Objectives: To identify the influence of: 1) background determinants of behavioral change (demographics, previous exercise experience, social influences) on women's adherence to a 24 week homebased moderate intensity walking program; 2) exercise motivation, a potentially modifiable determinant of behavior change on adherence to the walking program; and 3) demographics, previous exercise experience, social influences and adherence to the walking program on changes in exercise motivation.
Design: The study utilized an experimental design with random assignment to an experimental group (exercise) and a delay group. Measures were taken at baseline, 24 and 48 weeks. For the experimental group 24-week measures marked the end of the intervention phase and beginning of a 24-week maintenance phase. For the delay group the 24-week measures marked the end of the control delay phase and beginning of the intervention phase. This report focuses on data from the intervention phase only.
Sample and Years: The volunteer sample included 153 women who were, healthy, African American or Caucasian, employed, sedentary and between 45 to 65 years of age. Women were excluded who were on hormone replacement therapy and had more than 3 risk factors for cardiovascular disease. Women were staggered into the study over a 3 year time period.
Intervention and Outcome Variables: The intervention consisted of an exercise prescription and interaction component. The prescription was standardized to mode (walking), duration (30 minutes), frequency (3 to 4x/week) and intensity (moderate). The orientation was standardized through use of a videotaped presentation. The interaction component included meeting with a staff member every 2 weeks to transfer heart rate monitor data to a computer and to receive tailored feedback, health information, and support. The outcome measures included changes in exercise motivation (self-efficacy, competency and self-determinism) and adherence to the walking intervention.
Methods: At preintervention the women responded to self-report questionnaires on demographics (number of children, marital status, education, professional status) and previous exercise experience (Life Long Leisure Physical Activity). At pre and postintervention the women answered questionnaires on social role influences (Baruch and Barnet Role Quality Scales) and exercise motivation (McAuley Exercise Self-regualtory Efficacy Scale, Exercise Self-determinism Index). Adherence was measured with Polar XL heart rate monitors and an exercise log. Patterns of adherence were identified by examining the percentage of walks adhered to, the number of lapsed weeks (1 or more weeks without a walk) and the number of relapses (3 consecutive weeks without a walk). Women were then designated as following one of the mutually exclusive and exhaustive adherence patterns: Consistent (> 80% adherence, 0 lapses, 0 relapses), Occasional lapse (> 80% adherence, 1-3 lapses, 0 relapses), Low (< 80% adherence, 0- 3 lapses, 0 relapses), Sporadic (< 80% adherence, > 3 lapses, 0 relapses), Recycler (< 80% adherence, > 3 lapses, >1 relapses, >1 recycle), Relapser (< 80% adherence, > 3 lapses, >1 relapses, 0- >1 recycle) and Drop (not walking and did not complete post intervention measures).
Results: Caucasian women had a significantly higher percent adherence to frequency (mean=71%) than the African American women (mean=56%). Self-efficacy decreased (t=-2.72, df 135, p=007) and competency increased (t=5.53, df, 135, p=.001) pre to post intervention. Twelve percent of the variance in adherence was explained by race, previous exercise experience and preintervention self-efficacy. Self-efficacy and being Caucasian had independent positive effects and previous exercise experience had a negative effect on adherence. Twenty three percent of the variance in change in self-efficacy was explained by marital status, number of children, change in competency and adherence. Being married and having more children had a negative effect while higher adherence and higher change in competency had a positive effect on change in self-efficacy.
Conclusion: Self-regulatory efficacy appears to be an important predictor of adherence to a walking intervention while having previous exercise experience suggests risk for low adherence. Further, adherence to walking boosts self-efficacy as well as competency. Lower adherence to the walking intervention in African American than Caucasian women is consistent is consistent with cross-sectional survey data showing low physical activity levels in African American women
Implications: Future exercise intervention studies need to compare the success of varying behavioral strategies targeting exercise motivation. Also, additional consideration needs to be given to identifying and targeting our strategies to the unique challenges of African American women.
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