Skinfold thicknesses: is there a need to be very precise in their location?

Skinfold thicknesses represent a comparatively simple and reasonably accurate assessment of body fatness which is an important part of the estimation of nutritional state. However, much emphasis is placed on the necessity to be very precise in the exact position of the skinfold being measured and there is frequently concern, also, about the variability of the measurement by different observers using different types of caliper. Fifty-three women and forty-five men had four skinfolds (biceps, triceps, supra-iliac and subscapular) measured first at the standard sites (Tanner, 1953; Edwards et al. 1955), and then at deliberately chosen sites about 20 mm distant from the ‘correct’ ones. The effect on the estimation of body fatness by this manoeuvre resulted in a difference of usually less then 1% and, at a maximum, 3%. In the light of the uncertainty of the basic assumptions which are made in extrapolating from skinfolds (or indeed densitometry, total body water, total body K, and others) to body fatness, these technical errors assume comparatively little importance.