scholarly journals Glenohumeral Rotational Motion and Strength and Baseball Pitching Biomechanics

2012 ◽  
Vol 47 (3) ◽  
pp. 247-256 ◽  
Author(s):  
Wendy J. Hurd ◽  
Kenton R. Kaufman
Keyword(s):  
Range Of Motion ◽  
Internal Rotation ◽  
Rotational Motion ◽  
Positive Relationship ◽  
External Rotation ◽  
Shoulder Range Of Motion ◽  
Arm Injuries ◽  
Baseball Pitchers ◽  
Clinical Measures ◽  
Insight Into

Context: Addressing loss of shoulder range of motion and rotator cuff weakness in injury-prevention programs might be an effective strategy for preventing throwing arm injuries in baseball pitchers. However, the influence of these clinical measures on pitching biomechanics is unclear. Objective: To evaluate the relationships among clinical measures of shoulder rotational motion and strength and 3-dimensional pitching biomechanics and to evaluate the presence of coupling between the shoulder and the elbow during pitching to provide insight into the influence of clinical shoulder characteristics on elbow biomechanics. Design: Cross-sectional study. Setting: Biomechanics laboratory. Patients or Other Participants: A total of 27 uninjured male high school baseball pitchers (age  =  16 ± 1.1 years, height  =  183 ± 7 cm, mass  =  83 ± 12 kg). Main Outcome Measure(s): Clinical measures included shoulder internal- and external-rotation range of motion and peak isometric internal- and external-rotator strength. Three-dimensional upper extremity biomechanics were assessed as participants threw from an indoor pitching mound to a target at regulation distance. Linear regressions were used to assess the influence of clinical measures on the peak shoulder internal and external rotation moments and the peak elbow-adduction moment. Results: We found a positive relationship between clinically measured internal-rotator strength and shoulder external-rotation moment (R2  =  0.181, P  =  .04) during pitching. We also noted an inverse relationship between clinically measured external-rotation motion and the elbow-adduction moment (R2  =  0.160, P  =  .04) and shoulder internal-rotation moment (R2  =  0.250, P  =  .008) during pitching. We found a positive relationship between peak shoulder internal-rotation moment and the peak elbow-adduction moment (R2  =  0.815, P < .001) during pitching. Conclusions: This study provides insight into the effects of shoulder strength and motion on pitching biomechanics and how these clinical measures might contribute to throwing arm injuries in the baseball pitcher. A relationship also was identified between peak shoulder and elbow moments in the throwing arm during pitching, providing biomechanical support for addressing clinical shoulder characteristics as a potential strategy for preventing elbow injury.

Shoulder External Rotational Properties During Physical Examination Are Associated With Injury That Requires Surgery and Shoulder Joint Loading During Baseball Pitching

2021 ◽  
pp. 036354652110398
Author(s):  
Hannah Stokes ◽  
Koco Eaton ◽  
Naiquan (Nigel) Zheng
Keyword(s):  
Physical Examination ◽  
Range Of Motion ◽  
Internal Rotation ◽  
Shoulder Joint ◽  
External Rotation ◽  
Joint Loading ◽  
Arm Injuries ◽  
Shoulder External Rotation ◽  
Baseball Pitchers ◽  
Shoulder Flexibility

