Bodyfat Testing

Azdak

Methodology depends on the skill of the user and the type of body you use it on.

I don't ever discuss DEXA because it is out of the reach of most people.

For low to mid bodyfat levels, for many body types, and in the hands of an experienced operator, a 3-site skinfold test has been shown to be as accurate as hydrostatic weighing. It's not good for large people or (esp men) those with a lot of visceral fat. However, in the 5%-30% body fat range, other than the above exception, I have found it extremely accurate. But I have also done about 10,000 of them, so I feel pretty comfortable both doing the measurements and interpreting the results.

Unfortunately, most people I see these days are so overweight that calipers aren't very useful.

One advantage of calipers --as someone mentioned earlier--is that they provide actual measurements instead of interpretations of OTHER measurements. So, even if the BF% number is inaccurate, a reduction in the actual skinfold thicknesses is a more consistent indicator of reduced body fat. Bioimpedance scales can't make the same statement.

In my new job, we have a clinical Tanita scale--I think it is the 418 model--the one that has the foot platform and the hand sensors and measures 5 segments. At times I have been impressed with it's accuracy--it has exactly matched about 6 people I did with calipers as well. OTOH, on me, it overestimated my Lean Body Mass by about 33 pounds and underestimated by BF% by at least 5%. I have also seen some widely varying LBM numbers when re-assessing members and comparing current numbers with past readings. That's really frustrating because it is so much more difficult to do effective interpretations.

I looked at a lot of home models when I bought my last scale and ultimately decided that even the more expensive Ironman Tanita scales were too unreliable--so I just opted for a nice $30 strain-gauge digital and my trusty tape measure.

Hydrostatic weighing is nice, but it is not easy to do. There are also several factors (water temp, actual measurement of residual lung volume vs using a reference text, clothing worn, among others) that are not always easy to control and that, in the end, can significantly increase the standard of error. I personally do not think that hydrostatic weighing is a practical method for assessing large numbers of people.

mworld

to answer your basic question the skin fold test is going to be a bit more accurate if done 'properly'...but there's of course WAY more margin of error if she's clueless trying to do it herself.


either way...the real question is what's the point? all you need is some measurement to gauage 'progress' (hopefully) by/

lvfunandfit

Methodology depends on the skill of the user and the type of body you use it on.

I don't ever discuss DEXA because it is out of the reach of most people.

For low to mid bodyfat levels, for many body types, and in the hands of an experienced operator, a 3-site skinfold test has been shown to be as accurate as hydrostatic weighing. It's not good for large people or (esp men) those with a lot of visceral fat. However, in the 5%-30% body fat range, other than the above exception, I have found it extremely accurate. But I have also done about 10,000 of them, so I feel pretty comfortable both doing the measurements and interpreting the results.

Unfortunately, most people I see these days are so overweight that calipers aren't very useful.

One advantage of calipers --as someone mentioned earlier--is that they provide actual measurements instead of interpretations of OTHER measurements. So, even if the BF% number is inaccurate, a reduction in the actual skinfold thicknesses is a more consistent indicator of reduced body fat. Bioimpedance scales can't make the same statement.

In my new job, we have a clinical Tanita scale--I think it is the 418 model--the one that has the foot platform and the hand sensors and measures 5 segments. At times I have been impressed with it's accuracy--it has exactly matched about 6 people I did with calipers as well. OTOH, on me, it overestimated my Lean Body Mass by about 33 pounds and underestimated by BF% by at least 5%. I have also seen some widely varying LBM numbers when re-assessing members and comparing current numbers with past readings. That's really frustrating because it is so much more difficult to do effective interpretations.

I looked at a lot of home models when I bought my last scale and ultimately decided that even the more expensive Ironman Tanita scales were too unreliable--so I just opted for a nice $30 strain-gauge digital and my trusty tape measure.

Hydrostatic weighing is nice, but it is not easy to do. There are also several factors (water temp, actual measurement of residual lung volume vs using a reference text, clothing worn, among others) that are not always easy to control and that, in the end, can significantly increase the standard of error. I personally do not think that hydrostatic weighing is a practical method for assessing large numbers of people.

Thank you for this reply! Your posts are always very helpful.
My friend who is a trainer had to reschedule with me to test my BF%. So, hopefully I'll find out what her calipers say. She trains women for IFBB competitions. She's pretty precise with everything she does. We'll see though. . . I just want to have a gauge and see how I've improved.

MacMadame

Actually, there are now places that will do a DEXA scan on you for about the same price as the hydrastatic testing. I think it's the new "in thing" in fitness. :happy:

Iceprincessk25

Methodology depends on the skill of the user and the type of body you use it on.

I don't ever discuss DEXA because it is out of the reach of most people.

