Originally published by 2 Minute Medicine® (view original article). Reused on AccessMedicine with permission.

1. Among children in elementary school, an internet-based intervention for teachers significantly improved cardiorespiratory fitness with sustained effect for 24 months.

Evidence Rating Level: 1 (Excellent)

Study Rundown:

Childhood cardiorespiratory fitness is an important marker of overall health and risk factors for disease in later life. Previous studies have demonstrated that school-based physical activities can improve students’ fitness. However, when similar studies were conducted in an attempt to create large-scale versions of school-based interventions, they demonstrated limited efficacy. Thus, there is limited evidence to support that school-based interventions can be implemented at a population level to improve children’s physical fitness. To address this gap in literature, this cluster randomized controlled trial evaluated the efficacy of a large scale online-based intervention in improving cardiorespiratory fitness amongst elementary school children.

From a cluster of 22 schools, the study randomly allocated 11 schools with 555 students to the intervention group and 11 schools with 631 students to the control group. The intervention was known as Internet-Based Professional Learning to Help Teachers Promote Activity in Youth (iPLAY). Each school identified 3 teachers who underwent education and mentorship to implement multidomain approach to promoting student physical activity. The training covered topics such as quality physical education, classroom energizers, implementing active homework, and community physical activity links. The primary outcome assessed was students’ cardiorespiratory fitness, measured by recording laps completed in 20-m multistage fitness test. It was found that students in the intervention group had greater increases from baseline in cardiorespiratory fitness at 12 and 24 months, as evidenced by increased laps completed. Furthermore, secondary outcome measures included measurement of the students’ activity across a week, students’ self-reported well-being, standardized academic test scores, and students’ body mass index. It was found that there was a significant increase in physical activity during school lunch and recess in the intervention group, but no other significant differences in the other secondary measures that were assessed.

A strength of the study was their blocked randomization process to ensure that schools in the trial were broadly representative of government schools in New South Wales. Additionally, in their statistical analysis, the study factored in preregistered demographic mediators of intervention effects including age, sex, ethnicity, body mass index, and family socioeconomic status. This helped mitigate confounding factors. Another strength was that the study retained 84% of their baseline sample, thus limiting attrition bias. One limitation in the study, inherent to the nature of intervention, was that the participants could not be blinded to their allocation. Additionally, the study reported that although blinding of research assistants was largely successful, there were 4 out of 22 instances for which they became unblinded. Lastly, the study did not examine the influence of between-school moderators (i.e., differences between schools allocated in control versus intervention group). Overall, the study demonstrated promising results due to the adequate effect size on a large sample population. However, additional studies are needed at a similar scale to demonstrate reproducibility of the favourable results.

In-Depth [randomized controlled trial]:

A total of 1219 participants from 22 schools were randomized (mean [SD] age = 8.85 (0.71) years, 49.38% female). The mean (SD) number of laps in control group at baseline was 25.83 (14.95) laps and for the intervention group was 22.84 (13.43). The intervention group schools received iPLAY training, while the control group schools received training in curriculum unrelated to physical activity, such as science. The mean (SD) number of laps in control group at 12 months was 27.87 (16.02) and for the intervention group was 25.54 (15.27). Thus, the mean adjusted difference at 12 months was 1.20 laps (95% CI, 0.17-2.24). The mean (SD) number of laps in control group at 24 months was 30.11 (17.21) laps and for the intervention group was 30.03 (17.47) laps. At 24 months, the study found a mean adjusted difference of 2.22 laps (95% CI, 0.89-3.55) between the control and intervention group.

©2020 2 Minute Medicine, Inc. All rights reserved. No works may be reproduced without expressed written consent from 2 Minute Medicine, Inc. Inquire about licensing here. No article should be construed as medical advice and is not intended as such by the authors or by 2 Minute Medicine, Inc.