Cardiorespiratory functions in children with high and low performances in endurance running

To elucidate the characteristics of cardiorespiratory functions during exercise in young children in relation to their performances in endurance running, Twenty six 6-year-old children participated in the present study. They were divided into two groups (fast and slow) from the results of three endurance performances (1,500 m, 4,000 m, and 8,850 m). Maximal oxygen uptake ( {Mathematical expression}) in the fast group (X ± SD; 45.3±5.5 ml·kg^-1·min^-1) was significantly greater (p<0.05) than the slow group (39.8±5.9 ml·kg^-1·min^-1). The performances in endurance running were also significantly different between the two groups (p<0.01). There was, therefore, a significant correlation between {Mathematical expression} and endurance performance in 6-year-old children (p<0.05 or p<0.01), but the relationship was less than that of adults. During endurance running, the heart rate of the best performer stayed constant, while that of the worst performer decreased. This may indicate that the worst performer used a smaller percentage of {Mathematical expression}, which might be derived from a lower motivation for running. In conclusion, endurance performances in 6-year-old children was influenced by {Mathematical expression} as well as by the constant mobilization of cardiorespiratory functions throughout endurance running, probably due to high motivation.