Pitcher Research Articles

Effect of Quantitative Partial Valgus Stress During Baseball Pitching on Ball Velocity and Subjective Pitch-Effort.

Excessive elbow valgus stress can often cause pitching elbow injuries, and rehabilitation is usually required before an athlete can resume playing. However, there is a lack of information on the partial load rehabilitation of pitching elbow injuries caused by valgus extension overload based on elbow valgus stress. The purpose of this study was to clarify how quantitative partial elbow valgus stress while pitching affects ball velocity and subjective pitch-effort. Forty-six male baseball pitchers participated in this study. Each player wore a wearable device on the elbow that collected their pitch parameters. Ball velocity was measured using a radar gun. Each elbow valgus stress was measured while each player was instructed to throw five fastballs at full effort. Then, based on the average stress of the five throws (100% partial valgus stress), the 75% and 50% stresses were calculated (75% and 50% partial valgus stress, respectively). Each pitcher continued to pitch until the number of pitches thrown at the targeted elbow stress reached five. Each player was asked about their subjective pitch-effort after completing each type of partial valgus stress pitch. Outcomes were statistically evaluated using either a one-way repeated measures analysis of variance or two-way analysis of variance. The ball velocity was 72% (95% confidence interval [CI], 69%-75%) and 58% (95% CI, 55%-61%) during the 75% and 50% partial valgus stress, respectively (P < .001). Subjective pitch-effort was 41% (95% CI, 38%-44%) and 19% (95% CI, 16%-22%) while pitching at 75% and 50% partial valgus stress, respectively (P < .001). It may be desirable to instruct pitchers to throw at less than 20% subjective pitch-effort of the max if they want to pitch at 50% partial valgus stress. Elbow valgus stress might correlate with ball velocity at 75% partial valgus stress pitch. These results could enable clinicians and coaches to perform safer return-to-throwing programs and prevent excessive load on the elbow.

Pitching mechanics and performance of adult baseball pitchers: A systematic review and meta-analysis for normative data.

The aim of this systematic review was to critically review and synthesise the findings from primary studies on pitching mechanics and performance of healthy adult baseball pitchers. Systematic review with meta-analysis. Eight English- and Japanese-language databases were systematically searched from inception to 22nd July 2022. In total, 29 descriptive biomechanical studies were included. Overall study quality was moderate. In subgroup analyses, professional pitchers showed significantly higher stride length, peak shoulder internal rotation velocity, peak shoulder proximal force and ball velocity compared to collegiate pitchers. Conversely, collegiate pitchers were found to have significantly higher peak pelvis rotation velocity. Available normative data suggested potentially heterogeneous pitching mechanics and performance between professional and collegiate pitchers. However, the findings in this review should be interpreted cautiously. Since statistical heterogeneity was significant within most data sets, more detailed subgroup analyses are required. Additionally, more high-quality studies utilising measurement systems with established reliability are required to obtain accurate data in baseball pitching mechanics and performance.

The athlete's shoulder : overview of the typical clinical presentations

Shoulder injuries are common in athlete population. They can be due to trauma or overuse. Traumatic lesions are roughly the same in the non-athlete population. On the other hand, overuse lesions are specific to the sport, depending on the movements performed by the athlete. The majority of the early literature studied baseball pitchers. Pathophysiological theories have been applied to other overhead sport. In this article, we discuss briefly the main specificities and conditions of the painful athlete's shoulder.

Factors that Increase Elbow Stress in the Throwing Athlete: a Systematic Review of Biomechanical and Motion Analysis Studies of Baseball Pitching and Throwing.

