Reproducibility and Validity of the Kerlan-Jobe Orthopedic Clinic Shoulder and Elbow Score (Japanese Version).

BACKGROUND: The Kerlan-Jobe Orthopedic Clinic (KJOC) questionnaire is a self-reported performance and functional assessment tool with good reliability and validity for overhead athletes with shoulder and elbow injuries. This study aimed to develop a Japanese version of the KJOC (J-KJOC) to clarify its reproducibility and validity for use by Japanese university baseball players. METHODS: The J-KJOC was translated according to the guidelines for cross-cultural adaptation. A total of 88 university baseball players completed the J-KJOC and the Quick-Disabilities of the Arm, Shoulder, and Hand (Q-DASH) questionnaires. Thirty players completed the J-KJOC two times after a median interval of two weeks. We assessed the absolute reliability, construct validity, internal consistency, and test-retest reliability. RESULTS: Cronbach's alpha coefficients ranged from 0.88 and the intraclass correlation coefficient for the total score was 0.91. A fixed bias was absent in the J-KJOC scores (mean difference: -2.2, 95% CI: -4.8 to 0.5). Furthermore, the J-KJOC score was correlated with the Q-DASH-disability/symptom (r = -0.60, p<0.01) and Q-DASH-sports/music (r = -0.63, p<0.01) scores but not correlated with the Q-DASH-work score (r = -0.11, p = 0.316). CONCLUSIONS: The J-KJOC questionnaire demonstrated good reproducibility and validity for assessing upper arm performance in Japanese university baseball players. The results of this study support the use of the J-KJOC for Japanese-speaking baseball players. Further research using this instrument on other types of overhead athletes is needed to determine its wider utility in sports medicine applications.

Wrist Motion Assessment in Tennis Players using Three-Dimensional Motion Capture and Dynamic Electromyography.

Background Tennis players often present with ulnar-sided wrist pain, which may reflect repetitive stress and/or faulty mechanics. There is a role for investigating the biomechanics of tennis strokes and how they may relate to wrist pathology. The purpose of this study was to investigate whether three-dimensional motion capture technology and dynamic electromyography (EMG), when used to study groundstrokes in elite junior tennis players, reveals patterns of upper extremity motion that may correlate with the development of clinically relevant pathology. Case Description Three-dimensional kinematic and EMG data were collected from two United States Tennis Association-ranked adolescent tennis players during groundstrokes. There were several observed differences in the two players' degree and timing of pronation/supination, ulnar/radial deviation, and flexion/extension during their strokes. Clinical Significance Advanced motion capture technology facilitates a nuanced understanding of complex movements involved in groundstroke production. This methodology may be useful for identifying athletes who are at risk for injury and guiding rehabilitation for players experiencing pain. Level of Evidence IV.

A low carrying angle is measured in elite tennis players just before ball impact during the forehand, suggesting a dynamic varus instant accommodation moving towards full extension.

PURPOSE: The goal of this study was to use image analysis recordings to measure the carrying angle of elite male tennis players during the forehand stroke, with the hypothesis that elite tennis players overstress their elbow in valgus over the physiological degree in the frontal plane just before ball contact on forehand groundstrokes. METHODS: The carrying angle of male tennis players ranked in the top 25 positions in the ATP ranking was measured on selected video frames with the elbow as close as possible to full extension just before the ball-racket contact in forehands. These frames were extracted from 306 videos professionally recorded for training purposes by a high-profile video analyst. All measures were conducted by three independent observers. RESULTS: Sixteen frames were finally included. The mean carrying angle was 11.5° ± 4.7°. The intraclass correlation coefficient value was 0.703, showing good reliability of the measurement technique. The measured carrying angle was lower than what has been observed in historical cohorts using comparable measurement methodology, suggesting a possible instant varus accommodation mechanism before hitting the ball. CONCLUSIONS: The observed decrease in the carrying angle is a consequence of an increase in elbow flexion position dictated by the transition from a closed to open, semi-open stances. As the elbow flexes during the preparation phase, it is less constrained by the olecranon and its fossa, increasing the strain on the medial collateral ligament and capsule structures. Moving towards full extension before the ball-racket contact, the elbow is dynamically stabilised by a contraction of the flexor muscles. These observations could provide a new explanation for medial elbow injuries among elite tennis players and drive specific rehabilitation protocols. STUDY DESIGN: Descriptive epidemiology study. LEVEL OF EVIDENCE: Level IV.

