Lab 3

Skinfold Estimations of Body Composition

Skinfold Measurement

• Is simple and relatively accurate

• Requires a minimal amount of equipment

• Can be used with a large number of subjects in a field setting

• Produces results within 3 to 5 percent of underwater weighing

Principle Behind Skinfold Measurement

• Fat or fat-free tissues accumulate in relatively predictable patterns.

• If specific sites are measured, the size of such measurement will be influenced by the amount of the individual’s fat or fat-free tissue.

Equations/Calculations Slide 1Males (ages 18-61)

DB = 1.1093800 – (0.0008267 (X2)) + (0.0000016 (X2)2) – (0.0002574 (X4))

R = 0.91

SEE = 0.008 kg ∙ L-1

X2 = sum of chest, abdomen, and thigh

skinfolds in mm

X4 = age in yrs

Equations/Calculations Slide 2Females (ages 18-55)

DB = 1.0994921 – (0.0009929 (X3)) + (0.0000023 (X3)2) – (0.0001392 (X4))

R = 0.84

SEE = 0.009 kg ∙ L-1

X3 = sum of triceps, thigh, and suprailium

skinfolds in mm

X4 = age in yrs

Equations/Calculations Slide 3

% FAT = (((4.57 / DB) – 4.142) x 100)

Fat Weight = Body Weight x (% FAT / 100)

Fat-Free Weight = Body Weight – Fat Weight

Body Weight Goal = FFW / (1 – (Target % FAT / 100))

Skinfold Estimation Example 1

170-pound 22 year-old male

Skinfold measures:

• Chest = 10 mm

• Abdomen = 20 mm

• Thigh = 15 mm

Target % FAT = 10

Example 1, Slide 2

DB = 1.1093800 – (0.0008267 (45)) + (0.0000016 (45)2) – (0.0002574 (22)) = 1.07461 kg · L-1

Example 1, Slide 3

% FAT = (((4.57 / 1.07461) – 4.142) x 100)= 11.1Fat Weight = 170 x (11.1 / 100)= 18.87Fat-Free Weight = 170 – 18.87= 151.13Body Weight Goal = 151.13 / (1 – (10 / 100))= 168

Skinfold Estimations Example 2

140-pound 22 year-old female

Skinfold measures:

• Triceps = 12 mm

• Thigh = 17 mm

• Suprailium = 18 mm

Target % FAT = 15

Example 2, Slide 2

DB = 1.0994921 – (0.0009929 (47)) + (0.0000023 (47)2) – (0.0001392 (22)) = 1.0507 kg · L-1

Example 2, Slide 3

% FAT = (((4.57 / 1.0507) – 4.142) x 100)= 20.7Fat Weight = 140 x (20.7 / 100)= 28.98Fat-Free Weight = 140 – 28.98= 111.02Body Weight Goal = 111.02 / (1 – (15 / 100))= 131