Effects of Hip Abduction Fatigue on Trunk and Shoulder Kinematics During Throwing and Passive Hip Rotational Range of Motion

2019 ◽  
Vol 28 (4) ◽  
pp. 304-310 ◽  
Author(s):  
Gretchen D. Oliver ◽  
Jessica K. Washington ◽  
Sarah S. Gascon ◽  
Hillary A. Plummer ◽  
Rafael F. Escamilla ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Upper Extremity ◽  
Repeated Measures ◽  
External Rotation ◽  
Convenience Sample ◽  
Fatigue Protocol ◽  
Hip Abduction ◽  
Hip Abductor ◽  
Overhead Throwing ◽  
Shoulder Kinematics

Context:Hip abductor musculature contributes to the stability of the pelvis, which is needed for efficient energy transfer from the lower-extremity to the upper-extremity during overhead throwing.Objective:The purpose of this study was to examine the effects of a bilateral hip abduction fatigue protocol on overhead-throwing kinematics and passive hip range of motion.Design:Prospective cohort study.Setting:Controlled laboratory setting.Participants:A convenience sample of 19 collegiate female softball players (20.6 [1.9] y; 169.3 [9.7] cm; 73.2 [11.2] kg).Main Outcome Measures:Repeated hip abduction to fatigue was performed on an isokinetic dynamometer for 3 consecutive days. Trunk and shoulder kinematics during throwing and hip internal and external rotation range of motion were analyzed prior to fatigue on day 1 (prefatigue) and following fatigue on day 3 (postfatigue).Results:Repeated-measures analysis of variances revealed no statistically significant differences in trunk and shoulder kinematics prefatigue and postfatigue. A statistically significant time × side × direction interaction (F2,36 = 5.462,P = .02,) was observed in hip passive range of motion. A decrease in throwing-side hip internal rotation prefatigue to postfatigue (mean difference = −2.284; 95% confidence interval, −4.302 to −0.266;P = .03) was observed.Conclusions:The hip abductor fatigue protocol used in this study did not significantly alter trunk and upper-extremity throwing kinematics. The lack of changes may indicate that fatigue of the hip abductors does not contribute to trunk and shoulder kinematics during throwing or the protocol may not have been sport-specific enough to alter kinematics.

scholarly journals Shoulder Kinematics Is Not Influenced by External Load During Elevation in the Scapular Plane

2014 ◽  
Vol 30 (1) ◽  
pp. 66-74 ◽  
Author(s):  
Marcelo P. de Castro ◽  
Daniel Cury Ribeiro ◽  
Felipe de C. Forte ◽  
Joelly M. de Toledo ◽  
Daniela Aldabe ◽  
...  
Keyword(s):  
Repeated Measures ◽  
External Load ◽  
External Rotation ◽  
Angular Displacement ◽  
Neutral Position ◽  
Convenience Sample ◽  
Repeated Measures Design ◽  
Shoulder Kinematics ◽  
Shoulder Elevation ◽  
Scapular Plane

The current study aimed to compare the shoulder kinematics (3D scapular orientation, scapular angular displacement and scapulohumeral rhythm) of asymptomatic participants under unloaded and loaded conditions during unilateral shoulder elevation in the scapular plane. We used a repeated-measures design with a convenience sample. Eleven male participants with an age range of 21–28 years with no recent history of shoulder injury participated in the study. The participants performed isometric shoulder elevation from a neutral position to approximately 150 degrees of elevation in the scapular plane in intervals of approximately 30 degrees during unloaded and loaded conditions. Shoulder kinematic data were obtained with videogrammetry. During shoulder elevation, the scapula rotated upwardly and externally, and tilted posteriorly. The addition of an external load did not affect 3D scapular orientation, scapular angular displacement, or scapulohumeral rhythm throughout shoulder elevation (P> .05). In clinical practice, clinicians should expect to observe upward and external rotation and posterior tilt of the scapula during their assessments of shoulder elevation. Such behavior was not influenced by an external load normalized to 5% of body weight when performed in an asymptomatic population.

