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Background: Individual maximum joint and segment angular velocities have shown positive associations with throwing arm kinetics and ball velocity in baseball pitchers. Purpose: To observe how cumulative maximum joint and segment angular velocities, irrespective of sequence, affect ball velocity and throwing arm kinetics in high school pitchers. Study Design: Descriptive laboratory study. Methods: High school (n = 55) pitchers threw 8 to 12 fastball pitches while being evaluated with 3-dimensional motion capture (480 Hz). Maximum joint and segment angular velocities (lead knee extension, pelvis rotation, trunk rotation, shoulder internal rotation, and forearm pronation) were calculated for each pitcher. Pitchers were classified as overall fast, overall slow, or high velocity for each joint or segment velocity subcategory, or as population, with any pitcher eligible to be included in multiple subcategories. Kinematic and kinetic parameters were compared among the various subgroups using t tests with post hoc regressions and multivariable regression models created to predict throwing arm kinetics and ball velocity, respectively. Results: The lead knee extension and pelvis rotation velocity subgroups achieved significantly higher normalized elbow varus torque (P =.016) and elbow flexion torque (P =.018) compared with population, with equivalent ball velocity (P =.118). For every 1-SD increase in maximum pelvis rotation velocity (87 deg/s), the normalized elbow distractive force increased by 4.7% body weight (BW) (B = 0.054; β = 0.290; P =.013). The overall fast group was older (mean ± standard deviation, 16.9 ± 1.4 vs 15.4 ± 0.9 years; P =.007), had 8.9-mph faster ball velocity (32.7 ± 3.1 vs 28.7 ± 2.3 m/s; P =.002), and had significantly higher shoulder internal rotation torque (63.1 ± 17.4 vs 43.6 ± 12.0 Nm; P =.005), elbow varus torque (61.8 ± 16.4 vs 41.6 ± 11.4 Nm; P =.002), and elbow flexion torque (46.4 ± 12.0 vs 29.5 ± 6.8 Nm; P <.001) compared with the overall slow group. A multiregression model for ball velocity based on maximum joint and segment angular velocities and anthropometrics predicted 53.0% of variance. Conclusion: High school pitchers with higher maximum joint and segment velocities, irrespective of sequence, demonstrated older age and faster ball velocity at the cost of increased throwing shoulder and elbow kinetics. Clinical Relevance: Pitchers and coaching staff should consider this trade-off between faster ball velocity and increasing throwing arm kinetics, an established risk factor for elbow injury. [ABSTRACT FROM AUTHOR]

Background: Kinematic parameters predictive of pitch velocity have been evaluated in adolescent and collegiate baseball pitchers; however, they have not been established for high school or professional pitchers. Purpose: To create multiregression models using anthropometric and kinematics features most predictive for pitch velocity in high school and professional pitchers and compare them with prior multiregression models evaluating other playing levels. Study Design: Descriptive laboratory study. Methods: High school (n = 59) and professional (n = 337) baseball pitchers threw 8 to 12 fastballs while being evaluated with 3-dimensional motion capture (480 Hz). Using anthropometric and kinematic variables, multiregression models for pitch velocity were created for each group. A systematic review was conducted to determine previous studies that established kinematic models for ball velocity in youth, high school, and collegiate pitchers. Results: Leg length was predictive of pitch velocity for high school and professional pitchers (P <.001 for both). When compared with previously established models for pitch velocity, almost all groups were distinct from one another when assessing age (P maximum <.001), weight (P max =.0095), and pitch velocity (P max <.001). Stride length was a significant predictor for the youth/high school pitchers, as well as the current study's high school and professional pitchers (P <.001 for all). Maximal shoulder external rotation (collegiate: P =.001; professional: P <.001) and maximal elbow extension velocity (high school/collegiate: P =.024; collegiate: P <.001; professional: P =.006) were shared predictors for the collegiate and current study's professional group multiregression models. Trunk flexion at ball release was a commonly shared predictor in the youth/high school (P =.04), high school/collegiate (P =.003), collegiate (P <.001), and the current study's professional group (P <.001). Conclusion: Youth, high school, collegiate, and professional pitchers had unique, predictive kinematic and anthropometric features predictive of pitch velocity. Leg length, stride length, trunk flexion at ball release, and maximal shoulder external rotation were predictive features that were shared between playing levels. Clinical Relevance: Coaches, clinicians, scouts, and pitchers can consider both the unique and the shared predictive features at each playing level when attempting to maximize pitch velocity. [ABSTRACT FROM AUTHOR]

Background: When the lead leg of a pitcher contacts the ground, the knee braces and then rapidly extends, initiating energy transfer to begin pelvis and trunk rotation. Purpose: To investigate the relationship of lead knee extension during the pitching delivery with peak lead knee extension velocity, ball velocity, and elbow varus torque in high school and professional pitchers. Study Design: Descriptive laboratory study. Methods: Data from 50 professional (PRO) and 50 high school (HS) pitcher groups were retrospectively analyzed. Pitchers threw 8 to 12 fastballs under 3-dimensional motion analysis (480 Hz). The groups were divided according to high or low lead knee extension: PRO-high (n = 18), PRO-low (n = 16), HS-high (n = 16), and HS-low (n = 17). Lead knee flexion, lead knee extension velocity, ball velocity, and elbow varus torque were analyzed between groups. Regression analyses were performed to quantify associations between lead knee extension and ball velocity and elbow varus torque for all pitchers. Results: At foot contact, all pitchers landed with similar knee flexion. PRO-high and HS-high pitchers had significantly greater lead knee extension through remaining pitching time points compared with the PRO-low and HS-low pitchers. PRO-high pitchers had faster ball velocity than PRO-low pitchers (39.8 ± 1.1 vs 39.3 ± 1.3 m/s, respectively), and HS-high pitchers had faster ball velocity than HS-low pitchers (34.1 ± 2.6 vs 31.2 ± 1.8 m/s, respectively) (P <.05). PRO-high pitchers had decreased elbow varus torque compared with PRO-low pitchers (85.3 ± 10.7 vs 95.4 ± 13.3 N·m, respectively); conversely, HS-high pitchers had greater elbow varus torque than HS-low pitchers (64.2 ± 14.7 vs 56.3 ± 12.2 N·m, respectively). For every 1° increase in lead knee extension, ball velocity increased by 0.47 m/s (P <.001) and elbow varus torque increased by 0.27 N·m (P =.025). Conclusion: Proper lead knee extension allowed efficient energy transfer through the kinetic chain to produce optimal ball velocity and minimize elbow varus torque in professional pitchers. Conversely, while proper lead knee extension improved ball velocity among high school pitchers, this did not minimize elbow varus torque. Clinical Relevance: Professional pitchers can extend their lead knee with minimal impact at the elbow. In high school pitchers, cognizance of proper full-body pitching mechanics remains a priority over increased velocity. [ABSTRACT FROM AUTHOR]