Elbow pain poses a unique challenge in the throwing athlete. Due to the high levels of elbow stress during the throwing motion, elbow injuries are common in throwers of all ages. There are several postulated factors believed to contribute increased stress to the throwing elbow. A detailed review of the published biomechanical studies evaluating the stresses experienced by the throwing elbow is needed. Here, we review these biomechanical studies to extrapolate the contributing factors that increase stress, the modifications that may reduce such stress, and the post-injury rehabilitation that optimizes outcomes and reduces recurrence. The biomechanical forces on the elbow have been further investigated delineated in recent work. Rotational malalignment of the shoulder, including both GIRD and decreased adduction, increases torque experienced by the elbow during pitching motions. Exact interactions between lower extremity, lumbopelvic or trunk rotation, and elbow forces during throwing remain uncertain with mixed results in recent literature. Pitch types may influence elbow stresses although delivery mechanism and distance thrown do not. Several biomechanical factors influence the stresses imparted on the throwing elbow. Throwing volume, proper throwing mechanics, and appropriate rehabilitation are likely to be to be the most influential on mitigating unnecessary stresses imparted to the elbow in the throwing athlete. A proper understanding of these factors may reduce the occurrence of these injuries in this population. Moreover, an understanding of proper rehabilitation following injury may ensure optimized results and reduce recurrence.

The Associations between Glenohumeral Range of Motion (ROM) during Off-Season and On-Season and the Ball Speed among Collegiate Baseball Pitchers.

The Article Abstract is not available.

Shoulder stretching versus shoulder muscle strength training for the prevention of baseball-related arm injuries: a randomized, active-controlled, open-label, non-inferiority study

Glenohumeral internal rotation deficit (GIRD) and weakness in prone external rotation are risk factors for shoulder and elbow injuries in high school baseball pitchers. While a shoulder-stretching prevention program to improve GIRD decreases the injury rate, the effects of external rotation strength remain unclear. This non-inferiority (NI) study investigates the hypothesis that external rotation strength training is not inferior to sleeper stretching for shoulder and elbow injury prevention in high school baseball pitchers. Participants were randomly allocated to the stretching (n = 62; active control group) and muscle-training (n = 51) groups. Specific exercises were performed each night. Elbow and shoulder injuries were monitored for 150 days. Kaplan–Meier survival curves were generated, and the hazard ratios (HRs) for injury occurrence were calculated using multivariate Cox regression. The log-rank test was used to compare the injury-free time. A one-sided NI test using a fixed NI margin was performed (significance level, P = 0.025). The injury rates were 22.6% (n = 14) in the stretching group and 9.8% (n = 5) in the muscle-training group. The muscle-training group had a lower injury rate (P < 0.001) and a lower risk of injury than the stretching group (HR = 0.489). Therefore, external rotation muscle strength training is not inferior to stretching for preventing baseball-related arm injuries.

Comparison of Machine Learning Algorithms for Ball Velocity Prediction in Baseball Pitcher using a Single Inertial Sensor

Ball velocity of pitching is an important factor in baseball players. Commonly, ball velocity measurement requires specific devices such as radar gun. On the other hand, Gomaz et al. developed the accurate ball velocity measurement using two inertial sensors on pelvis and trunk. Recently, smartphone installed inertial sensor is popular device in daily life. Therefore, if ball velocity can be measured by only a single inertial sensor, baseball players can measure own ball velocity by only smartphone in daily life and various situations. Thus, the objective of this study is to propose and evaluate the ball velocity prediction method using the only a single inertial sensor. The proposed method predicts ball velocity using by a single inertial sensor and machine learning technique. Five machine learning algorithms (linear regression, support vector machine, gaussian process, artificial neural network, and M5P) predicted ball velocity by data of single inertial sensor, body height, and body weight. In this study, Gomaz et al.’s public data for ball velocity and inertial data during pitching of baseball players were used for this investigation. Sensor placement was either sternum or pelvis. Accuracy of prediction was evaluated by root mean square error (RMSE) between actual and predicted value via leave-one-out cross-validation. The results showed that greatest algorithm (M5P) could accurately predict ball velocity by only single inertial sensor and body parameters (RMSE &lt; 2.0 mph). These results suggest that ball velocity can be measured by only single inertial sensor such as smartphone.

