Transcript 13 - Body Composition - Central Connecticut State University

Presentation Package for
Concepts of Physical Fitness 14e
Section V: Concept 13
Body Composition
Possessing an optimal amount of body fat
contributes to health and wellness.
All rights reserved
Understanding & Interpreting
Body Composition Measures
• Component of health-related fitness & a
component of metabolic fitness.
• Standards have been established for
healthy levels of body fatness (see next
slide)
• Health standards have been established
for the Body Mass Index.
• Assessing body weight too frequently
can result in making false assumptions
about body composition changes.
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Concepts of Physical Fitness 14e
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Concepts of Physical Fitness 14e
Methods Used to Assess
Body Composition
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DXA
Underwater Weighing
Bod Pod
Skinfold technique
Other
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Concepts of Physical Fitness 14e
Dual-energy
Absorptiometry (DXA)
• “Gold Standard” measure of
body composition.
• Provides whole body
measurements of body fatness
as well as amounts stored in
different parts of the body.
• Highly accurate measure of body
composition for research and a
criterion measure that has been
used to validate other, more
practical measures of body
composition.
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Concepts of Physical Fitness 14e
Click for
more info
Underwater Weighing
A person is weighed in
air and under water, and
the difference in weight
is used to assess the
levels of body fatness.

Body fat provides
more buoyancy, so a
fatter person weighs
less (on a relative basis)
than a lean person.

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Concepts of Physical Fitness 14e
Web13-3 for info on underwater weighing
Bod Pod
• Uses the same principles as underwater
weighing, but relies on air displacement
to assess body composition.
• Evidence suggests that it provides an
acceptable alternative to underwater
weighing and is particularly useful for
special populations (obese older people
and the physically challenged).
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Concepts of Physical Fitness 14e
Skinfold Technique
Layers of
subcutaneous
fat are measured at
different sites of
body
to estimate total
body fat levels
Cross sectional
view
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Concepts of Physical Fitness 14e
Benefits of Skinfold Technique
• Skinfold measurements are the
preferred, practical method of assessing
body fatness.
• Fairly accurate
• Easy to perform
• Inexpensive
Lab 13a info
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Concepts of Physical Fitness 14e
Common Skinfold Sites
7 site procedure
Chest
Axilla
Tricep
Subscapular
Abdomen
Supraillium
Thigh
Chest
Abdomen
Thigh
Triceps
Supraillium
Thigh
Alternative Sites
(Males & Females)
Validation statistics on 3 site test:
- r = .97 with 7 site procedure
- R2 = .80 with underwater weighing
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Jackson and Pollack
Males
Female
Tricep
Abdomen
Calf
Concepts of Physical Fitness 14e
Web13-04
Research Quality
Skinfold Calipers
Harpenden Calipers
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Lange Calipers
Concepts of Physical Fitness 14e
Other Body Composition
Assessments
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Bioelectrical Impedance
Infra-Red Spectroscopy
Ultrasound
Imaging Techniques
Click to see
more info on all
techniques
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Concepts of Physical Fitness 14e
Lab 13b
info
Anthropometric
Measurements
• Body Mass Index (BMI)
More info
• Waist to Hip Ratio (WHR)
More info
• Circumference measures
More info
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Concepts of Physical Fitness 14e
Body Composition Assessment
Implications of Results
• Values are estimates (+/- 2-3% at best)
• Values are personal and confidential
Proper uses of results:
- Serve as baseline data for repeated testing
- Provide motivation for goal setting
- Provide awareness about health risks
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Concepts of Physical Fitness 14e
Health Risks Associated with
Being Overweight
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Coronary heart disease
Hypertension
Hypercholesterolemia
Diabetes
Premature death
Physical fitness provides protection
from the health risks of obesity.
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Conceptsassociated
of Physical Fitness 14e
There are also
health risks
with being too thin!
Click for more
info on fat
deposition
Regional Fat Deposition
• Abdominal body fat poses greater health
risks than fat stored in other areas
• Males store more fat
centrally and have
increased health
risks associated
with body fatness
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Male (apple)
Higher health risk
Concepts of Physical Fitness 14e
Female (pear)
Lower health risk
Health Risks Associated with
Excessively Low Body Fatness
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Anorexia Nervosa
Bulimia
Anorexia Athletica
Female Athlete Triad
Muscle Dysmorphia (males)
Fear of Obesity
Concepts of Physical Fitness 14e
The Origin of Fatness
Lab 13c info
• Obesity is a multifactorial disease that is
influenced by both genetics and the
environment.
• Body weight is regulated and maintained
through complex regulatory processes.
