Prevalence of movement behaviours among adolescents in the Republic of the Marshall Islands: a nationally representative study

Pacific nations remain underrepresented in the global movement behaviour literature. This study described the prevalence of physical activity, sedentary behaviour and sleep among a nationally representative sample of school-going adolescents in the Republic of the Marshall Islands (RMI), and examined sex- and age-related differences in these behaviours. Cross-sectional data from the 2023 RMI Global Youth Tobacco Survey were analysed. A total of 2479 students in Grades 7–12 from 26 secondary schools in RMI were invited to participate. An anonymous, self-administered questionnaire was used to assess physical activity (moderate- to vigorous-intensity physical activity [MVPA], muscle-strengthening activities, active school transport), sedentary behaviour and sleep. Survey-weighted descriptive statistics and generalised linear models were used to estimate the prevalence of these behaviours and examine differences by sex and age. Of the analytical sample (1970; 51.6% girls), 0.8% (95% CI 0.4−2.0) met the recommended ≥ 60 min of MVPA daily, whereas 53.5% [95% CI 50.7−56.0] achieved this activity threshold on ≥ 1 day/week. Approximately one-third engaged in muscle-strengthening activities (30.4% [95% CI 27.9−33.0]) or active school transport (32.6% [95% CI 27.8−38.0]) on ≥3 days/week. Nearly half reported high leisure-time sedentary behaviour (≥ 3 h/day; 44.6% [95% CI 41.2−48.0]) or met the age-specific sleep duration recommendations (≥ 9 h for ages 11–13 years and ≥ 8 h for ages 14–18 years; 44.2% [95% CI 40.8–48.0]). Boys demonstrated higher participation in MVPA, whereas girls reported higher sedentary behaviour. Older adolescents (> 14 years) generally showed higher participation in MVPA and sedentary behaviour and were more likely to obtain sufficient sleep than younger adolescents. Significant sex-by-age interactions were observed across all physical activity behaviours, with older boys consistently showing higher odds of participation than younger boys. Marshallese adolescents demonstrated low levels of physical activity participation, high levels of leisure-time sedentary behaviour and low adherence to sleep duration recommendations. These findings provide important baseline evidence to inform future surveillance efforts and support the development of targeted, age- and sex-responsive strategies to promote healthy movement behaviours in RMI.