Background: Improper sequencing order of maximal joint and segment velocities has been identified as an important predictor for both throwing arm kinetics and ball velocity. Purpose: To investigate the intrapitcher variation of maximal segment velocities and the relationship to throwing arm kinetics and ball velocity in high school (HS) and professional (PRO) pitchers. Study Design: Descriptive laboratory study. Methods: HS (n = 59) and PRO (n = 338) pitchers, instructed to throw 8 to 12 fastball pitches, were evaluated with 3-dimensional motion capture (480 Hz). Maximal joint and segment velocities were calculated for each pitch, and the standard deviation of the maxima was calculated per pitcher. These standard deviations were used to classify pitchers as "low variance" or "high variance" for each segmental velocity subgroup, "overall low variance" or "overall high variance" based on cumulative segment velocity variation, or "population," with any pitcher eligible to be included in multiple subcategories. Maximal velocities and throwing arm kinetics were compared among the various subgroups. Results: The HS low-variance shoulder internal rotation velocity subgroup (4949 ± 642 deg/s) had significantly lower maximal shoulder internal rotation velocity compared with HS population (5774 ± 1057 deg/s) (P <.001); similar findings were observed for PROs (5269 ± 835 vs 5824 ± 1076 deg/s; P <.001), as well as lower shoulder superior force compared with the PRO population (14.8% ± 8.8% vs 17.8% ± 8.8% body weight; P =.001). The PRO low-variance lead knee extension velocity subgroup had significantly lower maximal lead knee extension velocity (216 ± 135 vs 258 ± 125 deg/s; P =.001) and shoulder distractive force (111.5% ± 14.4% vs 115.6% ± 15.9% body weight; P =.003) compared with the PRO population. The PRO overall low-variance subgroup had significantly lower shoulder distractive force (111.8% ± 14.1% vs 119.6% ± 15.5% body weight; P =.008) and elbow anterior force (40.6% ± 5.0% vs 43.6% ± 6.2% body weight; P =.008) compared with the PRO overall high-variance subgroup. Conclusion: HS and PRO pitchers with low variance for joint and segment velocities achieved significantly lower maximal velocities in the subgroup of interest, while preserving ball velocity. PRO pitchers with overall low variance among multiple maximal joint and segment velocities demonstrated decreased shoulder distractive and elbow anterior force. Clinical Relevance: PRO pitchers with low intrapitch variation in maximal joint and segment velocities may be viewed as kinetically conservative throwers. These pitchers with similarly maintained mechanics between pitches may have an increasingly regimented form that preserves kinetic forces about the throwing arm. The opposite may be true for PRO pitchers with increased variability in segmental velocities during their pitching motion, as they showed increased throwing arm kinetics including shoulder distractive and elbow anterior force compared with the overall low-variance group, theoretically increasing their risk of injury. [ABSTRACT FROM AUTHOR]

Background: Excessive shoulder anterior force has been implicated in pathology of the rotator cuff in little league and professional baseball pitchers; in particular, anterior laxity, posterior stiffness, and glenohumeral joint impingement. Distinctly characterized motions associated with excessive shoulder anterior force remain poorly understood. Methods: High school and professional pitchers were instructed to throw fastballs while being evaluated with 3D motion capture (480 Hz). A supplementary random forest model was designed and implemented to identify the most important features for regressing to shoulder anterior force, with subsequent standardized regression coefficients to quantify directionality. Results: 130 high school pitchers (16.3 ± 1.2 yrs; 179.9 ± 7.7 cm; 74.5 ± 12.0 kg) and 322 professionals (21.9 ± 2.1 yrs; 189.7 ± 5.7 cm; 94.8 ± 9.5 kg) were included. Random forest models determined nearly all the variance for professional pitchers (R2 = 0.96), and less than half for high school pitchers (R2 = 0.41). Important predictors of shoulder anterior force in high school pitchers included: trunk flexion at maximum shoulder external rotation (MER) (X.IncMSE = 2.4, β = −0.23, p < 0.001), shoulder external rotation at ball release (BR)(X.IncMSE = 1.7, β = −0.34, p < 0.001), and shoulder abduction at BR (X.IncMSE = 3.1, β = 0.17, p < 0.001). In professional pitchers, shoulder horizontal adduction at foot contact (FC) was the highest predictor (X.IncMSE = 13.9, β = 0.50, p < 0.001), followed by shoulder external rotation at FC (X.IncMSE = 3.6, β = 0.26, p < 0.001), and maximum elbow extension velocity (X.IncMSE = 8.5, β = 0.19, p < 0.001). Conclusion: A random forest model successfully selected a subset of features that accounted for the majority of variance in shoulder anterior force for professional pitchers; however, less than half of the variance was accounted for in high school pitchers. Temporal and kinematic movements at the shoulder were prominent predictors of shoulder anterior force for both groups. Clinical relevance: : Our statistical model successfully identified a combination of features with the ability to adequately explain the majority of variance in anterior shoulder force among high school and professional pitchers. To minimize shoulder anterior force, high school pitchers should emphasize decreased shoulder abduction at BR, while professionals can decrease shoulder horizontal adduction at FC. [ABSTRACT FROM AUTHOR]

A pitcher's ability to achieve pitch location precision after a complex series of motions is of paramount importance. Kinematics have been used in analyzing performance benefits like ball velocity, as well as injury risk profile; however, prior utilization of such data for pitch location metrics is limited. To develop a pitch classifier model utilizing machine learning algorithms to explore the potential relationships between kinematic variables and a pitcher's ability to throw a strike or ball. This was a descriptive laboratory study involving professional baseball pitchers (n = 318) performing pitching tests under the setting of 3D motion-capture (480 Hz). Main outcome measures included accuracy, sensitivity, specificity, F1 score, positive predictive value (PPV), and negative predictive value (NPV) of the random forest model. The optimized random forest model resulted in an accuracy of 70.0 %, sensitivity of 70.3 %, specificity of 48.5 %, F1 equal to 80.6 %, PPV of 94.3 %, and a NPV of 11.6 %. Classification accuracy for predicting strikes and balls achieved an area under the curve of 0.67. Kinematics that derived the highest % increase in mean square error included: trunk flexion excursion(4.06 %), pelvis obliquity at foot contact(4.03 %), and trunk rotation at hand separation(3.94 %). Pitchers who threw strikes had significantly less trunk rotation at hand separation(p = 0.004) and less trunk flexion at ball release(p = 0.003) compared to balls. The positive predictive value for determining a strike was within an acceptable range, while the negative predictive value suggests if a pitch was determined as a ball, the model was not adequate in its prediction. Kinematic measures of pelvis and trunk were crucial determinants for the pitch classifier sequence, suggesting pitcher kinematics at the proximal body segments may be useful in determining final pitch location. [ABSTRACT FROM AUTHOR]

