It is known that functional types and subtypes of foot according to Root differ, among others, by the height of foot arch when load is applied. The study objective was to use the Chippaux-Smirak index (CSI) to evaluate the height of the longitudinal foot arch in functional (sub)types according to Root. The test group consisted of 141 women (17-85 year, x = 58.8, SD = 12) and 87 men (22-86 year, x = 58.7, SD = 11.91), mainly middle aged and older. One examiner assessed the foot types and subtypes in all test subjects - rearfoot varus compensated (RFvarC), partially compensated (RFvarP) and uncompensated (RFvarN), forefoot varus compensated (FFvarC), partially compensated (FFvarP) and uncompensated (FFvarN), forefoot valgus flexible (FFvalgF), semiflexible (FFvalgS) and rigid (FFvalgR) and neutral foot (N). The other examiner evaluated all footprints and he assessed CSI. The sequence was determined on the basis of average CSI; significance of the differences we found was tested by ANOVA and the post-hoc Fisher LSD test. The results showed that functional subtypes could be - with high significance - divided into 2 extreme groups. On one side of the spectrum are the compensated, resp. flexible subtypes with high CSI (thus lower longitudinal foot arch). On the other side of spectrum are uncompensated, respectively rigid subtypes with low CSI. In the central part of the spectrum there are intermediate subtypes. Neutral types can be placed in the central group, rather into its left side. Gender influence is negligible. The results also confirmed the assumption concerning the differences among functional (sub)types in the height of the longitudinal foot arch when load is applied. Nevertheless it cannot by itself replace a personal and physical examination by an examiner who is greatly acquainted with functional anatomy and kinesiology.
