Effects of a novel school-based cross-curricular physical activity intervention on cardiovascular disease risk factors in 11- to 14-year-olds: The activity knowledge circuit

Purpose. This study investigates cardiovascular disease risk factor response in adolescents following introduction of brisk walking into curriculum lessons. Design. Quasi-experimental. Setting. School-based. Subjects. An intervention group consisted of 115 (aged 12.4 ± 0.5 y) year eight participants, and 77 (aged 12.1 ± 1.1 y) year seven and year nine participants formed a control. Intervention. An 18-week cross-curricular physical activity intervention was implemented in one secondary school. Measures. Adiposity variables, blood pressure, lipids, lipoproteins, glucose, insulin, highsensitivity C-reactive protein, high-molecular-weight adiponectin, aerobic fitness, physical activity behavior, and diet were assessed preintervention and postintervention. Analysis. Dependent and independent t-tests. Results. Prevalence of elevated waist circumference (9.8% vs. 6.9%), systolic blood pressure (3.3% vs. 0%), triglycerides (2.5% vs. 1.2%), and reduced high density lipoprotein cholesterol (3.7% vs. 2.7%) decreased in the intervention group. Significant improvements in high density lipoprotein cholesterol to total cholesterol ratio (mean ± SD: 2% ± 4% [confidence interval (CI)_0.05 = 1% to 2%], t₈₀ = -3.5, p = .001) and glucose (-.1 ± .4 mmol/L [CI_0.05 = -.2% to 0%], t₇₉ = 3.2, p = .002) were evident for the intervention group. Conclusion. The Activity Knowledge Circuit may prove to be a sustainable, effective, and cost-effective strategy to engage schoolchildren in physical activity on a daily basis. A longerduration intervention is required to fully understand risk factor response in adolescents.