anthropometry and body composition

what is body composition?

relative proportion of different components (many types of elements) that make up human body

4 main tissue types

nervous, epithelial, muscle, connective tissues

types of nervous tissues

brain, spinal cord, nerves

types of epithelial tissues

skin linings of gl and other hollow organs

types of muscle tissues

cardiac, skeletal, smooth

types of connective tissues

fat, bone, tendon, cartilage

3 main strucutral components of the body

bone, muscle, fat

how does relative proportions vary

with gender, genetics, age , lifestyle

two- component model

amount of fat and fat free mass which the body is composed of

fat free mass

bone, muscle, water, vital organs, connective tissue

what is body mass made up of

fat mass and lean body mass

chemical model

fat, protein, carbohydrate, mineral, water

what is anthropometry?

quantitative measurement of body size and proportions

what is the purpose of anthropometry?

to understand human physical variation and body composition

what does anthropometry include?

skinfold thickness, bony widths, circumferences, lengths, height, body weight

why assess body composition?

1. determine optimal body composition for sports performances

2. develop sound weight reduction programs to modify body composition

3. monitor changes in body composition (growth, maturation, aging) associated with disease (eg: knowledge of bone mineral content in women and children)

4. track goals for weight management and strength training

5. determine body composition related health risk (low levels of fat is also a risk)

what are some complications with obesity?

1. type 2 diabetes

2. hypertension

3. coronary artery disease

4. higher chance of up to 1/3 of common cancers

what are some complications with excess thinness?

1. osteoporosis

2. reproductive disorders

3. cardiac arrhythmias and sudden death

4. renal disorders

what are eating disorders?

disturbance in eating behaviour that jeopardizes physical or psychological health

what are 4 examples of eating disorders?

anorexia nervosa, bulimia nervosa, binge eating disorder, female athlete triad

what does anorexia nervosa mean word for word?

anorexia: without appetite, nervosa: of nerve origin

who is most affected by anorexia nervosa?

90% are female, 40% are females between 15-19 years old

characterization of anorexia nervosa

1. refusal to maintain a minimally healthy body weight

2. self- starvation

3. a disturbed perception of body weight and shape

4. loss of bone mineral density

what is bulimia nervosa?

recurring episodes of binge eating combined with morbid fear of becoming fat, usually followed by self- induced vomitting or purging

what is emetic?

an agent that causes vomitting

what is binge eating disorder?

has similar criteria as bulimia nervosa but excluding purging

what is female athlete triad?

disordered eating combined with intense exercise and emotional stress supressing the hormones that control the menstrual cycle

what is amenorrhea?

when menstrual cycle stops for 3 consecutive months

what will prolonged amenorrhea cause?

drop in bone density and osteoporosis

what will happen if female athlete triad is left untreated?

can lead to decreased physical performance, increased risk of bone fractures and heart arrhythmia

what is essential fat?

fat required for normal physiological functioning

functions of essential fat?

1. structural components of cell membranes

2. required for synthesis of certain hormones

3. transportation of fat soluble vitamins (ADEK)

what is storage fat?

fat stored in adipose tissue for energy supply

location of storage fat

1. underneath skin

2. abdominal cavity

3. around certain organs

body composition of average male compared to female

taller, heavier, has larger muscle mass, lower body fat content

storage fat percentage of female and male

female: 15%, male: 12%

essential fat of female and male

female: 12%, male: 3%

location of female sex specific fat depot

breasts, pelvic, thigh regions

what does female sex specific fat depot serve as?

biologically important functions for childbearing and other hormone related functions

male type obesity

android (apple), associated with higher health risks

where is excess fat stored in male type obesity?

on upper torso and around abdomen

female type obesity

gynoid (pear), begin depositing more fat in abdominal area after menopause

where is excess fat stored in female type obesity?

below the waist in thighs, hips, buttocks

BMI regarding obesity

larger than 30

percent body fat regarding obesity

man: over 20%, female: over 30%

what is one of the largest epidemics around the world?

combination of diabetes and obesity

obese individualds can expect about a __ year decrease in longevity?

7

surviving rates increase/ decrease as BMI increase/ decrease?

increase, decrease or decrease, increase

how are today’s kids compared to kids in 1981 regarding obesity?

taller, heavier, fatter, and weaker

what’s the cause and consequences of childhood obesity?

decline in fitness, resulting in accelerated disease development, increased health care costs, loss of future productivity

obese kids have a % chance of becoming obese adults, which is __ times more risk of obesity compared to normal kid?

