FW190 Body Composition
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Transcript of FW190 Body Composition
Chapter
6
Copyright © 2017 McGraw-Hill Education. All rights reserved.
No reproduction or distribution without the prior written consent of McGraw-Hill Education. 1
Ahead:
What Is Body Composition,
and Why Is It Important?
Assessing Body Mass Index, Body
Composition, and Body Fat Distribution
Setting Body Composition Goals
Making Changes in Body Composition
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The human body is
divided into fat-free
mass and body fat
Fat-free mass is the body’s
nonfat tissues
▪ Bone, water, muscle, connective
tissue, organ tissues, and teeth
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Essential fat: fats incorporated in various
tissues of the body, critical for normal body
functioning
Adipose tissue: tissue in which fat is stored;
fat cells
Subcutaneous fat: fat located under the skin
Visceral fat: fat located around major organs;
also called intra-abdominal fat
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SOURCE: Adapted from Brooks, G. A., et al. 2005. Exercise
Physiology: Human Bioenergetics and Its Applications, 4th ed.
New York: McGraw-Hill; Santos, D.A., et al. 2014. Reference
Values for body composition and anthropometric measurements
in athletes. PLoS ONE 9(5): e97846.
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Most important consideration: proportion of
body’s total weight that is fat
Percent body fat: percentage of total body weight
that is composed of fat
Overweight: body weight that falls above the
recommended range for good health
Sometimes defined as a body mass index between
25 and 29.9, a measure of the proportion of weight
to height
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Obesity: severely overweight, characterized by
an excessive accumulation of body fat
May also be defined in terms
of some measure of total body
weight or a body mass index
of 30 or more
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Prevalence of obesity increased from 13% in
1960 to 27.7–34.9% today
62–69% of adult Americans are overweight
About 35.5% of men and 36.1% of women are
obese, according to the latest statistics
Obesity rates increased most among middle-aged
and older adults
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Possible explanations:
More sedentary work and leisure activities
Fewer short trips on foot, and more by automobile
Fewer daily gym classes for students
More meals eaten outside the home
Greater consumption of fast food
Increased portion sizes
More soft drinks and convenience foods
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Percentage Obese
Category 2008 2014 Difference (% points)
All adults 25.5 27.7 2.2
Ages 18-29 17.4 17.7 0.3
Ages 30-44 27.0 29.3 2.3
Ages 45-64 29.5 33.0 3.5
Ages 65 + 23.4 27.4 4.0
Women 23.9 26.7 2.8
Men 27.0 28.7 1.7
Whites 24.3 26.7 2.4
Hispanics 28.8 28.3 -0.5
Blacks 35.0 35.5 0.5
Annual income less than $36,000 30.0 32.3 2.3
Annual income $36,000-$89,999 25.8 27.7 1.9
Annual income $90,000 + 21.1 23.1 2.0
Midwest 26.8 29.7 2.9
South 26.9 29.2 2.3
East 24.7 26.6 1.9
West 22.8 24.6 1.8
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Metabolic syndrome: cluster of symptoms
present in many overweight and obese people
that greatly increases their risk of heart disease,
diabetes, and other chronic illnesses
Symptoms include insulin resistance, abnormal
blood fats, abdominal fat deposition, type 2 diabetes,
high blood pressure, and high blood glucose
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Conditions associated with metabolic
syndrome:
Chronic inflammation: a response of blood vessels
to such harmful substances as germs, damaged
cells, or irritants; can lead to heart disease, cancer,
allergies, and muscle degeneration
Fatty liver: increased fat storage in the liver; can
lead to liver inflammation and failure
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Distribution of body fat is an important indicator
of health
Apple shape versus pear shape
Abdominal fat may be more easily mobilized and
sent into the bloodstream, increasing disease-related
blood fat levels
Waist circumference helps assess risks of unhealthy
body fat distribution
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Too much body fat makes physical activity
difficult
Overfat people are less fit than others and lack
the muscular strength, endurance, and flexibility
that make normal activity easy
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Being perceived as fat can be a source of
ridicule and ostracism, and can contribute to
psychological problems
Popular image of the “ideal” body has changed
greatly in the past 50 years
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Overweight is associated with a substantial
increase in the risk of type 2 diabetes
Diabetes interferes with insulin production;
causes buildup of glucose in the blood
Types of diabetes
Type 1
Type 2
Gestational
Prediabetes
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Diabetes treatment
No cure
Managed through diet, exercise, medication
Diabetes prevention
90% of type 2 diabetes cases could be prevented by
lifestyle changes
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Warning signs and testing for diabetes
Frequent urination; extreme hunger and thirst,
unexplained weight loss; extreme fatigue; blurred
vision; frequent infections; cuts and bruises that are
slow to heal; tingling and numbness in the hands or
feet; generalized itching with no rash
Screening involves a fasting blood test to check
glucose levels