Effect of Scapular Retraction on Lower Trapezius, Infraspinatus, and Deltoid Muscle Electromyographic Activity During the Side-Lying Abduction Exercise.

Background: The lower trapezius (LT) muscle, which stabilizes the scapula posteriorly during arm elevation, has been interesting to both clinicians and researchers for its importance in throwing-related shoulder rehabilitation and injury prevention. Purpose: The purpose of this study was to investigate the electromyographic activity of the LT and other relevant muscles during scapular and shoulder activities in the side-lying position. Methods: Twenty collegiate baseball players volunteered to participate in this study. Electromyographic (EMG) output of the lower trapezius, infraspinatus, posterior deltoid, middle deltoid, serratus anterior, and upper trapezius muscles were collected. All the subjects performed isometric resistance exercises in four arm positions: 0° horizontal abduction from the coronal plane (NEUT) with protraction (NEUT-PRO), 15° horizontal adduction from the coronal plane (HADD) with protraction (HADD-PRO), and NEUT with retraction (NEUT-RET), and HADD-RET in a side-lying isometric abduction exercise with two external loads: a 9.1 kg dumbbell and 40% of the manual muscle test (MMT). The subjects also performed two more isometric resistance exercises: supine protraction and side-lying external rotation (ER) of the glenohumeral (GH) joint in GH adduction at 90° of GH ER or with as much ER as possible. All raw EMG data were normalized to maximal voluntary isometric contraction (% MVIC) of the corresponding muscle. Results: LT activity was significantly greater in HADD-RET with 9.1 kg than that of HADD-PRO (p < 0.001) (55 vs 21% MVIC) while middle deltoid muscle activity was significantly decreased in both NEUT and HADD-RET compared to that of NEUT and HADD-PRO (p < 0.001). In contrast, IS muscle activity was significantly increased in HADD-RET with 9.1 kg compared with that 40% MMT (p < 0.001) (41 vs 22% MVIC). Conclusion: LT activity was modulated by changes in scapulothoracic and glenohumeral joint positioning during a side-lying isometric abduction exercise. These findings may help clinicians to select exercises to improve scapular muscle balance ratios during rehabilitation of the shoulder complex. Level of Evidence: Level 3b, Controlled laboratory study.

Kinetic chain revisited: consensus expert opinion on terminology, clinical reasoning, examination, and treatment in people with shoulder pain.

BACKGROUND: The purpose of this study was to reach consensus on the most appropriate terminology and issues related to clinical reasoning, examination, and treatment of the kinetic chain (KC) in people with shoulder pain among an international panel of experts. METHODS: A 3-round Delphi study that involved an international panel of experts with extensive clinical, teaching, and research experience in the study topic was conducted. A search equation of terms related to the KC in Web of Science and a manual search were used to find the experts. Participants were asked to rate items across 5 different domains (terminology, clinical reasoning, subjective examination, physical examination, and treatment) using a 5-point Likert-type scale. An Aiken coefficient of validity (V) ≥0.7 was considered indicative of group consensus. RESULTS: The participation rate was 30.2% (n = 16), whereas the retention rate was high throughout the 3 rounds (100%, 93.8%, and 100%). A total of 15 experts from different fields and countries completed the study. After the 3 rounds, consensus was reached on 102 items: 3 items were included in the "terminology" domain; 17 items, in the "rationale and clinical reasoning" domain; 11 items, in the "subjective examination" domain; 44 items, in the "physical examination" domain; and 27 items, in the "treatment" domain. Terminology was the domain with the highest level of agreement, with 2 items achieving an Aiken V of 0.93, whereas the domains of physical examination and treatment of the KC were the 2 areas with less consensus. Together with the terminology items, 1 item from the treatment domain and 2 items from the rationale and clinical reasoning domain reached the highest level of agreement (V = 0.93 and V = 0.92, respectively). CONCLUSION: This study defined a list of 102 items across 5 different domains (terminology, rationale and clinical reasoning, subjective examination, physical examination, and treatment) regarding the KC in people with shoulder pain. The term "KC" was preferred and a agreement on a definition of this concept was reached. Dysfunction of a segment in the chain (ie, weak link) was agreed to result in altered performance or injury to distal segments. Experts considered it important to assess and treat the KC in particular in throwing or overhead athletes and agreed that no one-size-fits-all approach exists when implementing shoulder KC exercises within the rehabilitation process. Further research is now required to determine the validity of the identified items.

