Comparison of time-matched aerobic, resistance, or combined exercise training in women living with obesity. The EXOFFIT Study (Exercise for Obesity in Females to increase Fitness)

Background: Obesity in women has more than doubled in the past thirty years. This chronic relapsing disease is associated with increased risk of developing numerous comorbidities. Increasing research suggests that increased cardiorespiratory fitness (CRF) can largely attenuate the negative health risks associated with obesity. Though previous literature suggests that combined training may be the most effective for improving CRF in adults with obesity, there is minimal research investigating the efficacy of combined and resistance programmes in women with obesity. The overarching thesis aim was to conduct research that would generate evidence and advance knowledge regarding the design and feasibility of optimal exercise intervention(s) to increase fitness in women living with obesity. Methods: A mixed methods approach was used for this thesis. The thesis includes four studies which were conducted to address the aim of the PhD (three studies published in peer reviewed journals and one accepted for publication in a peer reviewed journal). An additional peer reviewed publication that was completed to complement this thesis is also includes in the appendices. Chapter 1 provides an overview of the background and rationale for this thesis. Chapter 2 provides a rigorous systematic review and meta-analysis which assessed the effectiveness of different exercise prescriptions for improving CRF and body composition outcomes in women with obesity. Chapter 3 detailed a protocol for a pilot feasibility RCT (the EXOFFIT study) comparing the feasibility, efficacy and acceptability of three time-matched exercise programmes in women with obesity. Chapter 4 involved the feasibility and efficacy evaluation of the EXOFFIT interventions. Chapter 5 involved both qualitative and quantitative analyses of the acceptability of the EXOFFIT programme and used the theoretical framework of acceptability (TFA) domains to structure the findings of semi-structured interviews and identify key themes of acceptability. In Chapter 6, the overall findings of this PhD described in context of the current literature and potential implications for practice, policy and research are outlined. Results: Chapter 2 revealed that the exercise literature in women with obesity is dominated by with AE interventions and is focused primarily on improving body composition. This study highlighted the need for more research investigating RE and COM and with a focus on improving overall health outcomes (i.e. CRF, strength, etc.). Chapter 4 revealed that all three 12-week exercise interventions (AE, RE and COM) were feasible and that interventions with a resistance component were the most effective for improving overall health outcomes. This study also showcased the importance of prioritising the inclusion of a resistance component in exercise programmes prescribed to women with obesity. Chapter 5 indicated that the EXOFFIT programme had a high level of acceptability and highlighted some key programme features that were valued by participants (i.e. women-only programme, privacy of exercise space, etc.). This study also identified family and work commitments and illness as the greatest barriers to programme engagement. Conclusion: The first research to evaluate the feasibility, efficacy and acceptability of three different exercise modes in women with obesity is described. This body of work has provided important insight into exercise for this cohort including the importance of prioritizing the inclusion of RE in programmes in practice and research and novel information regarding factors that might impact the acceptability of interventions in women with obesity. The findings of this PhD provide several key implications for practice, policy and research regarding exercise interventions in women with obesity. Ultimately, this research has brought the literature in this field one step closer to optimising the exercise prescription for improving overall health in women with obesity.

Appendices