Background: Currently, most pitching instructors suggest a shorter arm path—the total distance the arm travels during pitching. Theoretically, this combination allows for better body segment sequencing, a more efficient energy transfer through the kinetic chain, and increased ball velocity, while limiting elbow varus torque. Hypothesis: Shorter arm paths would be associated with increased ball velocity and decreased elbow varus torque. Study Design: Descriptive laboratory study. Methods: A total of 182 professional pitchers threw 8 to 12 fastball pitches while evaluated by 3-dimensional motion capture (480 Hz). The arm path was calculated as the total distance the hand marker traveled during the pitch. The pitch was divided into early, late, and total arm paths. A linear regression model assessed the interpitcher relationship between arm path, elbow varus torque, and ball velocity. A linear mixed-effects model with random intercepts assessed intrapitcher relationships. Results: Interpitcher comparison showed that total arm path weakly correlated with greater elbow varus torque (P =.025). Strong correlations were found between ball velocity and early (R 2 = 0.788; P <.001), late (R 2 = 0.787; P =.024), and total arm paths (R 2 = 0.792; P <.001). Strong positive intrapitcher correlations were found between elbow varus torque and early (R 2 = 0.962; P <.001) and total arm path (R 2 = 0.964; P <.001). For individual pitchers, there was a large variation in the early (30.1 ± 15.7 cm) and late (21.4 ± 12.1 cm) arm path. For every 30-cm (11.8-inch) increase in early arm path (the mean range for an individual pitcher), there was a 1.29-N (β = 0.0429) increase in elbow varus torque and a 0.354 m/s (0.79 mph) (β = 0.0118) increase in ball velocity. Conclusion: A shorter arm path correlated with decreased elbow varus torque and decreased ball velocity in intrapitcher comparisons. Determining the individual mechanics that decrease elbow varus torque may help coaches and trainers correct these patterns. Clinical Significance: A shorter arm path during the pitch can decrease elbow varus torque, which limits the load on the medial elbow but also has a detrimental effect on ball velocity. An improved understanding of the impact of shortening arm paths on stresses on the throwing arm may help minimize injury risk. [ABSTRACT FROM AUTHOR]

Pitch velocity (PV) is important for pitching success, and the pelvis and trunk likely influence pitch performance. The purposes of this study were to examine the differences in pelvis and trunk kinetics and kinematics in professional baseball pitchers who throw at lower versus higher velocities (HVPs) and to examine the relationships among pelvis and trunk kinetics and kinematics and PV during each phase of the pitch delivery. The pitch velocity, pelvis and trunk peak angular velocities, kinetic energies and torques, and elbow and shoulder loads were compared among HVPs (n = 71; PV ≥ 40.2 m/s) and lower velocities pitchers (n = 78; PV < 39.8 m/s), as were trunk and pelvis rotation, flexion, and obliquity among 7 phases of the pitching delivery. Relationships among the kinetic and kinematic variables and PVs were examined. Higher velocity pitchers achieved greater upper trunk rotation at hand separation (+7.2°, P <.001) and elbow extension (+5.81°, P =.002) and were able to generate greater upper trunk angular velocities (+36.6 m/s, P =.01) compared with lower velocity pitcher. Trunk angular velocity (r =.29) and upper trunk rotation at hand separation (r =.18) and foot contact (r =.17) were weakly related to PV. Therefore, HVPs rotate their upper trunk to a greater degree during the early phases of the pitching motion and subsequently generate greater trunk angular velocities and PV. [ABSTRACT FROM AUTHOR]

Background: Repetitive horizontal shoulder abduction during pitching can cause increased contact between the posterosuperior aspect of the glenoid and the greater tuberosity of the humeral head, theoretically putting baseball pitchers at increased risk of shoulder internal impingement and other shoulder pathologies. Hypothesis: Increased shoulder horizontal abduction is associated with increased shoulder anterior force, while increased horizontal adduction is associated with increased shoulder distraction force. Study Design: Descriptive laboratory study. Level of Evidence: Level 4. Methods: A total of 339 professional baseball pitchers threw 8 to 10 fastball pitches using 3D motion capture (480 Hz). Pitchers were divided into 2 sets of quartiles based on maximum shoulder horizontal abduction and adduction. Elbow flexion, shoulder external rotation, and peak shoulder kinetics were compared between quartiles with post hoc linear regressions conducted for the entire cohort. Results: At maximum shoulder horizontal abduction, there was no difference in ball velocity between quartiles (P = 0.76). For every 10º increase in maximum shoulder horizontal abduction, shoulder anterior force decreased by 2.2% body weight (BW) (P < 0.01, B = −0.22, β = −0.38), shoulder adduction torque decreased by 0.5%BW × body height (BH) (P < 0.01, B = −0.05, β = −0.19), and shoulder horizontal adduction torque decreased by 0.4%BW × BH (P < 0.01, B = −0.04, β = −0.48). For every 10º increase in maximum shoulder horizontal adduction, shoulder anterior force increased by 2%BW and ball velocity decreased by 1.2 m/s (2.7 MPH). Conclusion: Professional pitchers with the least amount of maximum horizontal adduction had faster ball velocity and decreased shoulder anterior force. Pitchers with greater maximum shoulder horizontal abduction had decreased shoulder anterior force, shoulder adduction torque, and shoulder horizontal adduction torque. To maximize ball velocity as a performance metric while minimizing shoulder anterior force, pitchers can consider decreasing maximum shoulder adduction angles at later stages of the pitch. Clinical Relevance: Identifying risk factors for increased throwing shoulder kinetics (ie, shoulder anterior force, shoulder adduction torque) has potential implications in injury prevention. Specifically, mitigating shoulder anterior forces may be beneficial in reducing risk of injury. [ABSTRACT FROM AUTHOR]

Movement screens are widely used to identify aberrant movement patterns in hopes of decreasing risk of injury, identifying talent, and/or improving performance. Motion capture data can provide quantitative, objective feedback regarding movement patterns. The dataset contains three-dimensional (3D) motion capture data of 183 athletes performing mobility tests (ankle, back bend, crossover adduction, crossover rotation, elbows, head, hip turn, scorpion, shoulder abduction, shoulder azimuth, shoulder rotation, side bends, side lunges and trunk rotation) and stability tests (drop jump, hop down, L-cut, lunge, rotary stability, step down and T-balance) bilaterally (where applicable), the athletes' injury history, and demographics. All data were collected at 120 Hz or 480 Hz using an 8-camera Raptor-E motion capture system with 45 passive reflective markers. A total of 5,493 trials were pre-processed and included in.c3d and.mat formats. This dataset will enable researchers and end users to explore movement patterns of athletes of varying demographics from different sports and competition levels; develop objective movement assessment tools; and gain new insights into the relationships between movement patterns and injury. [ABSTRACT FROM AUTHOR]