Background: Throwing arm injuries are common because of the demand on the shoulder. The shoulder is qualitatively checked regularly by team physicians. Excessive instability and joint loading in baseball pitching are risk factors for throwing arm injuries. Knowledge of shoulder flexibility, range of motion, and joint loading may provide new insights for treatments to reduce the likelihood of injury incidence. Purpose: To investigate the relationship among injuries, shoulder external rotational properties, and shoulder joint loading in baseball pitchers. Study Design: Descriptive laboratory study. Methods: Pitching kinetics, shoulder rotational tests, and self-reported injury questionnaires were used to study 177 collegiate baseball pitchers. Pitching motion data were collected at 240 Hz using a motion capture system. A custom program calculated the shoulder joint loading. The shoulder rotational test quantitatively records shoulder range of motion and flexibility using a custom-made wireless device. Self-reported injury questionnaires were filled out during tests and yearly follow-ups. The total length of the study was 5 years. Analysis of variance, chi-square, and regression tests were performed to compare differences among groups and detect correlations with surgery and shoulder joint loadings. Results: There were significant differences in shoulder flexibility among surgery groups. Shoulder external rotational properties during physical examination were significantly associated with shoulder joint loading in baseball pitching. High shoulder external rotation was associated with 14% to 36% lower shoulder posterior force and adduction, internal rotation, and horizontal adduction torque ( P < .05). High shoulder flexibility was associated with 13% higher anterior force ( P < .05). High shoulder external rotation before external rotation torque was applied was associated with 13% to 33% lower shoulder inferior force and adduction, internal rotation, and horizontal adduction torque ( P < .05). There were no significant differences in shoulder joint loading among the surgery groups. Conclusion: Shoulder injuries that require surgery were associated with shoulder external rotation flexibility. High shoulder external rotation may be advantageous because it lowers the force and torque on the shoulder joint. Clinical Relevance: The ability to understand shoulder external rotational properties, joint loading, and injury during baseball pitching helps further our understanding of injury mechanisms. The shoulder rotational test should be used as a screening tool to identify players at risk.

scholarly journals Shoulder Range of Motion and Baseball Arm Injuries: A Systematic Review and Meta-Analysis

2018 ◽  
Vol 53 (12) ◽  
pp. 1190-1199 ◽  
Author(s):  
Garrett S. Bullock ◽  
Mallory S. Faherty ◽  
Leila Ledbetter ◽  
Charles A. Thigpen ◽  
Timothy C. Sell
Keyword(s):  
Range Of Motion ◽  
External Rotation ◽  
Meta Analysis ◽  
P Value ◽  
High Quality ◽  
Level Of Evidence ◽  
Baseball Players ◽  
Shoulder Range Of Motion ◽  
Methodologic Quality ◽  
Arm Injuries

Objective Arm injuries in baseball players are a common problem. The identification of modifiable risk factors, including range of motion (ROM), is essential for injury prevention. The purpose of this review was to assess the methodologic quality and level of evidence in the literature and to investigate the relationship between shoulder ROM and the risk of arm injuries in baseball players. Data Sources Relevant studies in PubMed, CINAHL, Embase, and SPORTDiscus published from inception to August 1, 2017. Study Selection Only studies that encompassed healthy baseball cohorts who were assessed for shoulder ROM and prospectively evaluated for injuries throughout a baseball season or seasons were included. Data Extraction Six articles met the search criteria. Only 3 studies were included in the meta-analysis due to disparate participant groups. Data Synthesis The modified Downs and Black scale (0–15 points) was used to analyze methodologic quality. Study quality ranged from 11 to 14. Four studies received high-quality (≥12) and 2 studies received moderate-quality (≥10) scores. The overall pooled analysis demonstrated that absolute and internal-rotation deficits (–5.93 [95% confidence interval {CI} = –9.43, –2.43], P &lt; .001 and 4.28 [0.71, 7.86], P = .02, respectively) and absolute total ROM (TROM; –6.19 [95% CI = –10.28, –2.10]; P = .003) were predictors of injury, and these data exhibited homogeneity (absolute IR P value = .77, I2 = 0%; IR deficit P value = .41, I2 = 0%; absolute TROM P value = .78, I2 = 0%). No significance was observed for absolute external rotation (–2.86 [95% CI = –6.56, 0.83], P = .13), which had data with high heterogeneity (P = .003; I2 = 83%). A deficit in horizontal adduction was a predictor of injury (–8.32 [95% CI = –12.08, –4.56]; P &lt; .001); these data were homogeneous but yielded a moderate heterogenic effect (P = .16; I2 = 50%). Conclusions High-quality evidence demonstrated that deficits in throwing-arm TROM and IR were associated with upper extremity injury in baseball players. Heterogeneity across studies for horizontal adduction suggested that this may be a modifiable risk factor for injury, but it requires further research.

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.

