Week 07 - Body composition Flashcards
The 2 component model includes:
Fat free mass (FFM), Fat Mass (FM)
The 3 component model includes:
Fat Mass, Total Body Water (TBW), Fat Free Mass
The 4 component model includes:
Fat Mass, TBW, Bone, Protein/other
Normal range of essential body fat for males is…?
3%
Normal range of essential body fat for females is…?
12%
BMI = ???
BMI = body mass (kg) / height (m^2)
Density = ????
Density = mass / volume
% body fat = ?????
% body fat = (495/ body density) - 450
Air displacement Plethysmography (bod pod) pros and cons
- Measures whole body through air displacement
- Good reliability
- expensive
- 3-5 mins (quick)
- Can’t fit large people
Skinfold technique pros and cons
- Can only measure subcutaneous fat (not visceral)
- Fairly cheap
- most common
- invasive if insecure
Essential body fat includes:
- Nerve tissues
- Bone marrow
- Organs (membranes)
Storage includes:
- Energy reserve
- Accumulates when excess energy is ingested
- Declines when less energy is ingested then expended
Average male total body fat is…?
15%
Average female total body fat is…?
27%
Fat mass and performance have a ______ relationship
inverse
Body composition is used in three ways:
- Monitor effectiveness of training program or dietary regime
- Estimate optimal body weight or competition weight
- Screen and monitor health status
The waist-to-hip ratio is best used in …?
A clinical setting (not ideal for athletes)
Explain hydrostatic weighing process
- submerges individual in water
- MUST maximal exhale prior
- Reduce air remaining in the lungs (even then you have residual air in lungs)
Explain limitations to hydrostatic weighing
- Based on 2 compartment model (only fat and fat free)
- body comp changes after weight training
- In a muscular person the siri equation will over estimate body fat and under estimate fat free mass
What is the method of the Air Displacement Plethysmography (Bod Pod)?
- subject weighed outside
- sits 750L bod pod
- Persons volume = original volume in the chamber - the air that has been displaced with the subject inside
- measure pulmonary gas volume
- subtract pulmonary gas volume from persons measured volume = true volume
- Body density can then be calculated from volume and mass
Bioelectrical impedance analysis is based on the principle that….
Based on the principle that different tissues have difference impedance (resistance) to an electrical current
Explain the dual-energy x-ray absorptiometry (DEXA)
- clinical setting: looks at bone density
- Based on the absorption of x-rays
- 2 different intensity x-rays
- Underestimates body fat compared to water weighing
- Test conditions must be standardised (hydration status can influence)
Computed tomography (CT) provides what information (3)?
- total tissue area
- Thickness and volume of tissue within an organ
- Fat surrounding a tissue and fat within a tissue
Magnetic resonance imaging (MRI) explanation?
Magnetic fields and radio waves
All tissues within our body contain water which contain hydrogen atoms and they play a large role in the image that appears
Structures with more hydrogen atoms appear brighter than those with a low portion this is why fatty tissue appears much brighter than bone
