Sakiko Oyama

Asymmetric resting scapular posture in healthy overhead athletes.

CONTEXT Observation of the scapular posture is one of the most important components of the physical examination in overhead athletes. Postural asymmetry is typically considered to be associated with injuries. However, asymmetry in the overhead athletes scapula may be normal due to the dominant use of the limb. OBJECTIVE To quantify the differences in resting scapular posture between the dominant and nondominant sides in 3 groups of healthy overhead athletes (baseball pitchers, volleyball players, and tennis players) using an electromagnetic tracking device. DESIGN Cross-sectional design. SETTING University-based biomechanics laboratory. PATIENTS OR OTHER PARTICIPANTS A total of 43 players participated, including 15 baseball pitchers, 15 volleyball players, and 13 tennis players. All participants were healthy college-aged men. INTERVENTION(S) Bilateral 3-dimensional scapular kinematics with the arm at rest were measured using an electromagnetic tracking device. MAIN OUTCOME MEASURE(S) Bilateral scapular position and orientation were measured. Between-groups and between-sides differences in each variable were analyzed using separate analyses of variance. RESULTS In tennis players, the scapula was more protracted on the dominant side than on the nondominant side (P < .05). In all overhead athletes, the dominant-side scapula was more internally rotated (P = .001) and anteriorly tilted (P = .001) than the nondominant-side scapula was. CONCLUSIONS The dominant-side scapula of the overhead athletes was more internally rotated and anteriorly tilted than the nondominant-side scapula. The dominant-side scapula of the tennis players was more protracted than that on the nondominant side. Clinicians evaluating overhead athletes need to recognize that scapular posture asymmetry in unilateral overhead athletes may be normal. Our results emphasize the importance of the baseline evaluation in this population in order to accurately assess pathologic change in bilateral scapular positions and orientations after injury.

Reliability, Precision, Accuracy, and Validity of Posterior Shoulder Tightness Assessment in Overhead Athletes

Background Posterior shoulder tightness with subsequent loss of humeral internal rotation range of motion has been linked to upper extremity lesions in overhead athletes. A valid clinical assessment is necessary to accurately identify posterior shoulder tightness as a contributor to injury. Purpose To describe a modified supine assessment of posterior shoulder tightness by establishing the reliability, precision, clinical accuracy, and validity of the assessment. Study Design Cohort study (diagnosis); Level of evidence, 2. Methods Intrasession, intersession, and intertester reliability and precision were established by comparing the commonly used side-lying assessment of posterior shoulder tightness and the described modified supine assessment. Clinical accuracy of both methods was obtained using an electromagnetic tracking device to track humeral and scapular motion. Construct validity was established by identifying posterior shoulder tightness in a group of overhead athletes (baseball pitchers and tennis players) reported in the literature to have limited humeral internal rotation and posterior shoulder tightness. Results The side-lying intrasession intraclass correlation coeffecient (standard error of measurement), intersession intraclass correlation coeffecient (standard error of measurement), and intertester intraclass correlation coeffecient (standard error of measurement) were 0.83 cm (0.9), 0.42 cm (1.7), and 0.69 cm (1.4), respectively. The supine intrasession intraclass correlation coeffecient (standard error of measurement), intersession intraclass correlation coeffecient (standard error of measurement), and intertester intraclass correlation coeffecient (standard error of measurement) were 0.91° (1.1°), 0.75° (1.8°), and 0.94° (1.8°), respectively. In side-lying, the clinical accuracy expected was 0.9 ± 0.6 cm of error while, when measured supine, it was 3.5° ± 2.8° of error. Both assessments resulted in minimal scapular protraction (~3.5°). Between groups, baseball pitchers and tennis players had significantly less internal rotation range of motion (P < .0001) and greater posterior shoulder tightness (P = .004) when measured in supine, but not in side-lying (P = .312). Conclusion Both methods resulted in good clinician accuracy and precision, suggesting that both can be performed accurately. The supine method can be assessed more reliably than side-lying between both sessions and testers. Clinical Relevance Clinicians may want to consider use of the supine method given the higher reliability, validity, and similar precision and clinical accuracy.