Hip and ankle strength and range of motion in female soccer players with dynamic knee valgus

2021 ◽  
pp. 1-6
Author(s):  
Young Jin Jo ◽  
Young Kyun Kim
Keyword(s):  
Range Of Motion ◽  
Female Athletes ◽  
External Rotation ◽  
Preventive Measure ◽  
Control Group ◽  
Knee Valgus ◽  
Strength Ratio ◽  
Flexion Extension ◽  
Hip Abduction ◽  
Single Leg Squat

BACKGROUND: Dynamic knee valgus (DKV) is a known risk factor for acute and chronic knee injuries and is more frequently diagnosed in females. A real-time single-leg squat test (SLST) could screen for DKV to prevent injuries. OBJECTIVE: To compare the differences in lower extremity strength and range of motion (ROM) in female soccer athletes with and without DKV during an SLST. METHODS: Eighteen subjects with DKV (DKV group) and 18 subjects without DKV (control group) during a single-leg squat were included. Hip strength (flexion, extension, abduction, adduction, internal rotation, and external rotation) was measured with a hand-held dynamometer. Hip ROM (internal and external rotation), and ankle ROM (dorsiflexion with the knee flexed and extended) were measured. Independent t-test was used to compare the averages of the groups. RESULTS: There were significant differences in hip abduction to adduction strength ratio (DKV: 1.48 ± 0.3, control: 1.22 ± 0.26, p< 0.01) and ankle dorsiflexion with knee flexed (DKV: 17.22 ± 6.82, control: 21.22 ± 4.55, p< 0.05) and extended (DKV: 10.14 ± 4.23, control: 14.75 ± 3.40, p< 0.001) between the groups. CONCLUSION: The hip abduction to adduction strength ratio and gastrocnemius and soleus flexibility may be associated factors in dynamic knee valgus and therefore should be assessed and treated, if indicated, as a possible preventive measure in female athletes with this variation.

scholarly journals Passive Hip Range-of-Motion Values Across Sex and Sport

2018 ◽  
Vol 53 (6) ◽  
pp. 560-567 ◽  
Author(s):  
Jennifer A. Hogg ◽  
Randy J. Schmitz ◽  
Anh-Dung Nguyen ◽  
Sandra J. Shultz
Keyword(s):  
Range Of Motion ◽  
Repeated Measures ◽  
National Collegiate Athletic Association ◽  
External Rotation ◽  
Cruciate Ligament ◽  
Knee Valgus ◽  
Cross Sectional ◽  
Increased Risk ◽  
Hip Range Of Motion ◽  
Cross Country

Context:  Greater passive hip range of motion (ROM) has been associated with greater dynamic knee valgus and thus the potential for increased risk of anterior cruciate ligament injuries. Normative data for passive hip ROM by sex are lacking. Objective:  To establish and compare passive hip ROM values by sex and sport and to quantify side-to-side differences in internal-rotation ROM (ROMIR), external-rotation ROM (ROMER), and total ROM (ROMTOT). Design:  Cross-sectional study. Setting:  Station-based, preparticipation screening. Patients or Other Participants:  A total of 339 National Collegiate Athletic Association Division I athletes, consisting of 168 women (age = 19.2 ± 1.2 years, height = 169.0 ± 7.2 cm, mass = 65.3 ± 10.2 kg) and 171 men (age = 19.4 ± 1.3 years, height = 200.0 ± 8.6 cm, mass = 78.4 ± 12.0 kg) in 6 sports screened over 3 years: soccer (58 women, 67 men), tennis (20 women, 22 men), basketball (28 women, 22 men), softball or baseball (38 women, 31 men), cross-country (18 women, 19 men), and golf (6 women, 10 men). Main Outcome Measure(s):  Passive hip ROM was measured with the athlete lying prone with the hip abducted to 20° to 30° and knee flexed to 90°. The leg was passively internally and externally rotated until the point of sacral movement. Three measures were averaged for each direction and leg and used for analysis. We compared ROMIR, ROMER, ROMTOT (ROMTOT = ROMIR + ROMER), and relative ROM (ROMREL = ROMIR − ROMER) between sexes and among sports using separate 2 × 6 repeated-measures analyses of variance. Results:  Women had greater ROMIR (38.1° ± 8.2° versus 28.6° ± 8.4°; F1,327 = 91.74, P &lt; .001), ROMTOT (72.1° ± 10.6° versus 64.4° ± 10.1°; F1,327 = 33.47, P &lt; .001), and ROMREL (1.5° ± 16.0° versus −7.6° ± 16.5°; F1,327 = 37.05, P &lt; .001) than men but similar ROMER (34.0° ± 12.2° versus 35.8° ± 11.5°; F1,327 = 1.65, P = .20) to men. Cross-country athletes exhibited greater ROMIR (37.0° ± 9.3° versus 30.9° ± 9.4° to 33.3° ± 9.5°; P = .001) and ROMREL (5.9° ± 18.3° versus −9.6° ± 16.9° to −2.7° ± 17.3°; P = .001) and less ROMER (25.7° ± 7.5° versus 35.0° ± 13.0° to 40.2° ± 12.0°; P &lt; .001) than basketball, soccer, softball or baseball, and tennis athletes. They also displayed less ROMTOT (62.7° ± 8.1° versus 70.0° ± 9.1° to 72.9° ± 11.9°; P &lt; .001) than basketball, softball or baseball, and tennis athletes. Conclusions:  Women had greater ROMIR than men, resulting in greater ROMTOT and ROMREL. Researchers should examine the extent to which this greater bias toward ROMIR may explain women's greater tendency for dynamic knee valgus. With the exception of cross-country, ROM values were similar across sports. The clinical implications of these aberrant cross-country values require further study.

