This study aimed to develop and evaluate an innovative technology-based solution for effectively monitoring and promoting moderate to vigorous intensity physical activity among children aged 10 to 13 years.

Methods:
The project "Move and Know" (No. SRF-FAV-2022-1-0096) was implemented during the 2022-2025 academic year. Activities were conducted using an interactive wall, "Move and Know," during non-formal physical education (NFPE) sessions following regular school lessons. Nine groups of children aged 10 to 13 years (M = 11.4, SD = 0.80) from public schools in Klaipeda, Lithuania, participated in the project. Their participation in activities ranged from 2 to 4 sessions. In total, data from 524 children (249 girls, 275 boys) were analyzed.
All participants wore Polar Pacer wrist pulse meters to monitor heart rate (HR). This technology allowed the tracking of HR in 5-second intervals for each participant in real time. Data on children's gender and date of birth were also recorded. The pulse meters provided variables including minimum HR, mean HR, maximum HR (HRmax), total time of physical activity, and time spent in each HR zone (i.e., Zone 1 - very light: 50–60% of HRmax; Zone 2 - light: 60–70% of HRmax; Zone 3 - moderate: 70–80% of HRmax; Zone 4 - hard: 80–90% of HRmax; Zone 5 - very hard: 90–100% of HRmax). The calculation of HRmax was based on the traditional formula: 220 minus age.
The Association for Physical Education (2015) recommends that at least 50% of the total time spent in formal and non-formal physical education should be devoted to moderate to vigorous physical activity. According to the World Health Organization (2023), physical activity exceeding 50% of HRmax is classified as moderate to vigorous intensity.

Results:
The average duration of the activities was 59.11 ± 5.30 minutes. The mean HR was 136.01 ± 15.21 bpm, with a maximum HR of 175.30 ± 17.34 bpm. Analysis of load distribution by intensity zones revealed that most of the NFPE time was spent in Zone 1 (35.19 ± 23.21 minutes), Zone 2 (32.18 ± 13.45 minutes), and Zone 3 (23.01 ± 14.40 minutes). Zones 4 and 5, representing vigorous intensity physical activity, had shorter durations. Physical activity intensity in children reached Zone 4 for 15.45 ± 12.62 minutes and Zone 5 for 5.58 ± 6.63 minutes.
The results indicated that boys (M = 34.38 ± 13.46 minutes) spent significantly more time in Zone 2 than girls (M = 29.77 ± 13.05 minutes), p < 0.05. No other significant gender differences were observed in physical activity intensity.

Conclusion:
The intensity of the activities met the recommended guidelines, with more than 50% of physical activity during non-formal physical education being of moderate to vigorous intensity. These findings suggest that non-formal physical education, incorporating innovative technologies, significantly contributes to achieving the recommended intensity levels of physical activity for children.

Keywords: physical activity, children, heart rate, pulsometer.