BF% is wrong
Unfortunately, it's the scale, but it's not broken. It simply is telling you inaccurate information.
Some scales utilize Bioelectrical Impedance Analysis (BIA) technology. BIA uses very low levels of electrical impulses running from one metal contact
point/lead to another. Your body acts as the connector between the two
contact points, thus completing the circuit. Not all scales use this
means for calculating body fat percentage due to poor reliability and high fabrication costs.This method of measurement
requires very large contact points, as well as clean and moist skin
exposure. If you have dry/calluced feet, which is normal for most
Americans, the sensors can not accurately measure due to skin resistance.
Dry skin acts as a resistor to electrical impulse. Electricity passes through muscle and fat at
different rates. However, its measurements may be thrown off by how
hydrated you are and how much you've eaten; it may be too inaccurate
for anything other than comparative use. Users are encouraged to
establish a baseline measurement and repeat measurements under
consistent conditions over time to detect changes.
Many less expensive models simply use a body-fat calculator to average your imputed height in inches, waist measurement in inches and the current weight measurement recorded in lbs. The scale compares your measurement with the ideal norms inputed during the manufactoring process, thus giving you a comparison vs.imputed norms. People who are very, very fit can get
numbers 3 to 5 percent higher than their true percent body fat. Because they
don't have a lot of fat inside their muscles(visceral fat), the simple tape measure calculation test cannot adjust as it should indicate.
Conversely, if a person is skinny but not fit, this body fat test may yield a
number 3 to 5 percent lower than his or her true percent body fat. Though they
look thin, unfit skinny people really have more than the usual amount of fat
inside their muscles, which you can't see from the outside.
In either case, the scale is not necessary a measurement tool, due to high variables of test inaccuracy and interuser reliabilty; but, it is a good tool for comparing whether or not you are gaining/losing body fat.
If you would like a more accurate tool for simply measuring your body fat, you can pick up some pinch-calipers online for about the price of a scale. They come with an instructional pamphlet, very easy to use.
Jan 13, 2009 |
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