[quote]Ecchastang wrote:
[quote]Mad Martigan wrote:
[quote]Ecchastang wrote:
[quote]gregron wrote:
[quote]Professor X wrote:
[quote]Ecchastang wrote:
[quote]Professor X wrote:
[quote]Ecchastang wrote:
Also, 10% bodyfat will cause a person to be bouyant in water, and I sink like a rock. [/quote]
This is untrue. The lighter you are in body weight, the more bouyant you are all by itself.
One sinks until the density of the surrounding water equals one’s density,
The volume of air in your lungs changes with the surrounding pressure too.
[/quote]
The test is done after an exhale.[/quote]
I understand that. However, being “10%” itself does not affect bouyancy because there are too many other variables.
In fact, that number itself means nothing at all as far as any constant response seen.
As far as yourself, you look fine…and the exact number you are is irrelevant.[/quote]
Bone density is a big factor in sinking isn’t it?[/quote]
A hydrostatic test is not much difference than bouyance, as it is measuring water weight displacement. Also, bone density can only be changed very slightly with exercize, lifting, ect.[/quote]
The root of your argument was simply that a person at 10% bf or above would be buoyant, and because you are not buoyant, you must therefore be lower than 10% bf.
The Brodigal Son Who Hath Returned, Professor X, is pointing out the flaw in your logic by explaining that there are many other variables to consider. Somebody with high bone density and significant muscle mass may still sink at bf well above 10%, while another, slighter-boned, untrained individual at 10% bf may not.
You are correct that the ultimate issue is body density, but this point alone undermines your argument above, as reasonable people would agree that body density is affected by much more than bf % alone.[/quote]
You negate the accuracy of hydrostatic testing by your argument.[/quote]
No, I was simply pointing out that your buoyancy argument doesn’t work.
Furthermore, even hydrostatic testing is only an estimation, albeit more accurate than other methods. There is still appreciable error because of the things that have already been discussed; bone density, muscle mass, etc. It’s my understanding that it can be off by as much as 2-3%.