title: Physical and psychosocial predictors of functional trunk capacity in older adults with and without low back pain.
abstract: OBJECTIVE
  The purpose of this study was to determine the physical and psychosocial predictors of functional trunk capacity in a group of healthy elderly individuals and a group of elderly patients with chronic low back pain (LBP).
  
  
  METHODS
  The study was done in Canada and included 61 community-dwelling elderly individuals (29 patients with nonspecific chronic LBP and 32 healthy participants) who performed maximal trunk endurance and force tasks. Participants completed various psychologic and functional questionnaires. Sequential linear regression analyses were performed with functional capacity results (endurance and force) as dependent variables and questionnaire scores as independent variables.
  
  
  RESULTS
  Endurance time and peak force were significantly lower in patients compared with healthy elderly individuals (all P values < .001), whereas pain-related fear of movement, pain catastrophizing, and depression levels were higher in patients than their healthy counterpart (all P values < .001). After adjusting for physical activity and disability levels (R(2) = 33.7%-50.5% in patients; R(2) = 0.1%-5.7% in healthy individuals), none of the psychologic questionnaire could explain variations observed in functional capacity in patients (R(2) changes, 4.8%-6.7%) and in healthy participants (R(2) changes, 5.2%-10.6%).
  
  
  CONCLUSIONS
  Patients showed diminished functional capacity compared with healthy participants. Moreover, physical activity levels represent the most important predictors of functional capacity in elderly patients with LBP.
authors.affiliation: Département de Psychologie, Université du Québec à Trois-Rivières, Trois-Rivières, Québec, Canada.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Ledoux
authors.forename: Jean-Daniel
authors.initials: JD
authors.lastname: Dubois
authors.forename: Martin
authors.initials: M
authors.lastname: Descarreaux
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D004185:Disability Evaluation; D005080:Exercise Test / Q000379:methods; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D057187:Independent Living; D007537:Isometric Contraction / Q000502:physiology; D016014:Linear Models; D017116:Low Back Pain / Q000503:physiopathology* / Q000523:psychology*; D008297:Male; D008875:Middle Aged; D010369:Pectoralis Muscles / Q000502:physiology; D010807:Physical Endurance; D005082:Physical Exertion; D011237:Predictive Value of Tests; D011584:Psychology; D012016:Reference Values; D012720:Severity of Illness Index; D013909:Thorax / Q000502:physiology*