55% , 10 times

what is the adipose tissue?

not only a passive storehouse for fat, but an endocrine organ that secretes more than a dozen peptide and non peptide compounds that trigger changes throughout the body

5 causes of obesity epidemic

decreased physical activity, increased consumption of calories, social environment, genetics, role of virus?

what happens when fat cells in adipose tissues expand?

they release leptin, adiponectin, inflammatory proteins and less of others

when does weight gain and obesity occur?

when energy intake exceeds energy expenditure, too much food and too little activity, body is set up to deal with scarcity, not abundance

the average man and woman in the US now consumes an average of ___ more calories daily than in 1970

445

reasons for decreased physical activity regarding causes of obesity epidemic

automobiles, increased crowding, crime patterns, technological advances, automation in the home and workplace, watching TV, playing video games, sitting at the computer

examples of increased consumption of calories regarding causes of obesity epidemic

large portion size meals, high fat diets, high sugar intake

examples of social environment regarding causes of obesity epidemic

advertising, pressure to consume, influence of family and friends

Does one’s genetic makeup necessarily cause obesity?

no, it instead lowers the threshold for its development due to the impact of susceptibility genes

an example of the role of genetics in the development of obesity

data from overfeeding experiments with identical twins demonstrate that some individuals are more at risk than others to gain fat when energy intake surplus is maintained at the same level

what does NEAT stand for?

non exercise activity thermogenesis

what is NEAT?

the energy expended by physical activities other than planned exercise

examples of NEAT

sitting, standing, walking, fidgeting

obese participants were seated for ___mins longer per day than lean participants

164

what are some changes associated with aging in a prosperous, industrialized socity?

increased fat mass, decreased muscle mass (sarcopenia), decreased bone mass

how do you slow down changes associated with aging in a prosperous, industrialized socitey?

regular exercise program and proper dietary habits

what is skeletal fragility in elderly women related to?

failure to obtain an optimal level of bone mass during childhood, requires proper nutrition, healthy body composition (healthy diet and proper sleep) and regular exercise

2 methods for anthropometry

direct methods: chemical analysis of human cadavers, indirect methods: noninvasive techniques used on living persons

examples of indirect methods for assessing body composition

height-weight tables, body density and volume measurements, weight-height indices, waist circumference, skinfold measurements, csep path body composition assessment, o-scale system, bioelectrical impedance analysis (BIE)

what is the height-weight table?

predicts desirable weight with regard to the lowest death rates developed by insurance actuaries

what are 3 criticisms regarding the height-weight tables?

these tables do not consider body composition and most of the data comes from white, middle class U.S. adults age 25-59, this is not a representative sample of the general north american population, and no accepted method has been devised for determining frame size

body density formula

mass over volume

fat: ___ g/ml, water: g/ml, lean tissue: __ g/ml or higher

0.91, 1, 1.1

the greater/lower the proportion of fat, the greater/ lower the body density?

greater lower or lower greater

list ways to measure body volume?

underwater weighing or volumetry

what is underwater weighing replaced by?

air-displacement plethysmography

what is air displacement plethysmograph?

the subject is immersed in a closed air filled chamber (plethysmograph) to measure the volume of air displaced inside the closed chamber

what equation can be used to determine percent body fat?

siri equation

what assumptions do the siri equation make?

the human body has 2 compartments, fat and nonfat, and each of these compartments has densities which are known constants, assuming that fat has a density of 0.9 g/ml and nonfat has a density of 1.1 g/ml

what is hydrostatic weighing used as?

the “gold standard” method for validating skinfold caliper formulae

whats the problem with cadaver studies?

the density of nonfat compartment varies as a function of age, sex, racial group, so nonfat density value of 1.1 g/ml is not univerwsally applicable

what’s the conclusion for body density and volume measurements?

densitometry should not be used as a universal criterion for the prediction of percent fat, equations based on four component models are preferred over equations based on a two component model

BMI equation

weight in kg over height squared in meters

what is BMI used as?

an indicator of obesity

whats the BMI classification system for adults 20-70?

less than 18.5: underweight, 25-29.9: overweight, 30 or higher: obese

why is BMI not used to classify weight status in children?

change in BMI is expected as children grow and develop

why do BMI cut off points need to be revised?

the relationship between BMI and body composition and between indices of fat distribution and the actual amount of visceral fat differs across ethnic groups

an example of why BMI needing revision

asian populations have a higher body fat percentage at a lower BMI compared to caucasians

a research study found that for the same amount of body fat, _______ and _____ _____ people had a greater concentration of body fat in their inner abdomen where it poses the greatest risk for ________ and _____ disease

chinese, south asian, diabetes, heart

criticisms about BMI

it does not differentiate body composition

what may be a better predictor of obesity related health risks than BMI?

waist circumference or waist to hip ratio

waist circumference has excellent correlation with _________ imaging (__ and ___) and high association with ___ risk and _________

abdominal imaging, CT and MRI, cardiovascular disease risk and mortality

whats a problem with waist circumference measurement? what does north american agencies recommend?

different research studies have used up to 8 different locations of measurement, at the iliac crest

definition of rationale

the relationship between the fat located in the depots directly beneath the skin and internal body fat and body density

2 ways to use skinfolds

use the sum of a number of skinfolds as an indicator of relative fatness among individuals and compare the before and after in the same individual , use skinfolds in conjunction with equations or tables to predict percent body fat

what does the skinfold caliper formulae predict?

where percent fat are site and sample specific

5 assumptions in using skinfold measurements to predict percent fat

constant densities in a two compartment model, proper identification of measurement site and proper measurement technique, constant compressibility of skinfold, fixed adipose tissues patterning, fixed proportion of internal to external fat