question bout bf% scales

[KillahBee]

had a fight with some broad lastnight about these scales that u step on, punch in your age, and it tells you your weight, bf%, and % of "lean muscle". how the hell does this work, and is it any more accurate than putting in your weight and height into a bf% calculator on the computer? she seems to think that when you step on the scale it magically feels your bf %. I assumed that it was an estimate based on scientific ratios and averages and the data you punch in.

thanks fo the input

 

[Babyfaced Assassin]

it's done by electrical impedence
it sends a curent or something through your body to measure fat levels. Whilst it can be some what accurate they can be incosistent depending on how hydrated you are or if you've just eaten or trained etc.

 

[KillahBee]

so it isn't just data? you are saying that it actually send a current through the body and is able to test it that way? i did not know that

 

[nEwSkIn]

Definitely NOT just data... it´s a bit more elaborate than that

 

[mrzap]

Right, it sends current through your body and tests resistence.

I'd say its +/- 2% accurate for me.

 

[juiceheadnyc]

Yeah they r a little off, but its still kinda helpfull.

Lets just say today it says 12%, now 1 month later u try it again and it says 9%, then i guess that tells u ur doing something rite.....

 

[Naeem]

I dont know, mine jumps from 19% to something crazy like 27%. I had a caliper test done, and that came in around 18-19%, so sometimes I guess the scales can be accurate

 

[wetback]

Two sales in about an hour.
One said 24%(no way thats right) and the other said 13%.

Both cost over $100.00, SO I think the scales are all crap.

 

[lamp24]

i have one for $50 and i have just about a full 6 pack and i am 19% on that... then i ate an hour later i was 24%...not to trust worthy

 

[freag34]

yup, i think i've heard in a few places that the numbers out of those machines are completeley dependent on how much you just ate and drank, since that'll affect the current's path through your body. i would especially not trust the machine if you're either on the high side or low side body fat wise

i use lange calipers which are expensive (i used ebay), but i think it's been a really good investment. they might be off from an absolute point of view, but no question i can track my relative body fat loss really well as i diet. This past few weeks it's given me readings of 8.5, 8, 7.5, 7, each week showing i'm down 0.5%/week using the 7-site method and calculator found here: http://www.rustyiron.net/formmal7.htm

 

[Lao Tzu]

nice link freag34, but i have a question for anyone about calipers. Doesn't your total body weight factor in with the bodyfat measurements? I weigh 290, and the bioelectrical methods always say 29% (the caliper method and that website said 23%). Doesn't the fact that i have about 60 lbs more lean body mass than a normal person make my BF % even lower?

 

[bigguns15]

IMO, the bioelectrical impedence machines are crap. It all depends on your hydration status. The more dehydrated you are, the "fatter" you will register on these machines.

 

[TimeaJr]

mine is unreliable too. hydration seems to be the major factor. i know i am bloated (damn deca) and so lately i have not even bothered paying attention to the % on the scale because it is so off. i had my calipers done and it was 6% points out from what the scale was saying! the accuracy is usually better than this but it does vary a lot. imho do calipers...save that cash for gear.

 

[pwr_machine]

Pretty much like everyone said, this method uses electrical conductivity to estimate fat-free mass. Water conducts electricity. Muscle holds the majority of water in the body. Since this test is dependent upon hydration status, it can skew the results of his bodyfat. I've seen reports of these being about
+/- 8 to 10 % off.


Calipers are your best bet and readily available.