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To determine the cumulative elbow varus torque (EVT) experienced during created interval throwing programs (ITP) and derive innings pitched equivalent for each step.High school pitchers wearing the motusBASEBALL sensor who had at least 50 throws at 90, 120, 150, and 180 ft and game pitches were included in this analysis. Means for EVT per throw and torque per minute were calculated at each distance. Three throwing programs were created using a template of 1 phase at each distance with 2 steps per phase. Programs varied only by number of throws per set (20, 25, and 30 throws for Program A, B, and C, respectively). Total EVT for each step, phase, and program were calculated using mean EVT per throw at each distance. Total EVT for each step and program were converted to a mean inning pitched equivalent (IPE) and maximum pitch count equivalent (MPE), respectively, using in-game pitching torque values and expected mean pitch counts (15 pitches/inning and maximum 105 pitches/game).In total, 3,447 throws were analyzed from 7 subjects (16.7 years ± 0.8 years). EVT per throw increased at each distance (range 36.9-45.5 N·m), comparable to game pitches (45.7 N·m). Mean EVT per minute was highest for 90 ft throws (193.4 N·m/min) and lowest for game pitches (125 N·m/min). Throwing Program A had the lowest range of IPE (Step 1: 2.0 and Step 8: 3.7), and Program C had the highest range (Step 1: 3.0 and Step 8: 5.6). The phases of Program A never exceeded 1MPE. Program B exceeded this threshold after Phase 1, and Program C exceeded 1MPE at every phase. Total program MPE ranged from 3.5 to 5.2 (Program A and C, respectively).Programs requiring 25 or more throws per set reached approximately 5 IPE per day. Increasing throwing repetitions by 10 throws resulted in a nearly 50% increase in IPE and MPE.IV, retrospective cohort study.

Objectives: Completion of an interval throwing program (ITP) is a common benchmark for return to full competition following an injury to the dominant extremity of an overhead throwing athlete. While workload management for overhead athletes has evolved, the general structure of the ITP remains relatively unexamined. Furthermore, the daily and cumulative workload of ITPs is generally unknown. An ideal ITP would allow for a gradual increase in workload that eventually approximates, but does not exceed, workload measurements attained during competition. It is currently unknown if ITPs achieve this critically important objective. Therefore, the current study sought to 1) determine the daily and cumulative workload for common ITPs using elbow varus torque (EVT), and 2) compare EVT experienced during completion of ITPs to game pitching EVT values. Methods: A retrospective review identified high school pitchers with at least 50 throws at distances of 90, 120, 150, and 180 feet plus game pitches while wearing a MotusBASEBALL sensor. Averages for EVT per throw and torque per minute were calculated at each distance. Three throwing programs were created using a template of one phase at each distance with two steps per phase (Table 1). Programs varied only by number of throws per set (20, 25, and 30 throws for Programs A, B, and C, respectively). Total EVT for each step, phase, and program were calculated using average EVT values for each distance. Total torque for each step and program was converted to an average inning pitched equivalent (IPE) and maximum pitch count equivalent (MPE), respectively, using pitching EVT values and expected average pitch counts (16 pitches/inning and maximum 105 pitches/game). Results: 3,447 throws were analyzed from 7 pitchers with an average age of 16.7 yrs (0.8 yrs SD). EVT progressively increased with distance (range 36.9-45.5 N·m), comparable to game pitching (45.7 N·m). Average torque per minute was highest for 90 ft throws (193.4 N·m/min) and lowest for game pitches (125.0 N·m/min). Program A demonstrated the lowest range of IPE per step (2.0-3.7), and Program C had the highest range (3.0-5.6) (Figure 1). The phases of Program A never exceeded 1MPE. Program B exceeded this threshold after phase 1, and Program C exceeded 1MPE at every phase (Figure 2). Total program MPE ranged from 3.5 (Program A) to 5.2 (Program C). Conclusions: Performing long-toss throwing led to greater torque per minute compared to gameday pitching. Additionally, ITPs requiring 25 or more throws per set led to increased cumulative EVT, especially at distances greater than 150 ft, which can exceed typical values from gameday pitching. ITPs should be adjusted accordingly to encourage a slower pace of long-toss throws and less than 25 throws per set, especially at distances greater than 120 ft. Most ITPs currently recommend one rest day between steps. However, cumulative EVT at longer distances can exceed 5 IPE. Most pitch count rules require more than one rest day after a pitching outing that exceeds multiple innings pitched. Therefore, days off between steps and phases of an ITP should reflect these demands. We advocate for multiple days off between steps that require more than 3 IPE. Table 2 presents a novel ITP based on the findings of the current study.

