Effectiveness of the Let’s Move It multi-level vocational school-based intervention on physical activity and sedentary behavior: a cluster randomized trial

Abstract

Background: Low levels of physical activity (PA), more prevalent among those with low education, require effective interventions. Fewer trials have tested interventions to decrease sedentary behavior (SB). No school-based interventions have shown lasting effects on PA or SB in vocational schools. Purpose: To examine whether the Let’s Move It intervention has effects on behavioral and clinical outcomes among vocational students after 2 and 14 months. Methods: A cluster randomized trial in 6 school units in vocational education in Finland (N = 1112) (mean age 18.5 years, range 15–46). The multi-component intervention targeted in-class activity opportunities (eg, teacher-led activity breaks, equipment in classrooms), and students’ motivation and self-regulation (eg, 6 group sessions, à 45–60 min, during the intensive intervention period of 2 months). Valid (≥ 4 days, ≥ 10 h/ day) accelerometer data were obtained from 741 students at baseline, 521 (70.3%) at 2 months, and 406 (54.8%) at 14 months. Results: No evidence of a significant intervention effect on the co-primary outcomes (moderate-to-vigorous PA, SB, breaks in SB) was found. Participants in the intervention arm reduced their total daily SB time by 32 min (95% CI, −43.2 to −20.8) on weekdays, compared with the control arm’s reduction of 8.6 (95% CI, −19.5 to 2.3) and engaged in more accelerometer-measured light PA during school time. Few differences were found in secondary outcomes. The fidelity of intervention delivery was relatively good. Conclusions: This school-based intervention did not affect leisure-time activity.