Descriptive Profile of Hip Rotation Range of Motion in Elite Tennis Players and Professional Baseball Pitchers

2007 ◽  
Vol 35 (8) ◽  
pp. 1371-1376 ◽  
Author(s):  
Todd S. Ellenbecker ◽  
Gail A. Ellenbecker ◽  
E. Paul Roetert ◽  
Rogerio Teixeira Silva ◽  
Greg Keuter ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Internal Rotation ◽  
Hip Joint ◽  
External Rotation ◽  
Professional Baseball ◽  
Tennis Players ◽  
Active Range Of Motion ◽  
Baseball Pitchers ◽  
Hip Rotation ◽  
Bilateral Difference

Background Repetitive loading to the hip joint in athletes has been reported as a factor in the development of degenerative joint disease and intra-articular injury. Little information is available on the bilateral symmetry of hip rotational measures in unilaterally dominant upper extremity athletes. Hypothesis Side-to-side differences in hip joint range of motion may be present because of asymmetrical loading in the lower extremities of elite tennis players and professional baseball pitchers. Study Design Cohort (cross-sectional) study (prevalence); Level of evidence, 1. Methods Descriptive measures of hip internal and external rotation active range of motion were taken in the prone position of 64 male and 83 female elite tennis players and 101 male professional baseball pitchers using digital photos and computerized angle calculation software. Bilateral differences in active range of motion between the dominant and nondominant hip were compared using paired t tests and Bonferroni correction for hip internal, external, and total rotation range of motion. A Pearson correlation test was used to test the relationship between years of competition and hip rotation active range of motion. Results No significant bilateral difference (P > .005) was measured for mean hip internal or external rotation for the elite tennis players or the professional baseball pitchers. An analysis of the number of subjects in each group with a bilateral difference in hip rotation greater than 10° identified 17% of the professional baseball pitchers with internal rotation differences and 42% with external rotation differences. Differences in the elite male tennis players occurred in only 15% of the players for internal rotation and 9% in external rotation. Female subjects had differences in 8% and 12% of the players for internal and external rotation, respectively. Statistical differences were found between the mean total arc of hip range of internal and external rotation in the elite tennis players with the dominant side being greater by a clinically insignificant mean value of 2.5°. Significantly less (P < .005) dominant hip internal rotation and less dominant and nondominant hip total rotation range of motion were found in the professional baseball pitchers compared with the elite male tennis players. Conclusion This study established typical range of motion patterns and identified bilaterally symmetric hip active range of motion rotation values in elite tennis players and professional baseball pitchers. Asymmetric hip joint rotational active range of motion encountered during clinical examination and screening may indicate abnormalities and would indicate the application of flexibility training, rehabilitation, and further evaluation.

scholarly journals The Effect of Straight-Line Long-Toss Versus Ultra-Long-Toss Throwing on Passive Glenohumeral Range of Motion Recovery After Pitching

2021 ◽  
pp. 194173812098001
Author(s):  
T. David Luo ◽  
Aaron D. Sciascia ◽  
Austin V. Stone ◽  
Chukwuweike U. Gwam ◽  
Christopher A. Grimes ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Internal Rotation ◽  
National Collegiate Athletic Association ◽  
External Rotation ◽  
Level Of Evidence ◽  
Left Hand ◽  
Right Hand ◽  
Straight Line ◽  
Significant Difference ◽  
Baseball Pitchers

