Angle of gait: a comparative reliability study using footprints and the EMED-SF®

Background: Gait analysis using footprint impressions is a simple and inexpensive method of obtaining valuable information relating to foot dynamics. Objectives: To assess the reliability and comparability of two different measurement techniques to quantify angle of gait (AOG). Method: Part 1. Two observers measured angle of gait (AOG), in six asymptomatic adult subjects, three times at weekly intervals. Part 2. A comparison of AOG from powdered footprints, and foot progression angle (FPA), the equivalent to AOG, derived from the EMED-SF® force platform were simultaneously compared using 11 asymptomatic adult subjects. Results: A Pearson's product moment correlation of 0.94 for rater 1 and 0.93 for rater 2 was observed between trials 1 and 2. Between trials 2 and 3, a Pearson's product moment correlation of 0.95 was observed for rater 1 and rater 2. The mean difference was 0.26 (CI: −0.06, 0.57), indicating no significant difference (t = −1.63, P = 0.108). A Pearson's product moment correlation of 0.98 for AOG from powdered footprints and FPA from EMED-SF® was observed with a mean difference of 0.03 (CI: −0.54, 0.59), indicating no significant difference (t = 0.09, P = 0.93). Assessment of agreement using the Bland and Altman statistical model reflected moderate differences between raters and techniques of measuring AOG. Conclusions: Calculation of AOG from powdered footprints is a reliable and repeatable method, also demonstrating comparability to the FPA derived from the EMED-SF® platform.