Influence of humeral torsion on interpretation of posterior shoulder tightness measures in overhead athletes

Objective:To measure the influence of humeral torsion on interpretation of clinical indicators of posterior shoulder tightness in overhead athletes. Design:Cross-sectional control group comparison. Setting:A university-based sports medicine research laboratory. Participants:Twenty-nine healthy intercollegiate baseball players and 25 college-aged control individuals with no history of participation in overhead athletics were enrolled. Intervention:In all participants, bilateral humeral rotation and humeral horizontal adduction variables were measured with a digital inclinometry. Bilateral humeral torsion was measured with ultrasonography. Main Outcome Measures:Group and limb comparisons were made for clinical indicators of posterior shoulder tightness (humeral rotation and horizontal adduction variables) and humeral torsion variables. The relationship between humeral torsion and clinical indicators of posterior shoulder tightness were established. Results:The dominant limb of the baseball players demonstrated greater humeral torsion, and less internal rotation and total rotation range of motion, compared with control participants and the nondominant limb in both groups. Once corrected for torsion, no group or limb differences in internal rotation were present. Statistically significant relationships existed between the amount of humeral torsion and measures of posterior shoulder tightness. Conclusions:Although limb differences in clinical indicators of posterior tightness exist in healthy overhead athletes, these measures appear to be influenced by humeral torsion rather than soft tissue tightness. Once torsion is accounted for, the limb differences observed clinically were minimal in healthy overhead athletes. When possible, accounting for humeral torsion when interpreting clinical measures of posterior shoulder tightness may aid in treatment decisions.

Scapular dysfunction in high school baseball players sustaining throwing-related upper extremity injury: a prospective study

HYPOTHESIS AND BACKGROUND Though commonly suggested as an injury risk factor, scapular dysfunction has not been established as a prospective cause of throwing-related upper extremity injury in baseball players. The purpose is to determine whether scapular dysfunction identified during preseason screening is predictive of increased risk of throwing-related shoulder and elbow injuries in high school baseball players. MATERIALS AND METHODS The presence or absence of scapular dysfunction was obtained prospectively during preseason screenings in 246 high school baseball players over the 2010 and 2011 seasons. Exposure and injury surveillance data were then obtained weekly over the course of each season to determine whether scapular dysfunction was predictive of subsequent throwing-related upper extremities sustained. RESULTS There were 12 throwing-related upper extremity injuries sustained in the 246 participants, yielding an injury rate of 1.0 per 1,000 athlete exposures. There were no significant differences in injury rates between the participants with normal scapular function versus subtle scapular dysfunction (P = .62), normal scapular function versus obvious scapular dysfunction (P = .26), or subtle versus obvious scapular dysfunction (P = .45). CONCLUSION This study showed that scapular dysfunction identified during preseason screenings is not associated with subsequent throwing-related upper extremity injury.

Validity of Soccer Injury Data from the National Collegiate Athletic Association's Injury Surveillance System

CONTEXT Few validation studies of sport injury-surveillance systems are available. OBJECTIVE To determine the validity of a Web-based system for surveillance of collegiate sport injuries, the Injury Surveillance System (ISS) of the National Collegiate Athletic Associations (NCAA). DESIGN Validation study comparing NCAA ISS data from 2 fall collegiate sports (mens and womens soccer) with other types of clinical records maintained by certified athletic trainers. SETTING A purposive sample of 15 NCAA colleges and universities that provided NCAA ISS data on both mens and womens soccer for at least 2 years during 2005-2007, stratified by playing division. PATIENTS OR OTHER PARTICIPANTS A total of 737 mens and womens soccer athletes and 37 athletic trainers at these 15 institutions. MAIN OUTCOME MEASURE(S) The proportion of injuries captured by the NCAA ISS (capture rate) was estimated by comparing NCAA ISS data with the other clinical records on the same athletes maintained by the athletic trainers. We reviewed all athletic injury events resulting from participation in NCAA collegiate sports that resulted in 1 day or more of restricted activity in games or practices and necessitated medical care. A capture-recapture analysis estimated the proportion of injury events captured by the NCAA ISS. Agreement for key data fields was also measured. RESULTS We analyzed 664 injury events. The NCAA ISS captured 88.3% (95% confidence interval = 85.9%, 90.8%) of all time-lost medical-attention injury events. The proportion of injury events captured by the NCAA ISS was higher in Division I (93.8%) and Division II (89.6%) than in Division III (82.3%) schools. Agreement between the NCAA ISS data and the non-NCAA ISS data was good for the majority of data fields but low for date of full return and days lost from sport participation. CONCLUSIONS The overall capture rate of the NCAA ISS was very good (88%) in mens and womens soccer for this period.

