This study examined the kinematics and kinetics differences between the two kinds of baserunning starts, base-back and base-front starts, in baseball and softball. The subjects are fifteen players of the National Chinese Taipei Women's Softball Team (age=22.47±3.02yrs, weight=62.13±10.31kg, height=163.47±5.79cm, softball experience =10.00±2.56yrs). Two Sony 60Hz digital cameras and a synchronization of one-axial acceleometer (1000Hz) with a AMTI force platform were used for filming the two baserunning starts. All films were analyzed, filtered and linear-converted by ariel performance analysis system to obtain the baserunning time as well as the velocity of take-off. The force signals received by the Acknowledge 3.5.2 software were then analyzed and calibrated to get parameters of the maximum propulsive force, the propulsive impulse, the maximum vertical force and the vertical impulse. The resultant parameters were divided by individual bodyweight (BW) as the normalizer. The data were statistically analyzed with descriptive statistics and a paired sample t-test (α=0.5). The result indicated that base-back start is significantly better in baserunning time (3.19±0.11s vs. 3.28±0.14s), velocity of take-off (2.17±0.15m/s vs. 2.04± 0.25m/s), the propulsive impulse (0.03±0.014m/s vs. 0.02±0.012 m/s), the maximum vertical force (1.01±0.33Nt/BW vs. 0.53±0.34Nt/BW) and vertical impulse (0.19±0.068m/s vs. 0.08±0.048m/s) than the base-front start (p<.05). Because the base-back start saves more baserunning time than the Base-Front start, we suggested that softball players in all kinds of baserunning situations as well as the baseball players encountering the third-base outfield sacrifice fly adopt the base-back start for a better time advantage and a greater chance to reach the base safely.
This study examined the kinematics and kinetics differences between the two kinds of baserunning starts, base-back and base-front starts, in baseball and softball. The subjects are fifteen players of the National Chinese Taipei Women's Softball Team (age=22.47±3.02yrs, weight=62.13±10.31kg, height=163.47±5.79cm, softball experience =10.00±2.56yrs). Two Sony 60Hz digital cameras and a synchronization of one-axial acceleometer (1000Hz) with a AMTI force platform were used for filming the two baserunning starts. All films were analyzed, filtered and linear-converted by ariel performance analysis system to obtain the baserunning time as well as the velocity of take-off. The force signals received by the Acknowledge 3.5.2 software were then analyzed and calibrated to get parameters of the maximum propulsive force, the propulsive impulse, the maximum vertical force and the vertical impulse. The resultant parameters were divided by individual bodyweight (BW) as the normalizer. The data were statistically analyzed with descriptive statistics and a paired sample t-test (α=0.5). The result indicated that base-back start is significantly better in baserunning time (3.19±0.11s vs. 3.28±0.14s), velocity of take-off (2.17±0.15m/s vs. 2.04± 0.25m/s), the propulsive impulse (0.03±0.014m/s vs. 0.02±0.012 m/s), the maximum vertical force (1.01±0.33Nt/BW vs. 0.53±0.34Nt/BW) and vertical impulse (0.19±0.068m/s vs. 0.08±0.048m/s) than the base-front start (p<.05). Because the base-back start saves more baserunning time than the Base-Front start, we suggested that softball players in all kinds of baserunning situations as well as the baseball players encountering the third-base outfield sacrifice fly adopt the base-back start for a better time advantage and a greater chance to reach the base safely.