Current Best Treatment for Superior Labrum, Anterior to Posterior Tears

<h3>Objective(s)</h3> To investigate the current best treatment approach in regards to surgical and non-surgical approaches for Superior Labrum, Anterior to Posterior (SLAP) tears in the young athlete and older working adult population. <h3>Data Sources</h3> Google Scholar, PubMed, and ScienceDirect were searched for the terms(SLAP repair, biceps tenodesis, SLAP lesion, arthroscopic SLAP repair, and SLAP treatment).The search was limited to articles published between 2017 to present, English language and human participants. <h3>Study Selection</h3> Studies were selected based on approaches to SLAP tear i.e.: conservative rehabilitation, biceps tenodesis, SLAP repair, and combined biceps tenodesis with SLAP repair. From 31 articles that were initially adopted, 23 were selected and included in our review. <h3>Data Extraction</h3> Three reviewers independently reviewed each article and noted information provided in each article. The information included treatment methods (surgical vs rehabilitative) as well as differences in surgical approaches, return to play after various treatment methods, and cost analysis of various surgical approaches. <h3>Data Synthesis</h3> Individuals older than 35-40 with biceps tenodesis have lower risks of complications and revisions, decreased stiffness, less pain, and higher satisfaction rates with BT. SLAP repairs show better outcomes with younger athletes, SLAP repair in overhead athletes often leds to additional surgeries. However, no significant differences were found between the SLAP repair and BT for the overhead athletes. A combined SLAP repair and BT approach has shown the worst outcomes with less mobility, lower outcome measure scores, and increased pain. A conservative approach for 3 to 6 months however, is recommended before surgical options are considered. <h3>Conclusions</h3> Based on the current evidence, it appears that BT is an optimal choice for younger, less competitive athletes, as well as those individuals above the age of 35. Less favorable outcomes have been reported with the BT approach for competitive athletes and baseball pitchers; therefore, the healthcare team must work closely to determine the next best option on an individual basis. <h3>Author(s) Disclosures</h3> There are no conflict of interest associated with this study for any of the authors.

Development of an Injury Burden Prediction Model in Professional Baseball Pitchers.

Baseball injuries are a significant problem and have increased in incidence over the last decade. Reporting injury incidence only gives context to rate but not in relation to severity or injury time loss. The purpose of this study was to 1) incorporate both modifiable and non-modifiable factors to develop an arm injury burden prediction model in Minor League Baseball (MiLB) pitchers; and 2) understand how the model performs separately on elbow and shoulder injury burden. Prospective longitudinal study. The study was conducted from 2013 to 2019 on MiLB pitchers. Pitchers were evaluated in spring training arm for shoulder range of motion and injuries were followed throughout the season. A model to predict arm injury burden was produced using zero inflated negative binomial regression. Internal validation was performed using ten-fold cross validation. Subgroup analyses were performed for elbow and shoulder separately. Model performance was assessed with root mean square error (RMSE), model fit (R2), and calibration with 95% confidence intervals (95% CI). Two-hundred, ninety-seven pitchers (94 injuries) were included with an injury incidence of 1.15 arm injuries per 1000 athletic exposures. Median days lost to an arm injury was 58 (11, 106). The final model demonstrated good prediction ability (RMSE: 11.9 days, R2: 0.80) and a calibration slope of 0.98 (95% CI: 0.92, 1.04). A separate elbow model demonstrated weaker predictive performance (RMSE: 21.3; R2: 0.42; calibration: 1.25 [1.16, 1.34]), as did a separate shoulder model (RMSE: 17.9; R2: 0.57; calibration: 1.01 [0.92, 1.10]). The injury burden prediction model demonstrated excellent performance. Caution should be advised with predictions between one to 14 days lost to arm injury. Separate elbow and shoulder prediction models demonstrated decreased performance. The inclusion of both modifiable and non-modifiable factors into a comprehensive injury burden model provides the most accurate prediction of days lost in professional pitchers. 2.

Glenohumeral Instability and Arm Pain in Overhead Throwing Athletes: A Correlational Study.

