Lecture 3 - Body Comp

Question 1

What are ways in which we can evaluate body comp?

Answer 1

Circumference and areas
Skinfold Thickness
Bioelectrical Impedence Analysis
Dual Energy Xray 
Absorptometry
Air Displacement

Question 2

What is the MAMC?

Answer 2

Mid upper arm muscle circumference
-Calculated from MAC
-tricep skinfold thickness
MAMC=MAC-(piexTSF)

reflects skeletal muscle and bone in arm
-corrects fo subcutaneous fat

Question 3

What are the pros and cons for MAMC?

Answer 3

Pro:
-Quick and easy estimate of muscle mass

Con:

• Insensitive to small changes
• Assumes cylindrical Arm

Question 4

What is MAMA?

Answer 4

Mid upper Arm Muscle Area
-calculated from MAC

Reflects skeletal muscle and bone in arm
-corrects for subcutaneous fat

Question 5

Why is MAMA better than MAMC?

Answer 5

More accurate and sensitive estimate of skeletal muscle mass than MAMC

Question 6

What is MAFA?

Answer 6

Mid upper arm fat area
-calculated from MAC

Reflects body fat stores
Better indicator of body adipose tissue than one single skin fold thickness

Question 7

What and Why do we do skin fold thickness?

Answer 7

Estimates quaantity of subcutaneous adipose tissue in body

\Measurement at more than one site is more representative

Question 8

What do we assume when doing skin folds?

Answer 8

-Constant compressibility at a site and at different sites
-Proportion of internal to external fat is constant
-Body Fat is normally distributed
-Thickness of subcutaneous fat is constant within and between individuals
Thickness of the skin is negligible for a constant fraction at different Skin fold sites

Question 9

What is BIA?

Answer 9

Bioelectrical impedance analysis

• DETERMINE BODY COMP USING A SMALL ELECTRICAL CURRENT which passes through thee body
• Impedance is greatest in fat tissue, fat free tissue allows the current to pass quicker

Question 10

What are the types of BIA?

Answer 10

Supine arm to leg electrodes
Standing scale
Handhels

Question 11

What re the Pros and cons of BIA?

Answer 11

Pro

• Safe
• non invasive
• quick
• portable
• validated in healthy adults

Cons

• deosnt work if you have fever, extreme obesity, electrolyte imbalances, body asymmetry, metal in the body, tissue atrophy, pregnancy
• lots of things that patient has to do before they take the BIA

Question 12

What is DEXA?

Answer 12

Dual energy X-ray absorptiometry

-estimates bone mineral density, fat and boneless tissue

Question 13

What are the pros and cons to DEXA?

Answer 13

Pro

• Easy to use
• Low levels of radiation
• requires little help from patient

Con
-Inaccurate measurement can result if:
abnormal hydration status or abnormal bone or tissue calcificaiton

Question 14

What is a bod pod?

Answer 14

Air displacement plethysmography
-easier alternative to determine body volume compared to underwater weighting

Allows determination of body comp

Question 15

What is an ultra sound ?

Answer 15

Uses high frequency sound waves passed from transducer (probe) through the skin

• soundwaves echo back at different frequencies depending on the tissue
• reflecgt back on a grey scale

Question 16

What is an ultrasound excellent at?

Answer 16

Intra and interrrater reliability

• Inter: measurements taken on a patient by different people
• Intra: You taking the measurement only on a patient

Question 17

What are the advantages of ultrasounds?

Answer 17

No ratiation
Can be tiny
Easy
Safe
Noninvasive

Question 18

What are the kinds of measurements we can get from an ultrasound?

Answer 18

Quad muscle layer thickness (static measurement)
Quadriceps CSA (cross sectional surface area)
-more sensitive to changes
Diaphragm muscle thickness
Bicep muscle Thickness
Musclee Quality

Question 19

What are some limitations of ultrasound machines?

Answer 19

Access to US machine/expensive

Question 20

Should nutrition clinicians conduct ultrasounds on their patients?

Answer 20

Yes: we should cause it related to our practice

No: if we don’t have the training we shouldn’t really do it, need direction from a physician

• this is controlled act so we can’t do this
• we are only allowed to take finger prints

Question 21

Why do we measure hand grip strength?

Answer 21

Gives us an idea of functionality (strength) cs just how much muscle you have

Question 22

What is the range that grip strength is measured against?

Answer 22

Good grip strength is over 20lbs/ women and over 30lbs for men

Question 23

What are low levels of grip strength associated with?

Answer 23

Falls
Disability
Impaired QOL
Increase LOS (H)

Question 24

Is grip strength an exact or predicted measurement?

Answer 24

Predicted estimate

-because it is a prediction of our overall strength