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Published on: September 13, 2015
Effect of foot orthotics on quadriceps and gluteus medius electromyographic activity during selected exercises
Jay Hertel1, Brent R Sloss, Jennifer E Earl
1Kinesiology Program, University of Virginia, Charlottesville, VA 22904, USA. jhertel@virginia.edu
Objective:
To compare electromyographic activity of the vastus medialis, vastus lateralis, and gluteus medius during functional activities in subjects with different foot types while wearing various off-the-shelf foot orthotics.
Design:
Experimental, controlled; 3 foot-type groups (pes planus, pes cavus, pes rectus) each tested in 4 orthotic conditions while performing 3 different exercises.
Setting:
Laboratory.
Participants:
Thirty healthy young adults, 10 with each foot type.
Interventions:
Four conditions: no orthotic, 7 degrees medial rearfoot post, 4 degrees lateral rearfoot post, and neutral rearfoot post.
Main Outcome Measure:
Surface electromyographic activity for the vastus medialis, vastus lateralis, and gluteus medius during single-leg squatting, lateral stepdown, and maximum vertical jump exercises.
Results:
Greater vastus medialis and gluteus medius activity was found with all 3 orthotic conditions, regardless of subject foot type, during the single-leg squat and lateral stepdown. Less vastus lateralis activity was found with the vertical jump with all orthotic conditions, again regardless of foot type.
Conclusions:
During slow controlled exercises such as the single-leg squat and lateral stepdown, vastus medialis and gluteus medius activity may be enhanced with an off-the-shelf orthotic, regardless of posting or foot type. These same findings do not appear to carry over to a more explosive task such as the maximal vertical jump.