Getting Dunked! (Hydrostatic Weighing)

[ives]

I started a cut for the new year and wanted to get a baseline BF% so I can see my progress at the end of 3 or 4 months. I have an appointment for hydrostatic weighing tomorrow at UIC's performance lab. The woman on the phone gave me the following prep tips and I was wondering if anyone had anything to add (or ideas on what I can actually eat!):

-No beans, fruits, veggies, whole grains, or fiber for 24 hours.
-No carbonated beverages for 24 hours.
-NOTHING except plain water for 4 hours before the test.
-Skimpiest, simplest 2-piece bathing suit I own (I'm thinking of wearing an American Apparel single-layer tube top and teeny swim bottoms instead, as most of my swimsuits have mucho air-trapping padding in the top).

I figure it would be wise to do as similar a "prep" as possible for the two sessions, so I'll make sure to make the second appointment for the same ToM, eat the same foods in the 24 hours before the weighing, wear the same suit, etc. Is there anything I'm not thinking of? Any suggestions for making the weighing as accurate as possible and "keeping variables constant" between the two weighing sessions?

My (cheapo) BF-reading scale puts me pretty consistently at 22%, so I'll post the hydrostatic number (and maybe pictures?) tomorrow for comparison!

[ellybelle]

I started a cut for the new year and wanted to get a baseline BF% so I can see my progress at the end of 3 or 4 months. I have an appointment for hydrostatic weighing tomorrow at UIC's performance lab. The woman on the phone gave me the following prep tips and I was wondering if anyone had anything to add (or ideas on what I can actually eat!):

-No beans, fruits, veggies, whole grains, or fiber for 24 hours.
-No carbonated beverages for 24 hours.
-NOTHING except plain water for 4 hours before the test.
-Skimpiest, simplest 2-piece bathing suit I own (I'm thinking of wearing an American Apparel single-layer tube top and teeny swim bottoms instead, as most of my swimsuits have mucho air-trapping padding in the top).

I figure it would be wise to do as similar a "prep" as possible for the two sessions, so I'll make sure to make the second appointment for the same ToM, eat the same foods in the 24 hours before the weighing, wear the same suit, etc. Is there anything I'm not thinking of? Any suggestions for making the weighing as accurate as possible and "keeping variables constant" between the two weighing sessions?

My (cheapo) BF-reading scale puts me pretty consistently at 22%, so I'll post the hydrostatic number (and maybe pictures?) tomorrow for comparison!

i had a hydristatic done, and wasnt given any advice like that. all i was told was that the only things that float is fat and and air which is why they ask you to breathe all your air out. you dont need to wear a skimpy bathing suit, that wont make a difference. the only advice i can give is to practice breathing out as much of the air as possible in the bath tub. hope your happy with your results! i was very impressed with mine :)

[andre6313]

I started a cut for the new year and wanted to get a baseline BF% so I can see my progress at the end of 3 or 4 months. I have an appointment for hydrostatic weighing tomorrow at UIC's performance lab. The woman on the phone gave me the following prep tips and I was wondering if anyone had anything to add (or ideas on what I can actually eat!):

-No beans, fruits, veggies, whole grains, or fiber for 24 hours.
-No carbonated beverages for 24 hours.
-NOTHING except plain water for 4 hours before the test.
-Skimpiest, simplest 2-piece bathing suit I own (I'm thinking of wearing an American Apparel single-layer tube top and teeny swim bottoms instead, as most of my swimsuits have mucho air-trapping padding in the top).

I figure it would be wise to do as similar a "prep" as possible for the two sessions, so I'll make sure to make the second appointment for the same ToM, eat the same foods in the 24 hours before the weighing, wear the same suit, etc. Is there anything I'm not thinking of? Any suggestions for making the weighing as accurate as possible and "keeping variables constant" between the two weighing sessions?
My (cheapo) BF-reading scale puts me pretty consistently at 22%, so I'll post the hydrostatic number (and maybe pictures?) tomorrow for comparison!


