Tuesday, 22 May 2012

Air displacement (Bodpod) - Kang Yan S3-06

Video: http://www.youtube.com/watch?v=7QNlQqfqDtI&feature=related

From 00.40 to 2.22 sec of the video, it explains on how the bodpod works and the steps taken before someone enters the machine.

If the air displacement test is performed correctly according to the recommended guidelines, there is a ± 3% error.

Factors affecting the results obtained from air displacement method include:
- Hydration status and increases in muscle temperature, as it can adversely affect calculation results
- Movement and activity in the bodpod (It is imperative to breath normal, remain still, and keep hands in lap while being assessed by the Bod Pod. Any slight movement or change in breathing pattern may affect results.)

Advantages of air displacement (bodpod) method:
- Does not require anyone to get wet
- System is easy to operate
- Measurement time is short
- Well suited for special populations, which includes children, obese, elderly, and disabled people

Disadvantages of air displacement (bodpod) method:
- Very expensive (The machine used cost about $30,000 - $40,000)
- Only a few facilities have the Bod Pod, since it is expensive

Source: http://www2.gsu.edu/~wwwfit/bodycomp.html

Monday, 21 May 2012

Body Composition (Niklaus Teo)

Here, i got a neat 5 minute video explaining how the use of hydrostatic weighting is used to measure the body composition. The huge advantages of this method that includes short testing time and incredible accuracy makes it the gold standards of testing body composition. 

Sunday, 20 May 2012

Bioelectrical Impedance - Preston

This video pretty much explains everything about bioelectrical impedance.

Bioelectrical Impedance (Youtube)

Basically it measures the electrical impedance, or opposition to the flow of an electric current through body tissues which could be then used to calculate an estimate of total body water. Total body water can be used to measure fat-free body mass and, by difference with body weight, body fat. (Wikipedia)

I feel this is a good way of measuring body composition as it is non-invasive and is quite accurate. It can give you a variety of information that you or your doctor needs to know. However you need to adhere to certain requirements before you can test your body composition with the bioelectrical impedance.


Saturday, 19 May 2012

Methods to Measure Body Composition (Hao Ming)

6 Methods to Measure Body Composition: Skinfold Measurements, Underwater Weighing, Bioelectrical Impedence, Bod Pod (Air Displacement), Dual Energy X-Ray Absorptiometry (DEXA) and Near Infrared Interactance (NIR) Futrex 5000. Firstly, for Skinfold Measurements, there may be 2 types of it:

Skinfold Measurements involves assessing of percent body fat. It is quite accurate, with +/- 3% error:

Equipment: Skinfold Caliper, Designed for Simple Accurate Measurement of Subcutaneous Tissue.

7 Site Skinfold: Involves Chest, Triceps, Subscapular, Axilla, Suprailiac, Abdomen & Thigh (people).

3 Site Skinfold: Involves Chest, Abdomen and Thigh of Men, Triceps, Suprailiac & Thigh of Women.

To Find out more about its advantages and disadvantages, refer to the link to the site at the end of post.

Underwater Weighing involves methods from the principle which states that when a body is submerged underwater, there will be buoyant counter force equal to weight which is displaced (using weighing).

This is more accurate because if the guidelines are being carried out properly, it will have +/- 1.5% error.

Advantage: This method is considered the "gold standard" in percent body fat measurement. Repeat measures also mostly prove consistent, and can be used to chart progress. Hence, it is rather reliable.

 Disadvantages: Requires a lot of equipment and space, testing is time consuming and involved as well.

Bioelectrical Impedence involves electricity, where people will stand barefoot on metal foot plates and a low voltage electric current is sent up 1 leg and down the other. Percent body fat will be measured then.

Likewise, for this case, when guidelines are carried out correctly, there is a possibility of +/- 3% error.

Advantage: Requires little or no technical knowledge of operator, testing itself takes less than 1 minute.

Disadvantages: Method has a higher standard error range than most people desire (might have errors).

Bod Pod involves state of art technology, and it correlates nicely with the concept of hydrostatic weighing (underwater weighing), but instead of using water, it uses air displacement to measure then.

Bod Pod process, when carried out correctly, will have a possibility of a +/- 3% error (recommended).

Advantages: Does not require getting wet, it is not difficult to operate and measurement time is short.

Disadvantages: Very expensive ($30000 - $40000), and only a few facilities have the Bod Pod process.

Dual Energy X-Ray Absorptiometry (DEXA) involves the use of technology: 2 X-Ray Energies Used.

DEXA is considered to be more accurate and valid as it takes bone mineral content into consideration.

Advantages: Radiation exposure is low, DEXA is quick and one does not have to wear a bathing suit.

Disadvantages: DEXA is a costly machine and can cost as much as $300.

Near Infrared Interactance (NIR) Futrex 5000 measures body fat by light absorption, reflectance too.

This method is not the most accurate in measuring body fat through research and experiments.

Advantages: It is safe, it is non-invasive, it is fast and it is convenient as it only requires light properties.

Disadvantages: It is not one of the most accurate method in assessing body fat composition.

My preferred method above: DEXA, as it is the most accurate and it is fast, although it may be costly.

Link to Website: http://www2.gsu.edu/~wwwfit/bodycomp.html