Background: It has previously been speculated that baseball pitchers who display excessive forearm pronation at foot contact (FC) have a higher propensity toward ulnar collateral ligament injury and subsequent surgery. Purpose: To evaluate the association between degree of forearm pronation/supination at FC and throwing arm kinetics in high school and professional pitchers, at both the individual (intrapitcher) and the group (interpitcher) level. Study Design: Descriptive laboratory study. Methods: High school (n = 41) and professional (n = 196) pitchers threw 8 to 12 fastballs while being assessed with a 3-dimensional motion-capture system (480 Hz). Pitchers at each playing level were divided into a supination or pronation subgroup depending on degree of forearm pronation at FC. Regression models were built to observe the relationship between forearm pronation at FC and kinetic and kinematic parameters of interest. Results: At both the individual and the group level of high school and professional pitchers, there was no significant correlation between forearm pronation at FC and elbow varus torque (P min =.21). For every 10° increase in forearm pronation at FC in the individual high school pitcher, elbow flexion at FC decreased by 5°, whereas maximum elbow extension velocity was achieved 0.6% later in the pitch. In addition, elbow medial force increased by 4.1 N and elbow varus torque increased by 0.8 N·m for every 10° increase in forearm supination at FC. For every 10° increase in forearm supination in the individual professional pitcher, ball velocity increased by 0.5 m/s, shoulder external rotation at FC decreased by 11°, and elbow medial force decreased by 5.5 N. Conclusion: Supination- or pronation-predominant forearm motion during the pitch did not significantly differ between playing levels. Excessive forearm pronation at FC was not a significant risk factor for increased throwing arm kinetics for high school or professional pitchers. There was a weak positive association between forearm supination at FC and elbow varus torque in the individual high school pitcher. Ultimately, coaches and pitchers may be better served by redirecting their focus to other mechanical aspects of the pitch that may have stronger associations with injury risk implications as well as performance. [ABSTRACT FROM AUTHOR]

Objectives: The persistent high rates of elbow injuries among professional baseball pitchers indicates a critical gap in our understanding of how a pitch influences load on the elbow. Traditionally, research has examined the maximum value of various kinetics experienced at the throwing arm during a pitch, especially elbow varus torque. The maximum elbow varus torque has been used as a surrogate for potential elbow injury; however, the elbow injury epidemic has still persisted. It is possible that analysis focused on only the maximum value misses the total load experienced on the throwing arm. Therefore, the purpose of this study was to investigate different metrics to evaluate elbow stress, including maximum elbow varus torque, elbow loading rate, and cumulative varus torque between different pitch types. By evaluating these aspects of elbow stress, our study aims to uncover previously overlooked kinetic variables that might be potential contributors to elbow injuries, bridging the gap between existing kinetic analyses and the persistent high injury rates. Methods: Data from a cohort of 41 professional baseball pitchers were utilized for this analysis (188 ± 6 cm; 91.9 ± 8.2 kg). Pitchers threw a series of fastball, changeup, and curveball pitches (fastball: 10 ± 3 pitches, changeup: 3 ± 1 pitches, curveball: 4 ± 1 pitches) captured using a 3D motion capture system (480 Hz). Kinetic variables were calculated for each pitch, including maximum elbow varus torque, loading torque rate (measured as the derivative of the varus torque curve), and cumulative elbow varus torque (measured as the area under the elbow varus torque curve). A linear mixed effects model was employed to examine within player associations between pitch type and ball velocity, maximum elbow varus torque, loading torque rate, and cumulative elbow varus torque. Statistical significance was set at p<0.01. Results: Our findings reveal that the fastball pitch created greater loading on the elbow compared to the change up and curveball pitches (Table 1). Pitchers threw their fastball with increased ball velocity (40.3 ± 0.6 m/s) compared to throwing their changeup (36.6 ± 0.5 m/s) and curveball (33.7±0.5 m/s) (p<0.001). Maximum elbow varus torque was also greater in the fastball pitch (93.7 ± 3.3 N∙m) compared to the changeup pitch (84.1 ± 2.4 N∙m) and curveball (91.0 ± 2.3 N∙m) (p<0.001); the curveball pitch had greater maximum torque compared to changeup pitches (p<0.001). The loading rate was 15% lower for the changeup pitch (690.0 ± 49.4 N∙m/s) (p<0.001) and 6% lower for the curveball (753.6 ± 60.3 N∙m/s) compared to the fastball (820.1 ± 72.2 N∙m/s) (p<0.001). The cumulative elbow varus torque for the fastball was 4% greater than the changeup pitch (2996.9 ± 92.9 vs 2894.1 ± 84.1 N∙m) and 7% greater than the curveball pitch (2996.9 ± 92.9 vs 2797.2 ± 85.8 N∙m) (p<0.001). Conclusions: This study reveals the importance of considering pitch type when evaluating kinetic variables in professional baseball pitchers. The observed differences in elbow varus torque, loading rate, and other kinematic metrics between fastball, changeup, and curveball pitches highlights the need for a comprehensive understanding of biomechanical variations associated with different pitch types. These findings have implications for optimizing pitcher training programs, injury prevention strategies, and player management. By unraveling the intricate connections between kinetic variables and pitch types, this research contributes to advancing the biomechanical knowledge within the field of orthopedics and sports science. [ABSTRACT FROM AUTHOR]

Background: Early pelvic rotation has been associated with decreased throwing arm kinetics in college baseball pitchers, though professional pitchers have yet to be examined. Purpose: 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. Study Design: Descriptive laboratory study. Methods: 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. Results: 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). Conclusion: 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. Clinical Relevance: 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. [ABSTRACT FROM AUTHOR]

Background: It is unknown how different pitch count limits and rest day requirements affect cumulative pitch counts during a baseball season. Purpose: To determine (1) the variability of pitch count rules in high school baseball and (2) the theoretical effect of different pitch count limits and rest day combinations on game, weekly, and seasonal pitch totals in high school baseball pitchers. Study Design: Cross-sectional study. Methods: Pitch count rules for the 2019-2020 academic year for 48 sanctioned states were recorded from each state's athletic association website. Maximum pitch count limits were recorded along with the number of pitches allowed before requiring 0 to 5 rest days before the next pitching outing. Rules were also analyzed for several distinctions, including the athlete's level of competition, age, and grade. To determine the effect of pitch count rules and rest days, a theoretical 3-month season was calculated in the following scenarios: (1) variable maximum pitch count limits with a universal 3-day rest requirement, (2) universal 110 pitch count limit with variable rest day requirements (3, 4, or 5 days), and (3) actual pitch count limits and required rest days for every state assuming pitchers throw as many pitches as allowed. Analysis of variance and Student t tests were used to compare between-group and intragroup seasonal pitch totals based on variations in required rest days. Results: The most common maximum pitch count limit for a varsity high school athlete was 110 pitches (range, 100-125 pitches) with 4 rest days (range, 0-5 days). We found that 23 states (48%) did not make distinctions for pitch count rules based on the athlete's level of competition, age, or grade. We noted a 25% increase in total seasonal pitch counts between the smallest and largest pitch count limit when assuming constant 3-day rest. We found a 53% difference in total seasonal pitch count when rest days varied between 3 and 5 days with a constant 110-pitch limit. Allowing 140 pitches in a 4-day span without a specific rest day requirement resulted in the highest seasonal pitch count (Nevada). There was a 49% difference in maximum seasonal pitch counts between the most and least restrictive states (P <.001). Submaximum pitch limits resulted in higher seasonal pitch counts than maximum pitch limits in 56% of states. Conclusion: Pitch count rules vary widely by state. Required rest days influenced total seasonal pitch counts more than maximum or submaximum pitch count limits. [ABSTRACT FROM AUTHOR]

