Broadening Course YPHY0001 Practical Session II (October 11, 2006) Assessment of Body Fat

Transcription

1 Sheng HP - 1 Broadening Course YPHY0001 Practical Session II (October 11, 2006) Assessment of Body Fat REQUIRED FOR THIS PRACTICAL SESSION: 1. Please wear short-sleeve shirts / blouses for skin-fold measurements. 2. Calculator. Introduction Body composition can be assessed by numerous methods which range from simple anthropometry methods to complex instrumentation. I. Anthropometry methods Weight, height, and circumferences are easily measured: A. Growth charts for infants, children and adolescents. A. Desirable (ideal) weights from the Metropolitan Life Insurance weightheight tables for men and women: reflect weights of those with the lowest mortality of insured persons: 1. overweight: 10% above ideal weight; 2. obese: 20% above ideal weight. B. Waist - hip circumference ratio (abdominal/gluteal ratio): 1. android obesity: increased risk for obesity-related disease: a. male: ratio of 0.95 or >0.95; b. female: ratio of 0.8 or > 0.8. C. Body mass index (BMI): weight (in kilograms) height 2 (in meter 2 ) OR weight (in pounds x 703) height 2 (in inches 2 ): 1. <18.5: underweight; : normal; : overweight; 3. >30 obese. II. Skinfold measurement Skinfold measurement measures thickness of the subcutaneous fat tissue using skinfold calipers. This measurement assumes that 50% of body fat is subcutaneous. Sites identified as most reflective of body fatness are: biceps, triceps, subscapular, suprailiac, and upper thigh. Triceps and subscapular skinfold sites are most commonly used. Equations have been developed to calculate body fat from various skinfold measurement sites. It is practical for use in clinical settings. III. Bioelectrical impedance analysis (BIA) Bioelectrical impedance analysis is portable and is widely used in field study. It is based on the relationship of electrical conductance and fat-free mass. Fat-free body mass has a much greater conductivity than does fat because fat-free mass has a higher electrolyte content. 1

2 Sheng HP - 2 NAME: ; STUDENT #: ASSESSMENT OF YOUR OWN BODY FAT: TO BE HANDED IN AT THE END OF THE PRACTICAL CLASS 1. Ideal ( desirable ) body weight A. Weight (with shoes with 1-inch heels + indoor clothings): lb.; B. Height (with shoes with 1-inch heels): ft. and in.; C. Body frame size (see Appendix I):. D. Compare your own weight for height from "desirable" weight table (Appendix II): i. "desirable" body weight from table: lb.; ii. % "desirable" body weight: % EXAMPLE of calculation of % desirable body weight, assuming an individual is a female with the following characteristics: Height = 5'2"; Frame-size = small; From table in Appendix II, her "desirable" body weight is lb (average = lb); a. Assuming her body weight = 135 lb, % "desirable" body weight = ( ) x 100 = 118%; i.e. she is 18% above desirable weight; b. Assuming her body weight = 100 lb, % "desirable" body weight = ( ) x 100 = 83%; i.e. she is 17% below "desirable" weight; c. Assuming her body weight is between 108 and 121 lbs, her % desirable weight is 100%. 2. Percentile body weight, percentile height, and percentile weight-for-height (from growth charts available during the practical session): A. Body weight: percentile; B. Height (use the above weight less 1-inch for shoes): percentile; C. Weight-for-height: percentile. 2

3 Sheng HP Waist-hip circumference ratio A. Waist circumference: cm; B. Hip circumference: cm; C. Waist-hip ratio: 4. Body Mass Index (BMI) A. Weight: kg OR lb; B. Height: meters OR inches; C. BMI (weight/height 2 ): = kilogram (meter x meter) OR (pounds x 703) (inches x inches) =. 4. Skinfold thicknesses (graph for percentile available during practical session) A. Triceps: mm; percentile; 5. Bioelectrical impedance analysis A commercially available body fat monitor will be used. A. Body fat: % body weight. 3

4 Sheng HP - 4 Results Parameters measured Values Comments (values: low, average, or high) % desirable body weight Body weight percentile Height percentile Weight-for-height percentile Waist-hip circumference ratio BMI Triceps skinfolds (percentile): % body fat From body fat monitor: Conclusion: 1. Are your measured values consistent? If not, what explanation can you suggest? 2. From your measured values, do you think that you need to change your life-style? If you do, what should you do? 4

5 Sheng HP - 5 APPENDIX I: Determination of body frame size. Measure wrist with a tape measure and use the chart below to determine if you are small, medium, or large boned. Frame size Females Height <5'2" Height 5'2" - 5'5" Height >5'5" Small wrist size <5.5" wrist size <6.0" wrist size <6.25" Medium wrist size 5.5" " wrist size 6.0" " wrist size " Large wrist size >5.75" wrist size >6.25" wrist size >6.5" Frame size Males Height > 5'5" Small wrist size 5.5" - 6.5" Medium wrist size 6.5" - 7.5" Large wrist size > 7.5" 5

6 Sheng HP - 6 APPENDIX II: Desirable weights for adults aged 25 to 59 years based on lowest mortality. Data from height and weight tables of the Metropolitan Life Insurance Company, The weights assume you are wearing shoes with 1-inch heels and clothing weighing 3 lbs. Desirable weight table for Women ages 25 to 59. Height (with 1-inch heels Small Frame Medium Frame Large Frame shoes on) 4'10" lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb 5'8" lb lb lb 5'9" lb lb lb Desirable weight table for Men ages 25 to 59. Height (with 1-inch heels Small Frame Medium Frame Large Frame shoes on) lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb 6