Elizabeth E. Hibberd

Epidemiology of Acromioclavicular Joint Sprains in 25 National Collegiate Athletic Association Sports 2009-2010 to 2014-2015 Academic Years

Background: No previous studies have described the incidence of acromioclavicular (AC) joint injuries in a large sample of National Collegiate Athletic Association (NCAA) student-athletes. Such data are needed to understand the injury prevalence, mechanisms of injury, and recovery patterns in NCAA student-athletes. Purpose: To describe the epidemiology of AC joint sprain injuries in 25 NCAA championship sports. Study Design: Descriptive epidemiology study. Methods: AC joint sprains were analyzed from the NCAA Injury Surveillance Program during the 2009-2010 to 2014-2015 academic years. AC joint sprain injury rates, rate ratios, and injury proportion ratios (IPRs) were reported with 95% CIs. Results: In the 25 NCAA sports examined during the 2009-2010 to 2014-2015 academic years, a total of 844 AC joint sprains were reported, for a rate of 1.72 per 10,000 athlete-exposures (AEs). The majority of AC joint sprains were reported in football (50.4%, n = 425). Most AC joint sprains occurred in competitions (66.0%, n = 557), and the competition rate was 8.58 times the practice rate (95% CI, 7.44-9.89). In sex-comparable sports (ie, soccer, basketball, ice hockey, lacrosse, baseball/softball, indoor track, outdoor track, cross-country, tennis, and swimming and diving), the AC joint sprain rate in men was 4.67 times that of women (95% CI, 3.56-6.14). Most AC joint sprains were caused by player contact (54.7%, n = 462), followed by surface contact (29.0%, n = 245). Of all AC joint sprains, 47.5% resulted in a time loss of <24 hours, and 5.9% were severe. In addition, 9.7% were recurrent, and only 1.0% required surgery. In sex-comparable sports, male athletes had a larger proportion of injuries due to player contact than did female athletes (IPR, 1.50; 95% CI, 1.06-2.13); female athletes had a larger proportion of injuries due to surface contact than male athletes (IPR, 1.55; 95% CI, 1.01-2.38). Also, compared with women, men had a larger proportion of AC joint sprains that were recurrent (IPR, 10.29; 95% CI, 1.45-72.90). Conclusion: The highest rates of AC joint sprains occurred in men’s football, ice hockey, and wrestling as well as women’s ice hockey. Most AC joint sprains across all sports occurred because of a contact mechanism, particularly from player-player contact. Further research into the specific activities and exposures at the time of injury may lend a better understanding of the causation of these injuries and lead to appropriate interventions to decrease their incidence and severity.

Dominant-Limb Range-of-Motion and Humeral- Retrotorsion Adaptation in Collegiate Baseball and Softball Position Players

CONTEXT Biomechanically, the motions used by baseball and softball pitchers differ greatly; however, the throwing motions of position players in both sports are strikingly similar. Although the adaptations to the dominant limb from overhead throwing have been well documented in baseball athletes, these adaptations have not been clearly identified in softball players. This information is important in order to develop and implement injury-prevention programs specific to decreasing the risk of upper extremity injury in softball athletes. OBJECTIVE To compare range-of-motion and humeral-retrotorsion characteristics of collegiate baseball and softball position players and of baseball and softball players to sex-matched controls. DESIGN Cross-sectional study. SETTING Research laboratories and athletic training rooms at the University of North Carolina at Chapel Hill. PATIENTS OR OTHER PARTICIPANTS Fifty-three collegiate baseball players, 35 collegiate softball players, 25 male controls (nonoverhead athletes), and 19 female controls (nonoverhead athletes). INTERVENTION(S) Range of motion and humeral retrotorsion were measured using a digital inclinometer and diagnostic ultrasound. MAIN OUTCOME MEASURE(S) Glenohumeral internal-rotation deficit, external-rotation gain, total glenohumeral range of motion, and humeral retrotorsion. RESULTS Baseball players had greater glenohumeral internal-rotation deficit, total-range-of-motion, and humeral-retrotorsion difference than softball players and male controls. There were no differences between glenohumeral internal-rotation deficit, total-range-of-motion, and humeral-retrotorsion difference in softball players and female controls. CONCLUSIONS Few differences were evident between softball players and female control participants, although range-of-motion and humeral-retrotorsion adaptations were significantly different than baseball players. The throwing motions are similar between softball and baseball, but the athletes adapt to the demands of the sport differently; thus, stretching/strengthening programs designed for baseball may not be the most effective programs for softball athletes.

