Effect of Vibration Stimulus Applied to the Vastus Lateralis on the Muscle Activities of Knee Joint Extension.

[Purpose] To clarify the effect on muscles activities during knee extension of selective vibration stimulus of the vastus lateralis. [Subjects] The subjects were 10 healthy males (average age, 26.8 ± 9.2) who had no history of orthopedic or neurological disorders of the lower limbs. [Method] A continuous vibration stimulus was applied to the vastus lateralis, and we measured and compared the relative integrated electromyograms (%iEMG) of the activities of the vastus lateralis, vastus medialis, and rectus femoris, as well as the knee extension strength before and after the stimulus. [Results] The %iEMG value of the vastus lateralis during knee extension was low after the stimulus, and the ratio of the vastus lateralis and vastus medialis %iEMG values was high. [Conclusion] Selective stimulus of the vastus lateralis during knee extension suppressed the activity of the vastus lateralis, relatively promoting the activity of the vastus medialis. [ABSTRACT FROM AUTHOR]