This study explored motives and barriers to physical activity (PA) among older adults of differing socioeconomic status (SES) utilizing a self-determination theory and self-efficacy theory framework. Focus groups (n = 4) were conducted with older adults (n = 28) from two SES groups, using thematic analysis to identify motives and barriers. Integrated and identified regulations and, to a lesser extent, intrinsic motives, were evident across SES groups. Verbal persuasion and affective and physiological states emerged as prominent efficacy sources regardless of SES. More barriers were reported by the low SES group, with health conditions, neighborhood safety, and PA guidelines knowledge emerging as most salient. Time emerged as a prominent barrier for the high SES group. Integrated and identified regulations should be fostered in future interventions and policy regardless of SES. Barriers to PA varied across SES groups; thus future interventions and policy should account for such differences.

Objectives. This study explored the mechanisms of physical activity (PA) compensation among older adults who recently reduced their non-exercise physical activity (NEPA) in response to a structured PA intervention.Design. A post-trial, retrospective qualitative process evaluation using interviews was employed.Methods. Levels of PA compensation were determined by comparing NEPA prior to and during the final week of a 4-week structured PA intervention. Those who reduced their NEPA by 10% or greater were considered as compensators. Interviews were conducted with older adult compensators (mean age = 58.56 AE 3.88 years; n = 9), employing thematic analysis to identify potential mechanisms of PA compensation.Results. The findings suggest that the majority of participants were unaware that they had compensated in their PA, suggesting that this may be a non-volitional process. Most participants perceived PA compensation to hold negative implications for health and wellbeing. Physiological processes of fatigue and delayed onset of muscle soreness were cited as the principal cause of PA compensation, whereas psychological processes including a drive to be inactive, fear of overexertion, deficient motivation, and perceived time constraints were cited to a lesser extent. Conclusion.A range of physiological and psychological compensatory barriers were identified. Implications of and methods to overcome these compensatory barriers are discussed. Statement of contributionWhat is already known on this subject?Physical activity compensation holds negative implications for physical activity promotion and health. Older adults are an age group more likely to compensate in their physical activity levels.

An FEA model for understanding the effectiveness of fastener as crack arrest mechanism has been constructed. The effect of the fastener in the sliding direction (Mode II) is modeled using fastener flexibility approach. The FEA results show that the fastener provides significant crack retardation capability in both Mode I and Mode II conditions. The analyses provide insights into the problem of disbond/delamination arrest using fastener or similar mechanisms. An analytical model for the problem is developed. The model consists of a splitbeam with a fastener attached; the fastener is modeled as a system of springs. An elastic layer is placed between the beams on the cracked faces to resolve contacts. The problem is solved using energy principles. The mode-decomposed strain energy release rates (SERR) at the crack tip are solved analytically 11-13. The primary goal of the current work is to enhance the safety of bonded composite structures by providing analysis methods for arrest mechanism.

No abstract

The design and experimental validation procedures for a Mixed-Mode crack arrest specimen are presented. The specimen is a two-plate, one-crack design which is loaded nonsymmetrically in tension. The specimen is designed to allow for maximum crack propagation before net section failure load is reached. The design, fabrication, and experimental validation procedures are presented. Recommendations are made for future research.