Comparison of Upper Extremity Physical Characteristics Between Adolescent Competitive Swimmers and Nonoverhead Athletes.

CONTEXT Alterations to upper extremity physical characteristics of competitive swimmers (posture, range of motion [ROM], and subacromial-space distance) are commonly attributed to cumulative training load during a swimmers competitive career. However, this accepted clinical belief has not been established in the literature. It is important to understand whether alterations in posture and associated physical characteristics occur as a result of sport training or factors other than swimming participation to better understand injury risk and possible interventions. OBJECTIVE To compare posture, subacromial-space distance, and glenohumeral external-rotation, internal-rotation, and horizontal-adduction ROM between adolescent competitive swimmers and nonoverhead athletes. DESIGN Cross-sectional study. SETTING Local swimming pools and high school athletic training rooms. PATIENTS OR OTHER PARTICIPANTS Forty-four competitive adolescent swimmers and 31 nonoverhead athletes who were not currently experiencing any elbow, shoulder, neck, or back pain that limited their sport activity. INTERVENTION(S) Posture, subacromial-space distance, and glenohumeral ROM were measured using photography, diagnostic ultrasound, and a digital inclinometer, respectively. MAIN OUTCOME MEASURE(S) Forward shoulder posture, forward head posture, normalized subacromial-space distance, internal-rotation ROM, and external-rotation ROM. RESULTS No clinically significant differences existed between swimmers and nonoverhead athletes for posture, normalized subacromial-space distance, or external- or internal-rotation ROM. Swimmers presented with less horizontal-adduction ROM than nonoverhead athletes. CONCLUSIONS Factors other than swimming participation, such as school and technology use, play important roles in the adaptation of physical characteristics in adolescents. Adolescents, regardless of swimming participation, presented with postural deviations. It is important to consider factors other than swimming participation that contribute to alterations in physical characteristics to understand injury risk and injury-prevention strategies in competitive adolescent swimmers.

Assessing biological maturity: chronological age and the pubertal development scale predict free testosterone in adolescent males

Abstract Background: Pubertal development status has implications for development of physical characteristics, performance, and injury risk in school-aged athletes. Objective: The objective of this study was to evaluate the ability of non-invasive measures of biological maturity to predict salivary free testosterone. Participants: A total of 61 physically active males (ages 6–16) participated in this study. Methods: Participants had their anthropometrics measured, completed the Pubertal Development Scale (PDS), and reported their birthdays and the heights of their biological parents. Exact chronological age and percent of predicted height were calculated. Resting salivary samples were collected and assessed for free testosterone levels using enzyme-linked immunosorbent assay procedures. Variables were entered into a stepwise linear regression to predict free testosterone. Results: The regression model was statistically significant (R2=0.716, F2,61=74.2, p<0.005) with chronological age (β=0.66, t60=7.587, p<0.005) and PDS (β=0.26, t60=3.02, p=0.004) remaining as significant predictors of free testosterone. Conclusions: Chronological age and PDS adequately predict salivary free testosterone levels in school-aged males and may be an appropriate tool to evaluate physical maturity in school-aged males quickly, cheaply, and accurately.

Effect of Swim Training on the Physical Characteristics of Competitive Adolescent Swimmers

