BPK 142: lec 2 (anthropometry and body comp)

What are the top 3 elements that make up the body?

1. Oxygen = 65%

2. Carbon = 18.5%

3. Hydrogen = 9.5%

What are the 4 types of tissue in the body?

• Work together to comprise organs

1. Nervous

2. Epithelial

3. Muscle

4. Connective

Name the 3 structural components in the body

• Distribution of components depends on sex, age, genetics + lifestyle

1. Muscle

2. Skeleton (bone)

3. Fat

What does the two-component model state?

• Fat and Fat-free mass in body

• FFM = bone, muscle, water, organs + connective tissue

• Body mass = FM + FFM

What does the four component model state?

• Chemical model

• Fat

• Protein

• Mineral

• Water

Anthropometry

• Quantitative measurement of body size + proportions

• To understand physical variation + body comp

Why assess body composition?

• Monitor changes in body comp with growth

• Establish optimal ranges for health

• Track goals for weight management or strength

• Suitable body comp = good health

Eating disorders

• Disturbance in eating behavior that jeopardizes physical + psychological health

Essential fat

• Required for normal functioning

• Structural components of cell membranes

• Synthesis of hormones

• Transport of fat-soluble vitamins

Storage fat

• Stored in adipose (connective) tissue for energy supply

• Also stored underneath skin (subcutaneous) in abdominal cavity + around organs

Males vs female fat averages

• Females have sex specific fat depots

  • Breasts, pelvic regions, thigh

• Males = taller, heavier + larger muscles with LOWER fat

• Storage fat

  • F= 15%

  • M= 12%

• Essential fat

  • F= 12%

  • M= 3%

Is the android (apple) deposition pattern (loco of storage fat) a male or female pattern?

• Male pattern

• Upper torso + abdomen

Is the gynoid (pear) deposition pattern (loco of storage fat) a male or female pattern?

• Female pattern

• Thighs, hips, butt

• NOTE!!

  • After menopause females begin depositing more fat in the abdominal area

What BMI indicates obesity for men and women? Are they different?

• BMI ≥ 30

• Body Fat % ≥ 20% (men) or 30% (women)

Adult obesity in Canada

• 24% (~6 million adults) are obese

• 37% (~9 million adults) are overweight

• Total number overweight or obese >60%

• Overweight percentages are increasing every year

Childhood obesity in Canada

• Children now are taller, heavier, fatter and weaker

• Obese kids ages 6- 9 have 55% chance of becoming obese as adults

What are the 5 causes of the obesity epidemic?

1. Caloric intake exceeds caloric expenditure

   • Eating more calories

2. Decreased physical activity

   • Cars, work from home, TV, etc

3. Increased consumption of calories

   • Processed food, high sugar, etc

4. Social environment

   • Pressure to consume

5. Biology

   • Genes don’t cause obesity but can make you more susceptible

How does body composition change with aging?

• Changes associated with aging in industrialized society:

  • Increased fat mass

  • Decreased muscle mass (sarcopenia)

  • Decreased bone mass

• Slowed down w/ exercise + good diet

• Fragility in elderly women is related to failure to obtain an optimal level of bone mass during childhood

Describe height/weight tables

• Desirable weight with regard to the lowest death rates

• Predicted from tables developed by insurance actuaries

Height/weight table criticisms?

1. Do not consider body comp; they estimate health risk

2. Data comes from white middle class U.S adults 25-59 yrs

3. NO accepted method for determining frame size

Describe body density and volume measurements

• Density = mass/volume

• Body density varies with amount of body fat

  • Fat 0.91 g/mL

  • Water 1.0 g/mL

  • Lean tissue 1.10 g/mL and higher

• Greater proportion of fat = lower body density

• Use underwater weighing or volumetry to measure body volume

How is the air-displacement plethysmography used for finding body density and volume measurements?

• Subject is immersed in a closed air-filled chamber (plethysmograph)

• Measure volume of air displaced inside the closed chamber

What is the SIRI equation used for? What does is determine?

• Used for body density and volume measurements

• To determine % body fat

SIRI equation assumptions?

1. The human body has two compartments - fat and nonfat

2. Each of these compartments has densities which are known constants. Assume that:

   • Fat density = 0.90 g/ml

   • Nonfat density = 1.10 g/ml

Why is densitometry not used as a universal criterion for prediction of percent fat/ body density?

• Hydrostatic weighing was a universal method (gold standard)

• Cadaver studies have shown the density of nonfat compartment varies as a function of

  • Age, sex + race

  • Nonfat density value of 1.10 g/ml is not universally applicable

Describe weight/height indices (BMI)

• Body Mass Index (BMI)

• Used as an indicator of obesity

What are the 3 BMI classifications for adults?

• BMI less than 18.5 = underweight

• BMI of 25.0 to 29.9 = overweight

• BMI of 30 or higher = obese

Weight/height indices (BMI) criticisms

• BMI does not consider

  • Body composition

  • Fat distribution

  • Amount of visceral fat in dif ethnic groups

• Chinese and South Asian people have greater concentration of abdomen (visceral fat) compared to white people

• BMI assumed to be closely associated with body fatness and morbidity/mortality

• However, overweight does not always mean over-fat

  • Body builders obese according to BMI

Describe waist circumference

• Simple + cheap but effective

• Combination of BMI and waist circumference also used (CSEPPATH)

Skinfold measurements

• Relationship between fat in depots directly beneath the skin and body density

Skinfold measurements; 2 ways to use

1. • Use sum of a number of skinfolds as an indication of relative fatness among individuals

   • Compare "before" and "after" in the same individual

2. • Use fat folds in conjunction with equations or tables to predict percent body fat

Skinfold measurement assumptions

1. Constant densities in a two-compartment model

2. Proper identification of measurement site and proper measurement technique

3. Constant compressibility of the skinfold

4. Fixed adipose tissue patterning

5. Fixed proportion of internal to external fat

Describe the o-scale system

• O Scale developed to combat error of skinfolds

• Requires eight skin folds, ten girths, four skinfold-corrected girths and two bone breadths

• Provides: Adiposity rating + Proportional weight rating

Describe bioelectrical impedance analysis

• Electrical impedance units

• Used to measure resistance to flow of electricity in body

• Impedance is greater in adipose tissue (14 - 22% water) than in bone and muscle (71 - 75% water)

• Higher electrical impedance = fatter the subject

Bioelectrical impedance analysis criticisms

• Daily fluctuations in water content from exercise, dehydration, eating and drinking need to be standardized to obtain optimum impedance results

• Clients must adhere to strict pretest guidelines

  • To yield valid estimates of their body composition

Subcutaneous vs visceral fat

• Subcutaneous fat = found under skin

• Visceral fat = deep within abdominal cavity + surrounds your organs