Title

Electromyographic effects of foot orthotics on selected lower extremity muscles during running

Document Type

Article

Publication Date

1-1-1999

Abstract

Objective: To study the effects of foot orthotics on the mean electromyographic amplitude of proximal and distal lower extremity muscle groups during the first 50% of the stance phase during treadmill running. Design: Repeated measures. Setting: Subjects were recruited from the general community. Participants: Twelve recreational runners who were symptomatic for lower extremity pain. Clinical and radiographic findings confirmed the presence of structural malalignment of the foot. Intervention: Semirigid orthotics were fabricated for each subject, and like footwear provided. Main Outcome Measures: Surface electromyogram activity from the tibialis anterior, medial gastrocnemius, vastus medialis, vastus lateralis, and biceps femoris was collected during treadmill running at self-selected speeds for orthotic and nonorthotic conditions. Root mean square values were averaged across 10 cycles, normalized to time and expressed as a percentage of the nonorthotic condition. Results: Paired t test results showed statistically significant changes (p < .05) for the biceps femoris (-11.1%) and tibialis anterior (+37.5%) muscle groups during the orthotic condition. Electromyographic activity in the medial gastrocnemius, vastus medialis, and vastus lateralis with orthotic use was not significantly different from the nonorthotic condition. Conclusion: Although subjects' electromyographic responses to orthotic use were highly individualized, the findings of this study may enhance our understanding of muscle activity changes associated with positive outcomes from orthotic use.

Publication Name

Archives of Physical Medicine and Rehabilitation

Volume Number

80

First Page

540

Last Page

544

Issue Number

5

DOI

10.1016/S0003-9993(99)90196-X

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