Abstract
Objectives:
It is well known that baseball pitching requires correct function of the entire body from the lower to the upper extremity for its execution. From the kinetic chain standpoint, efficient transfer of the ground reaction force is necessary. Functional impairment and mechanical deterioration in any parts of the body can decline the efficient energy transfer. Since the foot works as the initial point of the pitching motion and kinetic chain, it must work as a stable yet dynamic base of support. From our retrospective study, players with disabled throwing shoulder and elbow tended to have high rates of impaired foot function in both feet, which insisted that these pathologies may have a relationship with the occurrence of throwing injuries. Furthermore, we have recently reported that players with disabled throwing shoulder/elbow had higher prevalence of impaired foot function and floating toes compared with those without it. In addition, we have gathered a data that those with impaired foot function showed inconsistency in pitching motion compared with those without it. However, there are no reports regarding how impaired foot function affects the pitching performance. The purpose of this study was to investigate the relationship between foot function and pitching performance.
Methods:
This study consisted of 15 youth male baseball players (age: 14.9 ± 1.7 years, height: 170.3 ± 6.3 cm, height: 66.2 ± 10.2 kg), who had no history of foot and/or ankle surgery or injury. None of the players had complaint of neither shoulder nor elbow pain at the time of measurement and evaluation. Foot function was evaluated by floating toes according to the previous reports. Instructions were given to the players to stand on a solid mat on both feet, having them in shoulder width apart and gaze at a marker 2 m ahead at eye level while standing in upright position. Floating toes were defined if all the toes were not in contact with the mat during the evaluating position. Players pitched from a standard elevated outdoor pitching mound. Portable baseball pitch tracker was used to measure the ball velocity (kilometers per hour: km/h), and ball spin (rotations per minute: RPM), which we determined as pitching performance variables. After warming up, each participants pitched at least 20 pitches of normal fastball to the catcher. The relationship between pitching performances and floating toes were statistically analyzed using Student’s t-test. The level of significance was set at P value of <.05.
Results:
Seven players (47%) showed floating toes on the throwing side and five players (33%) on the non-throwing side. A total of 232 pitches were able to analyze statistically, which the data gathered from portable baseball pitch tracker was complete. The total number of pitches from players with floating toes on the throwing side were 102, and those from the players with floating toes on the non-throwing side were 88.
The average pitch velocity and the average ball spin of the pitches from players with floating toes on the throwing side was 104.9 ± 7.2 km/h and 1510.0 ± 213.2 RPM, respectively. Meanwhile, those from players without floating toes on the throwing side was 107.3 ± 6.7 km/h and 1699.7 ± 169.3 RPM, respectively. The pitch velocity and ball spin of the players without floating toes on the throwing side was significantly greater than those from the players with them on the throwing side (P = .01 and <.0001, respectively).
The average pitch velocity and the average ball spin of the pitches from players with floating toes on the non-throwing side was 104.2 ± 5.6 km/h and 1571.6 ± 108.2 RPM, respectively. Meanwhile, those from players without floating toes on the non-throwing side was 107.3 ± 7.4 km/h and 1639.8 ± 246.5 RPM, respectively. The pitch velocity and ball spin of the players without floating toes on the non-throwing side was significantly greater than those from the players with them on the non-throwing side (P = .001 and =.01, respectively).
Conclusions:
The study revealed that regardless of the side, players with floating toes showed significantly slower ball velocity and smaller ball spin compared with those without floating toes. We have recently revealed that pitching motion of the players with floating toes on the throwing side showed inconsistency compared with those without them. Previous literature has reported that one of the biomechanical variables which affected ball velocity was “time of ball release relative to foot strike”. From these reports, inconsistent pitching motion, which the presence of floating toes may be one of the related factors, could lead to decline in ball velocity. As for those with floating toes on the non-throwing side, the same literature has reported that “time of peak pelvis rotation rate relative to foot strike” and “orientation of forearm relative to vertical at foot strike” was other biomechanical variables, which relates to the foot of the non-throwing side, since “foot strike” is the timing when the non-throwing side foot plants. With regard to ball spin, it has been reported that it positively correlates with ball velocity. Therefore, it is not surprising that the ball spin of the pitches from those with floating toes was significantly smaller compared with those without it, in the same way as ball velocity. Further study to analyze if improvement in foot function will have positive effect on pitching performance is required to reveal the true effect of foot function in pitching performance.
Relationship between foot function and pitching performance was investigated. Regardless of the side, players with floating toes showed decline in pitch velocity and ball spin compared with those without them. The presence of floating toes may negatively affect pitching performance.
