title: The associations between adolescent head-on-neck posture, backpack weight, and anthropometric features.
abstract: METHODS
  A Cross-sectional, observational study, examining the effects of backpack weight on adolescent posture.
  
  
  OBJECTIVE
  To investigate the response of the craniovertebral angle to backpack load.
  
  
  BACKGROUND
  There is a widely held belief that repeated carrying of heavy loads, such as school backpacks, places additional stress on rapidly growing adolescent spinal structures, making them prone to postural change.
  
  
  METHODS
  Ten volunteer state high schools in metropolitan Adelaide, South Australia, provided 985 students, aged 12 to 18 years and from five different high school years, for this study. Students' posture was measured with and without their school backpack. All data analyses were undertaken per school year level to account for specific load-carrying requirements and spinal development associated with the age group.
  
  
  RESULTS
  A significant change in craniovertebral angle was found at every year level, when comparing standing posture with no backpack with posture when carrying a backpack. The change was greatest for the youngest students. Incremental change in craniovertebral angle was not strongly associated with backpack loads. The association became stronger for the oldest girls when controlled for body mass index and for weight.
  
  
  CONCLUSIONS
  The results support a differential postural response per gender and per level of spinal development but also suggest that the craniovertebral angle may not be the most sensitive measure of head-on-neck postural change for adolescents.
authors.affiliation: University of South Australia, Adelaide, Australia. karen.grimmer@unisa.edu.au
authors.forename: K A
authors.initials: KA
authors.lastname: Grimmer
authors.forename: M T
authors.initials: MT
authors.lastname: Williams
authors.forename: T K
authors.initials: TK
authors.lastname: Gill
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000886:Anthropometry; D001315:Australia; D015992:Body Mass Index; D002574:Cervical Vertebrae / Q000503:physiopathology; D005260:Female; D006801:Humans; D017770:Lifting / Q000009:adverse effects*; D008297:Male; D011187:Posture; D012737:Sex Factors; D019291:Skull Base / Q000503:physiopathology; D016474:Weight-Bearing