The Effects of Bat Grip Type on Baseball Hitting Performance

Abstract

INTRO: The success of a hitter for the longest time was defined by batting average but in today’s game success is more focused on performance metrics such as bat speed, attack angle, and exit speed. One aspect of hitting that has been shown to have a potential effect on performance is the way you grip the bat. The few common ways to grip the bat include the “conventional grip” (aka normal grip), choked up grip, and the “palmar hamate grip” (aka pinky or pinky off grip). The palmar hamate grip is becoming more popular across baseball as there is belief that it can increase performance. If there is some type of performance benefit, it would be valuable to investigate the mechanism or explanation for the improvement in performance. With the wrist being near the bat and slight movements potentially affecting the orientation of the bat, an analysis should be performed to see if changes in wrist kinematics could explain potential performance benefits from the palmar hamate grip. Prior research in regards to the palmar hamate grip and its effect on performance and wrist kinematics is limited. Additionally, a major limitation in prior research is not accounting for grip preference. PURPOSE: The main purpose of this study was to analyze the effect of the palmar hamate grip on baseball hitting performance in comparison to the conventional grip, accounting for grip preference. The secondary purpose of this study was to analyze the effect of the palmar hamate grip on wrist kinematics in comparison to the conventional grip, also accounting for grip preference. METHODS: Twenty-one high school and collegiate right-handed hitters (ages 16-22) participated and were separated into two groups based on grip preference (conventional, n = 14; palmar hamate, n = 7). The study consisted of two conditions: in the first, participants completed 5 maximal effort swings off a tee with their preferred grip; in the second, participants completed 5 maximal effort swings off a tee with their non preferred grip. Bat speed and attack angle were measured via Blast Motion sensor, exit speed was measured via Stalker Sport 2 radar gun, and smash factor was calculated by dividing exit speed by bat speed. Wrist kinematics were measured via 12 camera Qualisys 3D motion capture system. Wrist angle at contact, wrist range of motion (ROM), wrist angular velocity at contact, and maximum angular velocity in all three axes (x-flexion/extension, y-ulnar/radial deviation, z-pronation/supination) for both left and right wrists were calculated in V3D. RESULTS: Statistical significances were found for attack angle and smash factor but not for bat speed or exit speed. For attack angle, a significant difference was found between the palmar preferred and conventional preferred group in the preferred grip condition (8.57 ± 4.29° vs. 4.37 ± 4.13°, p < 0.05). Additionally, within the palmar preferred group a significant difference was found between the preferred and non-preferred grip conditions (8.57 ± 4.29° vs. 7.14 ± 5.00°, p < 0.05). For smash factor, the only significant difference found was between the preferred and non-preferred grip conditions within the conventional preferred group (1.16 ± 0.03 vs. 1.18 ± 0.03, p < 0.05), however this difference is not meaningful (d = 0.46). Wrist kinematic variables that showed significance included: left wrist flexion/extension angle at contact, left wrist pronation/supination angle at contact, left wrist flexion/extension ROM, left wrist ulnar/radial ROM, left wrist flexion/extension angular velocity at contact, and left wrist flexion/extension maximum velocity. However, the significance found for these variables were not clear in their effect on performance. No other significances were found for other wrist kinematic variables. CONCLUSION: The findings of this study indicate that the palmar hamate grip has some influence on attack angle, but not bat speed, exit speed, or smash factor. Also, the palmar hamate grip had no clear effect on wrist kinematics, suggesting the change in attack angle seen could potentially be due to other body kinematics. The more positive attack angle seen with the palmar preferred group compared to the conventional preferred group in the preferred grip condition is meaningful. Having a more positive attack angle helps in matching the bat path with the downward angle of the incoming pitch which maximizes the chance of solid contact and generates more optimal launch angle potentially leading to increased power and ball flight distance. Given that the changes in attack angle acutely were modest, the findings suggest long term training with the palmar hamate grip would be needed to improve attack angle.