Considering current levels of overweight and obesity in the population and the associated adverse health consequences, engaging people with chronic exercise programmes is of heightened importance. During chronic structured exercise programmes, some adults experience adaptive compensatory behavioural responses through increased dietary intake and/or decreased free-living physical activity. These responses can negate the benefits of an exercise-induced energy deficit. However, it is unclear whether young people experience similar responses during chronic structured exercise. Therefore, the experimental research presented in this thesis examined the existence and extent of exercise-induced energy compensation in adolescent girls. To achieve this, a total of 92, 12 to 15 year old girls and 26 adults were recruited into six experimental studies. The Medical Research Council guidance for designing complex interventions was used to structure the experimental chapters into development (Chapters 4 to 7), piloting (Chapter 8) and evaluation (Chapter 9). The first experimental study (Chapter 4) demonstrated that typical daily variation of total energy expenditure (TEE) in adolescent girls is ~3% when estimated by the Actiheart. Physical activity energy expenditure (AEE) variation was found to be ~10%. In the second experimental study (Chapter 5) the agreement and variability of laboratory buffet meals test days was investigated. The results demonstrated typical daily variation of 8.7% in laboratory-based energy intake (EI) in adolescent girls aged 12 to 15 years. Furthermore, a buffet meals familiarisation day is recommended to reduce the variability in EI. Estimation of EI was further explored in Chapter 6 using a digital photography method. This study demonstrated potential for EI assessment using digital photography, but highlighted that, at present, a supplementary written record of EI is required to overcome the limitations associated with missing photographs. Chapter 7 explored themes related to recruitment and retention of adolescent girls to chronic exercise intervention studies. The seven recommendations identified were used to recruit and retain participants in a twelve week pilot exercise intervention study with adolescent girls (Chapter 8). There was no evidence of energy compensation behaviours on a group level; however, high individual variability in both EI and EE behaviours was apparent. The final experimental chapter (Chapter 9) evaluated the fidelity of the exercise intervention and compliance with the measurement of primary outcome variables. Intervention fidelity was largely upheld. On average, participants attended 94% of exercise sessions and 73% of the participants met their individual target heart rate zone. Focus groups with the participants and parents highlighted preference for school-based exercise sessions due to increased variety and convenience, and recommendations for future estimation of free-living EI and EE. Collectively, these studies suggest there is value in pursuing the investigation of energy compensation behaviours in adolescent girls using a mixed methods approach. These studies demonstrate the factors requiring attention when designing and delivering complex interventions to investigate exercise-induced energy compensation in adolescent girls. In particular, methods for estimating free-living EI and EE require further attention before attempting to conduct such research in a larger sample.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:697694 |
| Date | January 2016 |
| Creators | Massie, Rachel |
| Publisher | Loughborough University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://dspace.lboro.ac.uk/2134/23103 |
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