The overhead activity of throwing a baseball is arguably the most demanding athletic endeavor placed on the glenohumeral (GH) joint. Previous studies illustrate that 75-80% of baseball players will experience some degree of upper extremity (UE) pain. GH instability is thought to play a role. The purpose of this study was to investigate the relationship between GH joint hypermobility and instability with measures of arm pain and performance in overhead throwing athletes. Actively competing baseball pitchers were recruited and evaluated once with the anterior-posterior Load and Shift examination procedure, the Kerlan-Jobe Orthopedic Clinic Shoulder and Elbow Questionnaire (KJOC), and the Functional Arm Scale for Throwers (FAST). Multivariate analysis was performed to identify correlation between severe GH capsular laxity (GH instability), mild capsular laxity (GH hypermobility), no capsular laxity (GH normal), and presence of shoulder pain when pitching. Cross-sectional Study. Forty-five pitchers were evaluated, 62.2% of throwing shoulders were classified normal stability, 26.7% were classified hypermobile, and 11.1% were classified unstable. Average KJOC scores for pitchers with the three mobility categories were 66.1 (normal), 59.7 (hypermobile), and 45.0 (unstable). Average FAST scores among the pitchers were 19.9 (normal), 34.2 (hypermobile), and 32.2 (unstable). Pitchers with GH instability and GH hypermobility demonstrated increased arm pain compared to athletes with normal GH joints; KJOC scores of 3.2, 5.5, and 7.4 (p = 0.0007), respectively. Pitchers with GH instability and hypermobility demonstrated significantly increased ratings of arm pain compared to pitchers with no capsular laxity. 3b.

Optimal integration of kinematic and ball-flight information when perceiving the speed of a moving ball.

In order to intercept a moving target such as a baseball with high spatio-temporal accuracy, the perception of the target's movement speed is important for estimating when and where the target will arrive. However, it is unclear what sources of information are used by a batter to estimate ball speed and how those sources of information are integrated to facilitate successful interception. In this study, we examined the degree to which kinematic and ball-flight information are integrated when estimating ball speed in baseball batting. Thirteen university level baseball batters performed a ball-speed evaluation task in a virtual environment where they were required to determine which of two comparison baseball pitches (i.e., a reference and comparison stimuli) they perceived to be faster. The reference and comparison stimuli had the same physical ball speed, but with different pitching movement speeds in the comparison stimuli. The task was performed under slow (125 km/h) and fast (145 km/h) ball-speed conditions. Results revealed that the perceived ball-speed was influenced by the movement speed of the pitcher's motion, with the influence of the pitcher's motion more pronounced in the fast ball-speed condition when ball-flight information was presumably less reliable. Moreover, exploratory analyses suggested that the more skilled batters were increasingly likely to integrate the two sources of information according to their relative reliability when making judgements of ball speed. The results provide important insights into how skilled performers may make judgements of speed and time to contact, and further enhance our understanding of how the ability to make those judgements might improve when developing expertise in hitting.

Fastball pitching performance only slightly decreases after mobility impediment of the pelvis and trunk-Do (catch-up) compensation strategies come into play?

Baseball pitching performance can be mechanically explained by the summation of speed principle and the principle of optimal coordination of partial momenta. Impeding optimal energy generation or transfer by or between the pelvis and trunk segments could provide valuable insight into possible compensation or catch-up mechanisms that may manifest themselves based on these principles. The aim of the present study was to explore the effects of experimentally impeding the mobility of and between the pelvis and trunk segments (1) on ball speed and mechanical peak joint power, and (2) on mechanical peak load of the elbow and shoulder joints at maximal external rotation (MER) during fastball pitching. Eleven elite baseball pitchers (mean age 17.4, SD 2.2 years; mean pitching experience 8.9, SD 3.0 years) were instructed to throw at least 15 fastballs as fast and accurately as possible under two conditions. One condition involved impeding the mobility of the pelvis and trunk segments to hamper their ability to rotate independently, which consequently should affect the separation time, defined as the time interval between the pelvis and trunk peak angular velocities. In the other condition, pitchers threw unimpeded. Ball speed, mechanical peak joint power and peak net moment of the elbow and shoulder at MER were compared between conditions using Generalized Estimating Equations (GEE). In the impeded pitching condition, the mean difference of the separation time was 12.4 milliseconds [95% CI (4.0, 20.7)] and for ball speed 0.6 mph [95% CI (0.2, 0.9)] lower compared to the unimpeded condition. Only the peak pelvic angular velocity, in addition to the trunk, upper arm and forearm, was 45 deg/s [95% CI (24, 66)] higher impeded condition. The mean differences of the joint power and net moments at the shoulder and elbow did not reach statistical significance. In elite adolescent baseball, the observed pitching performance after experimentally impeding pelvic and trunk mobility undermines a potential distal catch-up strategy based on the summation of speed principle. The increased peak pelvic angular velocity may indicate a compensation strategy following the optimal coordination of partial momenta principle to practically maintain pitching performance.