Ultrasonographic Assessment of Humeral Retrotorsion in Baseball Players A Validation Study

Background: Recently, clinicians and researchers started using diagnostic ultrasound to measure humeral torsion as an alternative to radiological assessments in overhead-throwing athletes and other clinical populations. Ultrasound appears to be a reliable, nonradiological alternative, but ultrasound assessment has not been validated against computed tomography (CT), the current gold standard. Purpose: This study aimed to establish the validity of an ultrasound assessment of humeral torsion by comparing data obtained using both ultrasound and CT, the current standard. Study Design: Cohort study (Diagnosis); Level of evidence, 2. Methods: Humeral torsion was measured using both ultrasound and CT in 24 collegiate-aged baseball players. Comparisons between the assessments were made using both regression and Bland-Altman plots. Reliability and precision were also established. Results: A strong relationship existed between humeral torsion variables obtained with ultrasound and CT (R = .797, R2 = .635, P < .001). The ultrasound assessment yielded reliability coefficients ranging from .991 to .997, with approximately 1° of measurement error. The CT method’s reliability coefficients ranged from .805 to .933, with approximately 3.5° of measurement error. Conclusion: There was a strong relationship between humeral torsion obtained with ultrasound and CT, the current standard of assessment. Ultrasound provides a reliable, valid alternative to CT for obtaining an indication of the amount of humeral torsion in the upper extremity.

Humeral retrotorsion in collegiate baseball pitchers with throwing-related upper extremity injury history.

Background: Collegiate baseball pitchers, as well as position players, exhibit increased humeral retrotorsion compared with individuals with no history of overhead sport participation. Whether the humeral retrotorsion plays a role in the development of throwing-related injuries that are prevalent in collegiate baseball pitchers is unknown. Hypotheses: Humeral retrotorsion will be significantly different in collegiate pitchers with throwing-related shoulder or elbow injury history compared with pitchers with no injury history. Humeral retrotorsion can also discriminate participants with and without shoulder or elbow injury. Study Design: Cross-sectional study. Methods: Comparisons of ultrasonographically-obtained humeral retrotorsion were made between 40 collegiate pitchers with and without history of throwing-related shoulder or elbow injury. The ability of humeral retrotorsion to discriminate injury history was determined from the receiver operating characteristic area under the curve. Results: Participants with an elbow injury history demonstrated a greater humeral retrotorsion limb difference (mean difference = 7.2°, P = 0.027) than participants with no history of upper extremity injury. Participants with shoulder injury history showed no differences in humeral torsion compared with participants with no history of injury. Humeral retrotorsion limb difference exhibited a fair ability (receiver operating characteristic area under the curve = 0.74) to discriminate elbow injury history. Conclusions: Collegiate pitchers with a history of elbow injury exhibited a greater limb difference in humeral retrotorsion compared with pitchers with no history of injury. No differences in humeral retrotorsion variables were present in participants with and without shoulder injury history. Clinical Relevance: Baseball players with a history of elbow injury demonstrated increased humeral retrotorsion, suggesting that the amount of retrotorsion and the development of elbow injury may be associated.

Increase in Humeral Retrotorsion Accounts for Age-Related Increase in Glenohumeral Internal Rotation Deficit in Youth and Adolescent Baseball Players

