Slide 4 - Skinfolds Flashcards
What is a skinfold measurement measuring
Measuring 2 layers of skin and subcutaneous fat between the layers
What is a skinfold measurement
What does it evaluate
A technique where the thickness of the skin and subcutaneous fat is estimated
Evaluates localisation of storage fat
What type of method does skinfolds use
What is the basis of the method
Generalised/population-specific method
Based on the fact that subcutaneous fat is a proportion of total fat in the body
Equations made to estimate skinfold thickness to overall body fat
What do skinfold spring loaded calipers exert
Standardised pressure
What do plastic calipers do
Less scale precision
None constant tension throughout ROM
Smaller measurement scale
What should we do before measuring with a skinfold caliper
Check calibration
Use same caliper to monitor change
What are the site differences in males and females
Women 3 site:
Triceps
Suprailiac
Thigh
Men 3 site:
Chest
Abdomen
Thigh
What are the assumptions of skinfolds
Age is an independent predictor of body density for adults
Skinfolds are a good estimate of subcutaneous fat
Distribution of fat subcutaneously and internally (visceral) is similar for all individuals within each gender
The sum of several skinfolda can be used to estimate total body fat
There is a relationship between sum of skinfolds and body density
Density and proportion of tissues making FFM are constant
Someone who has more visceral than subcutaneous is at
Higher risk
What are the potential sources of error in skinfolds
Ease of separating adipose layers from underlying muscle
Compressibility of skin and adipose tissue
Different proportions of visceral and adipose tissue
Handedness
Skin thickness
What is validity
How do you know if something is valid
Accuracy of measurement
Comparison between calculation of gold standard vs alternative method
This is known as the validity coefficient
What is the validity coefficient
Correlation between gold standard and alternative method
What coefficient would show a perfect relationship
What is the rule of thumb
Coefficient of 1.0
The closer the R value to 1.0 the better = > 0.8 is good
What is the standard error of the estimate (SEE)
What does it quantify
What is the rule of thumb
Average degree of deviation of data around a line
Quantifies the accuracy or validity
The smaller the better
What is reliability
Assesses repeatability of measurement - looking for consistency and stability of scores
What is the reliability coefficient
What is the rule of thumb
Correlation between test 1 and test 2
The test method is the same each time
> 0.9 is good
What is objectivity
Inter-tester reliability
Comparison of scores by multiple technicians
What influences a technicians ability
Training
Practice
Standard procedures
What is objectivity coefficient
What is the rule of thumb
Correlation between tester 1 and tester 2
> 0.9 is good
Validity R value should be =
Reliability R value should be =
Objectivity R value should be =
> 0.8
> 0.9
> 0.9
What is a good ESTIMATE of subcutaneous fat
Skinfolds
In adults, what is a independent predictor of body density
Age
Distribution of fat subcutaneously and internally (visceral) is….
Similar for all individuals within each gender
What is a good ESTIMATE of TOTAL body fat
Sum of several skinfold
Is there a relationship between body density and sum of skinfolds
Yes
Density and proportion of tissues making up Fat free mass are…
Constant
When looking at validity, what is the RESIDUAL difference
Gold standard - alternative method
Midaxillary and abdominal sites for skinfold are horizontal fold from standardized (Harrison) sites
True
Calf skinfold site is a vertical fold at the level of maximal calf circumference on lateral aspect of calf with knee and hip flexed to 90 degree
False
Abdominal skinfold from Jackson is _______ fold and fold is taken _______ lateral to the umbilicus
Vertical 2 cm
If you use 3 skinfold sites from Jackson’s nomogram to estimate % body fat for women, which sites are correct ones to measure
Triceps
Supraillac
Thigh
During skinfold assessment, the underlying muscle may be contracted while applying the caliper
False
Validity is an accuracy of measurement, usually used to detect how accurate the alternative method is compared to gold standard
True
“Distribution of subcutaneous and visceral fat is similar for all individuals within each gender” is one of the assumptions for skinfold technique for assessment of body composition
True
The rule of thumb for validity is R value < 0.80 from correlation coefficient
False
Standard error of the estimate is the average of degree of deviation of data around a line. The smaller number quantifies the validity
True
For Sloan-Weir Nomogram, Jackson sites are used to estimate body density and % body fat
False
As the sum of skinfolds increases, the density of the body increases
False
The skinfold method accurately measures visceral fat
False
Skinfold thickness measurement measures one layer of skin and subcutaneous fat
False
When you make a fold, your thumb and index finger are placed approximately 8cm (3 inches) apart so that a full fold can be pinched up firmly and cleanly from the underlying tissue
True
Using Durnin and Womersley table, you can estimate % body fat by calculating the sum of biceps, triceps, subscapular, and suprailiac folds
True
If you are using standardized sites (Harrison’s), suprailiac fold is posteriorly measured from the midaxillary line above the iliac crest
True
Which of the following methods may be used to check the calibration of a skinfold caliper
Use a calibration bar. If the caliper correctly reads the size of the bar, the caliper is calibrated at that measurement
One of the assumptions of the skinfold method is that measuring skinfold thickness at multiple sites provides a good measure of subcutaneous fat. This assumption reflects which measurement concept
Validity of the skinfold method
From Durnin and Womersley table what can you estimate
What skinfolds are required in order to estimate it
% body fat
Biceps
Triceps
Subscapular
Suprailiac
Sloan weir nomogram predicts what
What skinfold method does it use
Body density
% Body fat
Standard
Jackson nomogram estimates
Uses what equation (how many skinfolds)
% body fat
sum of three skinfold
