Lower physical function, mobility disability and the possibility of subsequent physical disabilities are major public health issues due to the rapid and continuing growth of the older adult population. In addition, the risk for mobility disability and physical disability increases with age. Longer life expectancy, rapid population growth, and low physical activity participation rates among older adults justify the need for better understanding of perceived barriers to and facilitators of physical activity. However, perceived barriers and facilitators, modifiable intra- and extra-individual mechanisms in the disablement pathway, remain underexplored. This dissertation aimed to provide novel insight into the associations between perceived barriers and facilitators, physical activity and related programs, and functional limitations among older adults. First, there are a range of factors that contribute to engagement in lifestyle programs aimed at mobility disability prevention for sedentary older adults, and these factors may be related to the type of program. Next, barriers may attenuate the effect of a structured physical activity program aimed at reducing major mobility disability. Finally, evidence was provided supporting the importance of considering social support as a specific barrier/facilitator in interventions aimed at improving physical function. Low levels of social support over time may increase the risk for declining physical function and subsequent disability development compared with those reporting moderate or high levels of social support. This research provides novel evidence that perceived barriers and facilitators are important to consider as they play key roles in the ongoing disablement pathway toward physical disability in older adults. This could inform the development and translation of future intervention efforts aimed at mobility disability reduction and physical disability prevention. Dissemination of feasible, sustainable and low cost programs for older adults is an important public health issue currently gaining more attention. This research took steps toward understanding the complexities of the disablement pathway and where we might be able to intervene to reduce the negative impact of these outcomes on the individual, health care system, and society. Ultimately, generating information to assist public health and health care professionals in addressing functional decline and disability
