Throwing Arm Research Articles

Mutual Learning Transfer Between Wrestling and Sumo as Similar Combat Sports Activities: Impact on Youth’s Technical Performance and Intrinsic Motivation

Objectives. This study aimed to compare the effects of wrestling and sumo wrestling as similar combat sports activities in a training program on technical wrestling scores, wrestling performance indexes, and intrinsic motivation in youth practitioners. Materials and methods. A randomized controlled trial using a single-blinded design, and repeated measures of parallel groups (sumo-based group: EG, n = 19, aged = 12.42 ± 0.87 years; and only wrestling group: CG, n = 19, aged = 12.41 ± 0.78 years) was conducted. Three 65-minute weekly sessions for four weeks were dedicated to the interventions. A two-factor mixed analysis of variance (ANOVA) model with repeated measures was performed to assess the group vs. time impact analysis. Results. The findings revealed a significant interaction between the variables, whereby higher values were observed for technical wrestling scores on the attempted head and arm throw test (F1;18 = 356.2; p = < 0.0001; ES = 0.60), wrestling performance indexes on the pushing opponent test (F1;18 = 8.31; p = 0.009; ES = 0.08), intrinsic motivation for effort/importance item (F1;18 = 12.24; p = 0.003; ES = 0.82) and intrinsic motivation item (F1;18 = 19.36; p = 0.000; ES = 0.24) in favor of EG. Conclusions. In conclusion, the sumo-based training program produces significantly greater responses on technical performance, and intrinsic motivation, specifically regarding wrestling training.

Shoulder External Over Internal Rotation Ratio Is Related to Biomechanics in Collegiate Baseball Pitching.

Altering baseball pitching mechanics affects both performance and the risk of injury. The purpose of this study is to investigate the relationships of shoulder external over internal rotation ratio (SEIR) and other shoulder rotational properties during physical exam and biomechanics of pitching for 177 collegiate baseball pitchers. The shoulder range of motion was quantitatively measured using a custom-made wireless device. Pitching motion data were collected at 240Hz, and a custom program was created to calculate the throwing arm motion and loading during baseball pitching. Linear regression and analysis of variance tests were performed to investigate the relationships between the shoulder physical exam outcomes and throwing arm biomechanics. SEIR had significant correlations with shoulder horizontal adduction angle at foot contact, maximum shoulder external rotation angle, maximum shoulder linear velocity, and elbow angle at ball release. SEIR groups had significant differences in shoulder proximal force, adduction torque, internal rotation torque, and horizontal adduction torque, and in elbow medial force and varus torque. Glenohumeral internal rotation deficit and total rotational motion deficit had no relationships with throwing arm motions or joint loadings. Shoulder health should be monitored to improve understanding of pitching mechanics in collegiate baseball pitchers.

Characteristics of Lumbar Spondylolysis in Adolescent Baseball Players: Relationship between the Laterality of Lumbar Spondylolysis and the Throwing or Batting Side.

A retrospective, cross-sectional study was conducted to analyze the implications of asymmetric baseball movements on the incidence of spondylolysis. This study aimed to evaluate the relationship between asymmetric movements and the laterality of spondylolysis. Baseball, characterized by its asymmetric throwing and batting, may disproportionately stress one side. Lumbar spondylolysis is a frequent cause of lower back pain in young athletes, particularly those involved in activities with consistent unilateral rotations such as baseball. However, whether a link exists between the laterality in spondylolysis and the dominant throwing/ batting side or whether disparities exist between pitchers and fielders remains unclear. The study included 85 players. Participants were divided into two groups: pitchers and fielders. The association between the laterality of spondylolysis and the throwing/batting side in the overall cohort and between the two groups was evaluated. Among pitchers, 16 lesions appeared on the throwing side and 32 on the nonthrowing side (p =0.029). For fielders, no notable difference was observed between the two sides (p =0.363). Furthermore, batting preference did not influence the laterality of spondylolysis in either group. Adolescent baseball players, particularly pitchers, exhibited a higher incidence of lumbar spondylolysis on the side opposite their throwing arm. The findings of this study highlight the significant effect of asymmetrical sporting activities on the development of spondylolysis, to which pitchers are particularly susceptible.

