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

Study Overview
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Brief Summary
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The current study involves conducting an intervention based on self-determination theory (SDT) and motivational interviewing (MI) to promote physical activity in a racially-diverse sample. It is expected that this intervention will successfully increase physical activity in participants.

Detailed Description
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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.

Official Title
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Decreasing Disparities in Physical Activity: An Intervention Based on Self-Determination Theory and Motivational Interviewing

Conditions
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Exercise Promotion

Intervention / Treatment
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* Behavioral: MI and SDT Exercise Group
* Behavioral: Non-MI and SDT Exercise Group


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: MI and SDT Exercise Group<br>Intervention Condition: Participated in 12 weekly meetings led by MI- and SDT-trained exercise instructor. | Behavioral: MI and SDT Exercise Group<br>* The intervention group will participate in a group exercise class that will be held once a week for an hour. This class will be taught by an instructor trained in MI and SDT. This individual will lead group discussions and will have the participants exercise together.<br>|
| Sham Comparator: Non-MI and SDT Exercise Group<br>Control Condition: Participated in 12 weekly meetings led by an exercise instructor who was not trained in MI and SDT. | Behavioral: Non-MI and SDT Exercise Group<br>* This group will participate in a group exercise class that will be held once a week for an hour. This class will be taught by an instructor who was not trained in MI and SDT. This individual will lead a regular exercise class.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| International Physical Activity Questionnaire |  | 12 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Psychological General Well-Being Index |  | 12 weeks | 
| Basic Psychological Needs in Exercise Scale |  | 12 weeks | 
| Behavioural Regulation in Exercise Questionnaire |  | 12 weeks | 
| Physical Activity Adherence |  | 12 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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self-determination theory, motivational interviewing, exercise, physical activity