Lab 7 Body Composition

one group of researchers recommends a "health standards" body fat percentage range of ______ for women under 35 years old, and _______ for men under 35 years old

20--35% 8--22%

skin fold measurements sources of variability account for a standard error of approximately _______%

3.5%

The cutoff of EA at which negative health consequences occur varies between individuals, but studies in which EAhas been manipulated have shown clear deleterious effects with EA less than _______ kcal/kg FFM/day

30

refers to the measurement of the body

Anthropometry

Waist circumference is used in conjunction with _______ to assess health risk

BMI

a simple, inexpensive, quick, and non-invasive technique for measuring body composition

Bioelectrical impedance analysis (BIA)

__________ is a system that utilizes X-rays to scan and quantify the parameters of body composition

Dual-energy x-ray absorptiometry (DEXA)

This laboratory utilizes the _________ to predict percent body fat, which is a _________ equation

Siri equation generalizable

T or F Across the population, there are relationships between BMI and disease risk

T

T or F There are no accepted standards for percent body fat, and all methods of measurement are indirect and involve error.

T

T or F an individual who has a BMD t-score of -2.6 is deemed to have osteoporosis by WHO criteria

T

compares your bone density to the average bone density of someone your same age, sex, and race/ethnicity

Z score

waist circumference measures

abdominal obesity and fat distribution

________ represents how close a measured value is to the true value

accuracy

proportion of subcutaneous to total body fat varies with

age, sex, race or ethnicity, and several other factors

_________ represents whether there are systematic differences between measured and true values

bias

refers to the makeup of the body

body composition

_________ causes greater resistance (impedance) than _________ and slows the rate at which the current travels.

body fat (adipose tissue) fat- free mass

Although national standards have been adopted for BMI and waist circumference, none exist for estimates of _____________

body fat percentages

Lean mass (kg) equation

body mass (kg) - fat mass (kg)

normal bone density levels

bone density is within 1 SD (+1 or -1) of the young adult mean

energy availability (EA) is defined as

dietary intake - exercise energy expenditure)/fat free mass (FFM) and is expressed in kcal/kg

In general, the risk for bone fractures ______ with every SD below normal.

doubles

_________ methods are derived from indirect methods

doubly indirect

skinfold measurements are _______ - why

doubly indirect the equations to predict body density from skinfolds are based on hydrostatic weighing, an indirect method that utilizes water displacement to estimate fat mass.

why have waist circumference measurements not been widely adopted

due to questions in standardization

Bioelectrical impedance analysis (BIA) is based on the principle that

electrical current flows at different rates through the body depending upon its compositions

As methods become further away from the direct method, there is __________ error in the estimate

greater

Fat located in the abdominal region (visceral fat) is associated with a __________ health risk than peripheral fat

greater

Each component of the triad exists on a spectrum ranging from

health to disease

_______ methods are derived from direct methods involving cadavers

indirect

the athlete triad as a syndrome of three interrelated conditions that includes:

low energy availability (with or without disordered eating) functional hypothalamic amenorrhea (females) or hypogonadotropic hypogonadism (males) osteoporosis

The body is composed of

mostly of water with ions, through which an electrical current can flow also contains non-conducting materials (body fat) that provide resistance to the flow of electrical current

a complex, multifactorial disease involving the interaction of physiological, metabolic, genetic, social, cultural, and behavioral factors

obesity

It is well documented that the increasing prevalence of ____________ and ________ create significant health issues

overweight and obesity

_________ equations will be inaccurate if it is applied to individuals who differ in physical characteristics

population-specific

types of information derived from body composition

risk assessment individualization of exercise prescriptions evaluating interventional progress

If performed by a professionally trained technician with a quality skinfold caliper, __________ can assess percent body fat with a standard error of estimate (SEE) of ~3.5%

skinfold measurements

the DEXA scan can measure which types of fat

subcutaneous fat, but visceral, retroperitoneal, and intramuscular fat

Major limitations of the skinfold analysis include

technician training, applicability of equations to the individual being tested, skinfold site measurement accuracy, and measurement technique

One problem that is associated with BMI

there is no way to determine the composition of the weight. Therefore, BMI is not an adequate measurement of disease risk for some individuals (i.e., weight-training individuals).

individuals who are farther away from the average in physical characteristics can be ______ or ________ in terms of body fat percentage using the Siri equation

under or overestimated

which type of fat is an independent risk-predictor when BMI is not markedly increased.

visceral fat

a valuable measurement to assess central obesity

waist circumference

4 potential sources of error for anthropometric measurements (BMI and waist circumference)

- No way to determine composition - questions in standardization of weight - only measures waist, can carry fat in other places - weight training individuals

4 potential sources of error for skinfold measurements

- technician training - applicability of equations to tested individuals - skin fold site measurement accuracy - measurement technique

Skinfold measurements are based on two primary assumptions:

1. subcutaneous fat is directly proportional to total fat 2. the skin fold sites selected are representative of total body subcutaneous fat

Current BMI standards for adults are divided into ______ categories

6

T or F You can be certain that an individual with a z score of 0 does not have osteoporosis

F

compares your bone density to the average bone density of young healthy adults of the same sex

T score

at a given BMI, why does an elevated waist circumference confer increased risk of chronic disease

an elevated waist circumference is indicative of abdominal obesity, and a higher amount of visceral fat in the abdominal region is associated with greater health risks than peripheral fat

Fat mass (kg) equation

body mass x body fat % (as a decimal)

BMI is a measure of the ratio of what

body weight to height

screening programs asses which body measurments

body weight, body height, and waist circumference

osteoporosis bone density levels

bone density is 2.5 SD or more below the young adult mean (-2.5 SD or lower)

low bone density levels

bone density is between 1 and 2.5 SD below the young adult mean (-1 to -2.5 SD)

There are multiple ways to assess body composition, and each method is associated with its own ______

error

___________ equations are developed from diverse, heterogeneous samples, and accountfor differences in age, gender, race or ethnicity, and other characteristics

generalizable

the total percentage of body fat is often significantly _______ than anthropometric results.

higher

Because there is no direct in vivo method available to measure the different components of the body, any body composition technique performed on live humans is either_____ or __________

indirect or doubly indirect

DEXA differentiates body weight into three chemical components:

lean soft tissue, fat soft tissue, and bone

_________ represents how close measured values are to each other

precision

Body composition methods may utilize _________ equations to make estimates.

prediction

The bone mineral density (BMD) scores you receive from your DEXA scan are measured as

standard deviations (SD) from the mean (T and Z score)

____________ should be utilized for assessments of obesity and for monitoring the efficacy of weight-loss program

waist circumference