scholarly journals The Relationship Between Shoulder Range of Motion and Arm Stress in College Pitchers: A MOTUS Baseball Study

2020 ◽  
Vol 8 (7_suppl6) ◽  
pp. 2325967120S0040
Author(s):  
Caleb Gulledge ◽  
Toufic Jildeh ◽  
Joseph Tramer ◽  
Fabien Meta ◽  
Kevin Taylor ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Upper Extremity ◽  
Internal Rotation ◽  
External Rotation ◽  
Outcome Measurement ◽  
Overhead Athletes ◽  
Shoulder Range Of Motion ◽  
Patient Reported ◽  
The Relationship ◽  
Shoulder Range

Objectives: Overuse injuries in overhead athletes are becoming more prevalent, with an unclear relationship between shoulder biomechanics and medial elbow symptoms and injury. The purpose of this study was to investigate the relationship of shoulder range of motion to torque across the medial elbow in college pitchers using a validated MOTUS sensor baseball sleeve. Methods: Pitchers were recruited from three local university baseball teams. Exclusion criteria included injury or restricted activity due to pain. They were evaluated in the preseason, within two weeks before their first game of the season. Pitchers completed workload questionnaires and patient reported outcome measurement information system (PROMIS) pain interference (PI), physical function (PF), and upper extremity (UE) surveys. Shoulder range of motion and upper extremity lengths were measured bilaterally. After adequate warm-up, pitchers were fitted with a MOTUS sensor baseball sleeve (Motus Global, Massapequa, NY) and instructed to throw 5 fastballs in a standardized manner off the mound at game-speed effort. The sensor placed at the medial elbow reported elbow torque, arm speed, arm slot, and shoulder rotation for each pitch, while a radar gun measured peak ball velocity. The primary outcome was to evaluate the relationship between shoulder range of motion and increased stress across the medial elbow. Additional outcomes evaluated pitcher characteristics, demographics, and outcome scores. Outcomes were assessed via a multivariable model, which controlled for possible covariates. Results: Twenty-eight pitchers were included in the preseason analysis with an average (SD) age of 20.1 (1.3) years and playing experience of 15.3 (1.8) years, 2.5 (1.2) of those years at collegiate level. The dominant shoulder demonstrated decreased internal rotation (54.5+/-10.6 vs 65.8+/-9.1) and increased external rotation (ER, 94.1+/-10.4 vs 88.4+/-9.2) relative to the non-dominant side (p < 0.001), while total rotational range of motion (TRROM) was significantly decreased in the dominant arm (148.6+/-12.4 vs 154.1+/-10.6, p < 0.001). The average glenohumeral internal rotation deficiency (GIRD) was 11.3 (9.87) and average external rotation gain (ERG) was 5.71 (8.8). External rotation was found to be a predictor of arm stress, with an increase in 0.35 Nm of elbow torque for every degree increase in ER (beta = 0.35+/-0.06, p = 0.003); there was moderate correlation between ER and arm stress (r = .45, P<.001). Pitchers demonstrated significantly greater arm stress with the following shoulder ROM measurements: GIRD < 20 as compared to greater than 20 degrees (46.6 +/- 0.5 versus 43.5 +/- 1.1, P=.011), ERG greater than 5 as compared to < 5 degrees (47.4 +/- 0.7 versus 45.1 +/- 0.6, P=.014), and loss of total rotational ROM less than 5 as compared to > 5 degrees (46.6 +/- 0.5 versus 43.6 +/- 1.1, P=.013). Multivariate analysis demonstrated significant predictors of PROMIS PF and UE scores were arm stress, ERG, and GIRD (p<0.05), while increased PROMIS PI scores were predicted by increased ERG and GIRD (p<0.05). Conclusion: We found medial elbow stress, arm speed, arm slot, and shoulder rotation as measured by the MOTUS baseball sensor sleeve were influenced by rotational adaptations of the pitching shoulder in collegiate throwing athletes prior to their season. Likewise, arm stress and shoulder rotational adaptations were reflected as predictors of PROMIS PF, UE, and PI scores.

