Pitching Mechanics and the Relationship to Accuracy in Professional Baseball Pitchers

Background: Biomechanical predictors of pitching accuracy are underevaluated in baseball research. It is unclear how pitchers with higher accuracy differ in terms of kinematics and upper extremity kinetics. Purpose: To differentiate high- and low-accuracy professional pitchers by full-body kinematic and upper extremity kinetic parameters. Study Design: Descriptive laboratory study. Methods: In total, 121 professional baseball pitchers threw 8 to 12 fastballs while assessed with motion-capture technology (480 Hz). Pitchers were divided into high-accuracy (n = 33), moderate-accuracy (n = 52), and low-accuracy (n = 36) groups based on the absolute center deviation of each pitcher’s average pitch to the center of the pitching chart by greater or less than 0.5 SD from the mean, respectively. The 95% confidence ellipses with comparisons of major and minor radii and pitching probability density grids were constructed. Analysis of variance was used to compare kinematic and kinetic values between groups. Results: The absolute center deviation (14.5% ± 6.7% vs 33.5% ± 3.7% grid width; P < .001) was significantly lower in the high-accuracy compared with the low-accuracy group, with no significant difference in ball velocity (38.0 ± 1.7 vs 38.5 ± 2.0 m/s; P = .222). Lead knee flexion at ball release (30.6°± 17.8° vs 40.1°± 16.3°; P = .023) was significantly less for the high-accuracy pitchers. Peak normalized shoulder internal rotation torque (5.5% ± 1.0% vs 4.9% ± 0.7% body weight [BW] × body height [BH]; P = .008), normalized elbow varus torque (5.4% ± 1.0% vs 4.8% ± 0.7% BW × BH; P = .008), and normalized elbow medial force (42.9% ± 7.3% vs 38.6% ± 6.2% BW; P = .024) were significantly greater for the low-accuracy group compared with the high-accuracy group. Conclusion: Professional pitchers with increased accuracy experienced decreased throwing arm kinetics. These pitchers had increased lead knee extension at later stages of the pitch, potentially providing more stable engagement with the ground and transference of kinetic energy to the upper extremities. Professional pitchers can consider increasing lead knee extension at the final stages of the pitch to improve the accuracy of their throws and mitigate elbow varus torque. Clinical Relevance: Increased elbow varus torque, shoulder internal rotation torque, and elbow medial force in less accurate pitchers may contribute to increased injury risk in this group.

Motion Analysis Focusing on Rotational Movements of Professional Female Baseball Pitchers: Comparison with Male University Baseball Pitchers

Purpose: The purpose of this study was to compare pitching motion of the professional female baseball pitchers with the male university baseball pitchers focused on the pelvic and thoracic movements. Subjects and methods: The participants were 15 healthy professional female baseball pitchers (11 right-handers and 4 left-handers; age, 21.7 ± 3.2 years; height, 162.5 ± 5.1 cm; weight, 59.0 ± 6.6 kg) and 14 healthy male university baseball pitchers (12 right-handers and 2 left-handers; age, 19.9 ± 0.8 years; height, 176.4 ± 3.0 cm; body mass, 73.1 ± 3.0 kg). Throwing motion was captured by three-dimensional motion analysis system. Kinematic data of the lead hip, pelvis, thorax, and dominant shoulder were collected and the joint angle at maximum external rotation phase and ball release phase were compared. Results: The female baseball pitchers rotated pelvis and thorax more than the male at the maximum external rotation phase and ball release phase (p < 0.05). At the same, the pelvis and thorax of the female baseball pitchers were tilted significantly closer to horizontal plane than the male (p < 0.05). The pelvis and thorax of the male baseball pitchers was tilted to non-dominant lateral side. Conclusions: The results of this study indicate that the pelvic and thoracic movements of the professional female baseball pitchers was different from male university pitchers.

Biomechanical characteristics of scapula and glenohumeral movements during pitching motion in injury-prone college baseball pitchers

Coordination of glenohumeral and scapular movements plays an important role in the injury prevention of baseball pitchers. However, there is no objective data establishing the direct relationship between pitching injuries and associated glenohumeral and scapular movements. Therefore, the objectives of the present study were to demonstrate biomechanical differences in scapular and glenohumeral movements during pitching between injury-prone pitchers and healthy college baseball pitchers. Thirty collegiate baseball pitchers were classified into two groups according to their injury status: injury-prone group (N=15, 20.7±1.4 years, 180.1±6.5 cm, 78.9±5.4 kg) and control group (N=15, 20.9±1.1 years, 177.1±6.6 cm, 72.3±6.7 kg). We obtained the pitching motion data using the three-dimensional motion analysis technique with four high-speed cameras. The horizontal abduction angles of the glenohumeral joint during cocking and acceleration phases were significantly greater in injury-prone pitchers [19.0° (95% CI: 14.4–23.6) at foot contact, −4.0° (95% CI: −7.7 to −0.2) at maximum external rotation (MER), and −0.3° (95% CI: −4.8 to −4.2) at ball release] than in healthy controls [11.7 °(95%CI:7.1 to 16.3) at foot contact, −10.0°(95%CI: −13.7 to −6.3) at MER, and −6.9°(95%CI: −11.4 to −2.4)]( p <0.01). In addition, the external rotation angle (ER) of the scapula at MER was significantly greater in the injury-prone group [−0.1° (95% CI: −5.0 to 4.8)] than in the control group [−12.3° (95% CI: −17.2 to −7.4)] (p<0.01), but there was no difference in the scapular ER during foot contact between the two groups. These results suggests that injury-prone pitchers have less internal rotation of the scapula and more horizontal abduction of the glenohumeral joint during cocking and acceleration phases. Therefore, sports medicine practitioners may need to pay more attention to coordination of scapular and glenohumeral movements during the cocking and acceleration phases of pitching for prevention of shoulder injuries.

