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, high-sensitivity 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 [CI0.05 = −.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 longer-duration intervention is required to fully understand risk factor response in adolescents.