Physical Activity, Sedentary Behaviour, Weight Status, and Body Composition among South African Primary Schoolchildren

• Published in: International journal of environmental research and public health 2022-09, Vol.19 (18), p.11836
• Main Authors: Gerber, Markus, Lang, Christin, Beckmann, Johanna, du Randt, Rosa, Long, Kurt Z, Müller, Ivan, Nienaber, Madeleine, Probst-Hensch, Nicole, Steinmann, Peter, Pühse, Uwe, Utzinger, Jürg, Nqweniso, Siphesihle, Walter, Cheryl
• Format: Article
• Language: English
• Subjects: Accelerometers; Accelerometry; Bioelectricity; Body Composition; Body fat; Body Mass Index; Body water; Body Weight; Bone mass; Child; Children; Children & youth; Exercise; Exercise - physiology; Fat-free body mass; Female; Guardians; Humans; Informed consent; Male; Muscles; Nutrition; Obesity; Overweight; Overweight - epidemiology; Pediatric Obesity - epidemiology; Physical activity; Public schools; Sedentary Behavior; South Africa - epidemiology; Teenagers; Trends; Urban areas; Urban environments
• ISSN: 1660-4601; 1661-7827; 1660-4601
• DOI: 10.3390/ijerph191811836

Over the past decades, childhood overweight has increased in many African countries. We examined the relationship between sedentary behaviour, moderate-to-vigorous physical activity (MVPA), and body composition in South African primary schoolchildren living in peri-urban settings. MVPA was measured via 7-day accelerometry and body composition via bioelectrical impedance analysis in 1090 learners (49.2% girls, M = 8.3 ± 1.4 years). The relationships between MVPA and sedentary behaviour with the various body composition indicators (body fat and fat-free mass [total, truncal, arms, and legs], bone mass, muscle mass, and body water) were tested with mixed linear regressions. The prevalence of overweight and obesity was 9.8% and 6.6%, respectively; 77.1% of the children engaged in ≥60 min of MVPA/day. Girls were more likely to be overweight/obese, to accumulate less than 60 min of MVPA/day, and had significantly higher relative body fat than boys ( s < 0.001). Lower MVPA was associated with a higher likelihood of being overweight/obese, higher relative body fat, and lower relative fat-free mass, bone mass, muscle mass, and body water ( s < 0.001). For lower sedentary behaviour, the associations with body composition pointed in the opposite direction. In this South African setting, girls are a particularly relevant target group for future physical activity interventions to prevent overweight/obesity-related non-communicable diseases in later life.