Background: Childhood obesity causes psychological problems and decreases physical strength. This study was designed to investigate the effect of childhood obesity on physical strength and social skills.
Method: In this study 140 elementary students from 4th to 6th grades were recruited from Busan. These students joined a 3-day sports program. The students' body mass index were measured and they were categorized into three different weight groups (normal, overweight, obese) according to the age and sex-specific BMI percentile established by the Korean Academy of Pediatrics. Physical strength such as muscle strength,balance, flexibility, muscle endurance, agility and social skills were examined.
Results: Greater muscle strength was noted in the obese group compared to the normal weight group. The normal weight group had better agility level than the overweight or the obese group. Balance and muscle endurance were not significantly different between the three groups. In boys, flexibility was greater among the obese group than the normal or overweight groups. No significant difference in social skills was observed between the groups.
Conclusions: The characteristics of physical strength were different according to BMI. When planning future weight loss programs for children, different aspects of physical strength according to BMI levels should be taken into consideration to better enhance their health and social skills.

Keywords: Body mass index, Children, Obesity