Arm Health in Elite Collegiate Summer League Baseball Players Assessed by the Kerlan-Jobe Orthopaedic Clinic Score.

Collegiate baseball players with professional aspirations often participate in summer leagues; foremost among them is the Cape Cod Baseball League (CCBL). Injuries acquired during the collegiate baseball season can be carried into the CCBL season and vice versa. To assess the history of throwing arm injury and current functionality in midseason CCBL players. Cross-sectional study. Online questionnaire. A total of 123 CCBL players participated. Qualifying athletes were ≥18 years old and were rostered CCBL players with remaining collegiate eligibility. After collecting background information, we used the Kerlan-Jobe Orthopaedic Clinic (KJOC) Shoulder and Elbow questionnaire to assess the history of throwing arm injury and current functionality. The maximum KJOC score is 100.0; higher scores correspond with greater functionality. The mean KJOC score was 86.6 ± 14.5 (n = 92); 24.5% (23/94) of players reported a prior diagnosis of throwing arm injury other than a strain or sprain. A total of 49 (49/96, 51.0%) players had undergone rehabilitation for a throwing arm injury, and 7 (7/96, 7.3%) had experienced a medical procedure. Players with no previous treatment (n = 41, mean KJOC score = 88.9 ± 19.0) more frequently demonstrated KJOC scores of ≥90 than players with such treatment (n = 55, 80.9 ± 17.1; P < .001). The 18 players with time-loss arm injury in the last year had lower mean KJOC scores (71.3 ± 20.0) than players with no injury or time loss (90.3 ± 9.8; P < .001). Similarly, players who reported current arm trouble (n = 15) had lower KJOC scores (71.6 ± 17.5) than players with healthy arms (89.5 ± 11.9; P < .001). The average KJOC score of the CCBL players was <90, with particularly low scores in athletes with prior arm injury and treatment.

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

Throwing arm kinetics differ in pitchers at varying arm slot (AS) positions (frontal-plane arm position at ball release relative to the vertical axis). To determine how kinematic and kinetic values differ between professional and high school pitchers with varying AS positions, and whether these differences are similarly observed in both populations. High school (n = 130) and professional (n = 288) pitchers threw 8 to 12 fastballs under 3-dimensional motion capture technology. Pitchers in each cohort were subdivided based on mean AS position at ball release: AS1 (least degree of AS: most overhand throwing styles), AS2 (intermediate degree of AS: three-quarter throwing styles), or AS3 (greatest degree of AS: most sidearm throwing styles). Kinetic and kinematic parameters were compared between groups. Controlled laboratory study. High school pitchers had a more overhand AS at ball release (50° ± 11°) compared with professional pitchers (58° ± 14°) (P < .001). In both cohorts, AS1 pitchers had significantly greater shoulder abduction (high school, P <0.001; professional, P <0.0001) and lateral trunk flexion (high school, P < 0.001; professional, P <0.0001) at ball release compared with AS3 pitchers. Professional pitchers with an AS3 position had significantly delayed timing of maximum upper trunk angular velocity compared with AS1 pitchers (64% ± 7% vs 57% ± 7% of pitch time, respectively; P < .0001). A significant positive correlation between AS and elbow flexion torque was found in high school pitchers (P = .002; β = 0.28), and a significant negative correlation between AS and elbow varus torque (P < .001; β = -0.22) and shoulder internal rotation torque (P < .001; β = -0.20) was noted in professional pitchers. AS position was related to shoulder abduction and trunk lateral tilt. Professional and high school pitchers with varying AS positions did not experience similar changes in throwing arm kinetics. In professional pitchers, the earlier onset of maximum upper trunk angular velocity with overhand throwing style may reflect inappropriate pelvis-trunk timing separation, a parameter implicated in upper extremity injury, and the negative correlation between AS and elbow varus and shoulder internal rotation torque suggests that both excessive and minimal AS positions have negative implications.

Results of a National Survey on Sport Specialization Behavior and Throwing Arm Injury in Youth Softball Players.