The Effects of a Compensatory Training Program Adding an Isoinertial Device in the Shoulder Function on Young Tennis Players.

ABSTRACT: Fernandez-Fernandez, J, Moreno-Perez, V, Cools, A, Nakamura, FY, Teixeira, AS, Ellenbecker, T, Johansson, F, and Sanz-Rivas, D. The effects of a compensatory training program adding an isoinertial device in the shoulder function on young tennis players. J Strength Cond Res 37(5): 1096-1103, 2023-The aim of this study was to analyze whether a compensatory training program, including isoinertial flywheel training, could reduce shoulder imbalances in a group of asymptomatic young tennis players. After an initial evaluation, 26 young tennis players were assigned to either a supervised flywheel training group (FTG, n = 13) or a control group (CG, n = 13). Shoulder passive internal (IR) and external rotation (ER) range of motion (ROM) as well as shoulder IR and ER maximal isometric strength were measured before and after a 12-week training intervention, performed 3 times per week. After the intervention, results showed significant changes for IR ( p < 0.001, effect size [ES] = 1.83) and ER ( p < 0.001, ES = 1.77) on the dominant (D) side, and IR on the nondominant (ND) side ( p < 0.001, ES = 2.24) in the FTG compared with the CG. Regarding the ROM values, results showed that the FTG achieved significantly greater increases for the IR ROM ( p < 0.001, ES = 3.32) and total ROM (TROM) ( p = 0.004, ES = 1.39) on the D and ND sides (IR ROM: p = 0.002, ES = 1.53; TROM: p < 0.001, ES = 2.35) than the CG. Moreover, the CG displayed larger decrements in ER ROM ( p = 0.016, ES = 1.12) on the ND side after the training period than the FTG. The conducted compensatory training program was effective to increase the ER strength and IR mobility of the FTG players, which led to a reduction in the glenohumeral imbalances.

Bilateral Comparison of Anterior Shoulder Position in Elite Tennis Players.

Background: In elite tennis players, musculoskeletal adaptations in the dominant upper extremity have been reported for range of motion, strength, and scapular biomechanics. In addition to scapular dysfunction, tightness and inflexibility of the pectoral musculature have been identified as risk factors for the development of overuse shoulder injury in overhead athletes. Hypothesis: Differences in anterior shoulder position will be identified between the dominant and non-dominant extremity in elite tennis players. The purpose of this study was to examine bilateral differences in anterior shoulder posture measured using a double square in elite tennis players without shoulder injury. Study Design: Descriptive Laboratory Study. Methods: Three hundred and six uninjured elite tennis players were measured in the supine position using a double square method to measure anterior shoulder position. The distance from the surface of the table to the anterior most position of the shoulder (in millimeters) was measured bilaterally and compared. A dependent t-test was used to test for significant differences in anterior shoulder position between the dominant and non-dominant extremity. Results: One hundred thirty-three males and 173 females were included in this study with a mean age of 16.58 years. The mean difference between extremities indicates increased anterior shoulder positioning on the dominant shoulder of 7.65 mm in females, and 8.72 in males. Significantly greater (p<.001) anterior shoulder position measures were documented on the dominant shoulder as compared to the non-dominant shoulder. Conclusions: The results of this study showed significantly (p<.001) greater anterior shoulder position on the dominant extremity of elite male and female tennis players. The differences of 7-8mm between extremities has clinical application for interpreting anterior shoulder position test results in this population. Level of Evidence: 3.

Can the Scapular Dyskinesis Test be Associated with Throwing Related Injuries During the Course of Collegiate Baseball Seasons?

