Anthropometrics

bioelectrical impedance

based on lean tissues electrical conductivity and impedance compared to water basin on electrolyte content

Advantages: moderate cost, quick, comfortable

Disadvantages: results affected by hydration status, obesity, electrolyte imbalance, fever, fitness level, body temperature, time of day; poor accuracy-error rate of 8%; can’t be used with individuals with pacemakers and defibrillators

DEXA

gold standard for body composition-gray showing muscle, fat, and bone tissue-direct measure

advantages: error rate <2%; comfortable

disadvantages: expensive, exclusive to medical facilities; requires x-ray technician operator, not accurate for extreme obesity; may take up to 20 minutes

BodPod

Uses total body density, measures air displacement by the body-indirect measure

advantages: fast, safe, non-skilled technician; <2% error rate, able to test elderly, obese, and children

disadvantages: cost of machine, not portable

BMI equation

Wt(lbs)/ht(inˆ2)x 703.1

Ideal Body weight (Hamwi equation)

Men: 106lbs for first 5ft + 6lbs for every inch

Women: 100 for the first 5ft  + 5lbs for every inch

How does frame factor in to ideal body weight?

• Frame size (use range of +-10% to adjust for frame size for ideal body weight): ratio of height to wrist circumference 

Frame Size	Male	Female
Small	>10.4	>11.0
Medium	9.6-10.4	10.1-11.0
Large	<9.6	<10.1

What waist size increases the risk of metabolic disorders in men and women?

>40in for men

>35 for women

What waist to hip ration increases the risk of metabolic disorders in men and women?

>1.0 for men

>0.8 for women

accuracy

how close is the measurement to the true value?

validity

does it measure what it intended to be measured by the instrument/tool?

sensitivity

are large changes detected as a result of a small change?

In a BIA, what %TBW indicates dehyratation

<69%

BMI classifications

Underweight: <18.5

Normal: 18.5-24.9

Overweight: 25.0-29.9

Obesity 1: 30.0-34.9

Obesity 2: 30.0-39.9

Extreme Obesity: >40

How can you determine height from arm span?

(sternal notch to fingertips)x2