| Summary: | Obesity is a heterogeneous, complex, and chronic condition with large individual differences. Lifestyle modification has been widely acknowledged as the primary treatment for obesity. Objective – This PhD examined the effects of a non-dieting exercise-based lifestyle intervention programme (e.g. no calorie-restriction) using the tenets of the self-determination theory (SDT; Deci & Ryan, 1985b) to inform intervention decisions and identify individual differences (e.g. SDT was used to identify self-regulatory profiles), on physical and metabolic fitness, and psychological well-being among premenopausal, clinically obese women. The programme titled WHEEL focused on health outcomes rather than weight loss. Design – A randomised, delayed start RCT feasibility study. This longitudinal study ran for one year in two phases: a) 12 weeks of intensive intervention and b) a 40-week maintenance phase. Setting – Free living, general community setting. Participants – 62 predominantly white Caucasian (97%), clinically obese (BMI ≥30kg/m2), pre-menopausal women with a mean age of 40.2 years, free of obesity-related diseases and fit to for exercise were randomly assigned to a non-dieting lifestyle intervention group (n = 31) or waiting list control (n = 31). Intervention – Exercise: four hours of exercise per week chosen from the following options: Tai Chi, Circuit classes x 2; and Aqua aerobics. Participants were required to complete two sessions in a WHEEL class, but were encouraged to do all four. If this was not possible they had to agree the exercise of their choice with EB who checked their plan against the FITT principle of exercise. The tenets of SDT, namely autonomy, competence building, and relatedness were used to inform the design of exercise sessions. Autonomy: participants chose their own exercise programme structure. Flexibility within exercise sessions allowed for matching activities to participants’ current state of fitness. Those with high functional limitations were given alternative, seated exercises. Relatedness was fostered in different ways: 1) Outside of WHEEL:participants were encouraged to share their weight related experiences with each other. Routes to exercise venues were planned and they were encouraged to have a car-sharing scheme; and participants organised various charity walks for the group on their own accord. 2) Within WHEEL: participants generally worked in pairs whilst exercising in a group setting. After the initial 12-week intervention phase they were also allowed to invite a female friend or family member to join them in the classes. Competence building: participants were taught exercise skills; including naming and executing each exercise routine correctly, with a view of them joining ‘regular’ classes in the future. Furthermore, they were taught to take their own pulse and monitor their heart rate throughout sessions. The psycho-educational classes targeting dieting behaviours and eating regulation using Brief Cognitive Behavioural Therapy (CBT) techniques: a two one-hour session per week for three weeks, delivered in the 12-week intervention phase, challenging maladaptive eating behaviours, whilst educating participants about food labels and food choices. Educational Sessions: one per week for 12 weeks on physiological and psychological mechanisms of exercise and dieting (e.g. dangers of weight cycling due to dieting). Social Support: follow-up phone calls if two weeks of exercise sessions were missed. Adherence: attrition and attendance were monitored. Data Analysis – Mixed Method: sequential QUAN-QUAL data analyses. QUAN: intention to treat analysis, repeated measures analysis of variance, regression, and correlations. QUAL: analytic induction analysis using the QSR*NVivo qualitative data analysis software. Outcome measures at baseline, 12 weeks, and 52 weeks. QUAN Psychological Instruments: General Causality Orientation Scale (GCOS; Deci & Ryan, 1985b), General Well-Being Schedule (GWB; Dupuy, 1977 & 1978), Perceived Stress Scale (PSS; Cohen, Kamarck, & Mermelstein, 1983), Self-Perception Profile (SPP; Messer & Harter, 1986), State Self-Esteem Scale (SSES; Heatherton & Polivy, 1991), Multidimensional Health Locus of Control Scales (Form C) (MHLC; Wallston,Wallston, & DeVellis, 1978), and Social Support for Exercise Scale (SSSE; Fox & Dirkin, 1992). QUAN Physiology measures: metabolic and cardio-respiratory fitness. QUAL: 62 weight history interviews at baseline with 36 follow-up interviews, including 12 drop-outs. The semi-structured interviews explored participants’ history and prevalence of self-reported dieting and eating behaviours, assessed weight cycling prevalence and development of weight status up to baseline, investigated previous exercise history and skills, perceived health status and difficulties with physical activity including barriers, and examined motivation, goals, and expectation for WHEEL from the personal point of view and from the programme’s. The follow-up interviews at 52 weeks explored difficulties with exercise behaviour change, and quality of life. Results – Baseline: participants showed high levels of psychopathology indexed by high levels of stress, low levels of general well-being (81.8% in severely distressed category of the General Well-Being Schedule) and self-perceptions (e.g. self-esteem, body image), low autonomy and high impersonal orientation, and problems with emotional eating (78%) and dieting (86%). Also, participants had poor fitness levels (< 10% percentile for women) and metabolic profile with 50% of the participants meeting the metabolic syndrome criteria. Participants had unrealistic expectations (35% expected weight loss) and low exercise self-efficacy, low confidence in their ability to achieve, and a number of problems associated with their excess body weight. Finally, participants experienced societal prejudice in various aspects of their lives (e.g. healthcare, work). RCT phase: significant improvements in psychological functioning indexed by significant improvement in well-being (29.9% improvement in total score of GWB Schedule and all its subscales), self-perceptions (athletic, appearance, global self-worth scales of the SPP), and perceived received social support (reducing significantly the discrepancy between need for support and received support). In addition, cardiorespiratory fitness improved significantly in the intervention group (9.3% increase adjusted VO2, ml-kg- 1 min-1; 7.8% absoluteVO2, ml-min-1) as compared to controls (4% reduction adjusted VO2, ml-kg-1 min-1 & 3.2% absoluteVO2, ml-min-1). All these changes took place despite the absence of significant weight loss. Maintenance: those who continued the programme showed improved psychological functioning at 12. The participants showed significant improvements in general well-being: the average value at this stage was 74.4 (±16.6) bringing the group as a whole into the positive well-being category. Most subscales of the SPP showed significant improvements from baseline to 12 months and the discrepancy between needed and perceived provided social support for listening, information, and challenge support for exercise narrowed significantly. In support of SDT, participants felt more autonomous and more in control of their own destiny. Conclusion - Although there was a significant dropout in the study (60%) the present intervention was successful in bringing about behavioural change in those who stayed in the programme. Both the QUAN and QUAL results provided strong support for the improved psychological profile of participants in the absence of significant weight changes. Reasons for dropout included: research design, facilities, and personal. Although the study was not without limitations the underlying philosophy adopted was rarely questioned and would provide a basis for definitive RCT trail.
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