Background: Subacromial space distance and forward head and shoulder posture are common characteristics resulting from swim training. These alterations can cause abnormal scapular kinematics and positioning, potentially increasing compression of structures in the subacromial space and increasing the risk for the development of swimmer’s shoulder. Purpose: To evaluate the effect of the swim training season on subacromial space distance and forward head and forward shoulder posture as well as to determine the relationship between these variables. Study Design: Cohort study; Level of evidence, 2. Methods: Included in the study were 43 competitive adolescent swimmers and 29 nonoverhead adolescent athletes (controls) who were not currently experiencing any shoulder, neck, or back pain that limited their participation in sports activity. All participants were evaluated 3 times: once before the start of the swim training season and then at 2 follow-up sessions 6 and 12 weeks after the initial testing session. At each testing session, each participant completed a physical examination that included evaluation of posture and subacromial space distance. Results: Swimmers had significantly greater decreases in subacromial space distance during the training season compared with nonoverhead athletes. Swimmers also demonstrated significantly greater increases in forward shoulder posture compared with nonoverhead athletes. A significant relationship was noted between changes in forward shoulder posture and changes in subacromial space distance from the baseline testing session to the assessment 6 weeks after baseline assessment. As forward shoulder posture increased, subacromial space significantly decreased. Conclusion: Because of their training load, swimmers experience a decrease in subacromial space distance and an increase in forward shoulder posture over the course of 12 weeks of training, potentially making these athletes more vulnerable to the development of shoulder pain and injury.

Preseason screening of shoulder range of motion and humeral retrotorsion does not predict injury in high school baseball players

BACKGROUND Shoulder and elbow injuries are commonplace in high school baseball. Although altered shoulder range of motion (ROM) and humeral retrotorsion angles have been associated with injuries, the efficacy of preseason screening of these characteristics remains controversial. METHODS We conducted preseason screenings for shoulder internal and external rotation ROM and humeral retrotorsion on 832 high school baseball players and tracked their exposure and incidence on throwing-related shoulder and elbow injuries during a subsequent season. Poisson regression with robust error variance was used to determine whether preseason screening could identify injury risk in baseball players and whether the injury risk was higher for pitchers compared with players who do not pitch. RESULTS Shoulder rotation ROM or humeral retrotorsion at preseason did not predict the risk of throwing-related upper extremity injury (P = .15-.89). Injury risk was 3.84 higher for baseball players who pitched compared with those who did not (95% confidence interval, 1.72-8.56; P = .001). DISCUSSION Preseason measures of shoulder ROM and humeral retrotorsion may not be effective in identifying players who are at increased injury risk. Because shoulder ROM is a measure that fluctuates under a variety of influences, future study should investigate whether taking multiple measurements during a season can identify at-risk players. The usefulness of preseason screening may also depend on rigor of participation in sports. Future studies should investigate how preseason shoulder characteristics and participation factors (ie, pitch count and frequency, competitive level, pitching in multiple leagues) interact to predict injury risk in baseball players.

The Epidemiology of Deltoid Ligament Sprains in 25 National Collegiate Athletic Association Sports, 2009–2010 Through 2014–2015 Academic Years

CONTEXT   Deltoid ligament sprains among collegiate student-athletes have not been extensively investigated. Research regarding the mechanisms, participation-restriction time, and recurrence of deltoid ligament sprains in collegiate student-athletes is lacking. OBJECTIVE   To describe the epidemiology of deltoid ligament sprains in 25 National Collegiate Athletic Association championship sports. DESIGN   Descriptive epidemiology study. SETTING   National Collegiate Athletic Association Injury Surveillance Program. MAIN OUTCOME MEASURE(S)   We analyzed deltoid ligament sprains recorded in the Injury Surveillance Program for the 2009-2010 through 2014-2015 academic years. Deltoid ligament sprain injury rates, rate ratios, and injury proportion ratios with 95% confidence intervals (CIs) were reported. RESULTS   During the study period, 380 deltoid ligament sprains were reported, resulting in a combined injury rate of 0.79/10 000 athlete-exposures (AEs; 95% CI = 0.71, 0.87). Most deltoid ligament sprains occurred in practices (54.2%, n = 206). However, the competition injury rate was higher than the practice injury rate (rate ratio = 3.74; 95% CI = 3.06, 4.57). The highest deltoid ligament sprain rates were in womens gymnastics (2.30/10 000 AEs; 95% CI = 1.05, 3.55), mens soccer (1.73/10 000 AEs; 95% CI = 1.14, 2.32), womens soccer (1.61/10 000 AEs; 95% CI = 1.13, 2.09), and mens football (1.40/10 000 AEs; 95% CI = 1.18, 1.62). Nearly half of all deltoid ligament sprains (49.7%, n = 189) were due to player contact, and 39.5% (n = 150) were non-time-loss injuries (ie, participation restricted for less than 24 hours). Only 8.2% (n = 31) of deltoid ligament sprains were recurrent. CONCLUSIONS   The highest deltoid ligament sprain rates were in womens gymnastics, mens and womens soccer, and mens football. However, the rate for womens gymnastics was imprecise (ie, the CI was wide), highlighting the need for further surveillance of deltoid ligament sprains in the sport. Most deltoid ligament sprains were due to player contact. Future researchers should assess interventions that may prevent deltoid ligament sprains.

