title: Comparison of trunk electromyographic muscle activity depends on sitting postures.
abstract: BACKGROUND
  Different postural positions can be characterized by the activation and relative contributions of different postural muscles, and may variously contribute to the recovery from or worsening of chronic lower back pain.
  
  
  OBJECTIVE
  The present study aimed to investigates trunk muscle activities in four types of seated postures: cross-legged, long, side, and W-shaped.
  
  
  METHODS
  Eight healthy adults participated in the study. Trunk muscle activities of the external oblique (EO), rectus abdominis (RA), latissimus dorsi (LD), and erector spinae (ES) muscles in each of the sitting postures including cross-legged, long, side, and W-shaped were collected utilizing surface electromyography (sEMG). The mean sEMG signals in each of the sitting postures were used for statistical comparisons.
  
  
  RESULTS
  There were no significant differences in electromyographic muscle activity of EO, RA, LD, and ES in the four postures (p > 0.05). However, in the W-shape sitting posture, the left LD showed the greatest electromyographic muscle activity, followed by the right LD and left EO, respectively. The right and left LD in the long sitting posture and left ES in the side sitting posture showed greater electromyographic muscle activity than that of other muscles.
  
  
  CONCLUSIONS
  Based on the results, trunk muscle activity did not significantly differ between the four types of sitting postures. However, our study is limited by its experimental method and sample size. Thus, in the Future, further study will be needed.
authors.affiliation: Department of Physical Therapy, Graduate School of Kyungnam University, Changwon, Republic of Korea.
authors.forename: DongGeon
authors.initials: D
authors.lastname: Lee
authors.affiliation: Department of Physical Therapy, Graduate School of Kyungnam University, Changwon, Republic of Korea.
authors.forename: SeoJeong
authors.initials: S
authors.lastname: Yu
authors.affiliation: Department of Physical Therapy, Graduate School of Kyungnam University, Changwon, Republic of Korea.
authors.forename: SunHae
authors.initials: S
authors.lastname: Song
authors.affiliation: Department of Mechanical Engineering, Kyungnam University, Changwon, Republic of Korea.
authors.forename: Se-Han
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Department of Physical Therapy, National Rehabilitation Center, Seoul, Republic of Korea.
authors.forename: SeungHeon
authors.initials: S
authors.lastname: An
authors.affiliation: Department of Physical Therapy, College of Health Science, Gachon University, Incheon, Republic of Korea.
authors.forename: Hwi-Young
authors.initials: HY
authors.lastname: Cho
authors.affiliation: Department of Physical Therapy, Uiduk University, GyeongJu, Republic of Korea.
authors.forename: Ki-Hun
authors.initials: KH
authors.lastname: Cho
authors.affiliation: Department of Physical Therapy, Kyungnam University, Changwon, Republic of Korea.
authors.forename: GyuChang
authors.initials: G
authors.lastname: Lee
mesh_terms: D000071596:Abdominal Oblique Muscles / Q000502:physiology; D001696:Biomechanical Phenomena / Q000502:physiology; D003430:Cross-Sectional Studies; D004576:Electromyography / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D017568:Rectus Abdominis / Q000502:physiology; D056910:Republic of Korea; D064171:Superficial Back Muscles / Q000502:physiology; D060726:Torso / Q000502:physiology; D055815:Young Adult
keywords: Electromyographic activity; sitting posture; trunk muscle