Question1
First of all, what is Anthropometry? It is the scientific study of the morphology and composition of the human body in relation to movement and function, anthropometry are combination of measurements related to body size and composition. Anthropometry measures all physical aspects of your body. Measurements include height, width, skinfold, circumferences and mass. Here are some of the benefits and limitations of using anthropometric methods to assess body composition. One of the biggest advantages of anthropometry measurements is that the cost is very low due to equipment price are low and little equipment required. E.g. a skinfold caliper, Lufkin W606PM tape and a surgical skin marker will do for all ISAK level 1 measurements. Another benefit is that anthropometric measurements are easy to perform and all the equipment is transportable. The practical skill of anthropometric measurement is very easy and can be learn in a very short period of time. However the hard part is to take anthropometric measurements at the correct locations and for a precise and accurate result a skilled technician is required. In addition, because multiple measurements will be taken at each skinfold site, it is important to measure the exact same spot each time. For this reason it is necessary to mark each site before you take a measurement and make it precisely. A good technique would be marking the entire skinfold site and double check it first before taking a measure.
Question 2
If I have to choose a gold standard in order to check validity of the ISAK anthropometric measures especially for body fat I would use the dual energy x-ray absorptiometry method (DEXA). Although the current gold standard for body composition measurements is the underwater weighting method however there are a few disadvantages about it. First and foremost, it is expensive and requires a lot of space and time consuming. Additionally, subjects must completely submerge themselves underwater and expel all of the air in their lungs. Since air makes the body float, air in your lungs results in an inaccurate percentage of body fat, notes Georgia State University. This also might make the subject anxious or uncomfortable.
For DEXA, it said to be the gold standard in clinical body composition analysis recently. It originally developed for bone content analysis; it is now being indicated as a potential criterion method for body composition in the future. Compared with other criterion like MRI, it is currently more widely available as a research tool and is likely to be less expensive to operate and maintain also minimal effort needed by the subjects unlike the underwater weighting method. Another good thing about DEXA is that it can apply in humans at all ages and subjects are effortless. After all, the most concerns about these difference criterion is accuracy, and one of the biggest advantages of DEXA include good accuracy and reproducibility since it has only +/- 3% error fat and +/- 1%error bone mass due to DEXA takes bone mineral content into consideration when estimating body fat and muscle, therefore it is considered to be more accurate and valid than a two component model of body composition such as underwater weighing. Moreover, it provides for the assessment of regional body composition and nutritional status in disease states and growth disorders. DEXA able to partition the body into three components, bone mineral, fat and muscle tissue therefore it can give us a clear image of total or regional body composition values. DEXA can provide a total body composition test is fast and easy and relatively inexpensive considering the wealth of accurate, reliable information it yields. DEXA mostly run by software that are set in the machine therefore technician does not have to be trained extensively. Nonetheless, once validated against an imaging criterion such as MRI, DEXA may prove to be a useful addition to the body composition options and because of all these advantage, I decided to use the DEXA as a gold standard for determining body fat.

Question 3
All of the method mention in above paragraph has its own useful aspect but If I have to perform a small, low budget research study on health of Hong Kong adults I would pick the skinfold method to assess and determine which adults have good health compared to poor health. This method is very popular for checking body fat as well as health condition. The popularity of this method is credited to the many advantages associated with its use. These advantages include the fact that it is a noninvasive and fairly easy technique and that the skinfold calipers are cheap, easy to maintain, and simple and convenient to use which suitable in our case. They may be used in anywhere like outdoor field testing as well as in the laboratory due to their portability which appropriate in our case which large number of subjects needed to be tested and tester do not require extensive training for reliable use. On the other hand, in order to ensure validity, the correct procedure and skills are very important and must be used during anthropometric measurements. Potential sources of measurement error include caliper site selection and tester reliability. Tester reliability includes inter- and intra-measurement error as well as selection of skinfold site adjustment. A major limitation associated with skinfold measurement is the failure to estimate simultaneously all possible sources of measurement error. As this method requires quite a few body composition assessment techniques therefore limitations will be associated with skinfold measurement, which may result in unsuitable estimates of the fat thickness and consequently total body fat. These limitations include features such as the inability to palpate the interface of fat and muscle. Other problems include compression of the fatty tissue during measurement, fluid in compartments is hard to ascertain, the inability to control inter- and intra-subject variations and the fact that measurements may only be useful at certain sites.

References
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