Homonuncleus and others (hydrostatic testing)

[Doggcrapp]

Randy (or anyone for that matter) have you done hydrostatic testing offseason or precontest--and if so after learning your lean mass totals where you able to get close to your calculated 3%-4% or so in a show?

[Storm]

It will probaly be easier to go to a gynocologist(sp) or a radiology dept and get a bone density scan (DEXA)...It is suppose to be the most accurate way to do BF...I have seen where guys pay only 50-100 bucks but in my area it is 300...Getting a hydro test is sometimes hard to find where to get it done at..Big colloges sometimes have them but can be picky on who they let use it..Storm

[In-Human]

It will probaly be easier to go to a gynocologist(sp) or a radiology dept and get a bone density scan (DEXA)...It is suppose to be the most accurate way to do BF...I have seen where guys pay only 50-100 bucks but in my area it is 300...Getting a hydro test is sometimes hard to find where to get it done at..Big colloges sometimes have them but can be picky on who they let use it..Storm

You would be surprised, they show up at our gym with a truck mounted service and its $10.00 to dunk and hold your breath...

[homonunculus]

Dante,

Haven't done hydrostatic for years, but I did do it once a couple weeks after a show (my first, years ago) and it gave a good # (but I was 172 or so then...). There are equations that should be used instead of the Siri eq. (see Modlesky et al., circa 1998 I think) that will give a more accurate value for BF% based on density with males who train w/ weights...

The problem w/ comparing pre-contest w/ off-season is mainly d/t water retention (d/t gear, for instance), which violates the assumptions of the hydrostatic method. I'll spare the details, but basically, being water logged will decrease your measured density and therefore increase your estimate of BF%. Once you get dry and are show-ready, the density of your fat-free mass (simply from water loss) will increase, giving a reading of a lower %BF. (FYI, the opposite effect occurs when using bioelectrical impedance... LOL)

Take this example:

300lb offseason BB'er gets tested at 20% BF, giving 240lb of Fat-free mass (FFM). This BF%value is artificially high b/c he is water-logged. He actually has MORE fatfree mass than this. (If he were to drop his water, he would be maybe 285, and test at say 11%, giving ~253 lb of fat-free mass.)

He comes in 2 weeks out from the show, but has dropped a ton of water (as well as fat). He weighs in at 250, and tests at 5%, giving 237lb of fat-free mass.

Given the confounding effects of water retention, he appears to have lost only 3 lb of fat-free mass, while losing 47 lb of fat.

The gym performance speaks differently, as does the estimates of FFM when the water retention is under control. If he were to have taken an off-season measurement when not watter logged, he would calculate a loss of 16lb of fat-free mass (muscle essentially) and this is what is seen in the gym: a ~10-15% loss of strength.

I think I've managed to get to 3% for this show. (The last time I was tested, I was 30 lb lighter, 2 weeks post-show and not as lean as I am now.) However, it really don't make a damn bit of difference, IMO.

For me: the mirror and the weights don't lie. If I lose strength, I've lost muscle. If I look leaner, i've lost fat.

I personally think a better way to deal with this is actually to use gym strength (e.g., like with your programs, Dante) and just use a caliper measurement or two at strategic locations (not necessarily those for BF estimation protocols). Pick a place or two where the person holds fat (abs and front of thigh are good) and use a landmark (bone, freckle, other anthropometric measure - whatever) to make sure the fold location is somewhat standardized.

Weights go up - more muscle.
Skinfolds go down - less fat.

(Hope this answers your question, or at least gives some info to think about... Sorry I don't have more practical experience - I've had plenty of opportunity to do this, but didn't really see the point. If only I could use a BF% test as a trump card to win over the judges when its a close call... LOL)

-R

[tpc]

we used to have hydrostatic tank at school in our department, we also had this thing called a bod pod. it looks like an egg and extremely accurate, quick and easy.

d

[homonunculus]

we used to have hydrostatic tank at school in our department, we also had this thing called a bod pod. it looks like an egg and extremely accurate, quick and easy.

d

TPC, where'd you go to school?... PM me if ya want...

-R

[tpc]

penn state

[homonunculus]

Know Bill Kraemer or Jeff Volek?...

-R

[tpc]

i don't know them, but i know of them. used to love reading their studies on creatine. small world, why do you know them.

d

[homonunculus]

i don't know them, but i know of them. used to love reading their studies on creatine. small world, why do you know them.

d

I'll PM ya on that one... Time to hit the sack...

-R

[nemo]

from what i have heard the problem with hydrostatic is you have to blow out as much of your air as possible and stay that way for a bit while underwater. how much air thats left in different peoples lungs varies and this affects the accuracy. also some people get freaked out about the whole being underwater while blowing out their air part.

DEXA and Bod Pod are the best. Bod Pod uses air displacement and is really easy to do

[Ken Skip Hill]

Dexa is the way to go. The most accurate and very easy to do. You keep your clothes on, lay on the table very still for about 4-5 minutes while you are basically X-rayed. It breaks down bodyfat levels in different areas of your body - ie: right arm vs. left arm, right leg vs. left leg, torso, etc..

There are small upstart companies that go around to larger gyms and do these for only about 50 bucks. It is money well spent. I used it every 4 weeks during this last prep of mine.

Skip

[PTAaron]

I've read about DEXA, but never heard of the Bod Pod... how does air displacement give an estimate of body composition? Just curious.

EDIT: Okay, looked at www.bodpod.com - makes sense... never mind ... :chair:

[homonunculus]

Skip's right - I'd take DEXA (or DXA) every time over hydrostatic or the BodPod. (FYI, the bodpod and hydrostatic are both based on the principle that the body is composed of 2 components (fat-free mass and fat mass), having distinctly different values. The body pod gets body density the same as hydrostatic does, just differently - air diplacement vs. water displacement. The bodpod is simply much more convenient...)

-R

[SweatMachine]

I work here at the space center and have access to a tank. Its a pain in the ass to schdule but you all think its accurate enough to be worht my time I would go get tested. Ive heard it wasnt much more accurate than calipers....