Evaluation of the McKenzie Intervention for Chronic Low Back Pain by Using Selected Physical and Bio-Behavioral Outcome Measures

Objectives To assess the bio-behavioral and physical performance characteristics of individuals with chronic low back pain who demonstrated the pain centralization phenomenon and received the McKenzie intervention using selected bio-behavioral and physical performance measures at intake and at 5 weeks and 10 weeks after treatment. Design A prospective cohort study with assessment at baseline and 2 follow-ups after completion of the McKenzie intervention. Setting Outpatient orthopedic physical therapy clinics. Participants Sixty-two volunteers with chronic low back pain (28 men, 34 women; average ages 41.9 and 37.1 years, respectively). Methods The subjects completed pain and related fear and disability questionnaires, underwent McKenzie mechanical assessment, and executed selected physical performances. They then received the McKenzie intervention. Main Outcome Measurements Outcomes measurements were repeated at the end of the 5th and 10th weeks after treatment completion. Pain-related disability and fear beliefs were assessed by using the Disability Belief Questionnaire and Fear Avoidance Belief Questionnaires, respectively. The time for repeated sit to stand, trunk forward bending, and customary and fast walking were measured by stopwatch. Pain (anticipated versus actual reported) was measured before and immediately after a given physical performance. Descriptive statistics, paired t -tests, and repeated measures analysis of variance were used. Results Significant improvements peaked at the end of the 5th week for all outcome measures ( P < .001), with slight increase in bio-behavioral variables at the end of the 10th week. Conclusions McKenzie intervention reduced pain and related fear and disability beliefs and improved physical performances in individuals with chronic low back pain. Improvements in physical performances remained stable 10 weeks after treatment, regardless of the elevation in bio-behavioral factors.