Skinfold compressibility in Japanese university students.

It is well known that caliper readings decline after the initial application of the caliper to the skinfold (dynamic compressibility). In addition to this compressibility, there is also a variability of skinfold compressibility at different body sites (static compressibility). To investigate this static variability, a comparison was made between skinfold thickness obtained from using caliper and thickness derived from an ultrasound image (B scan-mode) at sixteen skinfold sites of 96 non-athletic students in good health (45 men and 41 women). The skinfold compressibility is defined as: (uncompressed value-compressed value) x 100/uncompressed value. The patterns created by the plots of skinfold compressibility across the sixteen body sites were similar for both sexes although the inter-site variability is quite large (significant at 0.01 level on ANOVA). Women tend to have greater skinfold compression in the trunk area and less in the limbs as compared with men. This sex difference may be caused by the sex differences of skin thickness and skin tension (subcutaneous space pressure). The marked inter-site variability in skinfold compressibility suggests the need for caution in estimates of fat mass using skinfold calipers.