Background: Early pelvis rotation has been associated with decreased throwing arm kinetics and conventionally was considered a component of proper pitching form in baseball throwers. However, previous assessments of pelvis rotation style have not accounted for confounders such as playing level, anthropometric characteristics, or ball velocity and have not evaluated sufficient sample sizes. Purpose: To compare kinetic and kinematic parameters based on pelvis rotation style in high school and professional pitchers. Study Design: Descriptive laboratory study. Methods: High school and professional baseball pitchers threw 8 to 12 fastball pitches while being evaluated using 3-dimensional motion capture (480 Hz). These pitchers were 1:1 propensity score matched by age, height, weight, handedness, and ball velocity based on early (<60°) versus late (≥60°) pelvis rotation style at foot contact. A total of 26 kinematic and 10 kinetic parameters were compared between groups. The kinematic parameters were used to conduct a linear regression between early and late pelvis rotation at foot contact. Results: Pelvis rotation at foot contact was not significantly associated with ball velocity for either high school (P =.243) or professional pitchers (P =.075). No difference was found in elbow varus torque between high school early rotators (57.5 ± 14.9 N·m) and late rotators (51.3 ± 14.7 N·m; P =.036) and between professional early rotators (80.1 ± 11.8 N·m) and late rotators (79.0 ± 11.2 N·m; P =.663). At foot contact in high school pitchers, stride length increased by 2.1% of body height (B = −0.205; β = −0.470; P <.001), trunk rotation increased by 4.2° (B = −0.417; β = −0.488; P <.001), and trunk flexion at foot contact decreased by 4.4° (B = 0.442; β = 0.476; P <.001) with every 10° increase in pelvis rotation. At foot contact in professional pitchers, stride length increased by 2.3% of body height (B = –0.229; β = –0.478; P <.001), trunk rotation increased by 4.3° (B = –0.431; β = –0.515; P <.001), and trunk flexion decreased by 4.0° (B = 0.404; β = 0.373; P <.001) with every 10° increase in pelvis rotation. Conclusion: Pelvis rotation at foot contact was associated with several kinematic parameters in both groups and may influence mechanics further along the kinetic chain. Landing open or closed was not significantly associated with throwing arm kinetics or ball velocity for both high school and professional baseball pitchers, contrary to previous thought. Clinical Relevance: Coaches and players may better focus their efforts on refining other kinematic parameters for enhanced performance outcomes and safe pitching mechanics. [ABSTRACT FROM AUTHOR]

Background: The relationships between shoulder abduction and external rotation with peak kinetic values at the shoulder and elbow in professional baseball pitchers are not well established. Methods: Professional pitchers (n = 322) threw 8–12 fastballs under 3D motion analysis (480 Hz). Pitchers were stratified into quartiles by shoulder abduction and external rotation at distinct timepoints. Regression analyses were performed to quantify associations between shoulder position and kinetics. Results: Shoulder abduction remained relatively consistent throughout the pitch (foot contact–ball release: 85.5 ± 11.1–90.7 ± 8.4°); shoulder external rotation increased dramatically (foot contact–ball release: 30.8 ± 24.6–165.2 ± 9.7°). For every 10° increase in maximum shoulder rotation, shoulder superior force increased by 2.3% body weight (p < 0.01), shoulder distraction force increased by 5.9% body weight (p < 0.01), and ball velocity increased by 0.60 m/s (p < 0.01). Shoulder abduction was significantly associated with shoulder superior force at all timepoints but not with ball velocity (p > 0.05). For every 10° increase in shoulder abduction at ball release, shoulder superior force increased by 3.7% body weight (p < 0.01) and shoulder distraction force increased by 11.7% body weight (p < 0.01). Conclusion: Increased shoulder abduction at ball release and increased maximum shoulder external rotation were associated with greater superior and distraction forces in the shoulder. Pitchers can consider decreasing shoulder abduction at later stages of the pitch to around 80° in order to minimize shoulder superior force, with no impact on ball velocity. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: Baseball workloads are monitored by pitch counts, appearances, innings per appearance, ball velocity, and distance, whereas current workload standards neglect throws made during nongame situations. The association between total workloads, subjective measures, and injury in baseball is poorly understood. The question remains whether baseball athletes are at higher risk of injury by throwing more often or if they generate injury resilience when appropriately transitioned into the higher demands of throwing.Hypothesis: Increased chronic load, along with subjective arm health measures, are related to decreased injury risk.Study Design: Clinical research.Level Of Evidence: Level 3.Methods: A total of 49 male baseball players (age 17.9 ± 0.4 years, height 181.8 ± 6.8 cm, body mass 80.6 ± 9.1 kg) competing at the varsity high school level were included in this 3-year retrospective data analysis from 2016 to 2019. Players wore the motusTHROW sleeve and sensor during all throwing activities.Results: A total of 898,492 throws and 9455 athletic exposures were captured with the motusTHROW sensors. There were 24 injuries recorded throughout the 3-year analysis, with 11 throwing-related and 13 non-throwing related injuries. Results of the 1-way analysis of variance found chronic load was significantly related to throwing-injury occurrence (P < 0.01). Six of the throwing-related injuries occurred when athletes had a chronic load greater than 11.3, marking 75th percentile across all observations. There was a relationship between arm health and throwing arm-related injury occurrence (P < 0.01). Higher chronic load was associated with increased throwing-related injuries even when adjusted for arm health (P = 0.01). Specifically, injuries were more likely to occur in pitchers (either as a combination player or pitcher only) with a chronic load greater than 9.2.Conclusion: This study revealed a significant relationship between chronic load, subjective arm health, and throwing-related injury in varsity high school baseball players. Contrary to our hypothesis, increased chronic load was associated with increased injury risk. However, subjective arm health measures remain a relevant factor in assessing injury risk. Normative data for this population also provide key information around positional demands along with overall demands of the sport during the competitive season and off-season. [ABSTRACT FROM AUTHOR]

Professional basebal pitchers (n =315) were divided into quartiles based on increasing stride length and random intercept linear mixed-effect models were used to correlate stride length with ball velocity, pelvis and trunk rotation at foot contact, and throwing arm kinetics. Average stride length among all pitchers was 78.3±5.3%body height (%BH). For every 10% increase in stride length, ball velocity increased by 0.9 m/s (B =0.089, β =0.25, p <0.001) and trunk rotation initiation occurred 4.23 ms earlier (B =−0.42, β =−0.14, p <0.001). When divided into quartiles pelvis rotation was less towards home plate in Q1 compared to Q3 and Q4 (70.0±10.7° vs. 60.9±8.9° and 58.6±9.1°, p <0.001). No significant differences in shoulder internal rotation torque (p =0.173) or elbow varus torque (p =0.072) were noted between quartiles. Professional baseball pitchers who reached stride lengths of 80%BH or greater achieved faster ball velocity without an increase in elbow varus torque. This may, be a byproduct of rotating the pelvis for a greater proportion of the pitching motion and thereby more effectively utilising the lower extremities in the kinetic chain. Encouraging players to achieve this threshold of stride length may enhance ball velocity outcomes. [ABSTRACT FROM AUTHOR]