scholarly journals Hip Muscle Activity During 3 Side-Lying Hip-Strengthening Exercises in Distance Runners

2012 ◽  
Vol 47 (1) ◽  
pp. 15-23 ◽  
Author(s):  
Joseph M. McBeth ◽  
Jennifer E. Earl-Boehm ◽  
Stephen C. Cobb ◽  
Wendy E. Huddleston
Keyword(s):  
Muscle Activity ◽  
Repeated Measures ◽  
External Rotation ◽  
Gluteus Maximus ◽  
Gluteus Medius ◽  
Electromyographic Activity ◽  
Maximal Voluntary Isometric Contraction ◽  
Strengthening Exercises ◽  
Hip Abduction ◽  
Hip Strengthening

Context: Lower extremity overuse injuries are associated with gluteus medius (GMed) weakness. Understanding the activation of muscles about the hip during strengthening exercises is important for rehabilitation. Objective: To compare the electromyographic activity produced by the gluteus medius (GMed), tensor fascia latae (TFL), anterior hip flexors (AHF), and gluteus maximus (GMax) during 3 hip-strengthening exercises: hip abduction (ABD), hip abduction with external rotation (ABD-ER), and clamshell (CLAM) exercises. Design: Controlled laboratory study. Setting: Laboratory. Patients or Other Participants: Twenty healthy runners (9 men, 11 women; age = 25.45 ± 5.80 years, height = 1.71 ± 0.07 m, mass = 64.43 ± 7.75 kg) participated. Intervention(s): A weight equal to 5% body mass was affixed to the ankle for the ABD and ABD-ER exercises, and an equivalent load was affixed for the CLAM exercise. A pressure biofeedback unit was placed beneath the trunk to provide positional feedback. Main Outcome Measure(s): Surface electromyography (root mean square normalized to maximal voluntary isometric contraction) was recorded over the GMed, TFL, AHF, and GMax. Results: Three 1-way, repeated-measures analyses of variance indicated differences for muscle activity among the ABD (F3,57 = 25.903, P&lt;.001), ABD-ER (F3,57 = 10.458, P&lt;.001), and CLAM (F3,57 = 4.640, P=.006) exercises. For the ABD exercise, the GMed (70.1 ± 29.9%), TFL (54.3 ± 19.1%), and AHF (28.2 ± 21.5%) differed in muscle activity. The GMax (25.3 ± 24.6%) was less active than the GMed and TFL but was not different from the AHF. For the ABD-ER exercise, the TFL (70.9 ± 17.2%) was more active than the AHF (54.3 ± 24.8%), GMed (53.03 ± 28.4%), and GMax (31.7 ± 24.1 %). For the CLAM exercise, the AHF (54.2 ± 25.2%) was more active than the TFL (34.4 ± 20.1%) and GMed (32.6 ± 16.9%) but was not different from the GMax (34.2 ± 24.8%). Conclusions: The ABD exercise is preferred if targeted activation of the GMed is a goal. Activation of the other muscles in the ABD-ER and CLAM exercises exceeded that of GMed, which might indicate the exercises are less appropriate when the primary goal is the GMed activation and strengthening.

scholarly journals Correlation of 3-Dimensional Shoulder Kinematics to Function in Subjects With Idiopathic Loss of Shoulder Range of Motion

2005 ◽  
Vol 85 (7) ◽  
pp. 636-647 ◽  
Author(s):  
Peter J Rundquist ◽  
Paula M Ludewig
Keyword(s):  
Range Of Motion ◽  
Multiple Regression ◽  
External Rotation ◽  
Regression Equation ◽  
Multiple Regression Equation ◽  
3 Dimensional ◽  
Shoulder Range Of Motion ◽  
Shoulder Kinematics ◽  
And Function ◽  
Shoulder Range