There are few data on throwing arm and shoulder injury in youth softball athletes, and no data on the influence of sport specialization on injury in softball. We hypothesized that highly specialized athletes, and pitchers in particular, demonstrating various sport specialization behaviors would be more likely to report an upper extremity overuse injury in the previous 12 months. Cross-sectional survey. Level 4. An online, anonymous, cross-sectional survey was distributed to a national sample of female youth softball players between the ages of 12 and 18 years in fall 2021. Topics included were indicators of sport specialization and self-reported injuries to the throwing arm. A total of 1309 participants (mean age, 15.1 ± 1.7 years) completed the survey; 19.4% (N = 254) scored as highly specialized, 69.7% (N = 912) as moderately specialized, and 10.9% (N = 143) with low specialization. Of all participants, 27.3% (N = 357) pitched in the previous year. A minority of all players (43.7%; N = 572) reported arm injury in the previous 12 months, with 45.9% of pitchers (N = 164) reporting the same. Multivariate regression showed increased adjusted odds ratio (aOR) of injury history for athletes playing >30 games per year (aOR, 1.74; 95% CI, 1.26-2.40), participating on a club team (aOR, 3.36; 95% CI,1.85-6.07), and in pitchers participating on club teams (aOR, 2.97; 95% CI, 1.18-7.45). Decreased aOR of injury was noted in those participating in >8 months of softball per year (aOR, 0.25; 95% CI, 0.12-0.51) and in pitchers who were moderately specialized (aOR, 0.39; 95% CI, 0.17-0.92) and playing >8 months per year (aOR, 0.33; 95% CI, 0.11-0.96). This sample provides a large proportion of athletes classified as high or moderately specialized in youth softball (89%). A large proportion (43.7%) of subjects reported arm injury in the past year, and insight into injury risk is provided. The results present conflicting data on the risk versus protective effect of specialization in youth softball athletes. This project is a first step toward understanding sport specialization behavior and its influence on injury in youth softball.

Forearm Pronation at Foot Contact: A Biomechanical Motion-Capture Analysis in High School and Professional Pitchers.

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. 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. Descriptive laboratory study. 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. 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. 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.

Effect of a High-Intensity Handball-Specific Fatigue Protocol Focused on the Leg Contralateral to the Throwing Arm on Interlimb Asymmetries.

Janicijevic, D, Pérez-Castilla, A, Miras-Moreno, S, Ortega-Becerra, M, Morenas-Aguilar, MD, Smajla, D, Sarabon, N, and García-Ramos, A. Effect of a high-intensity handball-specific fatigue protocol focused on the leg contralateral to the throwing arm on interlimb asymmetries. J Strength Cond Res 37(7): 1382-1389, 2023-This study aimed to elucidate which countermovement jump (CMJ) variant (unilateral or bilateral) is more sensitive to detect the decrement in kinetic CMJ-derived variables of the leg more actively involved in a handball-specific fatigue protocol. Seventeen female handball players (age: 20.6 ± 2.5 years) performed a fatigue protocol consisting of 8 repetitions of the following circuit separated by 10 seconds: 10 m sprint, 180° change of direction with the leg contralateral to the throwing arm, 10 m sprint with ball reception at 7 m, and handball throw preceded by a jump over a 40 cm hurdle with the leg contralateral to the throwing arm. Before and after the fatigue protocol, 6 unilateral CMJs (3 with each leg) and 3 bilateral CMJs were performed on a dual Kistler force platform (model 9260AA6). Bilateral CMJ height was reduced by 5.4% after the fatigue protocol (p < 0.001). However, the fatigue protocol did not promote any significant change in peak force, mean force, and propulsive impulse or in their asymmetry values (17 of 18 comparisons). The decrement of 6.1% during the unilateral CMJ in the propulsive impulse developed by the leg ipsilateral to the throwing arm (less involved in the fatigue protocol) was the only variable that reached statistical significance (p = 0.038). The pre-post fatigue changes in asymmetry values presented negligible correlations between both CMJ variants (rs = 0.01 to -0.19). These results suggest that neither unilateral nor bilateral CMJs are able to detect changes in interlimb asymmetries after a high-intensity handball-specific fatigue protocol.

