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Friday, 17 May 2013

Body Composition: Skin-fold measurements - Desiree

Skin fold measurements is a way to estimate your body's fat composition. I prefer this method compared to the rest as it is easily available, simple, inexpensive, relatively accurate and not painful.

The Skinfold caliper is needed to carry out the measurements.

The Skin fold caliper is a device which measures the thickness of a fold of your skin with its underlying layer of fat. By doing this at the key locations can be a quite accurate representative of the total amount of fat that is on your body, it is also possible to estimate the total percent of bodyfat on your body.

Areas to test out: Triceps, biceps, shoulder blades and waist:


Tuesday, 14 May 2013

Body Com Bioelectrical impedance analysis Shaun Ng

Bioelectrical impedance analysis (BIA) is a commonly used method for estimating body composition, the method has become popular owing to its ease of use, portability of the equipment and its relatively low cost compared to some of the other methods of body composition analysis. It is familiar in the consumer market as a simple instrument for estimating body fat. It actually determines the electrical impedance, or opposition to the flow of an electric current through body tissues which can then be used to calculate an estimate of total body water (TBW). TBW can be used to estimate fat-free body mass and, by difference with body weight, body fat.

However, it is deemed not that accurate and the results varied a lot. 

Body Composition DEXA - Kai En

DEXA has many functions such as detecting the presence of osteoporosis in men and women with particular risk factors and monitoring bone density in those with low normal levels and in those with osteoporosis undergoing treatment. This method has multiple functions with low or no risks at all. And, all the patient has to do during this is to just lie down while the scanner passes over the patient's body. During this procedure, the patient will not feel any discomfort so it will be quite ideal. For this treatment, only simple preparations has to be made such as not consuming calcium supplements or avoid clothes with metal on them. This method is also one of the most accurate ones. Hence, this method is the most suited one.

Monday, 13 May 2013

DEXA- Ryan

Dual Energy X-Ray Absorptionmetry (DEXA)

2 X-ray beams of different energy levels are targeted at the subject's bones. Some of the beam is absorbed by the bone and the rest passes through it. In essence, it is an X-ray and will also show the broken bones of the subject. It is the most accurate way of measuring the total amount of fat in a person.

Pros: Extremely Accurate, most accurate among the other methods

Cons: Very costly to operate and use with each use going up to a few thousand. (due to the nature of how it works)

Preferred Mode of Measurement of Body Composition – Justin

I like the Bioelectrical Impedance that makes use of electrical impedance/conductivity in the body to measure the amounts of body fats and lean mass for the following reasons:

1. Readily available since the 1980s
It is very available, which saves time and costs when wanting to know our body composition.

2. Makes use of body compositions
Rather than using air pressure or measurements, the BI makes use of the Total Body Water standard in our bodies to accurately measure how much fat content we should have.
The disadvantage of this is the consumption of water, which may cause this value to alter. 

Body Composition: Wee Chang Han, Skinfold measurement

The Skinfold measurement is the most efficient method to measure one's body composition in my opinion as it is quick and easy to do.

Some of the advantages of the Skinfold measurements is that it is widely utilized to assess body composition. It is a lot simpler than hydrostatic weighing and many of the other body composition techniques. After the original outlay for calipers, the daily tests costs are minimal.

Thus, the skin fold method can be used by many clinics and hospitals as it does not cost a fortune and does not require a huge amount of time to be spent on training. It can also measure up to many different parts of the body, unlike other methods which can only measure the entire body at once. This can accurately pinpoint the area that needs fats to be removed.

Due to its reliance of human, human error may be inevitable and present in the recording, which results in a need of an average or another device to confirm the results.

Body Composition - DEXA Scan (Mason Sim)

DEXA Scan 
It is the most accurate and efficient method to measure body composition . There is very little chance for human error , increasing the reliability of the machine . Also , it is able to detect other things as well (Bones Density)

Disadvantages : It is extremely costly and the scanner is only of a certain width , making it unsuitable for people of certain sizes to use the machine .

Mason Sim 

Sunday, 12 May 2013

Measuring Body Composition: Underwater Weighing (Farrell Nah)

                                                                  Underwater Weighing

Underwater (hydrostatic) weighing is done based on Archimedes' Principle. Because body fat is less dense than water, it increases one's buoyancy while the fat-free mass, which has a density greater than water, makes one sink. This is once considered the gold standard, as it is more accurate than other methods such as skinfold measurement but the emergence of newer and more sophisticated methods are now more accurate than this method


The largest source of error in underwater weighing is thought to be the determination of residual volume (RV; the amount of air remaining in the lungs following maximal expiration). When RV is estimated rather than measured, the precision of underwater weighing is little better than anthropometric (skinfold) determination.

  1. Weigh the subject to the nearest 0.1 kg.
  2. Measure or estimate the subject's RV. If possible, directly measure RV using the diluted helium or oxygen techniques. Otherwise, RV can be estimated by measuring vital capacity (VC) and multiplying it by 0.24 or 0.28 for males and females, respectively.
    • VC is the amount of air that can be maximally exhaled. To measure VC, place a noseclip on the subject. Have the subject maximally inhale, place the mouthpiece from the spirometer in his/her mouth, and then maximally exhale. Perform 2-3 trials and use the highest volume. Also, correct the volume to BTPS by multiplying the volume by the correction factor (see an instructor for this value).
  1. Tare (zero) the scale in the underwater weighing tank. While seated in the tank, instruct the subject to blow out all the air that he/she can exhale, bend slowly forward until the top of his/her head is underwater, and to remain motionless until the scale has settled and the computer indicates that it has a reading. Have the subject perform 6-10 trials and average the heaviest 2-3 readings.

Determination of Body Density 
Body Density = dry weight / [((dry weight - wet weight) / water density)- RV - 0.1]  
Note: Units for all weights are in kg and RV is in L. The 0.1 represents an estimated volume (L) of gas in the GI tract.

Estimation of Percent Fat
The two most commonly used equations for estimating percent fat from body density are the Siri (1961) and Brozek (1963) formulae. A limitation to these formulae is that they assume the density of fat-free mass to remain a constant across the population when in fact is varies. Thus, the actual percent fat tend to be slightly higher than the measured percent fat in the lean, muscular individual and the opposite effect in obese individuals.
Percent Fat = [(495 / Body Density) -450] * 100
Percent Fat = [(4.570 / Body Density) - 4.142] * 100

Bioelectrical Impedance (Jemima)

I like the bioelectrical impedance because it is easy to use, portable and it is relatively cheaper. However, it might not be very accurate as the machine might not be working well and the results obtained will be inaccurate. Research studies have shown that it is quite variable and it was not regarded by many as providing an accurate measure of body composition. They tend to under-read fat percentage.

My preference

I choose the skinfold measurement because it is the most easily available  and can other results like X-rays even though it is measuring body composition. It is better than the rest as underwater weighing, bioelectrical impedence and Bod Pod are all not accurate.How Therefore, I chose this method.

Body Composition - Skinfold (Kaelan)

Skin fold method involves the measurement of fat under the skin.

It is advantageous as the equipment is cheap and easy to maintain and is faster than the other methods. This makes it much cheaper than other methods and allows the measurement to be taken conveniently in places such as schools and clinics


I choose the DEXA because it is the most accurate and can other results like X-rays even though it is measuring body composition. It is better than the rest as underwater weighing, skinfold measurements, bioelectrical impedence and Bod Pod are all not accurate. Therefore, I chose this method.