Effect of Foot Orthotics on Calcaneal Eversion During Standing and Treadmill Walking for Subjects With Abnormal Pronation.

Genova JM, Gross MT (Duke Physical Therapy, Mebane Outpatient Community Office, Mebane, NC; Division of Physical Therapy, Program in Human Movement Science, University of North Carolina, Chapel Hill, Chapel Hill, NC), J Orthop Sports Phys Ther. 2000; 30:664-675.

The purposes of this study were to investigate the effects of foot orthoses on calcaneal movement during treadmill walking and to examine the effect of shoes and foot orthoses on the static position of the calcaneus bone.

This study used a within-subject with repeated measures design and an intervention of foot orthoses. The researchers tested 13 subjects (8 men [mean age = 35.8 [+ or -] 12.7 years], 5 women [mean age = 30.4 [+ or -] 10.6 years]; age range = 18-55 years) who met the inclusion criteria of abnormal pronation pertaining to the longitudinal arch angle and calcaneal angle.

A custom-made plastic mold was used to indicate calcaneal position inside the shoe during static standing and treadmill walking. Three conditions were tested in static standing: barefoot before the start of the test, in shoes without orthoses, and in shoes with orthoses. All subjects also were asked to walk quickly (average velocity = 1.9 m/s) on the treadmill with and without foot orthoses. One video camcorder was used to film the calcaneal motion in both walking and static standing conditions from the posterior view at 60 Hz. Kinematic data was processed using the Peak automatic digitizing module. The dependent measure used for static standing was calcaneal angle, and the dependent measures for treadmill walking included peak calcaneal eversion angle, calcaneal eversion angle at heel rise, stance time, time to initiation of calcaneal inversion, and percent stance time for calcaneal inversion initiation.

The results of a Tukey Honestly Significant Difference post hoc analysis and a one-way ANOVA showed that the calcaneal eversion angle for barefoot standing (15.3 [degrees] [+ or -] 3.8 [degrees]) was significantly greater than the calcaneal eversion angles for the shoe conditions with and without foot orthoses (10.0 [degrees] [+ or -] 4.0 [degrees] and 10.9 [degrees] [+ or -] 4.6 [degrees], respectively); there was no difference in calcaneal eversion angle between the 2 shoe conditions. In treadmill walking, paired t tests showed that using foot orthoses significantly reduced both the maximum calcaneal eversion angle and average calcaneal eversion angle at heel rise by 2.1 and 2.2 degrees, respectively. The other 3 dependent measures (stance time, time to initiation of calcaneal inversion, and the percent stance time for calcaneal inversion initiation) did not show significant differences. The authors indicated that the poor statistical powers (.07-.18) for these 3 dependent measures might explain the inability to detect any difference between orthotic and nonorthotic conditions.

The authors concluded that foot orthoses resulted in significant reductions in maximum calcaneal eversion and calcaneal eversion at heel rise during treadmill walking. They argued that shoes with motion control features and the same shoes with foot orthoses could effectively reduce the standing eversion angle. Shoes could be used in conjunction with foot orthoses for lower-extremity disorders.

Bob Chen, PT, PhD
New York, NY