title: A new method for calculating saddle seat height with an emphasis on optimal posture based on trigonometric relations.
abstract: BACKGROUND
  Based on the literature, the ergonomic saddle chair provides the most appropriate posture for users. Determination of the seat height is critical to establish the proper posture, carried out using various methods of anthropometry. This study aimed to develop a simple and applied method for determining the saddle seat height with an emphasis on appropriate posture.
  
  
  METHODS
  In this study, anthropometric dimensions including weight, body height, popliteal height and seat height at 135° knee angle in 150 male and female dentists were measured. In the laboratory, to determine the 'acetabuloischial number', 25 male and female natural hip bones were measured. The mean saddle-chair height with knee angle of 135° was then compared by two different methods, field measurement and the new calculation method.
  
  
  RESULTS
  The results showed a strong correlation between data gathered from the two different methods, the field measurement and the new calculation method (98%), and Cronbach's α from the intraclass correlation was equal to 0.994 (p < 0.05). This indicated that the two methods produced similar results.
  
  
  CONCLUSIONS
  The new method can be applied to calculate the optimal height of the saddle seat based on body height and popliteal height.
authors.affiliation: a Shiraz University of Medical Sciences , Iran.
authors.forename: Hamidreza
authors.initials: H
authors.lastname: Babaei
authors.affiliation: a Shiraz University of Medical Sciences , Iran.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Razeghi
authors.affiliation: a Shiraz University of Medical Sciences , Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Choobineh
authors.affiliation: a Shiraz University of Medical Sciences , Iran.
authors.forename: Hamidreza
authors.initials: H
authors.lastname: Pakshir
authors.affiliation: a Shiraz University of Medical Sciences , Iran.
authors.forename: Abdolreza
authors.initials: A
authors.lastname: Rajaeifard
authors.affiliation: a Shiraz University of Medical Sciences , Iran.
authors.forename: Jafar
authors.initials: J
authors.lastname: Rezaian
mesh_terms: D000328:Adult; D000368:Aged; D000886:Anthropometry; D004867:Equipment Design / Q000379:methods*; D006804:Ergonomics / Q000379:methods*; D005260:Female; D006801:Humans; D007374:Interior Design and Furnishings / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D011187:Posture / Q000502:physiology*
keywords: acetabuloischial; anthropometry; ergonomics; height determination; saddle seat