frustrating body-composition moments

[moominmolly]

I know I don't want to lose weight just for the sake of weighing less. I want to be in better shape. I want to be able to do more things, and I want the muscles that I've worked for to show up. :) So last night, ectophylla and I tested our body fat percentages with skinfold calipers. I figure that between my strength, my endurance, and my body fat percentage, I can keep a reasonably objective tab on how "fit" I am. I own these calipers. They came with a little booklet that looks like it was printed out of the back of a van in the 1970's, but which has detailed instructions for a 4-site testing method. That is, pinch four particular areas on your body, measure how big the pinches are, add those numbers up, and then look up the sum in a little chart based on your age and gender. But, I wondered, wouldn't a 7-site method be more accurate? The method used at that last site is also used in other places online, and uses the equations from studies like this one. So we popped our measurements into those 3-site and 7-site test method equations and ended up with very different numbers. Personally, my 3- and 7-site numbers were very close to one another, and were both 6 - 7 points lower than my 4-site number.

Six or seven percentage points is a lot. The 3- and 7-site methods both took my legs into account, which the 4-site method did not, and my legs are pretty lean. But still.

We were both much more flattered by the 3- and 7-site method tests, but I don't want to trust them more just because they're nicer to me. I'd be lying if I said "all I want is a consistent measurement so I can see if it goes down", since I do also want some little gold star for being in decent shape. What I really want, though, is not a low number, but an accurate one. SO! All of that frustrating pinching and adding is uninteresting to me if I don't have some way of verifying its accuracy. What I'd like to find, now, is a place in Boston that does either hydrostatic weighing (dunk tank!) or has a (sigh) BOD POD. And my two-minute-google-search-attention-span didn't turn anything up! Help?

Comments

Random question

[zogathon.livejournal.com]

You may be able to fuzzily gauge accuracy by paying attention to the differences. What were the sites for the 3, 4, and 7 site tests?

I'd probably guess the 7 site test to be more accurate, and I'd also hazard a guess that the site pinched in the 4 site test but *not* in the 3 site test is a place where you store fat out of proportion to the rest of you.

(And, fwiw, whenever I've had a personal trainer do body fat measurements, they've used 7 places.)

Re: Random question

[moominmolly.livejournal.com]

the site pinched in the 4 site test but *not* in the 3 site test is a place where you store fat out of proportion to the rest of you.

True. Even better -- the 3-site isn't just the 4-site - 1. It's the 4-site - 2 + 1, and they chose to remove two unflattering sites and add in a flattering one (my THIGHS OF DOOM). That explains me, but it doesn't explain ectophylla, whose bodyfat distribution is way leaner on top than mine and who was still getting lower numbers with the 3- and 7-site tests.

I guess the 4-site is just bogus. It just feels to good to be true! As in, I got much leaner just by walking downstairs and plugging some numbers into a java calculator. Oh well, I guess I'll just go with it. :)

Re: Random question

[veek.livejournal.com]

NEVER underestimate the benefits of a java calculator.

Re: Random question

[vokzal.livejournal.com]

ihnj, ij LOVE the sound of this!

Re: Random question

[moominmolly.livejournal.com]

whenever I've had a personal trainer do body fat measurements, they've used 7 places.

Oddly, that does more to reassure me than any amount of Medline-cruising did. Hah.