Background: Repetitive throwing in baseball pitchers can lead to pathologic changes in shoulder anatomy, range of motion (notably glenohumeral internal rotation deficit), and subsequent injury; however, the ideal strengthening, recovery, and maintenance protocol of the throwing shoulder in baseball remains unclear. Two strategies for throwing shoulder recovery from pitching are straight-line long-toss (SLT) throwing and ultra-long-toss (ULT) throwing, although neither is preferentially supported by empirical data. Hypothesis: ULT will be more effective in returning baseline internal rotation as compared with SLT in collegiate pitchers after a pitching session. Study Design: Cohort study. Level of Evidence: Level 3. Methods: A total of 24 National Collegiate Athletic Association Division I baseball pitchers with mean age 20.0 ± 1.1 years were randomized to either the ULT group (n = 13; 9 right-hand dominant, 4 left-hand dominant) or SLT group (n = 11; 10 right-hand dominant, 1 left-hand dominant). Measurements (dominant and nondominant, 90° abducted external rotation [ER], internal rotation [IR], and total range of motion [TROM]) were taken at 5 time points across 3 days: before and immediately after a standardized bullpen session on day 1; before and immediately after a randomized standardized ULT or SLT session on day 2; and before practice on Day 3. Results: ULT demonstrated significantly greater final ER compared with baseline (+10°; P = 0.05), but did not demonstrate significant IR changes. Similarly, SLT demonstrated significantly greater post-SLT ER (+12°; P = 0.02) and TROM (+12°; P = 0.01) compared with baseline, but no significant IR changes. Final ER measurements were similar between ULT (135° ± 14°) and SLT (138° ± 10°) ( P = 0.59). There was also no statistically significant difference in final IR between ULT (51° ± 14°) and SLT (56° ± 8°) ( P = 0.27). Conclusion: The routine use of postperformance, ULT throwing to recover from range of motion alterations, specifically IR loss, after a pitching session is not superior to standard, SLT throwing. Based on these findings, the choice of postpitching recovery throwing could be player specific based on experience and comfort. Clinical Relevance: The most effective throwing regimens for enhancing performance and reducing residual impairment are unclear, and ideal recovery and maintenance protocols are frequently debated with little supporting data. Two strategies for throwing shoulder recovery from pitching are SLT and ULT throwing. These are employed to help maintain range of motion and limit IR loss in pitchers. The routine use of ULT throwing for recovery and to limit range of motion alterations after a pitching session is not superior to SLT throwing.

scholarly journals A Comparison of the Immediate Effect of Swedish Massage vs Passive Stretching on Range of Motion in Overhead Athletes

2020 ◽  
Vol 22 (3) ◽  
pp. 1-7
Author(s):  
Jim Schilling ◽  
Sujeiry Guzman ◽  
Chad Lewis ◽  
Jupil Ko
Keyword(s):  
Range Of Motion ◽  
Internal Rotation ◽  
External Rotation ◽  
Intervention Group ◽  
Post Treatment ◽  
Static Stretching ◽  
Post Intervention ◽  
Overhead Athletes ◽  
Passive Stretching ◽  
Shoulder Range Of Motion

OBJECTIVES To compare the clinical outcome and effectiveness of Swedish massage and a traditional passive stretching program, on the shoulder of ROM in overhead athletes.PARTICIPANTS A total of 10 overhead throwing overhead male athletes (age= 23.5 ± 1.5yrs; height= 186.69 ± 6.35 cm; mass= 91.86 ± 12.48 kg).METHODS Participants were randomly assigned to either Swedish massage or a traditional passive static stretching program for 1 session of 5 minutes. Baseline and post-intervention shoulder ROM to end range in the flexed, external rotation, internal rotation, horizontal adduction and abduction positions. The Pearson chi-square test was applied to compare the differences of shoulder ROM of both therapeutic variables. Recorded outcome measures on the participants’ shoulder ROM (flexion with scapula fixed, horizontal adduction, horizontal abduction, internal rotational & external rotation) pre- & post-interventions.RESULTS Results indicate that participants in the Swedish massage therapeutic intervention group had significant improvements in their internal rotation post-treatment (M=5.20, SD= 1.304, p=.038) and the traditional passive stretching protocol group had significant improvements in shoulder external rotation post-treatment (M=11.20, SD=2.68, p=.016).CONCLUSION Swedish massage had better effects in four out of the five shoulder motions measured compared to passive static stretching. Educating overhead athletes on the potential beneficial effects of massage therapy and its role in maintaining shoulder range of motion.

scholarly journals A comparative study on the effectiveness of Mulligan mobilization versus Positional release therapy technique in patients with Adhesive capsulitis

