|Abstract or Summary
- A life course perspective provide a meta-theoretical framework to understand human development. This perspective is characterized by studying the changing lives within the changing environment (George, 2004). Building upon the literature in the psychosocial paradigm and ecological models, Manuscript 1 discusses the uniqueness and the practical importance of a life course perspective for research in physical activity (PA) promotion. The organizing structure of time, together with the paradigmatic principles of a life course perspective, was described within the context of PA. Finally, the implications, methodological issues, and the possibilities of research within the aging population were discussed.
Two empirical studies that applied the principles of a life course perspective were used to illustrate its potential use, as well as the substantive implications of the studies. Manuscript 2 presents the first empirical study titled “Life-Threatening Diseases and Physical Activity Trajectories Along the Marriage Life Course: Opportunity or Obstacle?” This study explored the concordance of PA trajectories between husbands and wives and the relationships between life-threatening diseases (LTDs) and PA trajectories using the Panel Study of Income Dynamics. Stable active (SA), activity adopters (AA), activity relapsers (AR), and stable sedentary (SS) were four of the five theoretical PA trajectories developed from the transitional shift patterns in previous research (Levy & Cardinal, 2006), and that were included in the current study. Three relationships were hypothesized including 1) the relationship between wives’ PA trajectories and husbands’ PA trajectories, 2) the curvilinear relationships between husbands’ and wives’ LTD-related limitations and husbands’ PA trajectories, and 3) the interaction effect between age and husbands’ LTD-related limitations on husbands’ PA trajectories. A latent class growth analysis (LCGA) was used to extract the four PA trajectories for husbands and for wives. Results from the LCGA model showed that wives’ PA trajectories were related to husbands’ PA trajectories. Wives’ LTD-related limitations were not associated with husbands’ PA trajectories, while a curvilinear relationship was found for husbands’ LTD-related limitations on being in SA rather than AR. People diagnosed with LTDs with no resulting limitation showed an increased likelihood to be in SA rather than AR for vigorous PA. However, this protective effect declined and became negative with increased LTD-related limitations. The curvilinear relationship was moderated by age. Specifically, younger individuals were more strongly associated with both positive and negative effects of LTD-related limitations compared with older adults. Findings suggested couples and families can be viable intervening units for PA promotion, and that strategies should be tailored to meet the needs of people at different ages during the experience of LTDs.
Manuscript 3 presents the second empirical study titled “Change and Continuity of Physical Activity Trajectory at the Transition of Spousal Loss: The Australian Longitudinal Study of Aging.” This study examined 1) whether pre-spousal loss PA trajectories including SA, AA, AR, and SS explained the post-spousal loss PA trajectories, and 2) whether advanced age predicted less favorable post-spousal loss PA trajectories. In addition, the multiple influences of contact with children, spousal care, and depression on the post-spousal loss PA trajectories were also explored. The sample included 930 widowed participants selected from the Australian Longitudinal Study of Aging (ALSA). The pre-spousal loss PA trajectories, age, contact with children, depression, spousal loss, and other covariates were used to predict the membership of the post-spousal loss PA trajectories using sequential LCGA. The pre-spousal loss PA trajectories (ORs=7.90-16.59, ps<.01) and spousal loss (ORs=4.10-4.63, ps<.05) were shown to predict the post-spousal loss PA trajectories. Early intervention aimed at developing habitual PA may prevent the less favorable PA trajectories after spousal loss. For future interventions, the social and environmental factors that may contribute to the changes in the PA trajectories in the transition of spousal loss should continue to be explored. Other life course events and transitions should also receive more attention for PA promotion.