Physical Activity, Sedentary Behaviour and Physical Fitness among Male Adolescents with and without Intellectual Disability in Kinshasa, Democratic Republic of Congo

Background: Physical activity, sedentary behaviour, and physical fitness are key health indicators, yet they remain under-documented in the Democratic Republic of Congo, particularly among adolescents with intellectual disability (ID).

Objective This study aimed to (i) compare levels of physical activity, sedentary behavior, body composition, and physical fitness between adolescents with and without intellectual disability, and (ii) examine the associations between body composition and physical fitness variables.

Method:  A cross-sectional analytical study was conducted over a three-month period (November 2022 to February 2023) among 322 male adolescents aged 12-17 years attending school in Kinshasa, Democratic Republic of Congo. A stratified convenience sampling strategy was used, whereby schools were first stratified by type (specialized vs. mainstream), and participants were then recruited based on availability within each stratum. The sample included 180 adolescents with clinically diagnosed moderate intellectual disability and 142 without ID. Physical fitness (balance, flexibility, and upper limb strength) was assessed using standardized EUROFIT tests. Body composition (waist circumference, fat mass, and muscle mass) was measured using anthropometry and bioelectrical impedance. Physical activity and sedentary behavior were assessed using the validated CAPAS-Q questionnaire. Group comparisons were conducted using Student’s t-test or Mann–Whitney U test, and χ² tests for categorical variables. Effect sizes (Cohen’s d, Cramér’s V) and regression analyses were computed.

Results: Adolescents with ID showed higher waist circumference (66.2±1.5 vs 65.6±1.3, d = -0.42, p < 0.001) and body fat percentage (21.0±1.9 vs 20.6±1.6, d = -0.26, p = 0.017), and lower muscle mass (20.9±2.6 vs 25.5±2.9, d = 0.69, p < 0.001) compared to peers without ID. They also demonstrated lower flexibility (8.3±2.1 vs 12.8±1.8, d = 2.26, p < 0.001) and balance (6.8±3.4 vs 10.0±2.2, d = 1.09, p < 0.001). Sedentary behavior was significantly higher (Cramér’s V = 0.73–0.88, p < 0.001), while physical activity levels were lower (Cramér’s V = 0.50–0.84, p < 0.001). Regression analyses indicated that muscle mass positively predicted flexibility (β = 0.57, p < 0.001) and balance (β = 0.81, p < 0.001), whereas waist circumference negatively predicted both outcomes.

Conclusion: Adolescents with intellectual disability exhibit lower physical activity, higher sedentary behavior, poorer body composition, and reduced physical fitness compared to their peers. Body composition, particularly muscle mass and abdominal adiposity, is strongly associated with physical fitness outcomes. These findings highlight the need for targeted, inclusive physical activity interventions in the Congolese context.