Margin of error in hydrotank BF?

lorrpb
lorrpb Posts: 11,463 Member
edited December 2024 in Fitness and Exercise
My friend and I both got our body fat tested in the hydro tank yesterday. We each were about 5% higher than our trainer thinks makes sense based on his visual assessment and knowledge of our progress and abilities (meaning he knows us well and neither of us are so-called skinny-fat). The difference between us (4%) does make sense because we are at different places in our fitness regimen. My friend was 25% and expected to be in low 20s. I was 29% and expected to be below 25. We are both age 61. (I had planned to get a DEXA too, but the machine was broken.) I have looked at the example pics online and feel I look like 25 or less, not 30.

Is it possible for the tank to be this far off?

Replies

  • deluxmary2000
    deluxmary2000 Posts: 981 Member
    Looks like it can be off by as much as 5.3%...
    www.ncbi.nlm.nih.gov/pubmed/8695593
    Althoug I think this study shows that densitometry will tend to underestimate, not overestimate. Admittedly I only scanned the abstract.
  • rainbowbow
    rainbowbow Posts: 7,490 Member
    According to the ACSM hydrostatic weighing only has 2-3% error rate, usually underestimating.

    I'd say it's correct or pretty damn close.
  • sgt1372
    sgt1372 Posts: 3,997 Member
    rainbowbow wrote: »
    According to the ACSM hydrostatic weighing only has 2-3% error rate, usually underestimating.

    I'd say it's correct or pretty damn close.

    This is my understanding as well. Once got a DEXA & a hydrostatic weighing w/in a day of each other. The results were similar but the DEXA BF% was slightly higher.
  • lorrpb
    lorrpb Posts: 11,463 Member
    Ok, it is what it is!
  • jemhh
    jemhh Posts: 14,260 Member
    5-6% in individuals

    http://weightology.net/weightologyweekly/?page_id=162

    Dexa - 5-10% in individuals

    http://weightology.net/weightologyweekly/index.php/free-content/free-content/volume-1-issue-5-the-pitfalls-of-body-fat-measurement-parts-5-and-6-skinfolds-and-dual-energy-x-ray-absorptiometry-dexa/the-pitfalls-of-body-fat-measurement-part-6-dexa/

  • jemhh
    jemhh Posts: 14,260 Member
    edited September 2016
    lorrpb wrote: »
    My friend and I both got our body fat tested in the hydro tank yesterday. We each were about 5% higher than our trainer thinks makes sense based on his visual assessment and knowledge of our progress and abilities (meaning he knows us well and neither of us are so-called skinny-fat). The difference between us (4%) does make sense because we are at different places in our fitness regimen. My friend was 25% and expected to be in low 20s. I was 29% and expected to be below 25. We are both age 61. (I had planned to get a DEXA too, but the machine was broken.) I have looked at the example pics online and feel I look like 25 or less, not 30.

    Is it possible for the tank to be this far off?

    I have not had a hydro tank test done but I had a DEXA that came in at 36% in August. :astonished: I'm not convinced that I am still obese.
  • middlehaitch
    middlehaitch Posts: 8,488 Member
    I read those links @jemhh posted a while ago and I decided I didn't want any kind of body test done.

    Ok, on my really svelt and muscly feeling days I swither.

    I like how I look, and what I can do, and think if I got a number I wasn't pleased with I would be gutted and try to achieve an unreasonable goal- for me.

    @lorrpb you looked great in your 5 km pics, don't fret about the number.

    Cheers, h.
  • jemhh
    jemhh Posts: 14,260 Member
    middlehaitch wrote: »
    I read those links @jemhh posted a while ago and I decided I didn't want any kind of body test done.

    Ok, on my really svelt and muscly feeling days I swither.

    I like how I look, and what I can do, and think if I got a number I wasn't pleased with I would be gutted and try to achieve an unreasonable goal- for me.

    @lorrpb you looked great in your 5 km pics, don't fret about the number.

    Cheers, h.

    I just had to look up swither. That's a new word for me :)

    Agreed on all counts for your post. Both you and lorrpb look great and healthy. And, yeah, getting a displeasing number is, well, displeasing :wink:
  • Cortelli
    Cortelli Posts: 1,369 Member
    edited September 2016
    Ignore - wrong thread.
This discussion has been closed.

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