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Anthropometry. Chapter 5. Anthropometry. The measurement of the size and shape of the body. height, weight, length, breadth, circumference, diameter, and skinfold thickness. Anthropometry. Advantages: Instruments are portable Relatively inexpensive Disadvantages:
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Anthropometry Chapter 5
Anthropometry • The measurement of the size and shape of the body. • height, • weight, • length, • breadth, • circumference, • diameter, • and skinfold thickness.
Anthropometry • Advantages: • Instruments are portable • Relatively inexpensive • Disadvantages: • Less accurate
Anthropometry • Procedures are noninvasive, and training can be provided “on the job” without prerequisite courses.
Anthropometry • Methods are applicable to large samples • Can provide national estimates • Provides data for the analysis of secular changes.
Anthropometry Assumption: • the tissues included in the measurement are in a “standard” state, • for example, that muscles are relaxed and that soft tissues are normally hydrated.
Anthropometry • If these conditions are not met, the interpretation may be invalid.
Height and Weight • Initial attempts to gauge the relationship between body type and health relied on measures of height and weight. • Driven by the life insurance industry.
Body Mass Index • BMI is determined by measuring your weight in kilograms and dividing it by your height in meters2 • This allows for comparisons of “stoutness”, not body composition.
BMI • Used to classify individuals at risk for obesity-related diseases, and to monitor changes in body fatness of clinical populations.
BMI • BMI is a significant predictor of cardiovascular diseases and type 2 diabetes.
BMI • BMI is widely used in population-based and prospective studies to identify at-risk individuals.
BMI • However, BMI is limited as an index of obesity (i.e., body fatness) because it does not take into account the composition of an individual’s body weight.
BMI • In addition, factors such as age, ethnicity, body build, and frame size affect the relationship between BMI and %BF.
BMI • Using BMI as an index of obesity may result in misclassifications of underweight, overweight, and obesity. • It is also not a preferred method of assessing fat distribution.
BMI (kg/m2) Obesity Class Underweight <18.5 Normal Wt 18.5-24.9 Overweight 25-29.9 Obesity 30-34.9 I 35-39.9 II > 40 III Overweight and Obesity (BMI) WHO 1998
Anthropometry • Lengths and breadths are interpreted as skeletal dimensions because they are made between bony landmarks. • Table 5.2, p 71 contains information on commonly measured sites.
Lengths and Breadths • The effects of soft tissues on recorded lengths and breadths can be reduced and made less variable by the use of recommended calipers and the application of firm pressure.
Circumferences • Limb and trunk circumferences are measured with a tape measure while minimal tension is applied so that the soft tissues will not be compressed; therefore enlargement of muscle and SAT due to edema increases the recorded measurements.
Circumferences • Figure 5.1, p. 72 shows the locations of common circumference measures. • Table 5.1, on pp. 69-70 describes how these measures should be taken.
Circumferences • Circumferences of the limbs are difficult to interpret because they include skin, SAT, muscle, bone, blood vessels, nerves, and small amounts of deep adipose tissue (DAT).
Circumferences • It is even harder to interpret trunk circumferences, which include organs in addition to various tissues.
Circumferences • Interpretation of buttocks (hip) circumference is uncertain because it includes large amounts of adipose tissue and muscle and it is affected by pelvic size and shape.
Circumferences • Even standing for 1-2 hrs., or prolonged sitting, causes an accumulation of extracellular fluid in the lower limbs leading to increases in ankle and calf circumferences.
Circumferences • Abdominal circumferences are correlated with body density (r = -0.7), and the correlation of limb circumferences with body density are about -0.4.
Circumferences • The correlation of abdominal and limb circumferences with FFM are about 0.6 in each gender.
Waist to Hip Ratio • The WHR is commonly used as an indirect measure of lower and upper body fat distribution. • Figure 5.4, p. 74 (pdf file) illustrates how these measures are made.
WHR • Upper body or central adiposity, measured by the WHR, is moderately related (r = 0.48 to 0.61) to risk factors associated with cardiovascular and metabolic diseases in men and women.
WHR • Young adults with WHR values in excess of 0.94 for men and 0.82 for women are at high risk for adverse health consequences.
WHR • Limitations: • In women, it is affected by menopausal status. • Not valid for evaluating fat distribution in prepubertal children. • The accuracy of assessing VAT decreases with increasing levels of fitness.
WHR Limitations • And finally: • Hip circumference is influenced by subcutaneous fat deposition only, whereas waist circumference is affected by both VAT and SAT. • Thus, the WHR may not accurately detect changes in VAT.
WHR • Table 5.4, p. 78 (pdf file) contains norms for waist-to-hip circumference ratios for men and women.
Waist Circumference • WC is gaining support as an alternative to WHR for assessing regional adiposity in field and clinical settings.
WC • Compared to the WHR, WC provides a more accurate indirect measure of visceral fat and is not greatly influenced by age, gender, standing height, and degree of overall adiposity.
WC • WC is highly related (r = 0.76 to 0.88) to MRI and CT measures of intra-abdominal (visceral) fat in men and women, and to cardiovascular risk factors in older (67-78 yrs) women.
WC • The National Cholesterol Education Program (2001) recommends using WC cutoff values of > 102 cm (40 in) for men and > 88 cm (34.6 in) for women to evaluate obesity as a risk factor for coronary heart disease and metabolic disease.
Anthropometry • Anthropometry, when used in relation to body composition, is based on the assumption that the tissue composition is independent of tissue size.
Anthropometry • This assumption may be violated. • For example, the fat content of adipose tissue is positively related to SAT thicknesses within age groups and the fat content becomes larger as SAT thicknesses increase during growth.
Anthropometry • The choice of anthropometric measures, and the procedures used, differ for some groups.
Anthropometry • For example, the precise measurement of infants and preschool children requires that they be content; one cannot obtain precise measurements of hungry or thirsty children.
Anthropometry • Precise refers to repeatability judged from inter- or intraobserver differences, and the term validity refers to comparisons between observed measures and the true values.
Anthropometry • Disabled and elderly subjects who cannot stand erect must be measured recumbent to obtain precise and valid data.
Anthropometry • The utility and interpretation of anthropometric variables are related to their short-term variations.