Differences in Segmental Speeds as a Function of Maturation in Youth Baseball Pitchers

Abstract

The purpose of this study was to determine how stride length, segmental sequencing of the pelvis, trunk, humerus, and forearm velocities and accelerations, and the timing of these values change as youth mature. Thirteen youth baseball pitchers participated at three consecutive time points: visit 1 (10.7±1.3 years; 151.8±10.7 cm; 45.0±9.65 kg), visit 2 (11.5±1.6 years; 155.5±11.1 cm; 50.4±10.0 kg), and visit 3 (12.4±1.7 years; 161.5±11.7 cm; 56.4±10.8 kg). Participants executed three pitches for a strike to a catcher. The maximum value of stride length and segmental speeds and accelerations was recorded. The point at which these maximum values occurred during the throw was calculated as a percentage from hand separation to maximum internal rotation of the shoulder. Repeated measures ANOVAs and Friedman Tests revealed no statistically significant differences between stride length, segmental speeds and accelerations, and their percentage of the pitch between the three visits. However, there was a significant increase in ball velocity across visits. No significant changes occurred in pitching mechanics between the ages of 10-12. The authors speculate the lack of differences can be accounted for because these ages are prior to any significant pubescent changes. Future research should consider pre- and post- pubescent age groups.

Longitudinal changes in youth baseball batting based on body rotation and separation

“…This tendency affected the ball contact, with the U8 exhibiting a narrower upper trunk-to-pelvis separation angle than the U10. Notably, the lower extremity and trunk provide a foundation for the kinetic chain [ 10 , 23 ] and contribute approximately 54% of the total force developed during a tennis serve—a rotational motion similar to baseball batting. In addition, when the trunk movement exerts its maximum power, it is predicted that the ball will be hit more strongly if the extra power to twist the trunk is still reserved during ball contact.…”

“…Assaiante and Amblard [ 9 ] reported that little head-to-upper trunk separation occurs during rotational movements until approximately 6 or 7 years. However, young pitchers show poor pelvic and trunk rotation timing, resulting in these segments facing the target too early during the throwing motion [ 10 , 11 ]. Batting requires the simultaneous motion of both arms; therefore, it is easily affected by the turning motion.…”

Relationship Between Humeral Energy Flow During the Baseball Pitch and Glenohumeral Stability

“…This result provides preliminary support for the use of the closed kinetic chain upper extremity stability test as a clinical assessment of a pitcher's ability to efficiently transfer energy within the upper extremity during the pitch. pitching motion utilizing proximal stability for distal mobility would require less muscular torque from the shoulder because of efficient energy transfer from more proximal segments, potentially reducing the risk of injury [11][12][13]. However, the intersection of efficient energy flow and joint stability within the GH joint has not been examined.…”