Background: A pattern of scapular dyskinesis on the dominant side has been demonstrated to be associated with a decrease in throwing arm conditions identified by a self-report outcome assessment in collegiate baseball pitchers during the course of a single season. However, it is unclear if symptomatic shoulders in baseball pitchers may be associated with the presence of scapular dyskinesis. Purpose: To study the relationship between the presence of scapular dyskinesis and throwing-related injury in collegiate baseball pitchers during each respective course of up to four subsequent seasons. Methods: A single Division 1 National Collegiate Athletic Association team participated in this study over a four-year-period. The scapular dyskinesis test was implemented during the preseason for baseball pitchers. Players were followed throughout each respective season to track the incidence of throwing-related upper extremity injuries. Results: A total of 36 collegiate baseball pitchers (height: 185.3 ± 5.6 cm, weight: 88.8 ± 7.8 kg, age: 20.0 ± 1.5 years) consisting of 57 pitcher seasons were followed in this study, in which 18 pitchers remained with the team for more than one year. Twenty-seven of the 57 pitchers were classified as having scapular dyskinesis demonstrated at around 90° of shoulder flexion on the throwing side. Five injuries (13.2% of a total of 38 injuries) were diagnosed as throwing-related shoulder injuries during the course of the intercollegiate baseball seasons. Four of the five throwing-related shoulder injuries occurred in pitchers who had scapular dyskinesis on their dominant side. Consequently, the odds ratio was 5.04 for the collegiate pitchers with scapular dyskinesis on the throwing arm side associated with a throwing-related shoulder injury compared to those with no scapular dyskinesis (p = 0.16). No relationship was identified between scapular dyskinesis on the throwing arm side and throwing-related elbow injury. Eighty-one percent of the scapular dyskinesis test results were not changed on the throwing side from the previous to the following year for those 18 pitchers who were followed for more than one season, whereas 42.9% of the results remained unchanged on the non-throwing side. Conclusion: The results suggest that collegiate baseball pitchers with dominant arm scapular dyskinesis likely are at increased risk of throwing-related shoulder injury. Level of evidence: Level 2, Prospective Cohort Study.

Rehabilitation and Return to Sport Following Elbow Injuries.

Elbow injuries are frequently seen in throwing and overhead athletes. This review provides a framework for diagnosis, treatment, and particularly rehabilitation of common elbow pathologies, including ulnar collateral ligament injury, valgus extension overload, and medial and lateral epicondylitis. Advanced rehabilitation facilitates complete return to functional sport-specific activity and is based on objective criteria. As diagnostic and therapeutic modalities improve our understanding of elbow pathologies in the athletic patient, continued research will further elucidate objective evidence-based rehabilitation techniques.

A comparison of teres minor and infraspinatus muscle activation in the prone position.

BACKGROUND: The electromyography (EMG) activity of the teres minor (TMi) and infraspinatus (IS) muscle has been demonstrated to vary depending on the arm position, such as in the coronal or scapular position, during intervention exercises. This may be reflected by different EMG activities demonstrated between the TMi and IS muscle during the acceleration and deceleration phases of the pitching motion. Tenderness in the scapular attachment site of the TMi muscle is often seen in baseball pitchers after pitching but not the attachment site of the IS muscle. However, few studies have investigated an interaction between TMi and IS muscle activity across different resistance exercises with different arm positions. The purpose of this study was to identify the feature of TMi and IS muscle activity in the presence of manual resistance applied in the prone position. METHODS: Eighteen collegiate baseball players volunteered their participation. Raw EMG amplitudes of the TMi, IS, posterior deltoid, middle deltoid, and upper trapezius muscles on the dominant shoulder were measured during intervention exercises. All subjects performed manual isometric resistance exercises: horizontal abduction (HABD) and external rotation (ER) of the glenohumeral joint with 40% of the manual maximum strength test in prone. The subjects also performed each of the HABD and ER resistance exercises with the arm actively positioned at 0° and 45° of ER of the glenohumeral joint in the coronal and scapular planes. RESULTS: Both TMi and IS muscle activities significantly increased with the arm positioned at 45° of ER compared with 0° of ER regardless of the exercise (P < .05). TMi activity was significantly greater with HABD resistance than IS muscle activity regardless of the arm positions, whereas it was significantly less with ER resistance than IS muscle activity. CONCLUSION: The findings of this study indicated that the TMi and IS muscles were most highly activated during the HABD resistance with the arm actively positioned at 45° of ER in the coronal plane. The results of this study have clinical implications regarding the careful selection of arm position in both exercise and clinical examination for the TMi and IS muscles.

Age and Gender Differences in Injuries and Risk Factors in Elite Junior and Professional Tennis Players.