Elbow stress in youth softball windmill pitchers: predictors of increased torque

Purpose: To assess torque at the elbow in the underhand throwing motion utilizing wearable sensor technology and discover the predictors of medial elbow toque in young female softball pitchers. Methods: Female softball players 12 to 18 years old whose primary position was pitcher and actively participating in sport were studied. Players experiencing throwing arm pain, lower extremity injury hindering pitching motion, or prior surgery were excluded. Age, handedness, height, weight, and throwing arm dimensions were measured and recorded. Pitchers threw 15 pitches, max effort from 43 feet and were given 30 to 60 second rest between pitches. A wearable sensor was placed inside an athletic compression sleeve which recorded data. Measurements included medial elbow torque (Newton-meters; NM), arm speed (peak rotational velocity of the forearm; in rotations per minute; RPM), arm slot (forearm angle in relation to the ground at release; in degrees), and shoulder rotation (maximum forearm angle during the 12 o’clock phase; in degrees). Peak ball velocity in miles per hour (MPH) was measured by a radar gun. Results: Twenty females mean age 15.2 years (range, 12.6-16.9 years) achieved an average elbow stress of 35.5 NM (14-78 NM). Average arm speed measured 583.8 RPM (3502.8 deg/sec) and ball speed ranged from 33-56 mph with an average of 44.1 mph. Multivariate analysis demonstrated arm stress significantly associated with increasing age (P-value 0.00003), and arm length (P-value 0.000006); however, increased forearm length measured a decreased arm stress (P-value 0.00007). Conclusions: There was significant stress measured across the medial elbow in young softball pitchers. Elbow torque was associated with increasing age and total arm length; however, increased forearm length was associated with decreased elbow torque.

Elbow stress in youth softball windmill pitchers: predictors of increased torque

Purpose: To assess torque at the elbow in the underhand throwing motion utilizing wearable sensor technology and discover the predictors of medial elbow toque in young female softball pitchers. Methods: Female softball players 12 to 18 years old whose primary position was pitcher and actively participating in sport were studied. Players experiencing throwing arm pain, lower extremity injury hindering pitching motion, or prior surgery were excluded. Age, handedness, height, weight, and throwing arm dimensions were measured and recorded. Pitchers threw 15 pitches, max effort from 43 feet and were given 30 to 60 second rest between pitches. A wearable sensor was placed inside an athletic compression sleeve which recorded data. Measurements included medial elbow torque (Newton-meters; NM), arm speed (peak rotational velocity of the forearm; in rotations per minute; RPM), arm slot (forearm angle in relation to the ground at release; in degrees), and shoulder rotation (maximum forearm angle during the 12 o’clock phase; in degrees). Peak ball velocity in miles per hour (MPH) was measured by a radar gun. Results: Twenty females mean age 15.2 years (range, 12.6-16.9 years) achieved an average elbow stress of 35.5 NM (14-78 NM). Average arm speed measured 583.8 RPM (3502.8 deg/sec) and ball speed ranged from 33-56 mph with an average of 44.1 mph. Multivariate analysis demonstrated arm stress significantly associated with increasing age (P-value 0.00003), arm length (P-value 0.000006); however, increased forearm length measured a decreased arm stress (P-value 0.00007). Conclusions: There was significant stress measured across the medial elbow in young softball pitchers. Elbow torque was associated with increasing age and total arm length; however, increased forearm length was associated with decreased elbow torque.

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

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

Early Sport Specialization and Long-term Throwing Arm Health in College Baseball Players.

Early sport specialization is associated with increased risk of overuse injuries in several sports, including baseball. However, limited evidence exists evaluating how early sport specialization affects patient-reported outcome measures as they age. The purpose of this study was to determine differences in Kerlan-Jobe Orthopedic Clinic (KJOC) Shoulder and Elbow Scores among collegiate baseball players based on the grade when a participant first reported high specialization behaviors. Baseball players who were highly specialized at a younger age will have worse throwing arm health while participating in college. Cross-sectional study. Level 3. A total of 752 college baseball players was contacted through their institution's athletic trainer. We measured baseball specialization and KJOC scores using the validated Baseball and Sport Experience survey. Data were summarized using means and SDs, medians and interquartile ranges (IQRs), and frequencies and percentages. A Kruskal-Wallis test was used to determine differences in mean KJOC scale scores based on the earliest time the participant reported high-level specialization. A total of 294 baseball players completed the survey (response rate: 39.1%). Of the 294 participants, 280 completed the KJOC scale questions to generate a total KJOC score (median: 90.5; IQR: 76.6-97.2). No significant differences in KJOC total scores (P = 0.78) existed based on the grade period in which the athlete was first highly specialized. Early baseball specialization as a youth baseball player may not impact throwing arm health in college baseball athletes. Early specialization has been linked to increased risk for overuse injuries in certain sports, but may not lead to poorer throwing arm health in college baseball players. Sports medicine clinicians and researchers may use this information to educate various stakeholders about the benefits and risks associated with early sport specialization.

