Body Composition & Weight Management Flashcards
Rationale for Body Comp Assessment
- Indicates many chronic diseases
- Detection of obesity
- Its development are of primary importance for many health and exercise science professionals
- Assessment of muscle mass
- Bone density
Chronic Diseases indicated by Body Comp Assessment
- Type 2 diabetes
- Hypertension
- Hyperlipidemia
- Metabolic syndrome
- CAD
- Certain types of cancer
Assessment of Muscle Mass (Rationale for Body Comp Assessment)
- LBM
- Muscle wasting (sarcopenia)
Bone density (Rationale for Body Comp Assessment)
Risk of osteoporosis
Selection of Methodology for Body Comp Assessment
- There are no direct in vivo methods
- Cost
- Availability
- Technician training
- Individual characteristics
- Performance requirements
Criticism of BMI (Health Risk Assessments)
- Poor predictor of % body fat
- Results in inaccurate classifications for some individuals
- SEE + 5% for predicting % body fat
For non-athletic population Health Risk Assessments are…
Reasonably accurate
Therefore, BMI meets the… (Health Risk Assessments)
Objectives of assessing health risk
Direct Body Comp Method
- Chemical analysis of the whole body or cadaver
- Not suitable for living human body comp assessment
Indirect Body Comp Method
- Derived from the direct method of chemical analysis
- Hydrodensitometry
Doubly Indirect Body Comp Method
- Derived from an indirect method
- Generally prone to greater error in measurement
- Skinfold analysis
Property-Based Methods (Indirect Methods)
- Measurement of body volume
- Decay properties of specific isotopes
- Electrical resistance
- Estimation of total body water (TBW) from tritium dilution (most common)
Component-Based Methods (Indirect Methods)
- The measured quantity is first assessed using a property-based method and
- The component is estimated by application of the model
- FFM can be estimated from body water by use of tritium dilution to measure TBW
Body Fat Prediction Equation Selection
- To whom is the specific % body fat equation used applicable?
- Was an appropriate compartment model used to develop the equation used?
- Was a representative sample of the population studied?
- How were the predictor variables measured?
- Was the equation cross-validated in another sample of the population?
- Does the equation give accurate estimates of % body fat?
General Error Concepts in Body Comp Assessment
No method is perfect; Error is expressed as the + SEE
+ 1 SEE refers to 68% of population
SEE is a measure of the variability of a population’s actual % BF values
Example of General Error Concepts in Body Comp Assessment
-68% of similar individuals (16.5 to 23.5%)
-32% have % BF values > + 3.5%
=< 16.5% or > 23.5%
Skinfold Analysis
- Considered a doubly indirect method
- Based on 2C model
- Based on the principle that amount of subcutaneous fat is directly proportional to the total amount of BF
- Specific skinfold regression equation used must match population measured
However, proportion of subcutaneous fat to total fat varies with… (Skinfold Analysis)
Gender, age, race and other factors
Limitations of Skinfold Analysis
- Technician training
- Skinfold site measurement accuracy
- Measurement technique
Bioelectrical Impedance Analysis (BIA)
Noninvasive and Easy-to-administer
Basic Premise of Bioelectrical Impedance Analysis (BIA)
Mass of FF tissue is proportional to the electrical conductivity of the body; LBM is good electrical conductor
Fat is poor conductor (Bioelectrical Impedance Analysis (BIA)
Impedes electrical current
Uses equations for % BF (3C model) using assumptions about
Bioelectrical Impedance Analysis (BIA
- Hydration levels
- Exact water content of various tissues
Factors affecting BIA (Bioelectrical Impedance Analysis (BIA)
-Fluid intake Meal timing Bladder fullness Diuretic or Caffeine use Recent exercise
