1. Lab 3 Skinfold Estimations of Body Composition

2. 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

3. 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.

4. Equations/Calculations Slide 1 Males (ages 18-61) DB = 1.1093800 – (0.0008267 (X 2 )) + (0.0000016 (X 2 ) 2 ) – (0.0002574 (X 4 )) R = 0.91 SEE = 0.008 kg ∙ L -1 X 2 = sum of chest, abdomen, and thigh skinfolds in mm X 4 = age in yrs

5. Equations/Calculations Slide 2 Females (ages 18-55) DB = 1.0994921 – (0.0009929 (X 3 )) + (0.0000023 (X 3 ) 2 ) – (0.0001392 (X 4 )) R = 0.84 SEE = 0.009 kg ∙ L -1 X 3 = sum of triceps, thigh, and suprailium skinfolds in mm X 4 = age in yrs

6. 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))

7. Skinfold Estimation Example 1 170-pound 22 year-old male Skinfold measures: Chest = 10 mm Abdomen = 20 mm Thigh = 15 mm Target % FAT = 10

8. Example 1, Slide 2 DB = 1.1093800 – (0.0008267 (45)) + (0.0000016 (45) 2 ) – (0.0002574 (22)) = 1.07461 kg · L -1

9. Example 1, Slide 3 % FAT = (((4.57 / 1.07461) – 4.142) x 100) = 11.1 Fat Weight = 170 x (11.1 / 100) = 18.87 Fat-Free Weight = 170 – 18.87 = 151.13 Body Weight Goal = 151.13 / (1 – (10 / 100)) = 168

10. Skinfold Estimations Example 2 140-pound 22 year-old female Skinfold measures: Triceps = 12 mm Thigh = 17 mm Suprailium = 18 mm Target % FAT = 15

11. Example 2, Slide 2 DB = 1.0994921 – (0.0009929 (47)) + (0.0000023 (47) 2 ) – (0.0001392 (22)) = 1.0507 kg · L -1

12. Example 2, Slide 3 % FAT = (((4.57 / 1.0507) – 4.142) x 100) = 20.7 Fat Weight = 140 x (20.7 / 100) = 28.98 Fat-Free Weight = 140 – 28.98 = 111.02 Body Weight Goal = 111.02 / (1 – (15 / 100)) = 131