Validity of baseball batting performance evaluation using a simple measurement device

Abstract

In recent years, simple measuring devices for evaluating baseball batting performance have become widespread. However, it is not clear to what extent the measurement accuracy of these devices is guaranteed. Therefore, the purpose of this study was to clarify the validity of a simple device measuring baseball batting performance, using the analysis value by 3D motion capture as the criterion. Three independent variables were examined including exit velocity, launch angle and exit direction for the hitting trials using a tee stand. The degree of agreement between methods were calculated by a Pearson correlation coefficient and Bland-Altman analysis, to clarify the validity. Results demonstrated that the exit direction was highly valid between methods, with trivial bias (0.057 deg) and 95% limits of agreement (-2.09 ~ 2.21 deg). In addition, the relative evaluation of exit velocity and launch angle could be done with the same measuring machine, but underestimated values were found compared to the criterion.