Abstract
Introduction The measurement of field-based cardiorespiratory fitness (CRF) has been identified as a feasible way to study the link between physical activity (PA) and health in children and adolescents at a population level (Lang et al., 2018a). Indeed, a former Chief Medical Officer for England called for the measurement of CRF as a surveillance tool almost a decade ago, yet no initiative has been put in place (Department of Health, 2010). Therefore, the overarching aim of this thesis was to determine whether there is a case for CRF testing of children in primary schools in England.Methods Following institutional ethical approval, the following participants were recruited; children aged 8-11 years from 17 primary schools in the London boroughs of Camden and Islington; children aged 9-11 years from nine elementary schools in Birmingham, Alabama and Oakland, California in the US; and seven teachers from the primary schools in the London boroughs of Camden and Islington. CRF was measured by the 20m Multistage Shuttle Run (20mMSR) as part of an initiative called the My Personal Best Challenge (MPBC). Height and weight were also obtained to calculate body mass index (BMI). Testing was completed by trained coaching staff from Premier Education during a Physical Education (PE) lesson.Results Study 1 involved performing a systematic review, meta-analysis and meta-regression to investigate whether changes in CRF, as a result of a PA intervention, had a significant impact on executive function or academic performance. Key Findings from Study 1: PA interventions can improve CRF in children and adolescents (effect size (ES) = 0.24 [95% confidence interval (CI) = 0.09, 0.40]), yet do not impact executive function (ES = 0.14 [95% CI = -0.12, 0.41]) or academic performance (ES = 0.11 [95% CI = -0.16, 0.38]). Furthermore, the improvements in CRF produced by PA interventions are not associated with changes in executive function or academic performance, including no negative effect on either executive function or academic performance. Given that most of the PA interventions included in the meta-analysis took place in time allotted for other curricular activities, this finding is particularly noteworthy given the health benefits associated with improving CRF. Study 2 aimed to compare the CRF of children who took part in the MPBC from primary schools in London with other studies in English, as well as to provide an international comparison between children who completed the MPBC in England with a convenience sample of children from the US.Key Findings from Study 2: The current data on children’s CRF levels in England is limited, with a lack of raw data available, difference in reporting methods, and data restricted to certain regions. However, comparison of group statistics found that children in the MPBC cohort from London had significantly lower CRF than boys and girls from the East of England (p < 0.001) and boys from Liverpool (p < 0.001). Study 2 also demonstrated how the implementation of a CRF testing programme could be completed successfully in two different countries, with children from the MPBC London cohort having significantly higher CRF than children in the US cohort (p < 0.001). Study 3 analysed the relationship between BMI with CRF, as well as applying a CRF cut-point to identify the percentage of children at an increased risk of cardiometabolic disease (CMD) in the different BMI weight categories. Key Findings from Study 3: There was a significant, but weak, correlation between BMI and CRF in children in England (r = -0.35, p < 0.001). Furthermore, over half of children were at an increased risk of CMD due to low CRF (boys = 51.9%, girls = 55.2%), and approximately a quarter of children (boys = 24.1%, girls = 30.5%) were not being identified by current national measures based upon their BMI as they were “lean but unfit”. Study 4 explored how CRF levels of children in primary schools in England change over a 3-year period. Key Findings from Study 4: Children’s CRF levels improved during the final years of primary school after accounting for age, sex, socio-economic status, and BMI. Children who attended schools where a higher percentage of children were eligible for the Pupil Premium (PP) had significantly lower CRF (20mMSR z-scores mean difference = 0.64 [95% CI = 0.18, 1.1]), especially younger children, though this difference became less pronounced and disappeared by the end of primary school. Study 5 provided a retrospective examination of the perceptions of primary school teachers, through semi-structured interviews on fitness testing of children and collected feedback on the MPBC programme. Key Findings from Study 5: Teachers had positive perceptions overall about fitness testing in primary schools (n = 6) and believed that children enjoyed participating in fitness tests (n = 5).
Conclusions Overall, this body of work has considered the case for whether CRF testing should be implemented in primary schools in England. This thesis has shown that CRF testing in schools can: be used as a tool to evaluate PA interventions, identify children at an increased risk of CMD, track the CRF of children over time and observe how changes in CRF may differ between groups, and make cohort comparisons nationally and internationally. Further, this thesis has demonstrated that teachers have positive perceptions of fitness testing in schools, and that children enjoy participating. As a result of the included studies, this thesis can conclude that there is indeed evidence for the implementation of standardised CRF testing and that it could help develop policy approaches to children’s PA, and be used to evaluate their success.
| Date of Award | Apr 2021 |
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| Original language | English |
| Supervisor | Elizabeth Horton (Supervisor) & Cain Clark (Supervisor) |