Pain is a complex phenomenon not easily discerned from psychological, social, and environmental characteristics and is an frequently cited as a hindrance to return to work for people experiencing low back pain (LBP). The purpose of this study was to evaluate a path-analytic mediation model to examine how motivational enhancement physiotherapy, which incorporates tenets of motivational interviewing, improves physical functioning of patients with chronic LBP. Seventy-six patients with chronic LBP were recruited from the outpatient physiotherapy department of a government hospital in Hong Kong. The re-specified path-analytic model fit the data very well, χ (2)(3, N=76)=3.86, p=.57; comparative fit index=1.00; and the root mean square error of approximation=0.00. Specifically, results suggest that (a) using motivational interviewing techniques in physiotherapy had an association with increased working alliance with patients, (b) working alliance increased patients’ outcome expectancy and (c) greater outcome expectancy resulted in a reduction of subjective pain intensity and improvement in physical functioning. Change in pain intensity also directly influenced improvement in physical functioning.
The effect of motivational enhancement therapy on physical functioning can be explained by social-cognitive factors such as motivation, outcome expectancy, and working alliance. The use of motivational interviewing techniques to increase outcome expectancy of patients and improve working alliance could further reinforce the impact of physiotherapy on rehabilitation outcomes in individuals with chronic LBP.