Background: Glenohumeral internal rotation deficit (GIRD) is the difference in internal rotation range of motion (IRROM) between the dominant and nondominant limbs. Pathological GIRD of greater than 15° to 25° has previously been linked to shoulder and elbow injuries in baseball players. Because of its relationship to shoulder and elbow disorders, research has focused on understanding the underlying factors that contribute to changes in IRROM and ultimately GIRD. The rotation deficit reportedly increases during adolescence, but it remains unclear whether this change is caused by changes in osseous properties or soft tissue tightness. Purpose: To evaluate the influence of age group on GIRD, humeral retrotorsion, retrotorsion-adjusted GIRD, and total range of motion (TROM) in healthy baseball players. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Four groups of healthy baseball players participated in the study: 52 youth (aged 6-10 years), 52 junior high school (JH) (aged 11-13 years), 70 junior varsity (JV) (aged 14-15 years), and 113 varsity (aged 16-18 years) players. Internal rotation range of motion, external rotation range of motion (ERROM), and humeral retrotorsion were measured bilaterally using a digital inclinometer and diagnostic ultrasound. Retrotorsion-adjusted IRROM was calculated as the available IRROM from the humeral retrotorsion position; TROM was calculated as the sum of IRROM and ERROM; and GIRD, the difference in humeral retrotorsion between limbs, adjusted GIRD, and the difference in TROM between limbs were calculated as the difference between the dominant and nondominant sides. Four separate analyses of variance were used to compare these variables between age groups. Results: There was a significant group difference in GIRD (F3,284 = 8.957; P < .001) and a difference in humeral retrotorsion between limbs (F3,284 = 9.688; P < .001). Also, GIRD was greater in varsity participants compared with youth (mean difference [MD], 5.05°) and JH (MD, 4.95°) participants and in JV participants compared with JH (MD, 5.36°) and youth (MD, 5.47°) participants. The difference in humeral retrotorsion between limbs was greater in varsity participants compared with youth (MD, 8.79°) and JH (MD, 5.52°) participants and in JV participants compared with youth participants (MD, 7.88°). There were no significant differences in adjusted GIRD (F3,284 = 1.136; P = .335) or TROM (F3,284 = 1.214; P = .305). Conclusion: Glenohumeral internal rotation deficit and humeral retrotorsion increased with age in youth/adolescent baseball players, while retrotorsion-adjusted GIRD and TROM remained unchanged. An age-related increase in GIRD is primarily attributed to humeral retrotorsion rather than soft tissue tightness. Clinical Relevance: While there was an increase in GIRD from youth league to high school participants, TROM and retrotorsion-adjusted GIRD remained constant across the age groups, indicating that this increase between the age groups is not pathological GIRD and may not contribute to an increased injury risk.

Three-Dimensional Scapular and Clavicular Kinematics and Scapular Muscle Activity During Retraction Exercises

STUDY DESIGN Controlled laboratory study. OBJECTIVES To describe and compare scapular and clavicular kinematics and muscle activity during 6 retraction exercises in young healthy adults (mean +/- SD age, 23.2 +/- 2.4 years). BACKGROUND Based on the association between shoulder injuries and scapular/clavicular movement, muscle activity during various exercises that target muscles surrounding the scapula have been investigated. However, the scapular and clavicular movements occurring during these exercises remain uninvestigated. Evaluation of the scapular and clavicular kinematics in addition to muscle activity provides additional information that allow clinicians to select exercises that best meet the patients needs. METHODS Three-dimensional scapular and clavicular kinematics and scapular muscle activity data were collected while the participants performed 6 scapular retraction exercises. One-way repeated-measures ANOVA and post hoc analyses were used to determine differences in scapular/clavicular kinematics and activation levels of the upper, middle, and lower trapezius and serratus anterior muscles occurring during the exercises. RESULTS The general pattern of the kinematics observed during all retraction exercises was scapular external rotation, scapular upward rotation, scapular posterior tilting, clavicular retraction, and clavicular depression. However, the exercises resulted in varying amounts of scapular movement and muscle activity. CONCLUSION Clinicians can select appropriate exercises for their patients based on their need to strengthen specific retractor muscles and to improve specific scapular and clavicular movement patterns, pre-existing conditions, and available range of motion.

The effects of sleep quality and sleep quantity on concussion baseline assessment

Objective:Proper concussion assessment is imperative for properly caring for athletes who sustain traumatic brain injuries. Decreased sleep quality and sleep quantity affect cognition and may threaten the validity of clinical measures often used as a part of the concussion assessment. The purpose of this study was to determine if sleep quality or sleep quantity affects performance on clinical measures of concussion. Design:Prospective cohort design. Setting:Clinical research center. Participants:One hundred fifty-five college student-athletes (57 females, 98 males; age = 18.8 ± 0.8 years; mass = 78.4 ± 19.6 kg; height = 177.4 ± 12.3 cm). Interventions:We performed preseason baseline testing by using a well-accepted and multifaceted protocol inclusive of neurocognition, balance performance, and symptom reporting. Information related to sleep quality and sleep quantity was also collected during preseason baseline testing. Main Outcome Measures:The CNS Vital Signs battery (computerized neurocognitive test), Sensory Organization Test (computerized dynamic posturography), and a Graded Symptom Checklist (symptom evaluation) were used. Results:Subjects with a low sleep quantity the night before baseline reported both a greater number of symptoms and higher total symptom severity score. No clinically significant effects for sleep quality were observed. Conclusions:Sleep-deprived athletes reporting for baseline testing should be rescheduled for testing after a normal nights sleep.