Longitudinal changes in children's overarm throw ball velocities.

Abstract Longitudinal changes in horizontal ball velocities of 54 children performing the overarm throw for force were examined from kindergarten through second grade using a repeated measures ANOVA. The boys' ball velocity increased by 5 feet/second each year; the girls' increased by 3 feet/second; the change over years was significant (p < .05) as was the Sex × Year interaction (p < .05). These changes could be considered meaningful “longitudinal units of change,” which future intervention studies should have the statistical power to detect and thus could assess results in terms of the number of “developmental years” their subjects had improved. Since boys and girls differed in their yearly developmental progress, the authors concluded that treatment effects should be evaluated separately for the sexes. No long-term effects of a kindergarten teaching intervention program were detected in the ball velocities at first and second grade. Year-to-year correlations indicated a modest tendency for the children...