Are Aspects of a Motivational Interview Related to Subsequent Changes in Physical Activity and Regulatory Style? Examining Relationships among Patients with Rheumatoid Arthritis

Objectives: To determine whether the integrity of motivational interviewing (MI) delivery relates to short-term changes in physical activity (PA) and regulatory style within a sample of patients with rheumatoid arthritis, and to examine whether therapist proficiency in MI improves over time. Methods: During a randomized controlled trial to promote PA, 27 patients received a MI from one of three trained physical therapists, which was coded with the Motivational Interviewing Treatment Integrity scales (MITI). Pearson correlations examined associations between MITI scores and changes in PA and regulatory style. Linear regression examined therapist proficiency over time. Results: MIs with greater reflection-to-question ratios and higher MI proficiency scores were related to increases in PA. MIs higher in global spirit and with a greater percentage of MI-adherent behaviors were associated with decreases in introjected regulation. Therapist proficiency in MI delivery tended to improve over time. Conclusions: Characteristics of motivational interviews are related to favorable shifts in regulatory style and PA behavior. Although MI proficiency increases over time and with feedback, a 15-hour training course seems insufficient for physical therapists to obtain basic MI proficiency. Practice Implications: Providing feedback to therapists new to delivering MI seems to improve MI proficiency and should help therapists to avoid using MI-non-adherent techniques.