AbstractBackground and Purpose. People with idiopathic loss of shoulder range of motion (ROM) have difficulty completing activities of daily living. This investigation was performed to determine the association between active glenohumeral ROM and function and to develop a multiple regression equation to explain variation in function in people with idiopathic loss of shoulder motion. Subjects and Methods. This was a comparative study of 21 subjects (18 female, 3 male), using measurements of shoulder kinematics and administration of the Shoulder Rating Questionnaire (SRQ). Electromagnetic tracking sensors monitored the 3-dimensional position of the scapula and humerus throughout active shoulder motions. Correlations were performed between the active ROMs of interest and various demographic factors and the SRQ. A multiple regression equation was generated. Results. A multiple regression equation including scapular-plane abduction, external rotation at the side, external rotation at 90 degrees of abduction, and weight explained 69% of the variation in the SRQ scores. Discussion and Conclusion. The results suggest that active ROM can be used to predict function in people with idiopathic loss of shoulder ROM.

Infraspinatus Cross-Sectional Area and Shoulder Range of Motion Change Following Live-Game Baseball Pitching

2019 ◽  
Vol 28 (3) ◽  
pp. 236-242 ◽  
Author(s):  
Brett S. Pexa ◽  
Eric D. Ryan ◽  
Elizabeth E. Hibberd ◽  
Elizabeth Teel ◽  
Terri Jo Rucinski ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Athletic Training ◽  
Repeated Measures ◽  
External Rotation ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Shoulder Range Of Motion ◽  
Posterior Shoulder ◽  
Before And After

Context: Following a baseball pitching bout, changes can occur to glenohumeral range of motion that could be linked to injury. These effects are in part due to the posterior shoulder’s eccentric muscle activity, which can disrupt muscle contractile elements and lead to changes in muscle cross-sectional area (CSA), as measured by ultrasound. Objective: To assess changes in muscle CSA, and range of motion immediately before and after pitching, and days 1 to 5 following pitching. Design: Repeated measures. Setting: Satellite athletic training room. Patients: Ten elite college baseball pitchers participating in the fall season (age: 18.8 [1.2] y, height: 189.2 [7.3] cm, mass: 93.1 [15.3] kg, 8 starters, 2 long relievers). Intervention: A pitching bout of at least 25 pitches (63.82 [17.42] pitches). Main Outcome Measures: Dominant and nondominant infraspinatus CSA, as measured by ultrasound, and glenohumeral range of motion including internal rotation (IRROM), external rotation (ERROM), and total rotation range of motion (TROM) before pitching, after pitching, and days 1 to 5 following the pitching bout. Results: Dominant limb CSA significantly increased day 1 after pitching, and returned to baseline on day 2 (P < .001). Dominant and nondominant TROM did not change until day 5 (4.4°, P < .001) and day 3 (4.5°, P < .001), respectively, where they increased. Dominant IRROM was significantly decreased for 3 days (day 1: 1.9°, P < .001; day 2: 3.1°, P < .001; day 3: 0.3°, P < .001) following pitching and returned to baseline on day 4, with no such changes in the nondominant limb. Dominant external rotation significantly increased immediately post pitching (4.4°, P < .001) but returned to baseline by day 1. Conclusions: The results of the study demonstrate that infraspinatus CSA does not recover until 2 days following pitching, and IRROM does not recover until 4 days following pitching. Baseball pitching elicits damage to the posterior shoulder muscle architecture, resulting in changes to physical characteristics that last up to 4 days following pitching.

scholarly journals Influence of Body Position on Shoulder and Trunk Muscle Activation During Resisted Isometric Shoulder External Rotation

2018 ◽  
Vol 10 (4) ◽  
pp. 355-360 ◽  
Author(s):  
David A. Krause ◽  
Lucas G. Dueffert ◽  
Jaclyn L. Postma ◽  
Eric T. Vogler ◽  
Amy J. Walsh ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Muscle Activation ◽  
External Rotation ◽  
Body Position ◽  
Trunk Muscle ◽  
Trunk Muscles ◽  
Emg Activity ◽  
Convenience Sample ◽  
Overhead Athletes ◽  
Significant Difference