– Set-point
• Fatness early in life leads to adult fatness.
• Changes in basal metabolic rate can be the
cause of obesity.
• “Creeping Obesity” (see next slide)
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Concepts of Physical Fitness 14e
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Concepts of Physical Fitness 14e
Relationship Between PA &
Body Composition
• Combination of regular PA and dietary
restriction is the most effective means of
losing body fat.
• PA that can be sustained for relatively long
periods is considered the most effective for
losing body fat.
• Strength training can be effective in
maintaining a desirable body composition.
• Regular PA is critical for building and
maintaining bone health.
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Concepts of Physical Fitness 14e
Target Zone - Body Fat Reduction
Table 3, p. 285
Physical Activity
Diet
Daily moderate PA;
3-6 days/wk
vigorous PA
Consistently
and daily
Slow, low-intensity
that results in ≤1-2
lbs/week of fat loss
30-60 minutes
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Concepts of Physical Fitness 14e
Modest
caloric
restriction
Moderate
meals
Obesity Trends* Among U.S. Adults
BRFSS, 1990, 1995, 2005
(*BMI 30, or about 30 lbs overweight for 5’4” person)
1995
1990
2005
No Data
<10%
10%–14%
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15%–19%
20%–24%
25%–29%
Concepts of Physical Fitness 14e
≥30%
Web Links
• Behavioral Risk Factor Surveillance
System (BRFSS) Interactive Web Page
http://www.cdc.gov/brfss/
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Concepts of Physical Fitness 14e
Summary
• Obesity is prevalent in society.
• Need to find ways to maintain optimal
body composition.
• Use assessments to determine body
composition and make the necessary
healthy changes to physical activity
and diet.
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Concepts of Physical Fitness 14e
Web Resources
Online Learning Center
“On the Web” pages for Concept
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Concepts of Physical Fitness 14e
Supplemental
Graphics
•Lab Information
•Detail on BMI calculations
•Graphics on Obesity Trends
Lab 13a Information
Evaluating Body Composition - Skinfolds
• The purpose of this lab is to
evaluate body composition
with the skinfold assessment.
• Comparisons will be made
between different procedures
and testers to learn about the
accuracy of the tests.
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Concepts of Physical Fitness 14e
Lab 13a Information
Skinfold Technique
presentation
• Measurement Technique:
– Mark site with marker
– Pinch fold above and below
mark with left and right hand
– Measure fold with caliper
using the right hand
• Scoring Procedure:
– Sum skinfolds from the 3 sites
– Look up percent body fat value
from chart in the book
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Return to
Concepts of Physical Fitness 14e
Lab 13b Information
Evaluating Body Composition – Height, Weight, and
Circumference Measures
• The purpose of this lab is to
evaluate body composition
with some anthropometric
assessments
– Height/Weight
– Body Mass Index
– Waist to Hip Ratio
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Concepts of Physical Fitness 14e
Lab 13b Information
BMI Measurement Technique
Return to
presentation
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Convert weight to kilograms (2.2 kg/lb.)
Convert height to meters (.0254 m/in)
Square the height in meters
Divide the squared height value into the
weight value
BMI = Wt (kg) / Ht2 (m)
See Web13-06 for BMI calculators
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Concepts of Physical Fitness 14e
Lab 13b Information
WHR Measurement Technique
Return to
presentation
• Waist: Measure at the "natural waist"
(smallest circumference) or at the
level of the umbilicus
• Hip: Measure at the maximum
circumference of the buttocks
Divide the hip measurement into the
waist measurement to obtain the WHR
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Concepts of Physical Fitness 14e
Sample BMI Values
Return to
presentation
This chart reveals how BMI values change for a
hypothetical 6 foot tall person of different body weights
See Web1306 for BMI
calculators
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HT (in.)
WT (lb.) BMI
72
72
72
72
150
180
190
200
Concepts of Physical Fitness 14e
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25
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Definitions of Overweight
Return to
(Based on BMI values)
presentation
• BMI accounts for differences in frame size
better than height weight tables.
BMI = Wt (kg) / Ht2 (m)
Problem: BMI does not take
Standards:
muscles mass into account
– Overweight:
> 25
– Obesity:
> 30
– Severe obesity
> 40
Web13-1 for more
information on standards
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Concepts of Physical Fitness 14e
Lab 13c Information
Return to
Determining Your Daily Energy Expenditure
presentation
• Estimate your basal metabolism.
• First determine the number of minutes you sleep.
