The relationship between intensity, frequency, duration, and location of physical activity and motivation: A Self-Determination Theory perspective
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INTRODUCTION: As the prevalence of physical inactivity and the health risks involved with it continues to increase, effective intervention approaches have become a necessity. According to Self-Determination Theory (SDT), adherence to physical activity could be improved by designing programs or interventions that target the more autonomous reasons for exercise. In previous research, the exercise variable is often only defined in terms of frequency, duration, and intensity, and differentiation between locations of exercise has been neglected. Environments with natural features have been shown to heighten physical and mental health benefits, which could have important implications for public and environmental health. Given the positive outcomes of green exercise, it would be advantageous to investigate whether different types of motivation exist for all outdoor and, more narrowly, nature-based physical activity compared to other types of physical activity.
METHODS: Alumni of a large Midwestern University were invited to participate via email. Those who agreed to participate completed an online survey that included assessments of physical activity behavior by the 7-Day Physical Activity Recall (7-Day PAR), motivation for physical activity by the Behavioral Regulations in Exercise Questionnaire (BREQ-2), stage of change, and demographic variables such as age, sex, height, weight, place of residence, ethnic group, and level of education.
RESULTS: The final sample consisted of 1,051 active adults (mean age 43.5 ± 11.1 years). No relationship was found between the percentage of physical activities that took place in nature and the BREQ-2 subscales. The percentage of physical activities that took place outdoors was negatively correlated with integrated (r = -.12, p < 0.01), identified (r = -.11, p < 0.01), and introjected regulation (r = -.12, p < 0.01), contrary to the hypothesis. However, among a subsample of participants that were meeting the Physical Activity Guidelines for Americans (defined as a frequency ≥ 3x per week and intensity ≥ 600 MET-minutes; N = 849), the percentage of physical activities that took place in nature was found to be positively correlated with intrinsic motivation (r = .08, p < 0.05), integrated (r = .08, p < 0.05) and identified regulation (r = .07, p < 0.05). The percentage of physical activities that took place outdoors was negatively correlated with integrated (r = -.11, p < 0.01), identified (r = -.10, p < 0.01), and introjected regulation (r = -.13, p < 0.01). Consistent with previous research, there was a positive correlation between autonomous forms of motivation and exercise frequency, duration, and vigorous intensity activity. However, a negative correlation between moderate intensity activity and intrinsic motivation, integrated, identified, and introjected regulation was observed. Regression analyses revealed that introjected regulation was the strongest and only significant (yet negative) predictor of nature-based physical activity. Intrinsic motivation was a positive predictor of outdoor physical activity, while both integrated and introjected regulations were negative predictors.
CONCLUSION: The relationship between motivation and nature-based and outdoor physical activity is not clear, but it does appear that those who are physically active outdoors and in nature are less likely to be introjected, defined as performing the behavior out of guilt or shame. Intrinsic and other forms of autonomous motivation were associated with engagement in three or more days per week of vigorous intensity activity. Therefore, according to SDT, individuals whose physical activities have these characteristics may be more likely to adhere to their physical activity program. However, moderate intensity was negatively associated with the autonomous forms of motivation, which could have negative implications for physical activity adherence.