BACKGROUND: Elite tennis athletes experience injuries throughout the entire body. Impairments in trunk stability, lower limb flexibility, and hip range of motion (ROM) are modifiable risk factors that can impact injuries and performance. Information on nonmodifiable risk factors such as age and gender is limited. The purpose of this investigation was to provide information on risk factors to direct clinical decision-making and injury prevention and rehab programming in this population. HYPOTHESIS: Prevalence and location of injuries will differ by age group and gender. Trunk stability, lower limb flexibility, and hip ROM will differ by age group and gender. STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 3. METHODS: A de-identified database (n = 237; females = 126) from the United States Tennis Association High Performance Profile (HPP) 2014-2015 was used for the analysis. Subjects were elite junior and professional tennis players (mean age 14.6 [range, 9-27] years). The HPP is a tennis-specific assessment and questionnaire that includes retrospective information on injury history. Subjects were categorized by injury, gender, and age. Injury locations were classified by region. Trunk stability measures included drop vertical jump (DVJ), single-leg squat, and prone and side planks. Lower limb measures included hamstring, quadriceps and hip flexor flexibility, and hip rotation ROM. RESULTS: A total of 46% of athletes reported an injury. Significant differences were found for injury prevalence and location by age group. Adolescent athletes (age 13-17 years) had more trunk injuries, while adult athletes (age ≥18 years) had more lower limb injuries. Adolescent athletes performed worse on DVJ, dominant side plank, and hamstring flexibility compared with young (age ≤12 years) and adult athletes. Significant gender differences in hip ROM included internal rotation on both the dominant and nondominant sides. CONCLUSION: Impairments in trunk stability, lower limb flexibility, and hip rotation ROM may affect both health and performance outcomes in this population. Elite tennis athletes may benefit from additional off court programming to address trunk and lower limb impairments. CLINICAL RELEVANCE: Adolescent elite tennis athletes may be at higher risk of trunk injuries. Age, gender, injury history, and impairments should be considered with all assessments and programming.

Electromyography activity of the teres minor muscle with varying positions of horizontal abduction in the quadruped position.

BACKGROUND: The teres minor (TMi) muscle exposed relatively high activity during the acceleration and deceleration phases of the throwing motion, compared with the infraspinatus muscle. However, few studies have identified TMi muscle activity in intervention exercises. The purpose of this study was to investigate TMi muscle activities in different horizontal adduction positions in the quadruped horizontal abduction exercise. This study hypothesized that TMi muscle activity would differ in response to resistance application across different horizontal adduction positions. MATERIALS AND METHODS: Nineteen collegiate baseball players volunteered their participation. Raw electromyography activity of the TMi muscle along with 7 different muscles attached to the scapula on the dominant-side were collected, and normalized by each of the corresponding maximum voluntary isometric contractions. All subjects performed manual isometric resistance horizontal abduction exercises at 90° and 135° of abduction with 3 horizontal adduction angles in the quadruped position: 1) coronal, 2) scapular, and 3) sagittal plane. Electromyography data were also collected from rhythmical concentric contraction of horizontal abduction at 90° of abduction in the quadruped position. RESULTS: TMi muscle activity was significantly greater with the arm positioned in the coronal plane than that of the scapular and sagittal planes (41, 26, and 17% maximum voluntary isometric contraction, respectively) (P < .05). CONCLUSION: The present study demonstrated that TMi muscle activity varied depending on horizontal adduction positions.

Descriptive Strength and Range of Motion in Youth Baseball Players.

