PHYSICAL AND PSYCHOSOCIAL PREDICTORS OF FUNCTIONAL TRUNK CAPACITY IN OLDER ADULTS WITH AND WITHOUT LOW BACK PAIN

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%). Conclusion: 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. (J Manipulative Physiol Ther 2012;35:338-345)