Purpose In this study, the difference between kinematic and kinetic variables such as joint angles, angular acceleration, and torque, according to the speed of ball pitched has been investigated to clarify the relationships in the event of pitching fastball out of various pitches by means of three d...
Purpose In this study, the difference between kinematic and kinetic variables such as joint angles, angular acceleration, and torque, according to the speed of ball pitched has been investigated to clarify the relationships in the event of pitching fastball out of various pitches by means of three dimensional image analysis. To this end, the information obtained out of this study may provide scientific basic data and systematic solution for training in order to improve the speed of fastball. Methods The participants in this study are composed of four amateur baseball players and six Korean professional baseball players without injury history and an certified athletic trainer have confirmed that the participants currently do not have any injury before the experiments. The participants have been sorted into A group (M = 123.33 km/h) or B group (M = 140.67 km/h) according to the speed of ball pitched. The data collected have been analyzed using SPSS (Staticsical Package for Social Science) Ver 25.0. The methods exploited in this study are frequency analysis, Wilcoxon analysis, and correlation analysis. Frequency analysis has been conducted in order to yield the mean values and the standard errors of each group. Wilcoxon rank sum test, which is non-parametric analysis, has been conducted to elucidate the differences between kinematic variables in pitching. Finally, correlation analysis has been conducted to reveal the relationship between the kinematic and kinetic variables in pitching and the speed of ball pitched. The correlation was calculated with Pearson r. All statistical significance levels were set at the p value smaller than 0.05. Results and Conclusion 1. The difference of time lapse between groups and difference between the speed of ball and time lapse did not turn out to be statistical significant. 2. In the ground-contact event, shoulder external rotation (°) and lead knee flexion showed significant difference between groups (p < .05). In addition, the speed of ball, shoulder external rotation (°), and spine axial rotation (°) showed significant differences between groups (p < .05). 3. The differences of the maximum shoulder external rotation (°), and the maximum upper-body rotational angular velocity (°/s) in arm cocking phase between groups appeared to be are proximal to the statistical boundary. Meanwhile, the differences of the speed of ball and shoulder external rotation (°) between groups turned out to be statistically significant (p < .05) in the correlation analysis between the speed of ball pitched and arm cocking phase. 4. Although the difference of the maximal shoulder horizontal abduction torques in arm acceleration phase between groups were proximal to the statistical boundary, the correlation analysis between the speed of ball and the arm acceleration phase did not reveal the significant difference.
5. The trunk lateral tilt (°) in the ball release event showed statistically significant difference between groups (p < .05), whereas the correlation analysis study between the speed of ball and arm acceleration phase did not reveal the significant difference. 6. The difference between groups in arm deceleration phase and the difference between the speed of ball and arm deceleration phase did not turn out to be statistically significant.
Purpose In this study, the difference between kinematic and kinetic variables such as joint angles, angular acceleration, and torque, according to the speed of ball pitched has been investigated to clarify the relationships in the event of pitching fastball out of various pitches by means of three dimensional image analysis. To this end, the information obtained out of this study may provide scientific basic data and systematic solution for training in order to improve the speed of fastball. Methods The participants in this study are composed of four amateur baseball players and six Korean professional baseball players without injury history and an certified athletic trainer have confirmed that the participants currently do not have any injury before the experiments. The participants have been sorted into A group (M = 123.33 km/h) or B group (M = 140.67 km/h) according to the speed of ball pitched. The data collected have been analyzed using SPSS (Staticsical Package for Social Science) Ver 25.0. The methods exploited in this study are frequency analysis, Wilcoxon analysis, and correlation analysis. Frequency analysis has been conducted in order to yield the mean values and the standard errors of each group. Wilcoxon rank sum test, which is non-parametric analysis, has been conducted to elucidate the differences between kinematic variables in pitching. Finally, correlation analysis has been conducted to reveal the relationship between the kinematic and kinetic variables in pitching and the speed of ball pitched. The correlation was calculated with Pearson r. All statistical significance levels were set at the p value smaller than 0.05. Results and Conclusion 1. The difference of time lapse between groups and difference between the speed of ball and time lapse did not turn out to be statistical significant. 2. In the ground-contact event, shoulder external rotation (°) and lead knee flexion showed significant difference between groups (p < .05). In addition, the speed of ball, shoulder external rotation (°), and spine axial rotation (°) showed significant differences between groups (p < .05). 3. The differences of the maximum shoulder external rotation (°), and the maximum upper-body rotational angular velocity (°/s) in arm cocking phase between groups appeared to be are proximal to the statistical boundary. Meanwhile, the differences of the speed of ball and shoulder external rotation (°) between groups turned out to be statistically significant (p < .05) in the correlation analysis between the speed of ball pitched and arm cocking phase. 4. Although the difference of the maximal shoulder horizontal abduction torques in arm acceleration phase between groups were proximal to the statistical boundary, the correlation analysis between the speed of ball and the arm acceleration phase did not reveal the significant difference.
5. The trunk lateral tilt (°) in the ball release event showed statistically significant difference between groups (p < .05), whereas the correlation analysis study between the speed of ball and arm acceleration phase did not reveal the significant difference. 6. The difference between groups in arm deceleration phase and the difference between the speed of ball and arm deceleration phase did not turn out to be statistically significant.
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