BACKGROUND: There are limited studies reporting descriptive strength and range of motion in youth baseball players 12 years of age or younger. PURPOSE: To establish normative data for external (ER) and internal (IR) rotation range of motion (ROM), total arc range of motion (TROM), and isometric rotator cuff strength in youth baseball players, and to compare between the dominant throwing arm (D) to the non-dominant arm (ND). STUDY DESIGN: Cross-sectional. METHODS: Patient population included 50 (5 to 12-year-old) uninjured, healthy athletes. ROM measurements were performed preseason using a goniometer for IR and ER in the supine position with the shoulder in 90 degrees of abduction (abd) with scapular stabilization. Isometric strength measurements for IR and ER were collected in both neutral and 90 degrees (deg) of abduction with the use of a hand-held dynamometer and recorded in pounds (lbs) utilizing a "make" test. Descriptive statistics were obtained for all measures. RESULTS: All data were analyzed as a single group (average age: 9.02). No significant difference in average total arc of PROM (ER+IR=Total Arc) on the D side compared to the ND side (136.7 ± 12.7 deg vs. 134.3 ± 12.3 deg). There were statistically significant differences between ER ROM (102.2 ± 7.7 deg vs. 96.8 ± 7.4 deg) and IR ROM (34.4 ± 9.0 deg vs. 37.5 ± 9.5 deg) between D versus ND arms (p= .000, .006 respectively). Mean ER strength in neutral (13.6 ± 3.4 and 12.8 ± 3.6 lbs) and 90 deg abduction (12.3 ± 3.4 and 12.5 ± 4.3 lbs) did were not significantly different between D and ND arms, respectively. Mean IR strength in neutral (18.0 ± 6.0 and 15.7 ± 4.7 lbs) and 90 deg abd (16.4 ± 5.6 and 15.0 ± 5.7 lbs) was significantly greater in the D arm vs ND arm, respectively (p=.000, .001). CONCLUSION: These data can provide descriptive information for clinicians who treat very young baseball players. These data show sport specific adaptations occur at very young ages (5-12) and are similar to prior reports on adolescent, high school and professional baseball players regarding upper extremity ROM and rotator cuff strength. LEVEL OF EVIDENCE: 3.

Acute Tennis Injuries in the Recreational Tennis Player.

BACKGROUND: Epidemiological studies on tennis injuries are mainly conducted in either elite professional or junior players. Injury patterns might differ in the recreational tennis player. PURPOSE: To investigate acute injuries in the recreational tennis-playing population with an additional focus on acute injuries that require surgical treatment. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A retrospective data analysis was conducted among patients who sustained an acute tennis injury between January 2013 and December 2018 and who had treatment administered at a single university hospital. Demographic data, diagnosis, body region of the trauma, injury mechanism, and treatment methods were recorded. Data were evaluated using descriptive statistics. RESULTS: A total of 449 patients sustained 467 injuries (148 female, 301 male; mean age, 43.6 years; range, 8.2-84.4 years). The injuries occurred throughout the year, with an increased prevalence in the summer months. Injuries occurred in the lower extremity in 59%, the upper extremity in 30%, and the head and trunk in 11%. The main reason for an injury was a twist of a specific joint (n = 194) or a fall (n = 102). Harmless contusion or strains were the most common injury (49%). Ankle sprains were the most common serious injury, occurring in 11% of patients. Fractures occurred in 54 cases (12%). Overall, 9% of patients were treated surgically (fractures, n = 13; meniscal tears, n = 8; Achilles tendon ruptures, n = 6), and surgery was advised to another 1% who did not receive surgery at the study hospital. CONCLUSION: Typical acute injuries in recreational tennis players differ from acute injuries in elite and junior players, with an increased fracture occurrence. The main causes of acute tennis injuries are falls and twists, with 10% of injuries needing surgical treatment, mainly for fractures, meniscal tears, and Achilles tendon ruptures.

Tennis-specific extension of the International Olympic Committee consensus statement: methods for recording and reporting of epidemiological data on injury and illness in sport 2020.

The IOC has proposed standard methods for recording and reporting of data for injury and illness in sport. The IOC consensus statement authors anticipated that sport-specific statements would provide further recommendations. This statement is the tennis-specific extension of the partner IOC statement. The International Tennis Federation Sport Science and Medicine Committee, in collaboration with selected external experts, met in June 2019 to consider athlete health monitoring issues specific to tennis. Once the IOC consensus statement was finalised, the tennis-specific consensus was drafted and agreed on by the members over three iterations. Compared with the IOC consensus statement, the tennis consensus contains tennis-specific information on injury mechanism, mode of onset, injury classification, injury duration, capturing and reporting exposure, reporting risk and study population. Our recommendations apply to able-bodied as well as wheelchair tennis players. Where applicable, specific recommendations are made for wheelchair tennis.

Visual Observation of Apparent Infraspinatus Muscle Atrophy in Male Professional Tennis Players.

