Reliability. We used the intraclass correlation coefficient
(ICC) to evaluate intrarater reliability (ICC 3,1). Standard error
of the mean (SEM) was calculated to describe the precision
of the measurement.
Correlation. Correlation analyses between the VAS and
functional tests were evaluated using the Pearson correlation
coefficient.
Limb Symmetry Index. Statistical difference between individual
subjects’ limbs for the unilateral functional tests was
determined using a paired t test. Bonferroni correction was
applied to these 4 tests, setting the alpha level to .05/4 5
0.013. The statistical difference between subjects with PFPS
and normal subjects on functional test scores was determined
with independent t tests. Bonferroni correction was applied to
these 4 tests, setting the alpha level to .05/4 5 0.013. Limb
symmetry index was calculated with the formula (involved/
uninvolved) 3 100 for each group.