RELIABILITY OF PRESSURE DISTRIBUTION QUANTITIES DESCRIBING THE MOVEMENT OF THE FOOT

Abstract

The functional behavior of the foot in walking and running can be described using measurements of plantar pressure. The course of the gait line (GL) reflects the dynamic behavior of the foot in interaction with the ground (and the shoe). It has been shown thus far that the GL can be reliably described on the basis of geometric characteristics. The objective of this study was to check the reliability of dynamic GL characteristics. For this, measurements of plantar pressure were made on 24 healthy subjects (m = 12, f = 12) with running experience (> 50km/w) wearing their own shoes (OS) and wearing neutral running shoes (NS). The subjects ran in a test-retest procedure (1 week, M1/M2) on a treadmill at 12 km/h. The pressure distributions in the stance phase (SP) of 8–10 cycles were averaged. The individual GL of the subject can be calculated from this and the maximum velocity of the CoP determined in tangential (vt) and medial (vm) direction in the first third of the SP. The reliability (M1 vs. M2) for vt and vm was expressed by Pearson's correlation coefficients (r), test-retest-variability (TRV) and the BLAND-ALTMAN criteria (CBA). For vt ros = 0.90 and rNS = 0.77 were found at a TRV of 8% and 13%, resp.; for vm ros = 0.95 and rNS = 0.93 and TRV = 21% and 14%, resp. CBA was fulfilled for both variables and both shoes except for vt in OS. The results show that reliable determination of dynamic GL characteristics is possible. Thus it is possible to reliably measure differences in GL between healthy and unhealthy individuals.