Skinfold Measurements and Girth

1. Skinfold Measurements and Girth

2. Skinfold Measurements • Target Population: • Suitable for all populations, difficult to get reliable measurements with individuals who are obese • Validity: • + or – 3.5% • Can be used as a monitoring device to indicate changes in body composition over time • Reliability: • Can vary from tester to tester depending on their skill and experience • Advantages: • Widely utilized to assess body composition

3. Description of Skinfold Measurement • Estimation of body fat by skinfold thickness • Measurements can range from 3 to 9 different standard anatomical sites around the body • Triceps • Biceps • Chest • Midaxilla • Subscapular • Abdomen • Suprailium • Thigh • Calf

4. Skinfold Calipers Equipment Required • Flexible Tape Measure

5. Sanitization • Body Composition measurements require contact with the skin! • Professional Personal Trainers must take the necessary precautions to limit the spread of bacteria and/or viruses. YOU MUST SANITIZE EVERYTHING THAT COMES IN CONTACT WITH A CLIENT!

6. Sanitization • HAND WASHING IS THE MOST EFFECTIVE MEANS OF PREVENTING THE SPREAD OF INFECTION • Hand Washing Should Be Done: • Before and after client contact!

7. Sanitization • Wash hands, utilize gloves, antibacterial gel and/or disposable wipes before, during and after body composition measurements. • Clean and sanitize all equipment. This includes calipers and tape measures. • This also applies to stethoscopes utilized in blood pressure measurements

8. Procedures • Skinfold measurements should be made on dry skin, prior to exercise • The calipers are calibrated with a specific jaw pressure, abuse of the calipers can leave them useless due to inaccuracy • Fat compresses, thus it is essential that you rotate through measurement sites which allows time for skin to regain normal thickness • It takes experience before sufficient accuracy of measurements occurs

9. Procedures • All measurements should be made on the right side of the body (for consistency) • Grasp the skin firmly with the thumb and index finger to form a fold of skin and subcutaneous fat • Place the caliper perpendicular to the fold .5 to 1 inch away from the thumb and index finger • Release the caliper grip • Pinch should be maintained with thumb and index finger while reading the caliper

10. Procedures 6. Wait 1 to 2 seconds (not longer) before reading caliper 7. Read the dial on the caliper to the nearest 0.5 mm 8. Obtain one measurement from each site, and repeat all test sites for a second trial

11. Procedures • If the two measurements are within 1 to 2 mm take the average of the two 10. If the two measurements are not within 1 to 2 mm take two more additional measurements and average the two (rotate through the sites)

12. Triceps Triceps: • Use a tape measure • Arm held freely to the side of the body • Measure halfway between the acromion (shoulder) and olecranon processes (elbow) • Grasp a vertical fold of skin on the posterior surface of the arm (over the triceps muscle) • If you are unsure if you have pinched only skin and no underlying muscle tissue, ask the subject to flex the muscle while you pinch.

13. Biceps • Use a tape measure • Arm held freely to the side of the body with the palm supinated • Measure halfway between the acromion (shoulder) and radius • Take a vertical fold of skin on the anterior surface of the arm (over the biceps muscle) • If you are unsure if you have pinched only skin and no underlying muscle tissue, ask the subject to flex the muscle while you pinch.

14. Chest: • Measure mid-way between the anterior axillary fold (underarm) and nipple • Take a diagonal fold, with the long axis of the caliper directed towards the nipple of the chest

15. Midaxilla: • Measure from the midaxilla (middle of armpit) at the level of the xiphoid process of the sternum • Take a vertical fold

16. Subscapula: • A diagonal fold taken at a 45 degree angle; 1 to 2 cm below the inferior angle of the scapula (bottom point of the scapula) • If there is difficulty finding this landmark, get the subject to reach behind their back with their right arm, while feeling for the movement of the scapula • On females it is sometimes difficult to take this measure and maintain modesty, and also the bra-strap may often obstruct this site.

17. Abdomen: • Measure 1 inch to the right of the umbilicus (belly button) • Take a vertical fold • Do not place the caliper or fingers inside the navel

18. Suprailium: • Measure from the axilla (armpit) to above the crest of the ilium • Take a diagonal fold at a 45 degree angle above the crest of the ilium

19. Thigh: • Measure the mid-point of the anterior (front) surface of the thigh, midway between the hip and knee joints • Take a vertical fold  • Stand with the weight on the back foot

20. Calf: • Take a vertical fold at the maximum circumference of the calf on the midline of its medial border • The subject should place their foot on a chair or box so that the knee is at approximately 90 degrees

21. Results • There are hundreds of equations available for converting skinfold measurements to a percent body fat • It is best to use a formula that is based on a population sample that most closely resembles the person who is measured • You can use the sum of several sites to monitor and compare body fat measures • Go to http://www.linear-software.com/online.html to find out your body fat percentage

22. Table of general guidelines for using total sum (in millimeters) of the seven skinfold sites: triceps, biceps, subscapula, suprailium, abdomen, thigh, calf

23. Durnin-Womersley Formula • Biceps, Triceps, Subscapula, and Suprailium • Add the totals of the four sites and then find the gender and age categories for the body composition in the table provided or go to http://www.linear-software.com/online.html to find out your body fat percentage

24. Body Fat Percentage Ranges by The American Council on Exercise

25. Circumference • When measuring, you need to make sure the tape is not too tight or too loose, is lying flat on the skin, and with the tape horizontal

26. Circumference • Neck: • Across the Adam’s apple • Forearm: • The subject holds the arm out with the palm supinated • Maximum girth of forearm

27. Circumference Measurements • Biceps Relaxed: • Measure at the maximal circumference of the biceps, measure with the palm supinated • Biceps Contracted: • Arm is out to the side at a 90 degree angle and elbow is flexed • Fist clenched; maximally contract biceps • Largest circumference is measured

28. Circumference • Upper Chest: • Taken at the level of the middle of the sternum with the tape passing under the arms • Measurement taken at the end of a normal expiration • Lower Chest: • Across the nipple line

29. Circumference • Abdomen: • Level of umbilicus (belly button) • Waist: • Narrowest part of waist below the rib cage and just above the top of the hipbones.

30. Circumference • Hips: • With feet together, measure circumference at the widest portion of the buttocks • Thighs: • Measure 10 inches above the top of the patella (maximal girth of thigh below gluteal fold) • Calf: • The subject stands erect with their weight evenly distributed on both feet and legs slightly apart • Measure at the maximal circumference between the ankle and the knee