BACKGROUND: Previous studies have reported visually observed apparent muscle atrophy in the infraspinous fossa of the dominant arm of overhead athletes. Several mechanisms have been proposed as etiological factors, including eccentric overload, compressive spinoglenoid notch paralabral cysts, and cumulative tensile suprascapular neurapraxia. PURPOSE: To report the prevalence of apparent infraspinatus atrophy in male professional tennis players and to determine whether the suspected atrophy correlates with objectively measured weakness of external rotation. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 153 male professional tennis players underwent a musculoskeletal screening examination that included visual inspection of the infraspinous fossa. Infraspinatus atrophy was defined as hollowing or loss of soft tissue bulk inferior to the scapular spine in the infraspinous fossa of one extremity that was visibly different from the contralateral extremity. This finding was observed and independently agreed upon by both an orthopaedic surgeon and a physical therapist during the examination. Also assessed were rotator cuff instrument-assisted manual muscle testing, visual observation of scapular kinesis (or motion), and glenohumeral joint range of motion for internal and external rotation and horizontal adduction. RESULTS: In the 153 players, dominant-arm infraspinatus atrophy was observed in 92 players (60.1%), and only 1 player (0.7%) was identified with nondominant infraspinatus atrophy. A Pearson correlation showed a significant relationship between the presence of dominant-arm infraspinatus atrophy and dominant-arm external rotation strength measured in neutral abduction/adduction (at the side) (P = .001) as well as between the presence of dominant-arm infraspinatus atrophy and bilateral external rotation strength measured at 90° of glenohumeral joint abduction (P = .009 for dominant arm and .002 for nondominant arm). No significant correlation was found with scapular dyskinesis, glenohumeral range of motion, or instrument-assisted manual muscle testing of the supraspinatus (empty-can test). CONCLUSION: Visually observed infraspinatus muscle atrophy is a common finding in the dominant shoulder of asymptomatic male professional tennis players and is significantly correlated with external rotation weakness. This condition is present in uninjured players without known shoulder pathology and is not related to glenohumeral joint internal rotation, total rotation range of motion, or scapular dysfunction. Players with visually observed infraspinatus atrophy should be evaluated for external rotation strength and may require preventive strengthening.

PERCEIVED SELF-REPORT OF EFFORT DURING ROTATOR CUFF & SCAPULAR REHABILITATIVE EXERCISE IN PATIENTS AFTER SHOULDER SURGERY.

BACKGROUND: Rehabilitation following shoulder surgery involves the use of resistive exercise but dosing of these -exercises historically employs multiple sets of pre-determined repetitions and few reports document the perceived effort encountered by patients during these exercises for both elastic resistance and free-weights. The OMNI-Resistance Exercise Scale (OMNI-RES) has been tested and applied as a measure of perceived exertion (RPE) for resistive exercise but has not gained widespread acceptance as an optimal method for physical therapists to document RPE during rehabilitation of shoulder surgery. PURPOSE: To generate descriptive values of RPE encountered during common shoulder exercises of varying resistance in patients following shoulder surgery as well as provide a comparative analysis between perceived exertion ratings of similar exercise movement patterns using elastic and traditional isotonic resistance. STUDY DESIGN: Descriptive Cross-sectional Cohort. METHODS: Sixty-six subjects (mean age 53.3 + 12.8 years) were included in this study following shoulder surgery (RC repair n=22, labral repair n=10, SA n=34). Perceived exertion using the OMNI-RES was recorded during performance of seven rotator cuff and scapular rehabilitation exercises at 6- and 12-weeks following surgery. RESULTS: Mean RPE using OMNI-RES in combined surgical groups ranged between 3.6 and 5.7 (mean = 4.50 + 2.1) across all seven exercises (scale 0 = very easy to 10 = extremely hard). From the external rotation (ER) exercise pair, paired t-tests revealed standing ER w/ Thera-band® (ERB) had a significantly higher OMNI-RES score versus sidelying ER w/ cuff weight (SLERW) (mean: 5.13 vs 4.41, p = 0.001) while the extension exercise pair consisting of standing shoulder extension w/ band (EXTB) and prone extension w/ cuff weight (PEXTW) showed no significant difference in OMNI-RES score (mean: 3.54, 3.67, p = 0.626). CONCLUSION: Commonly prescribed resistance exercise in the rehabilitation following shoulder surgery show light-moderate ratings of perceived exertion at both 6 & 12 week post-operative timepoints across three surgical procedures. LEVEL OF EVIDENCE: 3b.

The Application of Double Elastic Band Exercise in the 90/90 Arm Position for Overhead Athletes.