Background: Inefficient energy transfer from the pelvis and trunk has been shown to increase compensation at the level of the shoulder. Kinetic chain sequencing of the core segments is underexamined in professional baseball pitchers, especially as it relates to changes in upper extremity kinetics. Purpose: To evaluate elbow and shoulder kinetics in a cohort of professional pitchers differentiated by instances of discordant pelvic to upper torso sequencing during the pitch. Study Design: Descriptive laboratory study. Methods: 285 professional baseball pitchers were evaluated using 3D motion capture (480 Hz). Pitchers were divided into "chronological" and "discordant" groups based on whether maximum pelvic rotation velocity occurred before (chronological) or after (discordant) maximum upper torso rotation velocity during the pitch motion. Pelvic, upper torso, and shoulder kinematic parameters, shoulder distraction force, shoulder internal rotation torque, and pitch efficiency (PE) were compared between groups. Results: Pitchers with discordant torso sequencing (n = 30; 110 pitches) had greater shoulder horizontal adduction at maximum external rotation (mean difference, 3.6°; 95% CI, −5.2° to −2.0°; t = −4.5; P <.001) and greater maximum shoulder external rotation (mean difference, 3.7°; 95% CI, 5.7° to 1.5°; t = −3.5; P <.001) than chronological pitchers (n = 255; 2974 pitches). PE did not differ between groups (P =.856), whereas ball velocity was significantly faster in the discordant group (mean difference, 0.6 m/s; 95% CI, −1.1 to −0.3 m/s; t = −3.3; P =.0012). Chronological pitchers had significantly reduced shoulder distraction force (mean difference, −4.7% body weight (BW); 95% CI, −7.9% to −1.5% BW; t = −2.9; P =.004) with no difference in shoulder internal rotation torque (P =.160). These kinematic and kinetic differences were not observed when accounting for interpitcher variability. Conclusion: Between pitchers, those who had a discordant pelvic to upper torso sequence experienced significantly greater shoulder distraction forces, potentially compensating by increasing maximum shoulder external rotation and horizontal abduction. Achieving maximal pelvic rotation velocity before maximal rotation velocity may be advantageous in preventing compensation at the upper extremity and excessive throwing arm loading. Clinical Relevance: Identifying risk factors for increased upper extremity forces has potential implications in injury prevention. Specifically, mitigating shoulder distraction forces may be beneficial in reducing risk of injury. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

While the performance metric ball velocity has often been associated with increased kinetics at the upper extremity and risk of injury in baseball pitchers, it is unclear if the performance metric pitch location consistency has any positive/negative associations with pitching kinetics. Professional pitchers subdivided into high(Hcon) and low(Lcon) consistency groups were instructed to throw 8–12 fastballs while assessed with motion-capture technology(480 Hz). To further assess pitching consistency, 95% confidence ellipses with comparisons of major and minor radii were conducted with an external comparison to a cohort of high school pitchers. Lastly, kinematic and kinetic values were compared between Hcon and Lcon professional pitchers. Professional baseball pitchers(n = 338) had consistency in pitch location comparable to high school pitchers(n = 59) (22.0 ± 6.7 vs. 23.2 ± 7.5% grid width respectively, p-value = 0.21). Hcon professional pitchers(n = 91) compared to Lcon pitchers(n = 98) had a smaller major radius(15.2 ± 3.0 vs. 26.3 ± 5.9 respectively, p-value<0.001) and a smaller minor radius(9.4 ± 1.9 vs. 16.1 ± 4.4 respectively, p-value<0.001) in the 95% confidence ellipses. Hcon pitchers compared to Lcon pitchers had increased arm slot(59.7 ± 13.5 vs. 54.7 ± 12.4° respectfully, p-value = 0.009), trunk tilt(-33.4 ± 9.1 vs. −37.2 ± 8.9° respectfully, p-value = 0.004), and trunk lateral flexion(-27.1 ± 9.3 vs. −31.8 ± 9.0° respectfully, p-value<0.001) at ball release. These pitchers also had lower shoulder(112.4 ± 15.9 vs. 118.3 ± 15.1% BW respectfully, p-value = 0.001) and elbow distraction forces(110.5 ± 17 vs. 117.0 ± 15.2% BW respectfully, p-value = 0.006) during arm deceleration. Professional pitchers who approach a sidearm style of pitching, typically involving less contralateral trunk tilt, may achieve higher consistency in their throws while also experiencing diminished peak distractive forces at the elbow and shoulder. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Because of the unique demands of a pitch, baseball players have the greatest percentage of injuries resulting in surgery among high school athletes, with a majority of these injuries affecting the shoulder and elbow due to overuse from throwing. These injuries are believed to occur because of repeated microtrauma to soft tissues caused by the repetitive mechanical strain of throwing. Researchers and practitioners have suggested that baseball pitchers' workloads are a significant risk factor for injury in adolescent players, resulting in lost time and slowing of performance development. The purpose of our review was to investigate the current research relative to monitoring workload in baseball throwers and discuss techniques for managing and regulating cumulative stress on the arm, with a focus on preventing injury and optimizing performance in adolescent baseball pitchers. [ABSTRACT FROM AUTHOR]

Background: Elbow injuries among adolescent baseball players have been outpacing those of college and professional players. In attempts to prevent injuries and maximize return-to-play potential following injury, attention has been focused on “return to throw” programs, which include long-toss throws. Because the few studies that were conducted on long-toss throwing focused primarily on college-aged athletes, it is not known what type of load is incurred at the elbow during interval throwing progression among high school baseball players. Purpose: To quantify the change in arm slot, arm speed, shoulder external rotation, and elbow varus torque across increasing throwing distances within a given athlete. Study Design: Descriptive laboratory study. Methods: Ninety-five high school baseball players performed a long-toss protocol while wearing an inertial sensor and sleeve. Each participant was tested for 5 throws at distances of 9 m, 18 m, 27 m, 37 m, and 46 m. Linear mixed-effects models and likelihood ratio tests were used to estimate the within-participant relationship between throw distance and arm slot, arm speed, shoulder external rotation, and elbow varus torque. Results: Arm slot (P < .01), arm speed (P < .01), shoulder external rotation (P < .01), and elbow varus torque (P < .01) were significantly associated with long-toss throw distance. As the throw distance increased, there was an increase in arm speed and shoulder external rotation and a decrease in arm slot for each distance. However, elbow varus torque increased with each distance up to 37 m and then remained the same at 46 m. Conclusion: The use of longer distances for conditioning and rehabilitation may be beneficial in increasing shoulder range of motion and arm speed; however, precaution needs to be taken, as throwing longer distances are accompanied by an increase in arm rotation, arm speed, and elbow torque, with a decrease in arm slot. Clinical Relevance: Return-to-throw programs have been utilized by sports medicine clinicians and coaches to help guide a player during rehabilitation. These programs involve throwing at increased efforts through increased distances with no immediate feedback on elbow stress. This investigation describes arm biomechanical changes during submaximum interval throwing and demonstrates a tool that can be utilized to measure arm stress in real time for clinicians and athletes progressing through an interval throwing program. [ABSTRACT FROM AUTHOR]