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.

Objectives: The timing for initiation of a throwing program following shoulder or elbow surgery in an overhead throwing athlete is dependent on a variety of factors, including surgical procedure performed, time from surgery, level of competition, and successful progression through a physical therapy program. Determining when it is safe for an athlete to begin a post-surgical throwing program is vitally important to ensure safe return to play, and objective data is often preferred to help accurately make such decisions. However, there is a paucity of objective data available to help guide the decision for the timing of initiation of a throwing program following shoulder and elbow surgery in overhead throwing athletes. Additionally, it is unknown what percentage of athletes typically achieve appropriate objective criteria at the presumed timepoint for initiation of a throwing program. Therefore, the objectives of the current study were the following: 1) to create a reproducible, objective return to throwing protocol, 2) to determine what percentage of post-surgical competitive baseball players successfully satisfied the objective return to throwing criteria at the presumed time of throwing program initiation, and 3) to determine what risk factors were most common in athletes who failed to meet objective criteria for return to throwing. Methods: Patients who were a competitive overhead throwing athlete and who underwent a shoulder or elbow surgery by one of the two senior authors were given the opportunity to perform an objective return to throwing evaluation at the presumed time of clearance by the treating physician. Figure 1 outlines the objective return to throwing criteria with the desired goal for each criterion. Each evaluation was performed by a single physical therapist with extensive experience in rehabilitation of overhead athletes. Patients who successfully accomplished all criteria at the time of evaluation were given a passing grade. Patients who failed the initial objective evaluation were re-tested two weeks later. Surgical procedure, level of play, and reason for failing were recorded for all players. Kinematic variables were compared between patients who passed versus those who failed using a two-tailed student’s t-test. Relative odds and risks ratios were assessed for level of play and type of surgery with 95% confidence intervals. Significance was set at pResults: A total of 48 players were evaluated, and level of play was divided into high school (20 patients), college (19 patients), and professional (8 patients). A total of 36 players (75%) obtained a passing grade at the initial evaluation while 12 players received a failing grade (25%). The distribution of passing grades based on surgery type was the following: arthroscopic shoulder surgery: 4/7 patients, UCL reconstruction: 23/31 patients, UCL repair: 3/3 patients, and other elbow surgery (i.e. ulnar nerve decompression transposition, isolated elbow arthroscopy): 5/6 patients. Level of play, type of surgery, and reason for failing is summarized for all players who received a failing grade (Table 1). All players who failed were retested at two weeks and received a passing grade after focused physical therapy to address any insufficiencies. Players who received a failing grade demonstrated significantly more elbow extension, less dominant arm maximum shoulder internal rotation strength, and less dominant arm maximum shoulder external rotation strength (Table 2). Players with a level of play beyond high school and college each showed an elevated odds ratio and relative risk for receiving a failing grade, yet this did not reach statistical significance. Undergoing ulnar collateral ligament reconstruction demonstrated a trend towards having a smaller odds ratio for a failing grade, but this also did not reach statistical significance (Table 3). Conclusions: The most important finding of the current study is that 25% of competitive baseball players did not pass an objective return to throw evaluation at the time of presumed clearance based on time from surgical procedure and objective in-office evaluation by the treating surgeon. All patients who failed were able to achieve a passing grade two weeks later after directed physical therapy to address all insufficiencies. No specific factor reached statistical significance for increasing the odds ratio or relative risk for receiving a failing grade, though undergoing UCL reconstruction demonstrated an insignificant trend for having a lower risk of failing. Our findings demonstrate that not all competitive baseball players will be objectively ready to throw at the presumed time point following shoulder and elbow surgery, and insufficient shoulder strength and/or endurance was the most common reason for failure. Creating objective criteria to help determine when to start a post-surgical throwing program is a critical step to ensure safe rehabilitation after shoulder and elbow surgery in competitive baseball players. The current study provides a foundation for establishing such objective criteria, and it highlights areas of improvement in rehabilitation protocols. Further research is needed to validate the objective testing protocol and its applicability in a larger population. [Figure: see text][Table: see text][Table: see text][Table: see text]