2021 ◽  
Vol 12 (1) ◽  
pp. 1-5
Author(s):  
Chandrasekaran K ◽  
Sundaram M S ◽  
Senthil Selvam P ◽  
Viswanath Reddy A ◽  
Senthilkumar S ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Internal Rotation ◽  
Functional Activity ◽  
External Rotation ◽  
Adhesive Capsulitis ◽  
Shoulder Range Of Motion ◽  
Release Technique ◽  
Group A ◽  
Group B ◽  
Shoulder Range

Adhesive capsulitis is a painful condition in which the movement of the shoulder becomes limited and functional activity is affected. Adhesive capsulitis occurs when the shoulder joint capsule become thick, stiff and inflamed. The aim of the study is to compare the effectiveness of Mulligan movement with mobilization versus Positional release technique on shoulder range of motion and functional activity in patients with adhesive capsulitis. 30 patients were randomly divided into two groups. Group A (N = 15) received Mulligan mobilization technique and Group B (N = 15) received positional release therapy. The shoulder range of motion (Abduction, External rotation, Internal rotation) was measured by goniometer, the functional activity by SPADI questionnaire. The results showed that significant differences in shoulder ROM Abduction (t = 14.18, p = 0.000), Internal rotation (t = 13.80, p = 0.000), External rotation (t = 15.87, p = 0.000) and SPADI questionnaire (t = 13.94, p = 0.000) were observed in group A patients when compared to group B. In conclusion the Mulligan mobilization technique was effective to improve the shoulder ROM and reduce functional disability in patients with adhesive capsulitis compared to Positional release technique.

scholarly journals Serratus Anterior Stretch: A Novel Intervention and Its Effect on the Shoulder Range of Motion

2020 ◽  
pp. 1-4
Author(s):  
Keramat Ullah Keramat ◽  
Mohammad Naveed Babar
Keyword(s):  
Range Of Motion ◽  
Internal Rotation ◽  
External Rotation ◽  
Scapular Dyskinesis ◽  
Serratus Anterior ◽  
Shoulder Dysfunction ◽  
Shoulder Range Of Motion ◽  
Before And After ◽  
Movement Screening ◽  
Shoulder Range

Context: Serratus anterior tightness is associated with scapular dyskinesis and overall shoulder dysfunction, which affects the range of motion. The most effective intervention to stretch the serratus anterior is unknown. Objective: To evaluate the effect of a therapist-administered novel serratus anterior stretch (SAS) on shoulder range of motion. Method: This study recruited 30 healthy subjects of age 21.20 (1.69) years, height 1.65 (0.11) m, and weight 60.90 (10.36) kg in equal ratio of males and females who scored 1 or 2 on the shoulder mobility test of functional movement screening. A single intervention of a novel SAS was applied to the shoulder. Outcome variables before and after the SAS included the following: shoulder ROM (flexion, abduction, internal rotation, and external rotation) and functional movements of reaching up behind the back and reaching down behind the neck. Results: A paired t test was used to analyze the data. Following the acute SAS intervention, all shoulder ROM improved significantly (P < .000). The change in internal rotation was 6.00° (7.47°), external rotation was 5.66° (9.35°), abduction was 13.50° (11.82°), flexion was 20° (13.33°), reaching up behind the back was 5.10 (2.21) cm, and reaching down behind the neck was 5.41 (2.89) cm. The most marked improvement was in reaching up behind the back (24.48%) and reaching down behind the neck (22.78%). A very large effect size (>1) was observed across most of the variables. Conclusion: An acute SAS intervention improves shoulder mobility in healthy individuals. It is recommended for the trial on the prevention and rehabilitation of shoulder pathologies with restriction in shoulder mobility.