Objectives: Though contralateral trunk tilt has been frequently studied in baseball pitchers, the phenomena of excessive ipsilateral trunk tilt has not been explored as a potential correlate with throwing arm kinetics. Excessive ipsilateral trunk tilt is often observed during earlier portions of the pitch cycle. High school pitchers with excessive contralateral trunk tilt during the late cocking phase of pitching have been noted to have significantly faster ball velocity, as well as increased elbow distraction force, shoulder distraction force, elbow varus torque, and shoulder internal rotation torque. Collegiate pitchers with excessive contralateral trunk tilt at maximum shoulder external rotation and at ball release have significantly faster ball velocity and higher elbow varus torque. The purpose of this study was to evaluate the effect of ipsilateral and contralateral trunk tilt on kinetic and kinematic parameters among high school and professional baseball pitchers. Methods: Professional and high school baseball pitchers were assessed with 3D-motion capture technology (480 Hz) while pitching in a controlled laboratory setting. Pitchers were grouped into ipsilateral, neutral, or contralateral trunk tilt groups based on the degree of lateral trunk tilt at foot contact (FC) and ball release (BR) (Figure 1). Trunk and shoulder kinematics, as well as throwing arm kinetics, were compared between subgroups with post-hoc regression analysis. Results: Professional pitchers (n=287) had significantly higher ipsilateral trunk tilt at FC (p<0.001) compared to high school pitchers (n=59) (Figure 2). High school pitchers with excessive contralateral trunk tilt at BR experienced significantly higher shoulder superior force (27.0 ± 7.4 vs. 17.6 ± 5.1 %Body Weight [BW] respectively, p<0.001) and shoulder anterior force (39.6 ± 8.2 vs. 35.7 ± 5.4 %BW respectively, p<0.001) compared to the ipsilateral trunk tilt cohort, while accomplishing comparable ball velocity (30.2±3.2 vs. 30.4±2.1m/s, p=0.633). For professional pitchers, for every 10° increase in ipsilateral trunk tilt at FC, ball velocity increased by 0.2 m/s (B: 0.02, β: 0.07, SE: 0.005, p=0.010), while elbow varus torque (EVT) decreased by 0.1%BWxHeight (B: -0.01, β: -0.08, SE: 0.002, p<0.001) and shoulder internal rotation torque (SIRT) decreased by 0.1 %BWxHeight (B: -0.01, β: -0.07, SE: 0.002, p=0.005). Conclusions: High school and professional pitchers with excessive ipsilateral trunk tilt at FC consistently demonstrated significantly decreased throwing arm kinetics (high school: shoulder anterior force, shoulder superior force; professional: SIRT, EVT) compared to pitchers with excessive contralateral trunk tilt at BR, with at least equivalent ball velocity. In addition, professional pitchers already appear to engage in significantly greater ipsilateral trunk tilt at early portions of the pitch cycle when compared to high school pitchers, which may represent a kinetically favorable method adopted by pitchers at higher playing levels to maintain adequate ball velocity while concomitantly minimizing throwing arm kinetics. While contralateral trunk tilt has previously been associated with throwing arm kinetics in high school and collegiate pitchers, ipsilateral lateral trunk tilt has not been assessed in professional pitchers, a subgroup characterized by distinct pitching kinematics compared to amateur pitchers. Further research is warranted to determine if the kinetic impact of trunk tilt during the throwing motion of baseball pitchers impacts the risk of injury. UPLOAD-https://planion-client-files.s3.amazonaws.com/AOSSM/blobs/ada6d538-50e8-460e-ac42-c385825f1ce4/1/Trunk%5fTilt%5fFig%5f2.docx Figure 1. Lateral trunk till in pitchers; (+) indicates ipsilaleral trunk till, (-) indicates contralateral trunk tilt. [ABSTRACT FROM AUTHOR]

Objectives: Arm path, or the distance the hand travels from the glove to ball release, has become an increasingly discussed topic within the baseball community. Arm path is a combination of elbow flexion, shoulder external rotation, shoulder abduction, forearm pronation, and wrist flexion movements. Traditionally, pitchers have been taught to throw with a longer arm path during the first part of the pitching motion, which includes extending the throwing arm away from the body and delaying shoulder external rotation. Advocates of the shorter arm path have recently made a push to get pitchers to shorten up as it is thought that it results in a more efficient motion and this in turn may decrease injury risk. By shortening the arm path, the throwing arm is closer to the body in a more loaded position theoretically creating less torque on the elbow. However, there is a lack of published data to support either claim of the benefits of a shorter or longer arm path. The purpose of this study was to determine if there was a relationship between arm path and elbow varus torque in professional pitchers. Methods: Data from 285 professional pitchers were included in this study (189.9±5.9 cm, 95.1±9.8 kg). Pitchers were tested pitching 8-12 fastballs at 480 Hz using a 3D motion capture system (Motion Analysis Corp., Santa Rosa, CA). The fastest pitch from each pitcher was used in the analysis. Arm path was measured as the total path the hand marker traveled during the entire pitch. Arm path was also normalized as a percentage of arm length (%AL). The pitch was broken down into four time points: maximum knee height (MKH), foot contact (FC), maximum external rotation (MER), ball release (BR). Linear regressions were calculated to evaluate the relationship between arm path and elbow varus torque at each time point. Significance was set at p<0.05. Results: There was no significant relationship between arm path and elbow varus torque (Figure 1). Arm path did not have a significant effect on elbow varus torque for MKH to BR (r2=.04, p<0.001), MKH to FC (r2=.05, p<0.001), and FC to BR (r2=0.00, p=0.207). Furthermore, there was no significant effect on elbow varus torque for MKH to BR, MKH to FC, and FC to BR when arm path was normalized by the pitcher's arm length (r2=0.00 p=0.262; r2=0.02 p=0.018; r2=0.01 p=0.081 respectively). Conclusions: Recent anecdotal trends towards a shorter arm path in pitchers does not alter elbow varus torque as compared to both average and longer arm paths in a sample of professional pitchers. None of the studied time periods within the pitching motion revealed correlations between elbow varus torque and shorter arm paths. This suggests that total distance travelled by the arm during the pitching motion may not be a significant risk factor for injury in professional level pitchers. However, it is possible that components of arm path (i.e. elbow flexion, shoulder rotation, and shoulder horizontal abduction) play a larger role in the influence on elbow varus torque than simply arm path. Future studies should investigate the combined effects of arm path and arm path's components on elbow varus torque. Figure 1. Correlations of arm path to elbow varus torque during a pitch. The left hand column measures arm path in centimeters and the right hand column uses arm path normalized to pitcher's arm length. There were no correlations in arm path to elbow varus torque. Maximum knee height. MKII; FC. foot contact; BR. ball release. [ABSTRACT FROM AUTHOR]

