A self-determination theory and motivational interviewing intervention to decrease racial/ethnic disparities in physical activity: rationale and design.

BACKGROUND: Although the mental and physical benefits of physical activity are well-established, there is a racial/ethnic disparity in activity such that minorities are much less likely to engage in physical activity than are White individuals. Research suggests that a lack of motivation may be an important barrier to physical activity for racial/ethnic minorities. Therefore, interventions that increase participants' motivation may be especially useful in promoting physical activity within these groups. Physical activity interventions that utilized the clinical technique of motivational interviewing (MI) in conjunction with the theoretical background of self-determination theory (SDT) have been effective in increasing White individuals' physical activity. Nevertheless, it remains unclear the extent to which these results apply to minority populations.

METHODS/DESIGN: The current study involves conducting a 12-week physical activity intervention based on SDT and MI to promote physical activity in a racially/ethnically-diverse sample. It is hypothesized that this intervention will successfully increase physical activity in participants. Specifically, it is expected that minorities will experience a greater relative increase in physical activity than Whites within the intervention group because minorities are expected to have lower baseline levels of activity.

DISCUSSION: Results from this study will give us a greater understanding of the generalizability of SDT interventions designed to improve motivation for physical activity and level of physical activity.

TRIAL REGISTRATION: Clinical Trials Gov. Identifier NCT02250950 Registered 24 September 2014.