Sensor Location Matters When Estimating Player Workload for Baseball Pitching.

Estimating external workload in baseball pitchers is important for training and rehabilitation. Since current methods of estimating workload through pitch counts and rest days have only been marginally successful, clubs are looking for more sophisticated methods to quantify the mechanical loads experienced by pitchers. Among these are the use of wearable systems. While wearables offer a promising solution, there remains a lack of standards or guidelines for how best to employ these devices. As a result, sensor location and workload calculation methods vary from system to system. This can influence workload estimates and blur their interpretation and utility when making decisions about training or returning to sport. The primary purpose of this study was to determine the extent to which sensor location influences workload estimate. A secondary purpose was to compare estimates using different workload calculations. Acceleration data from three sensor locations-trunk, throwing upper arm, and throwing forearm-were collected from ten collegiate pitchers as they threw a series of pitches during a single bullpen session. The effect of sensor location and pitch type was assessed in relation to four different workload estimates. Sensor location significantly influenced workload estimates. Workload estimates calculated from the forearm sensor were significantly different across pitch types. Whole-body workload measured from a trunk-mounted sensor may not adequately reflect the mechanical loads experienced at throwing arm segments. A sensor on the forearm was the most sensitive to differences in workloads across pitch types, regardless of the calculation method.

Validation of pitchAITM markerless motion capture using marker-based 3D motion capture

ABSTRACT This study sought to compare and validate baseball pitching mechanics, including joint angles and spatiotemporal parameters, from a single camera markerless motion capture solution with a 3D optical marker-based system. Ten healthy pitchers threw 2–3 maximum effort fastballs while concurrently using marker-based optical capture and pitchAITM (markerless) motion capture. Time-series measures were compared using R-squared (r2), and root mean square error (RMSE). Discrete kinematic measures at foot plant, maximal shoulder external rotation, and ball release, plus four spatiotemporal parameters were evaluated using descriptive statistics, Bland-Altman analyses, Pearson’s correlation coefficients, p-values, r2, and RMSE. For time-series angles, r2 ranged from 0.69 (glove arm shoulder external rotation) to 0.98 (trunk and pelvis rotation), and RMSE ranged from 4.37° (trunk lateral tilt) to 20.78° (glove arm shoulder external rotation). Bias for individual joint angle and spatiotemporal parameters ranged from −11.31 (glove arm shoulder horizontal abduction; MER) to 12.01 (ball visible). RMSE was 3.62 m/s for arm speed, 5.75% height for stride length and 21.75 ms for the ball visible metric. pitchAITM can be recommended as a markerless alternative to marker-based motion capture for quantifying pitching kinematics. A database of pitchAITM ranges should be established for comparison between systems.

Performance-environment mutual flow model using big data on baseball pitchers.

The study investigated the baseball pitching performance in terms of release speed, spin rate, and 3D coordinate data of the release point depending on the ball and strike counts. We used open data provided on the official website of Major League Baseball (MLB), which included data related to 580 pitchers who pitched in the MLB between 2015 and 2019. The results show that a higher ball count corresponds to a slower release speed and decreased spin rate, and a higher strike count corresponds to a faster release speed and increased spin rate. For a higher ball count, the pitcher's release point tended to be lower and more forward, while for a higher strike count, the pitcher's release point tended to be to the left from the right pitcher's point of view. This result was more pronounced in 4-seam pitches, which consisted the largest number of pitchers. The same tendency was confirmed in other pitches such as sinker, slider, cut ball, and curve. Our findings suggest that the ball count is associated with the pitcher's release speed, spin rate, and 3D coordinate data. From a different perspective, as the pitcher's pitching performance is associated with the ball and strike count, the ball and strike count is associated with pitching performance. With regard to the aforementioned factor, we propose a "performance-environment flow model," indicating that a player's performance changes according to the game situation, and the game situation consequently changes the player's next performance.

