This is one reason I really hate caliper testing...its a prediction based off a prediction of what another methodology would give you. It is highly inaccurate, even more so based on who is doing the test.
You can find the SEE's and SD's for these tests by examining the literature for each test. Those data are out there in all the validation studies that have been done... (ad nauseum) and have been around for decades (like most of the caliper equations and tables).
I had a figure chick with a str8 face actually tell me she was 10% bodyfat, because thats what her trainer told her after her caliper test. Not one ab showing, not one vein showing in the arm...and she honestly got upset at me when I told her that her test was BS. But I guess at the end of the day people hear what they wanna hear.
LOL. Yep.
I am not sure where you heard calipers do measure visceral fat or even incorporate it..but just to prove a point, this is pulled directly off a medical website...
Re-read what I wrote. ("Visceral fat is considered" because it is one component of the entire body's density.) Calipers gather data that are plugged into a regression equation that *predicts* results of hydrostatic (or a Body Pod's) measurement of body density (Db). The Db measurement is used most often with either a Siri or Brozek equation to get an estimate of body fat of the ENTIRE body, which includes subq and visceral adipose stores, as well as fats in the the membranes of cells, within body fluids, etc.
(To get at what you note about, as far as my sources, I've read the scientific literature (and have it in my office) on body comp. of reference man and studied the methodology in grad. school and taught the theory and application as a college professor...)
Here's a great resource, FYI:
Human Body Composition-2nd Edition
"...Developed in the 1970s as a simple and inexpensive way to analyze body fat, the skinfold test relies on an equation that factors the caliper measurements in millimeters with weight and age and produces an estimate of body fat percentage. Because the
body fat caliper cannot measure visceral fat, or fat stored deep among the organs, it is not 100 percent accurate at gauging body composition. If it is used at regular intervals, however, such as every four to six weeks, it can measure changes in body fat over time with reasonable accuracy.
Human error can affect the results of a body fat caliper test. It is important that the same person perform the test each time. Another variable that can affect reliability of these measurements is whether the individual administering the test pinches the exact same sites with a consistent amount of pressure, as human error can throw off the results..."[/QUOTE]
I would add the caliper estimation of body fat (total body fat) also do not "measure" subcutaneous fat, either. The technique is not meant to differentiate between adipose stores and subcutaneous stores, or to give an estimate of brain fat, bone marrow fat, etc. (So, I think we're on the same page...)
**by no means trying to start a argument about it...just saying thats all. maybe someone else has calculations that predict visceral fat, but standard testing I have seen/done..does not.
You can measure visceral fat indirectly with MRI and CAT. DEXA (e.g., trunkal fat) plus anthropometric measures will give you estimates based on what volume or single slice estimates from MRI / CAT will give for visceral fat. TBH, I'd have to dig into the literature (I can post a bunch of abstracts, but those are easy to find) to see how useful those predictions from a practical standpoint, as well as (the real biggie) how well they track with loss or gain of visceral fat (diet n' or getting older n' fatter).
-S