Lab quiz #7 Flashcards
why assess Body Composition?
- differentiate between _ and _
- determine _
- study _ and _
- lean body mass, fat mass
- an individual’s level of health
- gender and population differences
why assess Body Composition?
- describe _, _, _ and _
- establish a _ for reference (training program, dietary program)
- provide epidemiological data/info: _ and _ rates, _
- follow changes in status as it occurs during _
- (ab) normal growth, development, maturation, aging
- baseline
- overweight, obesity, weight loss
- pregnancy
- fitness centers
- sports teams
- athletic training
- wellness programs
- health clinics
where body comp is used
adipocytes are ~62% fat, ~31% water, ~7% protein
fat mass (FM)
- primarily muscle and bone tissue
- secondarily skin, blood, brain, and organs
- primary constituents - water, minerals, protein & glycogen
fat-free mass (FFM)
- used interchangeably with FFM, _ is slightly greater than FFM
- includes some essential fat (internal organs, bone marrow, CNS)
Lean body mass (LBM)
Types of body comp measurements:
- _: cadaver analysis - only tru measurement of body comp
- _: hydrostatic weighing, DXA, potassium 40, MRI, Bod Pod
- _: skinfolds, anthropometric, bioelectrical impedance analysis, infared
- direct
- indirect
- doubly indirect
Fat distribution:
- commonly associated with men
- abdominal/waist fat
android (“apple”)
Fat distribution:
- commonly associated with women
- hip, low abdominal, gluteal, appendage
gynoid (“pear”)
_ fat distribution is associated with a greater risk
android
- superficial measurements of the body to predict body comp
- circumferences/girths
- greater circumferences are associated with larger individuals
- ratios
- waist-to-hip
- waist-to-height
anthropometry
Anthropometry:
1 - Girth method:
- men: _
- women: _
2 - Girth method (men)
- _ + _
3 - Girth method (women)
- _ + _
1 - waist & BW, hip & height
2 - neck and abdominal + height
3 - neck, upper-abdominal, and hip + height
weight (Kg)/height^2 (m^2)
- used primarily by epidemiologists to determine rates of overweight and obesity in the population
- not used to establish body comp, but used to establish relationships between chronic diseases and obesity
Body Mass Index (BMI)
Body Mass Index (BMI)
- major flaw: does not account for _
- normal weight obesity (NWO) - acceptable weight; obeses by % fat metrics
- acceptable for general population, but can be problematic for some
LBM vs FM
- calipers are used to predict body fat based on specific _ measurements
- popular in labs, health clinics, & fitness centers
- numerous combinations are possible
- In lab we tested : _, _, _ and _
- skinfold
- subscapula, triceps, biceps, suprailiac
- based on the assumption 1/2 body’s fat is stored internally and 1/2 subcutaneously
- may be different across ages; true for young-adult populations
- prediction equation in use should match the population from which it was established
skinfold
- body comp measured via deliverance of an electrical current through the body; impedance (resistance) to the current determines BF%
- muscle tissue
- electricity flows easily
- lower impedance
- fat tissue
- electricity does not flow easily
- greater impedance
- hydration levels can affect BIA measurements - tissue composition
bioelectrical impedance analysis (BIA)
Best results obtained when the following conditions are employed:
- no exercise/sauna within 8hrs of test
- refrain from alcohol 12hrs prior
- Ht/Wt accurately reported
- no food/drink within 4hrs of test
- void within 30 minutes of test
- no diuretics within 7 days of test
Bioelectrical Impedance Analysis (BIA)
Infrared
- method based on _
- fat mass absorbs _ infrared light than fat-free mass
- used in early animal research to determine fat content of beef
- very accurate for animals, _ so accurate for humans
- different frequencies are used for animals and people
- light absorption
- more
- not
Dual-Energy X-Ray Absorptiometry (DXA)
- primarily used to assess _
- can also be used to asses _
- DXA aims x-rays at two different energies at the body
- differences in the absorption of the x-ray beam at those two energies are used to compute bone mass and soft tissue composition
- dose of radiation is relatively small; procedure is presumably safe for all populations
- proposed that DXA is taking over as the _ for body comp
- bone density (osteoporosis)
- soft tissue
- “gold standard”
Hydrostatic (underwater) weighing
- _ principle
- “a body immersed in water is buoyed up with a force equal to the weight of the water displaced”
- Density = mass/volume
- if we can accurately measure body density, we can accurately measure _
- consider the “gold standard”
- based on comparisons with cadaver studies to establish equations; only used a few cadavers
- accuracy is _
- ability to expel air to RV, comfortin water, movement in chair, osteoporosis, etc.
- Archimedes’
- fat
- individually dependent
Hydrostatic (underwater) weighing
- rationales based on interaction between physical and anatomical aspects
- physical: body density = _
- anatomical = total body mass is divided into _
- interaction of rationales (FFM>density than FM)
- density of _ and _ differ
- 1 kg of fat = 1.1 L of fat (greater volume occupied)
- 1 kg of muscle = 0.9 L of muscle (denser)
- temperature of water can affect buoyancy
- more buoyant in cold water; cool water is denser
- body mass/body volume
- compartments (2-, 3-, 4- compartment models)
- muscle, fat
_ method:
- also based on Archimedes’ Principle
- density = mass/volume
- volume is measured via _
- pressure of the box is measured before and after the subject is in the box and body volume is determined via the change in pressure
- accuracy is _
- Bod Pod
- displaced air
- fairly high
