Week 07 - Body composition

Question 1

The 2 component model includes:

Answer 1

Fat free mass (FFM), Fat Mass (FM)

Question 2

The 3 component model includes:

Answer 2

Fat Mass, Total Body Water (TBW), Fat Free Mass

Question 3

The 4 component model includes:

Answer 3

Fat Mass, TBW, Bone, Protein/other

Question 4

Normal range of essential body fat for males is…?

Answer 4

3%

Question 5

Normal range of essential body fat for females is…?

Answer 5

12%

Question 6

BMI = ???

Answer 6

BMI = body mass (kg) / height (m^2)

Question 7

Density = ????

Answer 7

Density = mass / volume

Question 8

% body fat = ?????

Answer 8

% body fat = (495/ body density) - 450

Question 9

Air displacement Plethysmography (bod pod) pros and cons

Answer 9

• Measures whole body through air displacement
• Good reliability
• expensive
• 3-5 mins (quick)
• Can’t fit large people

Question 10

Skinfold technique pros and cons

Answer 10

• Can only measure subcutaneous fat (not visceral)
• Fairly cheap
• most common
• invasive if insecure

Question 11

Essential body fat includes:

Answer 11

• Nerve tissues
• Bone marrow
• Organs (membranes)

Question 12

Storage includes:

Answer 12

• Energy reserve
• Accumulates when excess energy is ingested
• Declines when less energy is ingested then expended

Question 13

Average male total body fat is…?

Answer 13

15%

Question 14

Average female total body fat is…?

Answer 14

27%

Question 15

Fat mass and performance have a ______ relationship

Answer 15

inverse

Question 16

Body composition is used in three ways:

Answer 16

1. Monitor effectiveness of training program or dietary regime
2. Estimate optimal body weight or competition weight
3. Screen and monitor health status

Question 17

The waist-to-hip ratio is best used in …?

Answer 17

A clinical setting (not ideal for athletes)

Question 18

Explain hydrostatic weighing process

Answer 18

• submerges individual in water
• MUST maximal exhale prior
• Reduce air remaining in the lungs (even then you have residual air in lungs)

Question 19

Explain limitations to hydrostatic weighing

Answer 19

• Based on 2 compartment model (only fat and fat free)
• body comp changes after weight training
• In a muscular person the siri equation will over estimate body fat and under estimate fat free mass

Question 20

What is the method of the Air Displacement Plethysmography (Bod Pod)?

Answer 20

1. subject weighed outside
2. sits 750L bod pod
3. Persons volume = original volume in the chamber - the air that has been displaced with the subject inside
4. measure pulmonary gas volume
5. subtract pulmonary gas volume from persons measured volume = true volume
6. Body density can then be calculated from volume and mass

Question 21

Bioelectrical impedance analysis is based on the principle that….

Answer 21

Based on the principle that different tissues have difference impedance (resistance) to an electrical current

Question 22

Explain the dual-energy x-ray absorptiometry (DEXA)

Answer 22

• clinical setting: looks at bone density
• Based on the absorption of x-rays
• 2 different intensity x-rays
• Underestimates body fat compared to water weighing
• Test conditions must be standardised (hydration status can influence)

Question 23

Computed tomography (CT) provides what information (3)?

Answer 23

• total tissue area
• Thickness and volume of tissue within an organ
• Fat surrounding a tissue and fat within a tissue

Question 24

Magnetic resonance imaging (MRI) explanation?

Answer 24

Magnetic fields and radio waves
All tissues within our body contain water which contain hydrogen atoms and they play a large role in the image that appears

Structures with more hydrogen atoms appear brighter than those with a low portion this is why fatty tissue appears much brighter than bone