Ulnar Neuritis and Its Affect on Outcomes of Elbow Ulnar Collateral Ligament Reconstruction

Background: No study has specifically evaluated how ulnar neuritis and ulnar nerve transposition affect outcomes in baseball players undergoing ulnar collateral ligament (UCL) reconstruction (UCLR). Purpose: To evaluate the effects of ulnar neuritis and ulnar nerve transposition in baseball pitchers undergoing UCLR in regard to return to sport, time to return to sport, and need for revision or additional surgery. Study Design: Cohort study; Level of evidence, 3. Methods: At a single institution, all consecutive baseball pitchers undergoing UCLR between 2002 and 2015 were identified. Ulnar neuritis was diagnosed preoperatively by the following criteria: ulnar nerve symptoms, Tinel sign at the elbow, symptomatic subluxation, and numbness/paresthesia in an ulnar nerve distribution of the hand. The primary outcome of the study was return to sport. The secondary outcomes of the study were time to return to sport, length of playing career, and revision or additional surgery. Results: A total of 578 UCLRs were performed in baseball players; of these, 500 UCLRs were performed in pitchers. Ulnar neuritis was diagnosed in 97 (19.4%) baseball pitchers presenting with UCL injury. There were no significant differences in patient characteristics or surgical techniques performed for reconstruction between baseball pitchers with and without ulnar neuritis. In review of injury characteristics, ulnar neuritis was significantly more likely to be diagnosed in pitchers with an acute onset of UCL injury ( P = .03). Transposition of the ulnar nerve was more commonly performed in players with ulnar neuritis (47%) versus those without ulnar neuritis (10%; P = .0001). The players who had ulnar neuritis and underwent UCLR had a significantly lower odds of returning to sport (odds ratio, 0.45; P = .04); however, no significant difference was found for time to return to sport and length of playing career for those with and without ulnar neuritis ( P = .38 and .51, respectively). Conclusion: The study suggests that ulnar neuritis, when present preoperatively in baseball pitchers undergoing UCLR, may adversely affect their ability to return to sport, whereas ulnar nerve transposition at the time of UCLR does not alter the ability to return to sport.

Individualised Ball Speed Prediction in Baseball Pitching Based on IMU Data

Ball velocity is considered an important performance measure in baseball pitching. Proper pitching mechanics play an important role in both maximising ball velocity and injury-free participation of baseball pitchers. However, an individual pitcher’s characteristics display individuality and may contribute to velocity imparted to the ball. The aim of this study is to predict ball velocity in baseball pitching, such that prediction is tailored to the individual pitcher, and to investigate the added value of the individuality to predictive performance. Twenty-five youth baseball pitchers, members of a national youth baseball team and six baseball academies in The Netherlands, performed ten baseball pitches with maximal effort. The angular velocity of pelvis and trunk were measured with IMU sensors placed on pelvis and sternum, while the ball velocity was measured with a radar gun. We develop three Bayesian regression models with different predictors which were subsequently evaluated based on predictive performance. We found that pitcher’s height adds value to ball velocity prediction based on body segment rotation. The developed method provides a feasible and affordable method for ball velocity prediction in baseball pitching.

Are Baseball Statistics an Appropriate Tool for Assessing Return to Play in Injured Pitchers? Analysis of Statistical Variability in Healthy Players

Background: Basic pitcher statistics have been used to assess performance in pitchers after injury or surgery without being validated. Even among healthy pitchers, the normal variability of these parameters has not yet been established. Purpose: To determine (1) the normal variability of basic and advanced pitcher statistics in healthy professional baseball pitchers and (2) the minimum pitches needed to predict these parameters. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Publicly available data from the MLB Statcast and PITCHf/x databases were used to analyze MLB pitchers during the 2015 and 2016 seasons who recorded a minimum of 100 innings without injury. Basic and advanced baseball pitcher statistics were analyzed. The variability of each parameter was assessed by computing the coefficient of variation (CV) between individual pitchers and across all pitchers. A CV <10 was indicative of a relatively constant parameter, and parameters with a CV >10 were generally considered inconsistent and unreliable. The minimum number of pitches needed to be followed for each variable was also analyzed. Results: A total of 118 pitchers, 55 baseball-specific statistical metrics (38 basic and 17 advanced), and 7.5 million pitches were included and analyzed. Of the 38 basic pitcher statistics, only fastball velocity demonstrated a CV <10 (CV = 1.5), while 6 of 17 (35%) advanced metrics demonstrated acceptable consistency (CV <10). Release position from plate and velocity from the plate were the 2 most consistent advanced parameters. When separated by pitch type, these 2 parameters were the most constant (lowest CV) across every pitch type. Conclusion: We recommend against utilizing nonvalidated statistical measures to assess performance after injury, as they demonstrated unacceptably high variability even among healthy, noninjured professional baseball pitchers. It is our hope that this study will serve as the foundation for the identification and implementation of validated pitcher-dependent statistical measures that can be used to assess return-to-play performance after injury in the future.