Measurement of triceps skinfold thickness. An investigation of sources of variation.

A measurement of the thickness of subcutaneous skinfolds has been widely used as an index of body fat. Edwards et al. (1955) investigated the design and accuracy of skinfold calipers and made a number of recommendations for their construction which were incorporated in the Harpenden skinfold calipers. They found that the precision of the Harpenden skinfold calipers was adequate and that the difference between examples of this instrument was small. In contrast, the difference in skinfold measurements found between observers was large. They therefore suggested that the limitations of accuracy depend on locating the skinfold, and also on the manner in which it is picked up. We have investigated the variation of skinfold thickness when location of the skinfold site was varied, the depth of bite changed, and the skinfold either held or released while the skinfold thickness was read.