Table 1: Descriptive Statistics: Maximum Rearfoot Eversion Angle
N Minimum (°) Maximum(°) Mean (°) Std. Deviation (°)
Normal Group
FPI = 0 to +5 20 3 7 .4.95 1.16
Pronated Group
FPI = +6 to +9 20 7 14 10.71 1.42
relationship between maximum dynamic
rearfoot eversion and the total FPI score within
the entire population and within pronated
and normal groups. A possible relationship
between evidence of frontal plane dominance
of the subtalar joint, and maximum rearfoot
eversion and was also examined [12] . Planar
dominance was determined via a breakdown
of individual scores for the FPI. Subject scores
relating to inversion and eversion of the
calcaneus (associated with frontal plane motion)
and curvature above and below the lateral
malleolus (representing a combination of frontal
and transverse plane motion) were calculated
and correlated with maximum measurements
for eversion giving possible scores of -4 to +4
correlated against maximum angular eversion of
the rearfoot [9] .
Correlation values above 0.8 were considered
very strong, between 0.6 and 0.8 strong and
between 0.3 and 0.6 moderate. Correlation
coefficient values below 0.3 were considered
weak due to the relatively small sample size [15] .
Data were assessed for normality of distribution
via scatter plots and homogeneity of variance
using Levene's test to determine suitability for
linear regression analysis. Linear regression
analysis was performed between the total FPI
and maximum rearfoot eversion to determine
predictive capacity of rearfoot motion for the
total FPI score. All statistical analysis was
performed using SPSS version 17 (SPSS Science,
Chicago, Illinois) software.
Results
Descriptive statistics relating to maximum
rearfoot eversion angle are shown in Table
1. The total FPI score was correlated with
maximum rearfoot eversion angle for the
entire subject population (Figure 3). Positive
correlation between the total FPI score and
maximum eversion was found to be very
strong (r = 0.92, p < 0.05) indicating close
association between the total FPI score and
maximum rearfoot eversion. Correlations
between the FPI score and maximum rearfoot
eversion angle were performed on data subsets
representing a pronated foot group (FPI = +6
to +9) and a normal foot group (FPI = 0 to +5).
The relationship between the FPI score and
maximum rearfoot angle was stronger in the
pronated group (r = 0.81, p < 0.05) than in the
normal group (r = 0.76, p < 0.05). Correlations
between frontal plane rearfoot FPI score
and frontal plane motion during gait were
strong and statistically significant across all
participants (r = 0.83, p < 0.05), however, less
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