BACKGROUND: Traditional exercises performed with the shoulder in the position of 90° abduction and external rotation with elbow flexion (90/90) while using a single elastic band showed moderate activity of both the lower trapezius (LT) and infraspinatus (IS) muscle. The purpose of this study was to investigate activity of the teres minor (TMi) and the LT muscles during standing external rotation exercise with the shoulder in the 90/90 position with 2 elastic bands in both the frontal and the scapular plane. HYPOTHESIS: TMi, IS, and LT muscle activities will vary depending on whether the shoulder is positioned in the frontal or scapular plane with the application of 2 elastic bands. Also, the serratus anterior (SA) and teres major (TMa) muscles will produce different muscular activity patterns during exercises performed with 2 elastic bands in the frontal plane compared with the TMi and LT muscles. STUDY DESIGN: Controlled laboratory study. LEVEL OF EVIDENCE: Level 4. METHODS: A total of 21 collegiate baseball players volunteered to participate. The electromyography (EMG) activities of the TMi, IS, LT, SA, TMa, middle deltoid (MD), posterior deltoid, and upper trapezius (UT) muscles were measured with the 90/90 arm position during both isometric and oscillation resistance exercises with 2 elastic bands oriented in the frontal and scapular planes. RESULTS: A significant difference was observed in EMG activity of both the TMi and the LT muscles between single and double elastic band applications in the frontal plane (P < 0.05). In contrast, EMG activity of the IS, SA, and TMa muscles was significantly increased in the scapular plane compared with the frontal plane (P < 0.05). CONCLUSION: The standing 90/90 position effectively increased both TMi and LT muscle EMG activity with the double elastic band in the frontal plane while minimizing UT and MD muscle activity. EMG activity of the IS, SA, and TMa muscles increased with exercise in the scapular plane as compared with the frontal plane. CLINICAL RELEVANCE: Oscillation movement under double elastic band application differentiated external rotator muscle and scapular muscle activities between the frontal and scapular plane during the 90/90 exercise in the frontal plane compared with the scapular plane. Clinicians can utilize each of the scapular and frontal positions based on their desired focus for muscular activation.

ELECTROMYOGRAPHIC ANALYSIS OF THE SCAPULAR DYSKINESIS TEST IN A BASEBALL PITCHER WITH A SLAP LESION: A CASE REPORT.

BACKGROUND AND PURPOSE: The return to play percentage of baseball pitchers who have undergone isolated superior labrum anterior-posterior (SLAP) repair has been reported to be less than 60%. Scapular dyskinesis (SD), characterized by scapular prominence during dynamic scapulohumeral movements, may be used to assist in diagnosing a baseball pitcher with shoulder pathology including a SLAP lesion. The purpose of this case report was to describe the use of the SD test to assess the scapular muscles and report EMG findings in a college baseball pitcher diagnosed with a Type 2 posterior SLAP lesion. CASE DESCRIPTION: The subject was a NCAA-D1 senior collegiate baseball right hand 3/4 slot pitcher (21 years old) with a primary complaint of pain in the anterior portion of the shoulder during the entire fall practice season, which was attributed to labral surgery performed when he was a senior in high school. No positive clinical testing of the patient was found including: the sulcus sign, tests of gross instability, and the load & shift test. A Type II posterior SLAP lesion was identified via magnetic resonance imaging. The subject presented with glenohuemral internal rotation deficit (GIRD). The SD test identified moderate to severe prominence of scapular medial boarder in shoulder flexion/extension (FLX/EXT). Furthermore, surface EMG analyses indicated that the lower trapezius (LT) muscle was abruptly inhibited on the dominant side during the descending phase of FLX, compared with the non-dominant side. Additionally, a remarkably higher ratio of upper trapezius to LT muscle EMG activity on the dominant side compared to that of the non-dominant side was identified during the descending phase from flexion. DISCUSSION: After identification of SD, an off season conservative treatment program allowed him to compete in his last college baseball season, appearing 22 times out of the bullpen in which he was credited four wins with a 3.70 earned run average (ERA) in 41.1 innings in 57 games. The SD test may play a critical role in identifying rehabilitation potential and guide the focus of the rehabilitation program to improve scapulothoracic stability and mobility for unilateral repetitive overhead athletes. Particularly the descending phase during sagittal plane motion (FLX/EXT) may effectively accentuate the scapular prominence during movement, portentially due to LT muscle activity inhibition. LEVEL OF EVIDENCE: 5 Case Report.