Improving Clinical Utility of Real-World Prediction Models: Updating Through Recalibration.

Bullock, GS, Shanley, E, Thigpen, CA, Arden, NK, Noonan, TK, Kissenberth, MJ, Wyland, DJ, and Collins, GS. Improving clinical utility of real-world prediction models: updating through recalibration. J Strength Cond Res 37(5): 1057-1063, 2023-Prediction models can aid clinicians in identifying at-risk athletes. However, sport and clinical practice patterns continue to change, causing predictive drift and potential suboptimal prediction model performance. Thus, there is a need to temporally recalibrate previously developed baseball arm injury models. The purpose of this study was to perform temporal recalibration on a previously developed injury prediction model and assess model performance in professional baseball pitchers. An arm injury prediction model was developed on data from a prospective cohort from 2009 to 2019 on minor league pitchers. Data for the 2015-2019 seasons were used for temporal recalibration and model performance assessment. Temporal recalibration constituted intercept-only and full model redevelopment. Model performance was investigated by assessing Nagelkerke's R-square, calibration in the large, calibration, and discrimination. Decision curves compared the original model, temporal recalibrated model, and current best evidence-based practice. One hundred seventy-eight pitchers participated in the 2015-2019 seasons with 1.63 arm injuries per 1,000 athlete exposures. The temporal recalibrated intercept model demonstrated the best discrimination (0.81 [95% confidence interval [CI]: 0.73, 0.88]) and R-square (0.32) compared with original model (0.74 [95% CI: 0.69, 0.80]; R-square: 0.32) and the redeveloped model (0.80 [95% CI: 0.73, 0.87]; R-square: 0.30). The temporal recalibrated intercept model demonstrated an improved net benefit of 0.34 compared with current best evidence-based practice. The temporal recalibrated intercept model demonstrated the best model performance and clinical utility. Updating prediction models can account for changes in sport training over time and improve professional baseball arm injury outcomes.

Biceps Tenodesis cannot be used as primary treatment option in baseball pitchers with intact rotator cuff muscles

BackgroundSurgeons remain hesitant to perform biceps tenodesis in athletes with type II superior labrum anterior-to-posterior tears due to the lack of reported clinical outcomes for individual overhead throwing sports and associated concerns that this may predispose the joint to instability. This study aimed to assess the effect of biceps tenodesis on shoulder stability for major overhead throwing sports to aid sport-specific surgical decision-making for athletes with type II superior labrum anterior-to-posterior tears. MethodsThis is a combined modelling and experimental study. Motion data and external forces were measured from 13 participants performing five overhead throwing motions. These data served as input into a musculoskeletal shoulder model that quantifies shoulder stability and muscle loading. FindingsThe loading of the long head of the biceps brachii decreases significantly following biceps tenodesis in three overhead throwing motions (p = 0.02). The loss in joint stability following biceps tenodesis is compensated by a non-significant increase in rotator cuff muscle force which maintains shoulder stability across all overhead throwing motions, except baseball pitching (p = 0.01). The presence of a full-thickness supraspinatus tear post biceps tenodesis further decreases shoulder stability in four of the five overhead throwing motions (p = 0.01). InterpretationThe study findings demonstrate that an increase in rotator cuff muscle force maintains joint stability for all overhead throwing motions post biceps tenodesis, except baseball pitching. As the presence of a full-thickness tear of the supraspinatus significantly reduces joint stability, biceps tenodesis may be used as a primary treatment in overhead throwing athletes with intact rotator cuff muscles, except baseball pitchers. Level of evidenceControlled Laboratory Study; Level of Evidence 3.

Using Sensors for Player Development: Assessing Biomechanical Factors Related to Pitch Command and Velocity.

