RESUMO
Background: South African children show the same tendencies in overweight and obesity as children in developed countries a decade ago. Childhood overweight is associated with chronic diseases; early mortality in adulthood and psycho-social effects with lifelong consequences. This study aimed to determine relationships between overweight; obesity and physical fitness of nine- to twelve-year-old South African children. Methods: Anthropometric (body-mass index [BMI]; fat percentage) and physical fitness (cardiovascular endurance; body composition; muscle strength; muscle endurance; flexibility) measurements were obtained from 280 children aged nine to twelve years (128 boys; 152 girls) using the Fitnessgram and Bruininks-Oseretsky Test of Motor Proficiency II. International cut-off points were used to categorise children into normal-weight; overweight or obese categories. Data were analysed using descriptive statistics; Spearman rank order correlation and variance of analysis. Results: One in five children was overweight or obese; while girls were twice as likely as boys to be obese. Aerobic capacity and muscle strength; especially leg strength; decreased progressively with an increase in BMI. A progressive but nonsignificant decline was found in muscle endurance with increasing BMI; while flexibility showed the poorest relationships with various degrees of weight. Variance of analysis indicated significant relationships between BMI; cardiovascular endurance and strength (p 0.05); while different relationships were found when gender was taken into consideration. Conclusions: Health-enhancing physical fitness of young children is negatively affected by overweight and obesity; and intervention strategies are recommended to improve the quality of life of such childre;n but also to prevent early mortality during adulthood