Module 4 Body Composition

Question 1

The body’s relative amounts of fat and lean body tissue (or fat-free mass – FFM)

Answer 1

Body composition

Question 2

Components of FFM include:

Answer 2

• Muscle
• Bone
• Water
• Organ tissues

Question 3

total body fat equation

Answer 3

Question 4

Essential fat

Answer 4

Required for normal physiological function and consists of fat within:
* major organs (protective, insulative)
* muscles
* central nervous system (conduction)

Question 5

How much total body weight does essential fat account for?

Answer 5

• 3-5% total body weight in males
• 8-12% total body weight in females

Question 6

Male vs. female body composition breakdown

Answer 6

Question 7

What part of body composition influences BMR the most?

Answer 7

FFM

Question 8

Nonessential fat stored as adipose tissue near the body’s surface

Answer 8

storage fat
* Some sports and certain positions where storage fat actually affords a benefit. Such as in football having a bigger body makes it harder to get through you or wrestling in some cases

Question 9

Primary index used to evaluate body composition

Answer 9

% body fat
* Percentage of total body weight represented by fat

Question 10

Defined as body mass minus all extractable fat

Answer 10

Fat-Free Mass (FFM)

Question 11

Calculation for FFM

Answer 11

Question 12

What is a key rule of thumb in measuring FM?

Answer 12

What’s most important is how the measurement is done the second and third and so on. So use the same method to keep it consistent

Question 13

Purposes of evaluating body composition

Answer 13

1. To help assess health risks and determine needed behavior changes for optimal health
2. To help athletes determine the best body composition for performance in their respective sport

Question 14

Effects of Too Much Body Fat

Answer 14

Excessive body fat can increase risk of chronic diseases, such as:
* Cardiovascular disease
* Hypertension
* Type 2 diabetes
* Cancer

Question 15

hypertension causes and risk factors

Answer 15

Question 16

Effects of Too Little Body Fat

Answer 16

Extremely low levels of body fat can result in reproductive, circulatory, and immune disorders and are associated with RED-S and malnutrition.

Question 17

Common Methods for Assessing Body Composition

Answer 17

• Height, weight, BMI
• Waist-to-Hip ratio (and body girth measurements)
• Skinfold measurements
• Hydrostatic (underwater) weighing
• Air displacement plethysmography (ex. BodPod)
• Bioelectrical impedance analysis (BIA)
• Dual-energy X-ray absorptiometry (DXA)

Question 18

Assessment model types for body composition

Answer 18

• two compartment model: fat & FFM
• three compartment model: fat, lean mass & bone
• four compartment model: fat, protein, water, bone

Question 19

Methods of Assessing Height

Answer 19

Best measured using a stadiometer; ensure the subject:
* Removes shoes
* Stands straight up with heels together
* Holds deep breath during measurement

Question 20

Methods of Assessing Body Weight/Mass

Answer 20

Best measured on a calibrated scale at a
set time of day; Ensure the subject:
* Removes shoe
* Wears minimal clothing (if nude weight
isn’t possible)

Question 21

Body weight vs. body mass

Answer 21

BW = lbs; BM = kg (1kg = 2.2 lbs)

Question 22

Based on the concept that a person’s weight should be proportional to height

Answer 22

BMI

Question 23

What is BMI most often used for?

Answer 23

Used to estimate degree of obesity in large populations
* Insensitive to body composition - does not take into account % of fat or FFM

Question 24

What populations should BMI exclude?

Answer 24

pregnancy, athletes, elderly

Question 25

BMI calculation

Answer 25

Question 26

Categories of BMI

Answer 26

Question 27

Pros/cons of BMI

Answer 27

Question 28

Provides evaluation of body fat distribution

Answer 28

Waist-to-Hip Ratio

Question 29

Methods of assessing waist-to-hip ratio

Answer 29

* Waist circumference: Should be measured at the narrowest point below the ribs * Hip circumference: Should be measured at the widest point (around the gluteus maximus)

Question 30

What does the waist-to-hip ratio accuracy depend on?

Answer 30

Training and skill of the tester * Must be measured properly and hit the proper landmarks otherwise meaningless - hips and waist at the right spot

Question 31

What adiposity does waist-to-hip mainly look at?

Answer 31

abdominal adiposity

Question 32

Waist-to-hip ratio norms

Answer 32

Question 33

Pros/cons of waist-to-hip ratio

Answer 33

Question 34

Skinfold measurements

Answer 34

Multiple sites are measured and % BF is calculated using the sum of the sites * 3- site, 4-site, and 7-site methods are used * Measurements should be taken on the right side of the body

Question 35

Accuracy of skinfold measurements

Answer 35

Accuracy is predicated on the skill and experience of the tester * Highly correlated with other methods of measuring % BF (including DEXA and hydrostatic weighing)

Question 36

Pros/cons of skinfold measurements

Answer 36

Question 37

Hydrostatic Weighing

Answer 37

Uses whole-body density to calculate body comp. based on Archimedes’ principle - fat more buoyant than lean tissue * Also known as underwater weighing * Historically the most commonly used lab technique for measuring % BF

Question 38

Pros/cons of hydrostatic weighing

Answer 38

Question 39

Air Displacement Plethysmography

Answer 39

Uses computerized air pressure sensors to determine amount of air displaced and calculates % BF from body density

Question 40

Device used for air displacement plethysmography

Answer 40

BodPod

Question 41

Pros/cons of air displacement

Answer 41

Question 42

BIA

Answer 42

Bioelectrical Impedance Analysis Sends electrical current through the body to estimate body fat (based on the principle that fat is less conductive than lean tissue) * Return time from one lead to the other. Fat is insulator so if it takes longer then implies more fat

Question 43

Pros/cons of BIA

Answer 43

Question 44

DEXA

Answer 44

Dual Energy X-ray Absorptiometry Uses a series of low-dose, transverse radiation scans, providing high degree of accuracy * Provides measurements of bone mineral, fat, and nonbone lean tissue (able to measure visceral fat as well)

Question 45

How might DEXA be useful for athletes?

Answer 45

Maybe done as a screening thing for athletes or only for select who may looking for a certain condition or assessing some sort of specific purpose; not really used as a broad tool

Question 46

Pros/cons of DEXA

Answer 46

Question 47

Fitness categories for % BF for men and women by age

Answer 47

Question 48

% BF norms by sport

Answer 48

Question 49

Factors to Consider When Assessing Body Composition in Athletes

Answer 49

1. Needs/goals of the athlete (e.g. an athlete looking to increase lean mass) 2. The most appropriate method for your situation

Question 50

What should the method to assess body composition be based on?

Answer 50

* The resources (time, cost, etc.) and equipment available to you * Validity, accuracy, and reliability of the methods * Abilitytoobtainserial/repeatedmeasures

Question 51

Benefit of body composition measurements for nutrition strategies

Answer 51

Measurements can be used to help inform appropriate training and nutrition strategies * Fat loss * Muscle gain

Question 52

Why is body composition relevant?

Answer 52

1. help determine needed behavior changes for optimal health 2. help athletes determine what’s optimal for performance in their respective sport.

Question 53

How should body composition methods be used?

Answer 53

help inform appropriate training and nutrition strategies for athletes.