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Health experts generally view too little body fat
as a threat to health
Too little for women: less than 8–12%
▪ Amenorrhea: absent or infrequent menstruation, sometimes
related to low levels of body fat and excessive quantity or
intensity of exercise
Too little for men: less than 3–5%
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Female athlete triad: condition consisting of
three interrelated disorders
Abnormal eating patterns (and excessive exercising)
A lack of menstrual periods (amenorrhea)
Decreased bone density
(premature osteoporosis)
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Some methods based on body fat; others on
total body weight
Assessments can provide information about
health risks and help establish reasonable
goals
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Body mass index (BMI): measure of relative
body weight correlating highly with more direct
measures of body fat Calculated by dividing total body weight (in
kilograms) by the square of body height (in meters)
BMI between 18.5 and 24.9 is considered healthy
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Body Mass Index (BMI) Classifications
WEIGHT STATUS CLASSIFICATION BODY MASS INDEX
Underweight <18.5
Severe thinness <16.0
Moderate thinness 16.0-16.9
Mild thinness 17.0-18.4
Normal 18.5-24.9
Overweight 25.0-29.9
Obese, Class I 30.0-34.9
Obese, Class II 35.0-39.9
Obese, Class III ≥40.0
Waist Circumference Classifications
WAIST CIRCUMFERENCE IN INCHES
(CENTIMETERS)
WAIST CIRCUMFERENCE IN
INCHES (CENTIMETERS)
RISK CLASSIFICATION WOMEN MEN
Normal <32 in. (80 cm) <37 in. (94 cm)
Increased ≥32 in. (80 cm) ≥37 in. (94 cm)
Substantially increased ≥35 in. (88 cm) ≥40 in. (102 cm)
SOURCE: Adapted from World Health Organization. 2008. Waist Circumference and Waist-to-Hip Ratio. Report of a WHO
Expert Consultation. Geneva: WHO.
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Underwater weighing
Individual submerged and weighed under water
Percentage of fat and fat-free
weight calculated from body density
The Bod Pod
Small chamber containing
computerized sensors
measures body composition
by air displacement
BOD POD® Body Composition Tracking
System photo provided courtesy of
COSMED USA, Inc.
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Skinfold measurements
Measures thickness of skinfolds
at different places on the body
Caliper: pressure-sensitive
measuring instrument with two
jaws that can be adjusted to
determine thickness of the skinfold
Important to test exact sites, to measure several
different times, and to take measurements at
approximately the same time of day
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Photo
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Bioelectrical impedance analysis (BIA)
Works by sending a small electrical current through
the body and measuring the body’s resistance to it
Advanced techniques: DEXA and TOBEC
DEXA works by measuring tissue absorption of
high- and low-energy X-ray beams
TOBEC estimates lean body mass by passing a
body through a magnetic field
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WOMEN
Body Fat
Classification
20-39
YEARS
40-59
YEARS
60-79
YEARS
Essential* 8-12 8-12 8-12
Low/athletic** 13-20 13-22 13-23
Recommended 21-32 23-33 24-35
Overfat†
33-38 34-39 36-41
Obese†
≥39 ≥40 ≥42
MEN
Body Fat
Classification
20-39
YEARS
40-59
YEARS
60-79
YEARS
Essential* 3-5 3-5 3-5
Low/athletic** 6-7 6-10 6-12
Recommended 8-19 11-21 13-24
Overfat†
20-24 22-27 25-29
Obese†
≥25 ≥28 ≥30
NOTE: The cutoffs for recommended, overfat, and obese ranges in this table are based on a study that linked body mass index
classifications from the National Institutes of Health with predicted percent body fat (measured using dual-energy X-ray
absorptiometry).
*Essential body fat is necessary for the basic functioning of the body.
**Percent body fat in the low/athletic range may be appropriate for some people as long as it is not the result of illness or disordered
eating habits.
†Health risks increase as percent body fat exceeds the recommended range.
SOURCES: Gallagher, D., et al. 2009. Healthy percentage body fat ranges: An approach for developing guidelines based on body mass index. American
Journal of Clinical Nutrition 72: 694-701; Swain, D. P. 2013. ACSM's Resource Manual for Guidelines for Exercise Testing and Prescription, 7th ed.
Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins Health.
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Waist circumference measurement and
waist-to-hip ratio calculations are the easiest
to perform
Total waist measurement of more than
40 inches for men and 35 inches for women
and a waist-to-hip ratio above 0.94 for young
men and 0.82 for young women are associated
with increased risk of heart disease and
diabetes
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Endomorphs are round and pear shaped, with
wide hips and shoulders
Mesomorphs are lean and muscular and
respond well to exercise
Ectomorphs are thin and linear, with narrow
hips and shoulders
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If assessment tests indicate that fat loss would
be beneficial, the first step is to establish a
realistic goal
Be sure your goal is realistic and will ensure
good health
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If you are overfat or have known risk factors,
consult a physician to determine a body
composition goal for your individual risk profile
Decide whether the body weight the formulas
suggest is realistic, meets your goals, is healthy,
and is reasonable to maintain
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