Pitching biomechanical research is highly focused on injury prevention with little attention to how biomechanical data can facilitate skill development. The overall purpose of this study was to explore how sensor-derived segment kinematics and timing relate to command and ball velocity during baseball pitching. We used a cross-sectional design to analyze a series of pitches thrown from 10 collegiate baseball pitchers. We collected biomechanical data from six inertial sensors, subjective command from the pitchers, and ball velocity from a radar device. Stepwise regression analyses were used to explore biomechanical variables associated with command for all pitches and ball velocity for fastballs only. We found that only peak forearm linear acceleration was significantly associated with command, whereas several segment kinematic measures were significantly associated with ball velocity. Our results suggest that different biomechanical variables are linked to specific pithing skills. Our findings suggest that end-effector (forearm) movement is more important for pitch command, whereas proximal-to-distal (pelvis, trunk, upper arm, forearm) segmental movement is important for ball velocity.

Influence of Pelvic Rotation on Lower Extremity Kinematics, Elbow Varus Torque, and Ball Velocity in Professional Baseball Pitchers.

Early pelvic rotation has been associated with decreased throwing arm kinetics in college baseball pitchers, though professional pitchers have yet to be examined. To investigate the effect of pelvic rotation on trunk, pelvis and lower extremity kinematics, as well as throwing arm kinetics and pitch velocity in professional baseball pitchers. Descriptive laboratory study. Data were analyzed for 157 professional baseball pitchers throwing fastballs using 3-dimensional motion capture (480 Hz). Pitchers were divided into an open pelvis (rotated toward target; n = 78) and a closed pelvis (n = 79) group based on pelvic rotation at foot contact. Variables of interest were compared between the groups using t tests and 2-way analysis of variance, while Spearman correlation was used to measure relationships between the variables of interest. Pitchers in the open group had a longer stride length (81% ± 5% vs 77% ± 5% body height; P < .01, d = 0.74), greater lead knee flexion (49° ± 6° vs 47° ± 10°; P = .043, d = 0.33), faster peak knee extension velocity (424°/s ± 158°/s vs 325°/s ± 142 °/s; P < .01, d = 0.66), and faster ball velocity (39.1 ± 1.7 m/s vs 38.4 ± 2.1 m/s; P = .029, d = 0.35) compared with those in the closed group. There was no significant difference in elbow varus torque between the 2 groups (open: 87.8 ± 14.7 N·m, closed: 90.5 ± 17.2 N·m; P = .311). There were moderate negative relationships between pelvic rotation at foot contact and stride length (r S = -0.385, P < .001), lead knee extension (r S = -0.429, P < .001), and peak lead knee extension velocity (r S = -0.359, P < .001). Professional pitchers who landed with an open pelvis demonstrated longer stride length, greater lead knee extension, faster lead knee velocity, and faster ball velocity compared with pitchers with a closed pelvis at foot contact. This increase in segment velocities and ball velocity was not associated with an increase in elbow varus torque and displays a potentially efficient method in which pitchers can increase ball velocity without an increase in elbow varus torque. Instructing pitchers to rotate their pelvis toward the target at foot contact may allow pitchers to transfer momentum up the kinetic chain more efficiently, while producing greater ball velocity and limiting the torque sustained at the elbow.

Individualizing the Throwing Progression Following Injury in Baseball Pitchers: the Past, Present, and Future.

A critical component of any rehabilitation program following injury is a graduated exposure of pathologic or vulnerable tissue to sport-specific stressors. A foundational aspect in the return to sport process following an injury in baseball athletes is the development of an interval throwing program. A shift has occurred in recent years from generic programs to individualized progressions. The current review explores the evolution of interval throwing program construction and discusses the possibilities of the future with advancements in technology and understanding. Early interval throwing programs relied primarily on pre-determined throwing distance and volume to estimate total training load while following a fixed throwing schedule. Currently, clinicians have begun to utilize available technology in attempts to determine training prescription and obtain more accurate estimates of stresses placed upon the body. Thus, interval throwing programs have become more individualized and flexible to account for each athlete's individual differences and biological response to training. Future development may be able to predict specific internal response to stressors and proactively adjust training load to maximize positive adaptations while minimizing any maladaptive events. As with all concepts and principles within the realm of athlete rehabilitation, clinicians must continue to adapt how they conceptualize and develop individualized interval throwing programs for the overhead throwing athlete. We will continue to see a shift away from a responsive approach to a proactive one, where clinicians can utilize modern technologies to precisely prescribe a throwing dosage based upon expected tissue response within the athlete.