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