Effects of grip position and pitching speed on baseball bat swing

Abstract

A study was conducted to investigate differences in bat swing between the use of long and short bat grip positions. Fifteen male baseball players were videotaped at 250 Hz using two high-speed video cameras while they were batting balls placed on a batting tee and pitched at 80, 100, and 120 km/h by a pitching machine. The bat head and grip end were digitized, and the three-dimensional coordinates were calculated using the direct linear transformation (DLT) method. Bat head velocity at impact employing the long grip position was significantly higher than that when the short grip position was used, but grip velocity and bat angular velocity at impact employing the short grip position were significantly higher than those when the long grip position was used, independent of pitching speed. These findings suggest that bat head velocity at impact was affected mainly by the radius of gyration. Bat head velocity at impact using both grip positions decreased significantly as pitching speed increased. This may have reflected the efforts of the players to improve batting accuracy, since the bat head velocity at impact was significantly lower for the short grip position than for the long grip position at all pitching speeds. These results regarding the relationship between speed and accuracy indicate that the short grip position is advantageous for improving batting accuracy.