title: Factor Analysis of the Community Balance and Mobility Scale in Individuals with Knee Osteoarthritis.
abstract: OBJECTIVE
  The clinical assessment of balance is an important first step in characterizing the risk of falls. The Community Balance and Mobility Scale (CB&M) is a test of balance and mobility that was designed to assess performance on advanced tasks necessary for independence in the community. However, other factors that can affect balancing ability may also be present during performance of the real-world tasks on the CB&M. It is important for clinicians to understand fully what other modifiable factors the CB&M may encompass. The purpose of this study was to evaluate the underlying constructs in the CB&M in individuals with knee osteoarthritis (OA).
  
  
  METHODS
  This was an observational study, with a single testing session. Participants with knee OA aged 50 years and older completed the CB&M, a clinical test of balance and mobility. Confirmatory factor analysis was then used to examine whether the tasks on the CB&M measure distinct factors. Three a priori theory-driven models with three (strength, balance, mobility), four (range of motion added) and six (pain and fear added) constructs were evaluated using multiple fit indices.
  
  
  RESULTS
  A total of 131 participants (mean [SD] age 66.3 [8.5] years, BMI 27.3 [5.2] kg m-2) participated. A three-factor model in which all tasks loaded on these three factors explained 65% of the variance and yielded the most optimal model, as determined using scree plots, chi-squared values and explained variance. The first factor accounted for 49% of the variance and was interpreted as lower limb muscle strength. The second and third factors were interpreted as mobility and balance, respectively.
  
  
  CONCLUSIONS
  The CB&M demonstrated the measurement of three distinct factors, interpreted as lower limb strength, balance and mobility, supporting the use of the CB&M with people with knee OA for evaluation of these important factors in falls risk and functional mobility. Copyright © 2016 John Wiley & Sons, Ltd.
authors: Department of Physical Therapy, University of British Columbia, Vancouver, BC, Canada.
authors: Judit
authors: J
authors: Takacs
authors: Department of Physical Therapy, University of British Columbia, Vancouver, BC, Canada.
authors: Natasha M
authors: NM
authors: Krowchuk
authors: Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada.
authors: Charles H
authors: CH
authors: Goldsmith
authors: Department of Physical Therapy, University of British Columbia, Vancouver, BC, Canada.
authors: Michael A
authors: http://orcid.org/0000-0002-8648-1591
authors: MA
authors: Hunt
mesh_terms: D000368:Aged; D004185:Disability Evaluation; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D020370:Osteoarthritis, Knee / Q000175:diagnosis*; D004856:Postural Balance; D016059:Range of Motion, Articular
keywords: factor analysis; knee osteoarthritis; mobility limitations; postural balance