Association of Pitch Timing and Throwing Arm Kinetics in High School and Professional Pitchers

Abstract

Background: Understanding the relationship between the temporal phases of the baseball pitch and subsequent joint loading may improve our understanding of optimal pitching mechanics and contribute to injury prevention in baseball pitchers. Purpose: To investigate the temporal phases of the pitching motion and their associations with ball velocity and throwing arm kinetics in high school (HS) and professional (PRO) baseball pitchers. Study Design: Descriptive laboratory study. Methods: PRO (n = 317) and HS (n = 54) baseball pitchers were evaluated throwing 8 to 12 fastball pitches using 3-dimensional motion capture (480 Hz). Four distinct phases of the pitching motion were evaluated based on timing of angular velocities: (1) Foot-Pelvis, (2) Pelvis-Torso, (3) Torso-Elbow, and (4) Elbow-Ball. Peak elbow varus torque, shoulder internal rotation torque, and shoulder distraction force were also calculated and compared between playing levels using 2-sample t tests. Linear mixed-effect models with compound symmetry covariance structures were used to correlate pitch velocity and throwing arm kinetics with the distinct temporal phases of the pitching motion. Results: PRO pitchers had greater weight and height, and faster ball velocities than HS pitchers ( P < .001). There was no difference in total pitch time between groups ( P = .670). PRO pitchers spent less time in the Foot-Pelvis ( P = .010) and more time in the Pelvis-Torso ( P < .001) phase comparatively. Shorter time spent in the earlier phases of the pitching motion was significantly associated with greater ball velocity for both PRO and HS pitchers (Foot-Pelvis: B = −6.4 and B = −11.06, respectively; Pelvis-Torso: B = −6.4 and B = −11.4, respectively), while also associated with increased shoulder proximal force (Pelvis-Torso: B = −76.4 and B = −77.5, respectively). Decreased time in the Elbow-Ball phase correlated with greater shoulder proximal force for both cohorts (B = −1150 and B = −645, respectively) with no significant correlation found for ball velocity. Conclusion: Significant differences in temporal phases exist between PRO and HS pitchers. For all pitchers, increased time spent in the final phase of the pitching motion has the potential to decrease shoulder distraction force with no significant loss in ball velocity. Clinical Relevance: Identifying risk factors for increased shoulder and elbow kinetics, acting as a surrogate for loading at the respective joints, has potential implications in injury prevention.

Comparison of Trunk and Pelvic Kinematics in Youth Baseball Pitchers With and Without Upper Extremity Pain: A Cross-Sectional Study

“…This can offer insight into pitch timing, which is the time spent between peak angular velocities achieved by segments across the kinetic chain. 26 , 49 It has been reported that pitchers with decreased time in the early phases of the pitching motion (ie, foot contact to peak pelvic angular velocity) had increased shoulder joint forces. 2 , 26 , 49 In contrast, increased time spent in the late phases correlated with decreased shoulder forces.…”

“… 26 , 49 It has been reported that pitchers with decreased time in the early phases of the pitching motion (ie, foot contact to peak pelvic angular velocity) had increased shoulder joint forces. 2 , 26 , 49 In contrast, increased time spent in the late phases correlated with decreased shoulder forces. 1 One study observed that elite-level pitchers rotated their trunks later in the pitching cycle compared with lower-skilled pitchers.…”

Relationships Between Lower Extremity Power and Fastball Spin Rate and Ball Velocity in Professional Baseball Pitchers

“…During baseball pitching, force is initially generated in the legs and transferred to the hips, spine, and trunk before the upper extremity and ultimately out to the ball (3,15,20). Research indicates that pitching with proper kinematic sequencing may increase ball velocity (3,10,12,15,20). In addition to velocity, fastballs are commonly evaluated by their spin rate (21).…”

“…In addition to velocity, fastballs are commonly evaluated by their spin rate (21). Despite numerous studies examining the effects of lower-body pitching mechanics and ball velocity (3,10,12,15,20), there is no available information describing the relationship between lower extremity power and ball spin rate.…”

Kinematic and Kinetic Comparisons of Arm Slot Position Between High School and Professional Pitchers

“…Key differences in patterns of segmental motion have also been established between professional and high school pitchers. 32 These include the timing of maximum pelvic rotation velocity, maximum trunk rotation, and maximum shoulder internal rotation velocity, all of which act to optimize the kinetic chain. 3 In addition, high school pitchers do not demonstrate the same shoulder and elbow joint characteristics that are found typically in professional and collegiate pitchers, such as UCL thickening and ulnohumeral joint space laxity, differences that may be chronologic, adaptive, or pathologic.…”