title: Frequency of postural changes during sitting whilst using a desktop computer--exploring an analytical methodology.
abstract: BACKGROUND
  Dynamic movement whilst sitting is advocated as a way to reduce musculoskeletal symptoms from seated activities. Conventionally, in ergonomics research, only a 'snapshot' of static sitting posture is captured, which does not provide information on the number or type of movements over a period of time. A novel approach to analyse the number of postural changes whist sitting was employed in order to describe the sitting behaviour of adolescents whilst undertaking computing activities.
  
  
  METHODS
  A repeated-measures observational study was conducted. A total of 12 high school students were randomly selected from a conveniently selected school. Fifteen minutes of 3D posture measurements were recorded to determine the number of postural changes whilst using computers.
  
  
  RESULTS
  Data of 11 students were able to be analysed. Large intra-subject variation of the median and IQR was observed, indicating frequent postural changes whilst sitting.
  
  
  CONCLUSIONS
  Better understanding of usual dynamic postural movements whilst sitting will provide new insights into causes of musculoskeletal symptoms experienced by computer users.
authors.affiliation: a Department of Physiotherapy, FNB Movement Analysis Laboratory, Faculty of Medicine and Health Sciences , University of Stellenbosch , Cape Town , South Africa.
authors.forename: Sjan-Mari van
authors.initials: SM
authors.lastname: Niekerk
authors.forename: Quinette Abigail
authors.initials: QA
authors.lastname: Louw
authors.forename: Karen
authors.initials: K
authors.lastname: Grimmer-Sommers
mesh_terms: D000293:Adolescent; D001696:Biomechanical Phenomena; D003201:Computers; D006804:Ergonomics; D005260:Female; D006801:Humans; D008297:Male; D009068:Movement; D011187:Posture; D013334:Students
keywords: dynamism; posture measurement; sitting biomechanics