Balance and muscular strength in normal children aged 9-12 years

The purposes of this study were two fold. The first was to determine the effects of several independent variables on balance, and also on two muscular strength (dynamic and static) measurements respectively. The second purpose was to examine the relationship among the balance and the muscular strengths. Ninety-nine healthy children (58 boys and 41 girls) ranging in age from 9.6 to 12.7 years participated in this study. The subjects were selected from the 4th, 5th and 6th grades of an elementary school in Kaohsiung City. To assess balance, children were administered subtest 2 of Bruininks Oseretsky Test of Motor Proficiency (BOTMP). Dynamic strength was measured with the subtest 4 of the BOTMP. Static strength was measured quantitatively by "semi-squat two-hand lift". The Force Evaluation and Testing System was used for this testing. Height and weight measurements were obtained on each subject. The independent effects of variables on balance score and the two muscular strengths were assessed by stepwise multiple-regression analysis. The results revealed weight and dynamic strength were the effective predictors on estimating balance score. Gender and weight were found as important variables contributing in static load, whereas gender, weight, height and balance score were selected for significantly predicting dynamic strength score. Spearman correlation analysis revealed significant positive correlations between balance and dynamic strength and also between dynamic strength and static strength. The correlation analysis also showed a significant negative correlation between balance and static strength. Detailed implications of the results in the present study are discussed.