Background The association between ball velocity and elbow varus torque has shown differences when evaluated within a single pitcher and within a cohort. The impact of increasing ball velocity on additional throwing-arm kinetics, in particular shoulder distraction forces, with intra- vs. inter-pitcher evaluations has not been evaluated, even though these kinetic measures have been implicated in injury risk. The purpose of this study was to compare intra- vs. inter-pitcher relationships between ball velocity and all major kinetics at the shoulder and elbow in professional pitchers. Methods A total of 323 professional baseball pitchers threw 8-12 fastball pitches while simultaneously being evaluated with 3-dimensional motion-capture technology (480 Hz). A linear regression analysis was performed to evaluate pitch velocity as a predictor of peak kinetic values at the shoulder and elbow among pitchers. A linear mixed model with random intercepts was then created to evaluate ball velocity as a predictor of peak kinetic values when comparing pitches within an individual pitcher. Results 91 pitchers were included in the analyses. Ball velocity among pitchers had weak correlations with shoulder distraction force (R2 = 0.228, P 0.85) were observed for (1) shoulder internal rotation torque (P Conclusion Faster pitch velocity is a weak predictor of shoulder and elbow distraction forces experienced among professional pitchers. However, when controlling for an individual pitcher, peak kinetics at the shoulder and elbow can be strongly predicted by ball velocity. Therefore, the assumption that higher peak throwing-arm kinetic values are experienced by pitchers with faster ball velocity is likely an inappropriate assumption among pitchers but may be correct for each player who increases pitch velocity.

Objectives: High school baseball pitch count limits vary widely by state; however, it is unknown how these variations impact cumulative elbow varus torque (EVT) throughout a season. Specifically, pitch count limits are a popular method for preventing overuse in youth baseball players, but rest day requirements for different pitch count limits are often highly variable and less frequently analyzed. Therefore, the objectives of the current study were to (1) investigate variations in pitch count rules across all 50 states, (2) calculate maximum game, monthly and season-long EVT across all pitch count limits, and (3) calculate EVT across all pitch count limits after adjusting for rest days required by each state. We hypothesized that the number of required rest days based on gameday pitch count limits would lead to large variations in cumulative EVT workload over the course of a season. Methods: Pitch count allowances and required rest days for high school baseball pitchers were recorded from the athletic association website of each state. The Motus Global database was queried for all high school pitchers. Average EVT for game pitches was quantified and used to calculate cumulative game, weekly, monthly, and season EVT during a projected 3-month season for each maximum pitch count limit assuming a three-day rest period. Values were subsequently recalculated for each group of states based on pitch count allowances and actual required rest days. Results: The Motus Global database provided 65,928 pitches from 45 high school pitchers with an average age of 16.9 ± 0.8 years. Average EVT per pitch was 45.04 ± 10.46 N•m. High school baseball is not a sanctioned sport in 2 states (Montana and Wyoming), leaving 48 states for analysis. The most common midseason maximum pitch count limit was 110 pitches (19 states, range 100-125 pitches), and the most common required rest days was 4 days (24 states, range 0-5 days) (Table 1). Assuming three-days rest between maximum pitch outings, there was a 20% difference in cumulative EVT during a season between 100 and 125 maximum pitches. When maximum pitch counts were projected with required rest days, allowing a maximum of 140 pitches in a 4 day span without a specific rest day requirement resulted in the most EVT during a season (Nevada), followed by allowing a maximum pitch count of 125 pitches with a rest requirement of 3 days (Louisiana/Ohio, Figure 1). Pennsylvania and Wisconsin allowed the least amount of pitches (i.e. 100 pitches) with the shortest required rest days (i.e. 3 days), resulting in the lowest EVT for a game and week but the sixth highest season EVT. Conversely, South Carolina allowed 110 pitches but required the most rest days (5 days), resulting in the lowest season EVT. Overall, there was a 48.8% difference in EVT during a season between the most and least restrictive states. A greater seasonal EVT in the lowest pitch count range with 1 required rest day compared to the highest pitch range was observed in 28 states (58%). Average seasonal workload of every pitch count range per required rest days for all states is summarized in Figure 2. This generally demonstrates an inverse trend with a 30% greater EVT differential between the lowest pitch range with one required rest day and the highest pitch range with 5 required rest days. Only 1 state had equal seasonal EVT at both maximum and minimal pitch ranges (Pennsylvania). Conclusions: There is wide variability in pitch count rules between states. Required rest days are often an underappreciated aspect of pitch count rules, yet they may influence season-long EVT more than maximum pitch count allowances. For example, the maximal seasonal EVT did not occur at maximal pitch limits for the majority of states. Instead, it most frequently occurred at the lowest pitch count allowance with 1 rest day (58% of states). A primary example is Indiana, which has a 20% greater potential seasonal EVT in the lowest pitch range (36-60 pitches, 1 rest day requirement) compared to its maximal pitch limit (101-120 pitches, 4 rest day requirement). Pitch count rules should be analyzed to ensure that projected workload across all pitch count and rest day allowances are proportional. Therefore, standardization of pitch count rules across states should be considered with increased emphasis on rest day restrictions. [Table: see text]