Impact of a competition with two consecutive matches in a day on physical performance in young tennis players

2017 ◽  
Vol 42 (7) ◽  
pp. 750-756 ◽  
Author(s):  
Cesar Gallo-Salazar ◽  
Juan Del Coso ◽  
David Barbado ◽  
Alejandro Lopez-Valenciano ◽  
Francisco Javier Santos-Rosa ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Internal Rotation ◽  
Physical Performance ◽  
External Rotation ◽  
Isometric Strength ◽  
Tennis Players ◽  
Performance Variables ◽  
Change Of Direction ◽  
Shoulder Range Of Motion ◽  
Shoulder External Rotation

The purpose of this study was to analyze the effects of playing 2 tennis matches on the same day on physical performance in young tennis players. Twelve well-trained young tennis players took part in a simulated tennis competition consisting of 2 tennis matches on the same day (morning and afternoon sessions). Before and the day after the competition, physical performance was measured using a battery of countermovement jumps; a 10 m sprint; the 5–0–5 agility test; hip, grip and shoulder maximal isometric strength; shoulder range of motion; and a serve velocity test. Postcompetition results showed reduced performance in 10 m (–3.3%, effect size (ES) = small), dominant and nondominant 5–0–5 agility test (–4.6%, ES = moderate; –4.2%, ES = moderate, respectively), bilateral (–5.2%, ES = small), and unilateral countermovement jumps (dominant leg: –7.2%, ES = small; non-dominant leg: –9.1%, ES = small). Both dominant and nondominant shoulder external rotation range of motion increased (12.2%, ES = moderate; 5.6%, ES = small), whereas internal rotation decreased (–4.2%, ES = small; –3.3%, ES = small) in the postcompetition tests, together with the dominant shoulder external rotation (–10.7%, ES = moderate) and internal rotation (–9.3%, ES = small) strength. Physical impairments occurred in neuromuscular performance variables involving lower (e.g., jumping, sprinting, and change of direction) and upper (e.g., isometric strength and range of motion) limbs the day after playing a competition with 2 consecutive matches on the same day. These alterations in neuromuscular and sport-specific performance need to be taken into consideration when planning tournament schedules for young tennis players, as well as preparing match and recovery strategies.

Rotational Motion Changes in the Glenohumeral Joint of the Adolescent/Little League Baseball Player

2005 ◽  
Vol 33 (5) ◽  
pp. 693-698 ◽  
Author(s):  
Keith Meister ◽  
Timothy Day ◽  
Marybeth Horodyski ◽  
Thomas W. Kaminski ◽  
Michael P. Wasik ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Internal Rotation ◽  
Rotational Motion ◽  
Glenohumeral Joint ◽  
External Rotation ◽  
Age Groups ◽  
Baseball Player ◽  
Cross Sectional ◽  
Little League ◽  
Total Range

Background Differences in range of motion and rotational motion between the dominant and nondominant shoulders in throwing athletes are well documented, although the age at which these changes begin to occur is not known. Hypothesis Changes in glenohumeral rotational motion in the shoulder of the Little League/adolescent baseball player occur during the most formative years of physical development. Study Design Cross-sectional study. Methods Elevation, internal rotation at 90° of abduction, and external rotation at 90° of abduction were measured in the dominant and nondominant shoulders of 294 baseball players, aged 8 to 16 years. Results Analysis of variance revealed 2-way interactions between arm dominance by age for elevation (P =. 005) and internal rotation (P =. 001). Significant differences were noted between dominant and nondominant arms for internal rotation at 90° (P =.001) and external rotation at 90° (P =. 001). Elevation, internal rotation at 90°, external rotation at 90°, and total range of motion varied significantly (P =. 001) among age groups. Elevation in the dominant arms of 16-year-olds was on average 5.3° less than in 8-year-olds (179.6° vs 174.3°). In the nondominant arms, mean elevation for 16-year-olds was 5.6° less than in 8-year-olds (179.7° vs 174.1°). Internal rotation at 90° for the dominant arms averaged 39.0° at age 8 and only 21.3° at age 16. In the non-dominant arms, internal rotation for 8-year-olds averaged 42.2° and only 33.1° for 16-year-olds. Conclusions Elevation and total range of motion decreased as age increased. These changes may be consequences of both bone and soft tissue adaptation. The most dramatic decline in total range of motion was seen between the 13-year-olds and 14-year-olds, in the year before peak incidence of Little Leaguer's shoulder. This decrease in rotational motion may cause increased stress at the physis during throwing.

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