title: Examination of center of pressure displacement and muscle activity of the hip girdle muscles on lateral movement in the sitting position, focusing on kinematic features before and after the start of exercise.
abstract: [Purpose] This study aimed to evaluate the kinematic characteristics at the start of lateral movement in the sitting position, for application in physical therapy. [Subjects and Methods] Eleven healthy male subjects (mean age, 24.8 ± 3.7 years) were included in the study after they provided informed consent. The electromyographic activities of the tensor fascia lata, gluteus medius, and rectus femoris, and the center of pressure (COP) displacement during lateral reach in the sitting position were measured. The task was recorded on video for analysis. [Results] In almost all subjects, before the beginning of the task, the electromyographic activity in the opposite side of each studied muscle was recorded, and the opposite and anterior displacement of the COP was observed. The video analysis revealed that all subjects showed lateral displacement of the thoracic part of the trunk after the start of the task. However, the lumbar region and pelvis maintained their starting positions. [Conclusion] COP displacement occurred in the reverse reaction before the task, and this involved the hip girdle muscles of the opposite side. A reverse reaction displaced the pelvis to the opposite side to ensure instability of posture through side tilting of the trunk at the beginning of the task.
authors.affiliation: Department of Rehabilitation, Hachimine Clinic, Japan.
authors.forename: Kouji
authors.initials: K
authors.lastname: Ikeda
authors.affiliation: Medical Corporation Group Sekitetsukai, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Suehiro
authors.affiliation: Department of Rehabilitation, Medical Corporation Group Sekitetsukai, Japan.
authors.forename: Akito
authors.initials: A
authors.lastname: Kizu
authors.affiliation: Department of Rehabilitation, Medical Corporation Group Sekitetsukai, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Kunieda
authors.affiliation: Department of Rehabilitation, Medical Corporation Group Sekitetsukai, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Takasaki
authors.affiliation: Graduate School of Health Sciences, Graduate School of Kansai University of Health Sciences, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Suzuki
keywords: Hip joint; Lateral movement in the sitting position; Reverse reaction of COP displacement