An Examination of the Efficacy of a Self-Determination Theory and Motivational Interviewing Exercise Intervention

The mental and physical benefits of physical activity are well-established. However, there is a racial disparity in exercise, 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 minorities. Therefore, interventions which increase participants' motivation may be especially useful in promoting physical activity within these groups. A previous meta-analysis has found that physical activity interventions based on self-determination theory (SDT) and motivational interviewing (MI) are especially effective in increasing white individuals' physical activity (Miller & Gramzow, under review). However, it remains unclear the extent to which these results apply to minority populations. The current study involves conducting an intervention based on SDT and MI to promote physical activity in a racially-diverse sample. It is expected that this intervention will successfully increase physical activity in participants. Specifically, it is expected that there will be a greater relative increase in physical activity in minority individuals than white individuals within the intervention group because it is expected that their level of activity will be lower at baseline.

Inclusion criteria

• participants were were willing to attend an exercise class once a week for 12 weeks, were willing to complete questionnaires at baseline and 12 weeks, allowed the intervention staff to monitor their attendance at the YMCA for 6 months post intervention, and allowed the exercise instructor to create an audio recording of all of the intervention sessions.

Exclusion criteria

• not have any illnesses that would prevent them from exercising once a week, not be pregnant or planning to get pregnant within the next 3 months