title: Transient pain developers show increased abdominal muscle activity during prolonged sitting.
abstract: BACKGROUND
  Sitting is a commonly adopted posture during work and prolonged exposures may have detrimental effects. Little attention has been paid to the thoracic spine and/or multiple axes of motion during prolonged sitting. Accordingly, this study examined three-dimensional motion and muscle activity of the trunk during two hours of uninterrupted sitting.
  
  
  METHODS
  Ten asymptomatic males sat during a simulated office task. Kinematics were analyzed from six segments (Neck, Upper-, Mid-, and Lower-thoracic, Lumbar, and Pelvis) and electromyography was recorded from eight muscles bilaterally.
  
  
  RESULTS
  Four participants developed transient pain. These participants showed higher average muscle activations in the abdominal muscles. Additionally, the non-pain group showed less lateral bend positional change in the mid-thoracic region compared to the upper- and lower-thoracic regions. Weak-to-moderate positive correlations were also found between rated pain and low back muscle activation.
  
  
  CONCLUSIONS
  The results provided further evidence of reduced movement in non-pain developers and altered muscle activation patterns in pain developers. Low-level, prolonged static contractions could lead to an increased risk of injury; and though the increased abdominal activity in the pain developers was not directly associated with increased rated pain scores, this could indicate a pre-disposition to, or enhancer of, transient pain development.
authors.affiliation: School of Kinesiology & Health Science, Faculty of Health, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Nairn
authors.forename: Nadia R
authors.initials: NR
authors.lastname: Azar
authors.forename: Janessa D M
authors.initials: JD
authors.lastname: Drake
mesh_terms: D000009:Abdominal Muscles / Q000503:physiopathology*; D000328:Adult; D001696:Biomechanical Phenomena; D004576:Electromyography; D006801:Humans; D017116:Low Back Pain / Q000503:physiopathology*; D008297:Male; D009038:Motion; D009068:Movement / Q000502:physiology; D010147:Pain Measurement; D011187:Posture / Q000502:physiology*; D016059:Range of Motion, Articular; D013904:Thoracic Vertebrae / Q000503:physiopathology; D013997:Time Factors; D055815:Young Adult
keywords: Electromyography; Kinematic; Prolonged sitting; Spine