For low to mid bodyfat levels, for many body types, and in the hands of an experienced operator, a 3-site skinfold test has been shown to be as accurate as hydrostatic weighing. It's not good for large people or (esp men) those with a lot of visceral fat. However, in the 5%-30% body fat range, other than the above exception, I have found it extremely accurate. But I have also done about 10,000 of them, so I feel pretty comfortable both doing the measurements and interpreting the results.

Unfortunately, most people I see these days are so overweight that calipers aren't very useful.

One advantage of calipers --as someone mentioned earlier--is that they provide actual measurements instead of interpretations of OTHER measurements. So, even if the BF% number is inaccurate, a reduction in the actual skinfold thicknesses is a more consistent indicator of reduced body fat. Bioimpedance scales can't make the same statement.

In my new job, we have a clinical Tanita scale--I think it is the 418 model--the one that has the foot platform and the hand sensors and measures 5 segments. At times I have been impressed with it's accuracy--it has exactly matched about 6 people I did with calipers as well. OTOH, on me, it overestimated my Lean Body Mass by about 33 pounds and underestimated by BF% by at least 5%. I have also seen some widely varying LBM numbers when re-assessing members and comparing current numbers with past readings. That's really frustrating because it is so much more difficult to do effective interpretations.

I looked at a lot of home models when I bought my last scale and ultimately decided that even the more expensive Ironman Tanita scales were too unreliable--so I just opted for a nice $30 strain-gauge digital and my trusty tape measure.

Hydrostatic weighing is nice, but it is not easy to do. There are also several factors (water temp, actual measurement of residual lung volume vs using a reference text, clothing worn, among others) that are not always easy to control and that, in the end, can significantly increase the standard of error. I personally do not think that hydrostatic weighing is a practical method for assessing large numbers of people.

I absolutely agree about the hydrostatic weighing. Yes it's said to be the gold standard and blah blah blah......but has anyone ever had it done?? It SUCKS. It's impossible to blow out all the air they want you to and it's just a pain in the *kitten*.

SHBoss1673

I still feel like the Bod Pod is the best compromise. Does anyone have any experience with it? I'm thinking of going soon, just to see what it's like, I already know my BF% (approximately, it's been a while but my body hasn't changed a lot since I got it) but I'd like to be able to recommend or discourage the Bod Pod, and the only way I can do that is by trying it out.

From all my research it's supposed to be about the same accuracy as hydrostatic testing (about 1% margin for error). And you neither need to get wet, nor do you have to hold your breath. The bod pod uses Air Displacement Plethysmography to calculate body fat %. Essentially they take weight and volume of air, do a calculation to figure out specific density. I don't know all the details of the calculations, but the company is very receptive to questions, and open in their dissemination of research; that, more than anything else, tells me that they are on the up and up.

questionablemethods

I still feel like the Bod Pod is the best compromise. Does anyone have any experience with it? I'm thinking of going soon, just to see what it's like, I already know my BF% (approximately, it's been a while but my body hasn't changed a lot since I got it) but I'd like to be able to recommend or discourage the Bod Pod, and the only way I can do that is by trying it out.

From all my research it's supposed to be about the same accuracy as hydrostatic testing (about 1% margin for error). And you neither need to get wet, nor do you have to hold your breath. The bod pod uses Air Displacement Plethysmography to calculate body fat %. Essentially they take weight and volume of air, do a calculation to figure out specific density. I don't know all the details of the calculations, but the company is very receptive to questions, and open in their dissemination of research; that, more than anything else, tells me that they are on the up and up.

I've been looking into getting it done at the gym at my university. The cost isn't too much (around $50, if I recall). I would like to have a good idea of a goal weight to shoot that is based on an actual lean mass to fat ratio instead of "this number sounds good". I wouldn't be able to tell you the accuracy of the method, however, because I have no idea what my BF% is at the moment. Maybe I could get them to do caliper testing too and just see how well the two numbers match up.

MacMadame

.but has anyone ever had it done?? It SUCKS. It's impossible to blow out all the air they want you to and it's just a pain in the *kitten*.

Heh, I've done it and I thought it was fun!

But I also think biking 100 miles is fun so maybe my idea of fun isn't typical. :laugh:

I really want to get the DEXA scan done. I just had a chance to get the hydrostatic testing for $20 at a triathlon expo so I took it. But DEXA scans are $75-99 around here (and often the hydrostatic test is that much as well) and I just can't justify it.

I also want to get my RMR tested and my VO2 Max. I like numbers!

PJilly

Ha, I had it done last week, and I thought it was kind of fun too! I should go find a Bod Pod and do that so I can compare with my hydrostatic numbers.

lvfunandfit

well, it turned out I was a 17.9%! I'll take that for now! I'd like to be at 15-16%. I know it's not totally precise but the number made me happy!

chrisdavey

hmm, my omron is giving me readings between 8.1 & 8.5% BF. My accumeasure calipers say 6mm and for a 27 year old guy the charts say 8.4% so maybe the calipers were about right? I always thought they were optimistic :P Will see how the comparison figures go in the future.