Paper 35: High School and Professional Pitchers with Early Excessive Ipsilateral Trunk Tilt: A Newly Characterized Parameter for Biomechanical Evaluation

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_Tilt_Fig_2.docx Figure 1.Lateral trunk till in pitchers; (+) indicates ipsilaleral trunk till, (-) indicates contralateral trunk tilt.

Evaluating Pelvis Rotation Style at Foot Contact: A Propensity Scored Biomechanical Analysis in High School and Professional Pitchers

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.

Impact of Engaging the Nonthrowing Arm on Maximal Ball Velocity From an Overhand Throw With Both the Dominant and Nondominant Arms: A Pilot Study

The overhand throw is a complex whole-body motor skill that is fundamental to many sports and activities. When throwing properly, the momentum generated to complete the movement begins in the lower body and transfers through the trunk to the throwing arm. This proof-of-concept study’s primary purpose was to evaluate the impact of the nonthrowing arm on the ball speed during an overhand throw with both the dominant and nondominant arms. Eighteen participants (age: 20.20 ± 2.90 years, nine women) were divided into two intervention groups: a pulling group taught to engage the nonthrowing arm through a pull toward the body and a nonpulling group taught the overhand throw using a component-based physical education curriculum. Each participant completed 12 total throws, six for each side (dominant and nondominant arm). Ball speed and kinematic data were collected using an eight-camera motion analysis system and were assessed using a pre–post study design. The two groups showed significant improvements pre–post when throwing with both the dominant and nondominant arms. Based on effect size comparisons, engaging the nonthrowing arm makes a meaningful difference in maximal ball velocity.

Relationships Among Shoulder Rotational Strength, Range of Motion, Pitching Kinetics, and Pitch Velocity in Collegiate Baseball Pitchers.

Cross, JA, Higgins, AW, Dziuk, CC, Harris, GF, and Raasch, WG. Relationships among shoulder rotational strength, range of motion, pitching kinetics, and pitch velocity in collegiate baseball pitchers. J Strength Cond Res 37(1): 129-135, 2023-Throwing shoulder injuries are the most common type of injury experienced by baseball pitchers. Weakness in the shoulder musculature and insufficient throwing arm range of motion are both risk factors for developing a shoulder injury. The goal of this study was to determine correlations among shoulder rotational strength, range of motion, pitching kinetics, and pitch velocity in collegiate pitchers. Thirteen uninjured male college pitchers were evaluated. Clinical measures included shoulder internal and external rotation range of motion, peak isokinetic internal and external rotator strength, and peak isometric internal and external rotator strength. Three-dimensional biomechanics were assessed as subjects threw from an indoor pitching mound to a strike zone net at regulation distance. Pearson's correlations were used to assess the associations among the clinical measures and throwing metrics. Five significant correlations were found between peak shoulder compressive force and strength, and 4 significant correlations were found between pitching velocity and strength ( p < 0.05). No significant correlations were found between range of motion and pitching kinetics or velocity. Our results suggest that as shoulder rotational strength increases, the peak shoulder compressive force and pitch velocity both increase. Knowledge of relationships between strength metrics and pitching biomechanics may allow for improved strength training routines with the goal of increasing velocity without increasing injury risk.

Hip Abductor Strength Asymmetry: Relationship to Upper Extremity Injury in Professional Baseball Players.