Background: External rotation (ER) strengthening of the shoulder is an integral component of rehabilitative and preventative programs for overhead athletes. A variety of shoulder ER strengthening exercises are reported, including those intended to integrate the core musculature. The purpose of this study was to examine ER torque and electromyographic (EMG) activation of shoulder and trunk muscles while performing resisted isometric shoulder ER in 3 positions (standing, side lying, and side plank). Hypothesis: Significantly greater force and shoulder muscle activation would be generated while side lying given the inherent stability of the position, and greater trunk muscle activation would be generated in the less stable plank position. Study Design: Quasi-experimental repeated-measures study. Level of Evidence: Level 5. Methods: A convenience sample of 25 healthy overhead recreational athletes (9 men, 16 women) participated in this study. EMG electrodes were placed on the infraspinatus, posterior deltoid, middle trapezius, multifidi, internal obliques, and external obliques. EMG signals were normalized to a maximal isometric contraction. Participants performed resisted isometric ER in standing, side-lying, and side plank positions. Results were analyzed using a repeated-measures analysis of variance with post hoc Bonferroni corrections (α = 0.05). Results: There was no significant difference in ER torque between positions (α = 0.05). A significant difference in EMG activity of shoulder and trunk musculature between positions was found in 7 of the 8 muscles monitored. Significantly greater EMG activity in the infraspinatus, middle trapezius, and the nondominant external and internal obliques was found in the side plank position as compared with standing and side lying. Conclusion: While there was no difference in ER torque between the 3 exercise positions, EMG activity of the shoulder and trunk muscles was dependent on body position. Clinical Relevance: If a clinician is seeking to integrate trunk muscle activation while performing shoulder ER strengthening, the side plank position is preferred as compared with standing or side lying.

scholarly journals Effect of a 6-Week Weighted Baseball Throwing Program on Pitch Velocity, Pitching Arm Biomechanics, Passive Range of Motion, and Injury Rates

2018 ◽  
Vol 10 (4) ◽  
pp. 327-333 ◽  
Author(s):  
Michael M. Reinold ◽  
Leonard C. Macrina ◽  
Glenn S. Fleisig ◽  
Kyle Aune ◽  
James R. Andrews
Keyword(s):  
Range Of Motion ◽  
Training Program ◽  
Repeated Measures ◽  
External Rotation ◽  
Controlled Trial ◽  
Injury Rate ◽  
Control Group ◽  
Injury Rates ◽  
Shoulder External Rotation ◽  
Experimental Group

Background: Emphasis on enhancing baseball pitch velocity has become popular, especially through weighted-ball throwing. However, little is known about the physical effects or safety of these programs. The purpose of this study was to examine the effects of training with weighted baseballs on pitch velocity, passive range of motion (PROM), muscle strength, elbow torque, and injury rates. Hypothesis: A 6-week weighted ball training program would result in a change in pitching biomechanical and physical characteristics. Study Design: Randomized controlled trial. Level of Evidence: Level 1. Methods: During the baseball offseason, 38 healthy baseball pitchers were randomized into a control group and an experimental group. Pitch velocity, shoulder and elbow PROM, shoulder strength, elbow varus torque, and shoulder internal rotation velocity were measured in both groups. The experimental group then performed a 6-week weighted ball throwing program 3 times per week using balls ranging from 2 to 32 ounces while the control group only used a 5-ounce regulation baseball. Both groups performed a strength training program. Measurements were then repeated after the 6-week period. Injuries were tracked over the 6-week training program and the subsequent baseball season. The effect of training with a weighted ball program was assessed using 2-way repeated-measures analysis of variance at an a priori significance level of P < 0.05. Results: Mean age, height, mass, and pretesting throwing velocity were 15.3 ± 1.2 years (range, 13-18 years), 1.73 ± 0.28 m, 68.3 ± 11 kg, and 30.3 ± 0.7 m/s, respectively. Pitch velocity showed a statistically significant increase (3.3%) in the experimental group ( P < 0.001). There was a statistically significant increase of 4.3° of shoulder external rotation in the experimental group. The overall injury rate was 24% in the experimental group. Four participants in the experimental group suffered elbow injuries, 2 during the training program and 2 in the season after training. No pitchers in the control group were injured at any time during the study. Conclusion: Performing a 6-week weighted ball throwing program increased pitch velocity. However, the program resulted in increased shoulder external rotation PROM and increased injury rate. Clinical Relevance: Although weighted-ball training may increase pitch velocity, caution is warranted because of the notable increase in injuries and physical changes observed in this cohort.

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