF. Iron certainly has less than that.

160/191.4 = .835946....

.835946... * 0.28 = .23406...

= 23.406%



44.8 lbs of fat
146.6 lbs of muscle

[Toby]

Oh, OK. Silly me. I thought the final figure was supposed to already be in %. I should've realised that it was just a constant factor of 100. I guess I wasn't expecting 23.4% though :p. Anyway, I must've measured wrong because the suprailiac only measurements (a la Accumeasure brochure table) give me 15.7% at the moment. Plus I've almost got those visible abs that Iron keeps going on about and I wouldn't have those with 23.4%. Hmm, I took three measurements at each site and averaged. There was good consistency at each site too :confused:.

[Mika]

1) Cheap ones have many disadvantages compared to the more expensive ones. The tightness of the jaws comes to mind first. That is very important as to the reliability of the results.

2) I must have misunderstood something. Are we talking about measuring your own folds with a caliper? I am having problems picturing that procedure...

I must be mistaken. At any rate, I would say using the same professional pincher at the same time of day gives a fairly reliable sum of folds. Whether that's the actual fat percentage or not is of importance, of course, but I would say the relative change is what really counts.

Cheers :)

//mika

[IronFist]

Originally posted by rubthebuddha
your not eating enough hungry man dinners, obviously. :p

Correct.

[Toby]

Originally posted by Mika
1) Cheap ones have many disadvantages compared to the more expensive ones. The tightness of the jaws comes to mind first. That is very important as to the reliability of the results.Mmm. As I said, I'd love a Harkenden, but big dollars prohibits that. I'd rather get lots of things first. E.g. at the moment I want a heavy bag and some good gloves.


Originally posted by Mika
2) I must have misunderstood something. Are we talking about measuring your own folds with a caliper? I am having problems picturing that procedure...Check out the screenshot Ford posted. Also the link I posted in the first post. That's what I used this time. I might try to get a flexy tape measure and try Abobo's method for comparison.

[Ford Prefect]

My measurements come to 7.6%, so I don't think it goes over by much.

[Mika]

I understand. I feel you, man...:cool:

Okay, let me rephrase: if the results you get seem a little off the mark at times, there just might be something with the method. But if you find them to be very consistent, then :)

Is all...:cool: