technical training. This training includes proper positioning for measuring height (standard erect posture with the head and eyes in the Frankfurt horizontal plane), procedures for stepping on and off the scale (for example, some children may require assistance, and children must be kept from jumping on the scale), positioning for measuring waist circumference (feet together), identification of the correct level for measuring waist circumference, and identification of the correct sites for measuring the triceps and subscapular skinfolds. The level for measuring waist circumference and the sites for each skinfold measurement should be marked on the skin.

Height and weight typically are measured without shoes and in light indoor clothing (e.g., shorts and a t-shirt); the subscapular site is easily accessed by raising the back of the t-shirt. Waist circumference is measured from the side (measurements taken face-to-face are generally invasive). Two technicians may be needed to measure waist circumference in some overweight and obese youth. This should not be a problem as a separate individual (who is well versed in the measurement protocols) should serve as recorder for the measurements. Other duties of the recorder include observation of the position of the subject (e.g., young children often slouch after being placed in the standard erect posture), proper identification of skinfold and waist circumference sites; and in measurement of waist circumference, checking to ensure that the tape is horizontal or is not pulled too tightly, resulting in major skin and soft tissue compression. The lack of a recorder will slow down the measurement process and contribute to potential error in transcribing measurements.

GUIDANCE FOR INTERPRETATION OF TEST RESULTS

The committee acknowledges that there are multiple approaches to establishing cut-points (cutoff scores) for estimates of body composition depending on the purpose and on the available data. In general, the committee considered the following two approaches:

  • Direct associations with health-related biomarkers—This method involves examining associations between BMI, waist circumference, or sum of skinfold scores and cardiometabolic risk factors in youth. Ideally, as discussed in Chapter 3, data necessary to establish those associations will exist from broad populations of youth.
  • Indirect associations with health-related biomarkers using adult cut-points or data from other body composition measures—When the necessary data in youth are not available, associations can be examined in adult data, and cut-points established for adults can be projected to the corresponding percentile in children, if appropriate. When data needed to establish associations between a specific


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