Background: Likely due to the high level of strain exerted across the elbow during the throwing motion, elbow injuries are on the rise in baseball. To identify at-risk athletes and guide postinjury return-to-throw programs, a better understanding of the variables that influence elbow varus torque is desired. Purpose: To describe the within-subject relationship between elbow varus torque and arm slot and arm rotation in professional baseball pitchers. Study Design: Descriptive laboratory study. Methods: A total of 81 professional pitchers performed 82,000 throws while wearing a motusBASEBALL sensor and sleeve. These throws represented a combination of throw types, such as warm-up/catch, structured long-toss, bullpen throwing from a mound, and live game activity. Variables recorded for each throw included arm slot (angle of the forearm relative to the ground at ball release), arm speed (maximal rotational velocity of the forearm), arm rotation (maximal external rotation of the throwing arm relative to the ground), and elbow varus torque. Linear mixed-effects models and likelihood ratio tests were used to estimate the relationship between elbow varus torque and arm slot, arm speed, and arm rotation within individual pitchers. Results: All 3 metrics—arm slot (χ2 = 428, P < .001), arm speed (χ2 = 57,683, P < .001), and arm rotation (χ2 = 1392, P < .001)—were found to have a significant relationship with elbow varus torque. Within individual athletes, a 1-N.m increase in elbow varus torque was associated with a 13° decrease in arm slot, a 116 deg/s increase in arm speed, and an 8° increase in arm rotation. Conclusion: Elbow varus torque increased significantly as pitchers increased their arm rotation during the arm cocking phase, increased the rotational velocity of their arm during the arm acceleration phase of throwing, and decreased arm slot at ball release. Thus, shoulder flexibility, arm speed, and elbow varus torque (and likely injury risk) are interrelated and should be considered collectively when treating pitchers. Clinical Relevance: It is well established that elbow varus torque is related to ulnar collateral ligament injuries in overhead throwers. This study describes the relationship of arm slot, arm speed, and arm rotation to elbow varus torque in an attempt to identify modifiable risk factors for injury. [ABSTRACT FROM AUTHOR]

Objectives/hypothesis: This study was designed to examine speech recognition and self-perceived health-related quality of life (HRQoL) received from cochlear implantation among a cohort of adults and children with a short duration of unilateral hearing loss greater than 6 months, but less than 2 years.Study Design: Single-subject repeated measures prospective study.Methods: This study assessed changes in speech recognition and self-perceived quality of life by prospectively analyzing data at the preoperative evaluation and at the 3-month and 6-month postactivation intervals. Measurement tools included Medical Outcomes Study Questionnaire Short Form 36, Nijmegen Cochlear Implant Questionnaire, Speech Spatial and Qualities of Hearing-Comparative, and speech recognition measures in quiet and in noise.Results: Results indicated significant improvement in speech recognition, both in quiet and noise. Quality-of-life measures showed a significant increase in self-perceived benefit with disease-specific instruments, but remained constant with a generic HRQoL instrument.Conclusions: Cochlear implantation was a successful intervention for improved hearing in quiet and noise, and a self-perceived benefit for this group of adults and children with a short duration of unilateral hearing loss.Level Of Evidence: 4 Laryngoscope, 127:1683-1688, 2017. [ABSTRACT FROM AUTHOR]

Introduction: The benefits of cochlear implantation extend beyond improved speech recognition and into overall health-related quality of life (HRQoL). Several measures of HRQoL, categorized as generic or disease specific, have been used in the cochlear implant literature. The clinical utility of generic HRQoL measures have been reported to be variable by previous investigators. The degree to which HRQoL correlates to speech perception is largely unknown. Methods: A prospective single-subject design at a large tertiary care center. Self-reported HRQoL was measured at the preoperative and 12-month post-activation test intervals. The measures of HRQoL included a generic form, (Medical Outcome Study Short Form; SF-36), and disease specific form (Nijmegen Cochlear Implant Questionnaire; NCIQ). Speech recognition was measured at the preoperative, 6- and 12-months post-activation test intervals using the Consonant-Nucleus-Consonant (CNC) monosyllabic word test. Results: A total of 61 patients (mean 67 years; range 30–87 years) were included in the final analysis. Average speech recognition on the CNC word test was 10% pre-operatively, and 66.7% at 12-months post-activation. The HRQoL scores improved significantly for seven of the eight subdomains of the NCIQ, and one of the nine domains of the SF-36. Conclusion: Cochlear implantation significantly improves HRQoL, regardless of age. Disease specific measures, such as the NCIQ, are better able to demonstrate differences in HRQoL compared to general health surveys. [ABSTRACT FROM PUBLISHER]

Introduction: The benefits of cochlear implantation extend beyond improved speech recognition and into overall health-related quality of life (HRQoL). Several measures of HRQoL, categorized as generic or disease specific, have been used in the cochlear implant literature. The clinical utility of generic HRQoL measures have been reported to be variable by previous investigators. The degree to which HRQoL correlates to speech perception is largely unknown.Methods: A prospective single-subject design at a large tertiary care center. Self-reported HRQoL was measured at the preoperative and 12-month post-activation test intervals. The measures of HRQoL included a generic form, (Medical Outcome Study Short Form; SF-36), and disease specific form (Nijmegen Cochlear Implant Questionnaire; NCIQ). Speech recognition was measured at the preoperative, 6- and 12-months post-activation test intervals using the Consonant-Nucleus-Consonant (CNC) monosyllabic word test.Results: A total of 61 patients (mean 67 years; range 30-87 years) were included in the final analysis. Average speech recognition on the CNC word test was 10% pre-operatively, and 66.7% at 12-months post-activation. The HRQoL scores improved significantly for seven of the eight subdomains of the NCIQ, and one of the nine domains of the SF-36.Conclusion: Cochlear implantation significantly improves HRQoL, regardless of age. Disease specific measures, such as the NCIQ, are better able to demonstrate differences in HRQoL compared to general health surveys. [ABSTRACT FROM AUTHOR]

Determining and understanding baseball batting mechanics at various competition levels may help players and coaches identify key kinematics crucial to being a successful hitter. The purpose of this study was to compare batting kinematics across competition levels. Kinematic and temporal data were analysed for 170 male batters (youthn = 33; high schooln = 69; collegen = 22; professionaln = 46) using 3D motion capture (480 Hz). The results showed differences in angular positions between competition levels during the five phases of the swing, with the greatest differences seen between the youth and professional batters. At the instant of ball contact, professional batters held the bat farther away from their body, with greater back shoulder abduction (35°) and less back elbow flexion (78°) compared to youth (27° and 89°, respectively). These differences were associated with greater back elbow extension velocity for professionals (1539°/s) compared to youth (1174°/s). Additionally, higher level batters had higher bat angular and linear velocities compared to the youth batters. As batters progress through their career, they should focus on their back arm by keeping their elbow up and their arm extended in front of them. [ABSTRACT FROM AUTHOR]

It has been shown that elderly skeletal muscle does not respond as effectively to exercise as young muscle. This impairment not only limits the effectiveness of interventions in an elderly population but may also be a cause of sarcopenia. One possible explanation for diminished response to exercise is that stiffening of muscle tissue, as a result of glycation, changes the mechanical environment around the muscle cells and that the cells therefore experience less force for any given stimulus. To examine this possibility, it is necessary to manipulate muscle material properties. The purpose of this study is to examine the possibility of using caloric restriction to accomplish this. It was found that calorie-restricted rats were less sarcopenic than ad libitum (AL) fed rats and that there was a significant negative relationship between muscle stiffness and muscle size in all rats. While the caloric-restricted rats' muscles were not statistically less stiff than the AL-fed rats, the majority of them were less stiff and the use of this group broadened the range of muscle stiffness. In conclusion, caloric restriction appears to be a promising method to manipulate muscle stiffness to study the effects of stiffness on diminished response to exercise. [ABSTRACT FROM AUTHOR]