# APBA Kısa Özet

A cluster randomized trial in 11 elementary schools compared teacher-delivered versus video-delivered classroom activity breaks. Both interventions increased student moderate-to-vigorous physical activity (MVPA) by approximately 9 min/day, but there was no significant difference between groups. Low and variable implementation fidelity (~50% of intended breaks) limited conclusions on effectiveness.

# Çalışma neyi araştırdı?

The PAAC-3 Trial investigated whether classroom activity breaks delivered by teachers or via video recording would increase student physical activity more effectively under real-world school conditions. The study addressed a gap in the literature by directly comparing two common delivery formats in a cluster randomized design. Over one academic year, 11 elementary schools were assigned to either teacher-delivered (PAAC-T; 5 schools, 192 students) or video-delivered (PAAC-V; 6 schools, 276 students) classroom activity breaks. Teachers were trained to deliver two 10-minute breaks daily. Intervention delivery was tracked via a web-based platform, and classroom MVPA was assessed using accelerometers at baseline and follow-up.

# Yöntem

This was a cluster randomized trial involving 11 elementary schools assigned to either teacher-delivered (PAAC-T; 5 schools, 192 students) or video-delivered (PAAC-V; 6 schools, 276 students) classroom activity breaks across one academic year. Teachers received training to deliver two 10-minute activity breaks daily. Intervention delivery was tracked via a web-based platform, and classroom MVPA was assessed using accelerometers at baseline and follow-up. The primary outcome was change in daily classroom MVPA. Accelerometer data provided objective measures of physical activity, while the web-based platform monitored adherence to the intervention protocol.

# Temel bulgular

Both intervention groups showed statistically significant increases in classroom MVPA. The teacher-delivered group (PAAC-T) increased by 9.8 ± 15.9 min/day, and the video-delivered group (PAAC-V) increased by 9.1 ± 15.3 min/day (p < 0.001 for within-group changes). However, there was no significant intervention arm-by-time interaction (p = 0.43), indicating no statistically significant difference between the two delivery formats. Implementation fidelity was low and highly variable for both groups, with teachers delivering approximately 50% of the intended daily activity breaks (PAAC-T: 42.3 ± 57.1 breaks/teacher/year; PAAC-V: 39.2 ± 33.9; p = 0.96). Despite the significant increases in MVPA, the lack of difference between formats and the low fidelity rates suggest that delivery method alone does not guarantee enhanced physical activity outcomes.

# Bulgular ne anlama geliyor?

The results suggest that both teacher-delivered and video-delivered classroom activity breaks can modestly increase student MVPA. However, the lack of significant difference between formats and the low implementation fidelity indicate that simply assigning a delivery format is insufficient to guarantee effectiveness. The study highlights that implementation fidelity—how consistently and completely the intervention is delivered—is a critical factor in determining outcomes. Classroom physical activity breaks may increase student MVPA, but effectiveness in elementary schools appears to depend on implementation fidelity, administrative support, and equitable system-level infrastructure. These findings underscore the need for stronger implementation supports rather than focusing solely on the choice of delivery format.

# Klinik önem

While the study is educational rather than clinical, its findings have implications for school-based physical activity programming. The modest increases in MVPA (approximately 9 min/day) represent a meaningful contribution to daily physical activity goals. However, the low implementation fidelity underscores the need for stronger implementation supports, administrative commitment, and equitable system-level infrastructure to ensure that activity breaks are delivered as intended. Policymakers and school administrators should focus on facilitating consistent delivery rather than selecting a specific format as the primary lever for change. The approximately 9-minute increase in daily MVPA, while modest, can contribute meaningfully toward recommended physical activity guidelines for children when combined with other school-based initiatives.

# Sınırlılıklar

Several limitations affect the interpretation of these findings. Implementation fidelity was low and variable for both delivery formats, with teachers delivering only about half of the intended breaks. Cluster randomization may introduce school-level clustering effects that influence generalizability beyond the participating schools. No blinding of teachers or students was possible, which could introduce performance bias as participants were aware of the intervention condition. The follow-up period was limited to a single academic year, providing limited data on long-term sustainability of effects. Additionally, implementation fidelity data relied on web-based platform tracking, which may not capture all delivered breaks accurately, potentially underestimating actual delivery. These factors limit the precision of conclusions regarding the effectiveness of classroom activity breaks and highlight the need for future research with longer follow-up periods, objective fidelity measures, and strategies to improve implementation consistency.