A Study on the Differences of Quadriceps Femoris Activities by Knee Alignment
during Isometric Contraction |
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Authors: | Seol Park Yu-Min Ko Gwon-Uk Jang Yoon-Tae Hwang Ji-Won Park |
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Institution: | 1) Department of Physical Therapy, General Graduate School, Catholic University of Daegu, Republic of Korea;2) Department of Physical Therapy, Gangneung Yeongdong College, Republic of Korea;3) Department of Physical Therapy, College of Medical Science, Catholic University of Daegu, Republic of Korea |
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Abstract: | Purpose] This study attempted to identify how genu varum or valgum affects the
electromyographic activities of the vastus medialis, vastus lateralis, and rectus femoris
during knee isometric contraction. Subjects] Fifty-two healthy young adults were enrolled
in this study. They were enrolled and classified into three groups by knee alignment
conditions: the genu varum, genu valgum, and control groups. Methods] The
electromyographic activity ratio of the vastus medialis to the vastus lateralis and rectus
femoris were calculated using the percentage of maximum voluntary contraction. The
participants contracted their quadriceps during isometric contraction at 30 and 60° of
knee flexion. Results] The genu varum group had more activity in the vastus medialis than
in the vastus lateralis and rectus femoris, whereas the genu valgum group had more
activity in the vastus lateralis and rectus femoris than in the vastus medialis. There was
a significant difference in the muscle activity ratio between the vastus medialis and
vastus lateralis by angle of knee flexion degree only in the genu valgum. There were no
significant differences in any of the three groups in terms of the muscle activity ratio
of the vastus medialis to the rectus femoris by angle of knee flexion. Conclusion] The
quadriceps femoris was used for different strategies according to knee alignment during
isometric contraction at 30 and 60°. This study suggests that rehabilitation training
programs used to strengthen the quadriceps should consider the knee alignment conditions
of the target subjects.Key words: Electromyography, Quadriceps muscle, Isometric contraction |
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