Reliability and Interrelationships of Center of Pressure Sway Variables During the Stipulated Tempo Step in School Children

This study examines the reliability of the center of pressure (COP) sway variables during specified tempo steps and explores the relationships among these variables in school children. The study included 50 school children (25 boys and 25 girls) aged 6–12 years. Participants performed two 40-second trials at tempos of 40 bpm, 60 bpm, 90 bpm, and 120 bpm using a dynamic/static balance measuring system (From TAKEI SCIENTIFIC INSTRUMENTS CO., LTD.). Total path length, peripheral area, standard deviation X, and standard deviation Y were used as evaluation variables. Reliability of the COP sway variables was assessed using the intraclass correlation coefficient (ICC), and their interrelationships were analyzed using Pearson's correlation coefficient. ICCs exceeded 0.7 for all variables, except for the standard deviation Y at 40 bpm. Total path length and peripheral area were highly correlated, except at 40 bpm and 120 bpm. Standard deviation X showed high correlation across all tempos, while standard deviation Y showed high correlations only between 90 bpm and 120 bpm. The remaining variables showed moderate correlations across tempos. In contrast, within each tempo, correlations were high between total path length and peripheral area, between peripheral area and standard deviation Y across all tempos, between total path length and standard deviation X in 60 bpm, and between total path length and standard deviation Y at 120 bpm. The other variables exhibited moderate correlations. In conclusion, the reliability of the COP sway variables during the stipulated tempo step in the school children was relatively high regardless of a tempo difference. The COP sway variables have high relations among three tempos of 40 bpm, 60 bpm, and 120 bpm except for a few variables, and regardless of the tempo difference, the relation between total path length and peripheral area, and between peripheral area and standard deviation Y was high.