Relationship between physical activity and risk factors of body weight disorders among south African primary school children

The study determined the relationship between physical activity (PA) and risk factors of obesity among primary school children (boys: mean age 11.17 +/- 1.29, n=678; girls: mean age 10.88 +/- 1.27, n=683) in Limpopo and Mpumalanga provinces, South Africa. The children were classified according to age and sex-specific body mass index (BMI) categories (underweight: 0<18, normal weight: 18.5<25, overweight: 25<30 or obese: >30) and their blood pressure (BP) measurements. Health-related fitness was assessed with standardised test protocols. Using the International PA Questionnaire (IPAQ), the children's PA levels were judged as: Low (METs scores of less than 500); Moderate (METs scores from 500 to 1499) or High (METs >1500). The children were mostly underweight (74%) compared to other weight categories (normal weight: 23.7%; overweight: 1.0%; obese: 0.6%). Girls had non-significant elevated BP values (systolic: 112.94 +/- 11.28mmHg; diastolic: 79.40 +/- 12.80mmHg) than boys (systolic: 110.71 +/- 14.95mmHg; diastolic: 75.53 +/- 12.53mmHg) who had higher PA levels (METs = 1286.72 +/- 317.47) than girls (METs = 397.28 +/- 30.14) (p<0.01). The children's PA level correlated positively with BMI (. 86) (p<0.01) but negatively with % BF (-.67); weight circumference (WC) (-.41); SUP (sit-up) (-.22); and predicted VO(2)max (-.17) (p<0.05). BMI positively associated with SBP (standing broad jump) (. 06) and SAR (sit-and-reach) (. 16) (p<01) whereas, it was negatively related with DBP (-.15); % BF (-.67); WC (-.26); SUP (-.21) and predicted VO2max (-.12) (p<0.05). Understanding the relationship between body composition, PA and non-communicable disease risk among children could provide a reliable basis for designing appropriate intervention programmes needed to optimise health outcomes.