• Monitor your activity expenditure for 1 day. Record
the number of 5-, 15-, and 30-minute blocks of time
you perform each of the different types of physical
activities (e.g., if an activity lasted 20 minutes, you
would use one 15-minute block and one 5-minute
block). Be sure to distinguish between moderate
(Mod) and vigorous (Vig) intensity in your logging.
• Discuss your daily caloric expenditure. In addition,
comment on whether you think you should modify
your daily caloric expenditure for any reason.
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Concepts of Physical Fitness 14e
Regional Fat Deposition
Visceral Fat
• Visceral body fat poses greater health
risks because this fat is more labile and
has greater access to the circulation.
• The accumulation of visceral body fat is
typical of the android (male) fat pattern
– males: visceral accounts for 10-35% of total fat
– females: visceral accounts for 8-13%of total fat
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Concepts of Physical Fitness 14e
Abdominal Body Fat
Relationships with CHD Risks
• Abdominal obesity predicts CHD risk
independent of BMI, smoking, cholesterol
and hypertension.
(Kannel et al., J. Clin Epid., 44, 183-190, 1991).
• Abdominal obesity predicts CHD risk
independent of total body fatness.
(Larsson et al. ,Appetite, 13, 37-44, 1989).
• Abdominal obesity statisticallly accounts for
difference in CHD rates between men and
women. (Larsson et al., Am. J. Epi., 135: 266-273, 1992).
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Concepts of Physical Fitness 14e
Abdominal Body Fat
Relationships with other risk factors
• Abdominal obesity is strongly influenced by genetics similar gain among twins (r=.72).
(Bouchard, NEJM, 322, 1477-1482, 1990).
• Abdominal obesity is greater in smokers than nonsmokers due to the presence of androgens
(Barrett-Conner, Ann. Int. Med. 111, 783-787, 1989).
• Abdominal body fat is preferentially lost during a
physical activity program
(Kohrt, J. Gerontology, 47: M99-M105, 1992)
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Concepts of Physical Fitness 14e
Waist to Hip Ratio
(WHR)
Return to
presentation
• Waist to Hip Ratio is an effective way
to examine regional fat distribution.
HEALTH RISK
High Risk
Moderate Risk
Low Risk
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MEN
> 1.0
.90 -1.0
< .90
Concepts of Physical Fitness 14e
WOMEN
> .85
.80-.85
< .80
Underwater Weighing
Return to
presentation
Measurement issues
• Based on body density calculations
– Density of lean tissue = 1.1 g/cc
– Density of fat tissue = .9 g/cc
• Sources of error
– Residual lung volume
– Bone density varies by age, ethnicity and activity
level
• General conclusions
– Gold standard measure (1-2% error)
– Impractical for most applications
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Concepts of Physical Fitness 14e
Bioelectric Impedance
(Measurement Issues)
Return to
• Based on resistance to current flow
– Lean tissue has more water - less resistance
– Fat tissue has less water - more resistance
• Sources of error
– Temperature
– Hydration status
• General conclusions
– Overestimates lean / underestimates obese
– Practical, but expensive, measure for general
population
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Concepts of Physical Fitness 14e
presentation
Infrared Spectroscopy
(Measurement Issues)
Return to
presentation
• Based on differential absorbance rates
– Lean tissue has a different energy absorption
and reflectance pattern than fat tissue
• Sources of error
– Validity of absorbance readings is questionable!
• General findings
– NOT a valid measure!
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Concepts of Physical Fitness 14e
Ultrasound
(Measurement Issues)
• Based on reflection of sound
Return to
presentation
– Fat content increases the time is required
for sound to reflect off of bone and muscle.
• Sources of error
– Representative sites for measurement
– Measurement error
• General conclusions
– Highly accurate measure of body fat especially for obese
– Expensive and not practical for most
applications
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Concepts of Physical Fitness 14e
Imaging Techniques
(Measurement Issues)
Return to
presentation
• Based on imaging of body tissues
– Based on cross sectional area measures
calculated at different levels of the body
• Sources of error
– Representative sites for measurement
– Measurement error
• General conclusions
– Very precise measure of body composition
– Expensive and not practical measure for most uses
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Concepts of Physical Fitness 14e
Circumferences
(Measurement Technique)
Return to
presentation
• Based on circumference measures
– sample prediction equation:
% fat = - 47.372 + (.579 x abdomen) + (.252 x hip) +
(.214 x iliac) + (.356 x BW)
• Sources of error
– Location of sites
– Inability to distinguish fat and muscle
• General conclusions
– Provides reasonable estimate of body fat
– Not as accurate as skinfold and takes same time
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Concepts of Physical Fitness 14e