If you don't mind me asking, how did you find this place? I looked on line to find a place that does it by me and can't seem to come up with anything? Anyone know of any links? thanks
op-good luck with your appt!

[ives]

If you don't mind me asking, how did you find this place? I looked on line to find a place that does it by me and can't seem to come up with anything? Anyone know of any links? thanks
op-good luck with your appt!

My trainer mentioned there was a dunk-tank at University of Illinois - Chicago, and I found the Performance Lab's web page with some minor Googling. I would imagine that the trainers at your gym would be able to recommend a few places near you. If you go the Google route, some good search words to try might be:

Underwater weighing
Hydrostatic weighing
Body composition
Body fat testing

I also came across bodpod.com in my searching. It's some kind of pressurized pod rather than water dunking, but they at least have a website with a clear directory of where you can find them (it's a proprietary and fairly rare machine, apparently).

Also, check if your local college or university has any sort of kinesthesiology/sports medicine/exercise science program, or if the university gym/fitness center does the testing and accepts "outsiders." The UIC lab is cheaper for students, but they're happy to dunk me for a slightly higher fee.

[lauren921]

I second checking out one of the universities. I had my RMR tested at one and they do the BF testing as well, but they use dexa scan instead of hydrostatic. According to them, dexa is more reliable but who knows.

[andre6313]

My trainer mentioned there was a dunk-tank at University of Illinois - Chicago, and I found the Performance Lab's web page with some minor Googling. I would imagine that the trainers at your gym would be able to recommend a few places near you. If you go the Google route, some good search words to try might be:

Underwater weighing
Hydrostatic weighing
Body composition
Body fat testing

I also came across bodpod.com in my searching. It's some kind of pressurized pod rather than water dunking, but they at least have a website with a clear directory of where you can find them (it's a proprietary and fairly rare machine, apparently).

Also, check if your local college or university has any sort of kinesthesiology/sports medicine/exercise science program, or if the university gym/fitness center does the testing and accepts "outsiders." The UIC lab is cheaper for students, but they're happy to dunk me for a slightly higher fee.

oh ok cool. There aren't any trainers at the gym I go to so google it is lol. I'm going to check it out now, thanks so much! Good luck!

[SeekingD]

I started a cut for the new year and wanted to get a baseline BF% so I can see my progress at the end of 3 or 4 months. I have an appointment for hydrostatic weighing tomorrow at UIC's performance lab. The woman on the phone gave me the following prep tips and I was wondering if anyone had anything to add (or ideas on what I can actually eat!):

-No beans, fruits, veggies, whole grains, or fiber for 24 hours.
-No carbonated beverages for 24 hours.
-NOTHING except plain water for 4 hours before the test.
-Skimpiest, simplest 2-piece bathing suit I own (I'm thinking of wearing an American Apparel single-layer tube top and teeny swim bottoms instead, as most of my swimsuits have mucho air-trapping padding in the top).

I figure it would be wise to do as similar a "prep" as possible for the two sessions, so I'll make sure to make the second appointment for the same ToM, eat the same foods in the 24 hours before the weighing, wear the same suit, etc. Is there anything I'm not thinking of? Any suggestions for making the weighing as accurate as possible and "keeping variables constant" between the two weighing sessions?

My (cheapo) BF-reading scale puts me pretty consistently at 22%, so I'll post the hydrostatic number (and maybe pictures?) tomorrow for comparison!

Greetings,

Hope all went well for you!
Actually, the most accurate tub weighings require you to sit completely naked in a sling in the hydrostatic tub before you dip yourself underwater to blow out all the air in your lungs (much easier said than done, by the way). The test should be repeated several times and then backtested with calipers to your skin. The first time people do this test, they tend to blow the air out too slowly and they come up for air before an accurate measurement can be taken because they feel like they are drowning. You have complete control of when you stick your head above water so you would never really drown but the sensation of running out of air is there, nonetheless.