Hip strength is an important factor for control of the lumbo-pelvic-hip complex. Deficits in hip strength may affect throwing performance and contribute to upper extremity injuries. Deficits in hip abduction isometric strength would be greater in those who sustained an upper extremity injury and hip strength would predict injury incidence. Prospective cohort study. Level 3. Minor League baseball players (n = 188, age = 21.5 ± 2.2 years; n = 98 pitchers; n = 90 position players) volunteered. Hip abduction isometric strength was assessed bilaterally with a handheld dynamometer in side-lying position, expressed as torque using leg length (N·m). Hip abduction strength asymmetry was represented by [(trail leg/lead leg) × 100]. Overuse or nontraumatic throwing arm injuries were prospectively tracked. Poisson regression models were used to estimate relative risk ratios associated with hip asymmetry; confounders, including history of prior overuse injury in the past year, were included. Hip abduction asymmetry ranged from 0.05% to 57.5%. During the first 2 months of the season, 18 players (n = 12 pitchers) sustained an upper extremity injury. In pitchers, for every 5% increase in hip abduction asymmetry, there was a 1.24 increased risk of sustaining a shoulder or elbow injury. No relationship between hip abduction strength and injury was observed for position players. Hip abduction asymmetry in pitchers was related to subsequent upper extremity injuries. The observed risk ratio indicates that hip abduction asymmetry may contribute a significant but small increased risk of injury. Hip abduction muscle deficits may affect pitching mechanics and increase arm stress. Addressing hip asymmetry deficits that exceed 5% may be beneficial in reducing upper extremity injury rates in pitchers.

Pitching Mechanics and the Relationship to Accuracy in Professional Baseball Pitchers

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

Differences in Shoulder Internal Rotation Strength Between Baseball Players With Ulnar Collateral Ligament Reconstruction and Healthy Controls.

Background:Studies have indicated decreased shoulder internal rotation (IR) and external rotation (ER) strength in the throwing limb of baseball players after ulnar collateral ligament injury. There is limited evidence on the recovery of shoulder rotation strength after primary ulnar collateral ligament reconstruction (UCLR).Hypothesis:At the time of return to throwing, baseball players who underwent UCLR would demonstrate decreased IR and ER shoulder strength in the throwing arm as compared with healthy baseball players.Study Design:Cross-sectional study; Level of evidence, 3.Methods:Male competitive high school and collegiate baseball athletes participated in this study. Athletes who underwent UCLR were compared with healthy controls who were matched by age, height, weight, and position. Bilateral isometric shoulder ER and IR strength was measured using a handheld dynamometer for all participants at the time of initial evaluation (UCLR group) and throughout the course of a season (healthy group). Independent t tests were run to calculate mean differences in ER and IR shoulder strength between the groups, with significance set at P < .05.Results:A total of 86 baseball athletes participated in this study (43 UCLR group, 43 healthy group). At the time of return to throwing (mean ± SD, 194 ± 30 days postoperatively), the 2 groups demonstrated no significant differences in nonthrowing arm ER or IR strength (P = .143 and .994, respectively). No significant difference was found between groups for throwing arm ER strength (P = .921); however, the UCLR group demonstrated significantly less throwing arm IR strength than the healthy group (144.2 ± 27.8 vs 157.6 ± 27.1 N; P = .023).Conclusion:The results of this study demonstrate that throwing arm rotator cuff strength may not fully recover before the initiation of a return-to-throwing program after UCLR. These data provide a potential framework for clinicians to assist in the management and exercise prescription of the baseball athlete after UCLR and before medical release and the initiation of a return-to-throwing program.

The Youth Throwers Ten Exercise Program: A variation of an exercise series for enhanced dynamic shoulder control in the youth overhead throwing athlete.

The overhead throwing motion is an extremely stressful athletic movement. The high velocity and repetitive nature of this activity places immense pressure on the entire body, which can frequently result in injury to the throwing arm. Extensive literature exists with regards to the management of these injuries in the collegiate and professional level athlete; and it is well understood that a multiphasic approach is required to return an individual to prior level of play. However, there is a gap in the literature which fails to address the management of youth individuals. This article presents a new and innovative approach to the rehabilitation, training and management of the youth overhead throwing athlete, The Youth Throwers Ten Exercise Program. This program addresses principles of: coactivation, coordination, dynamic stabilization, neuromuscular control, proprioception, muscle strength, endurance and scapular rhythm all of which are vital for successful performance. This exercise series utilizes bodyweight and Theraband exercises that cater to the unique characteristics of the youth athlete making it a safe way to prepare for the demands of overhead throwing activities.