Rate of Upper Extremity Injury in High School Baseball Pitchers Who Played Catcher as a Secondary Position

CONTEXT   Many high school pitchers play another position after they have finished pitching for the day or on their rest days from pitching. Because of the cumulative demands on the arm, pitchers who also play catcher may have a greater risk of developing a throwing-related shoulder or elbow injury. OBJECTIVE   To compare the rate of throwing-related upper extremity injuries between high school baseball pitchers who also played catcher as a secondary position and those who did not play catcher. DESIGN   Prospective cohort study. SETTING   Field laboratory. PATIENTS OR OTHER PARTICIPANTS   A total of 384 male high school baseball pitchers were recruited from 51 high school teams. Pitchers who reported their secondary position as catcher were classified into the pitcher/catcher group and those who did not report playing catcher as a secondary position were classified into the other group. MAIN OUTCOME MEASURE(S)   Participants completed a demographic questionnaire preseason and then athlete participation and injury status were tracked during the subsequent season. Athlete-exposures were monitored and the shoulder and elbow injury proportion rates were calculated. RESULTS   Athlete-exposures did not differ between groups ( P = .488). The pitcher/catcher groups risk of shoulder or elbow injury was 2.9 times greater than that of the other pitchers (15% versus 5%; injury proportion rate = 2.9; 95% confidence interval = 1.03, 8.12). CONCLUSIONS   Pitchers who reported also playing catcher were at a greater risk of sustaining a throwing-related shoulder or elbow injury than the other pitchers. These findings suggest that pitchers should consider not playing catcher as their secondary position in order to allow adequate time for recovery and to decrease their overall throwing load. Serial physical examinations of pitchers/catchers during the season may be useful in determining if their physical characteristics are changing during the season because of the cumulative throwing load.

Ecological Influences on Employees’ Workplace Sedentary Behavior: A Cross-Sectional Study

Purpose: The purpose of this study was to explore the relationship between ecological factors and occupational sedentary behavior (SB). Design: Cross-sectional online survey. Setting: Participants were employees recruited from a large, public university in the Southeastern United States from August to November 2016. Participants: The final sample included 527 (56% response rate) employees. Measures: Data were collected through an 87-item survey using previously validated scales that assessed occupational SB, perceived behavioral control, barrier self-efficacy, self-regulation strategies, organizational social norms, office environment, and worksite climate. Analysis: One-way analysis of variance analyses were used to determine differences in occupational SB by demographic factors. A multivariate regression model was used to determine significant ecological determinants of occupational SB. Results: Mean SB was 342.45 (standard deviation = 133.25) minutes. Significant differences in SB were found by gender, education, and employment classification. Barrier self-efficacy and workplace connectivity, which evaluates the spatial layout of the office setting that may impact mobility within the workplace, were significant predictors of SB in the multivariate model. Conclusion: Results from this study provide new information regarding the potential impact of workplace barriers and connectivity on occupational SB. The findings from this study support the inclusion of intervention modalities to minimize workplace barriers and increase workplace connectivity to increase workplace mobility and decrease SB.

Comparison of Scapular Kinematics and Range of Motion Between Normal and Post-operative Shoulders Following Subpectoral Biceps Tenodesis

Objectives: Though many surgeons advocate biceps tenodesis for treatment of intra-articular biceps pathology, little is known about the biomechanical effects this may have on the glenohumeral joint. The purpose of the present study is to describe in detail the effect of biceps tenodesis on shoulder muscle strength, range of motion, and scapular motion. We hypothesized that post-surgical shoulders would not show significant differences in range of motion, strength, and kinematics when compared to the uninvolved shoulder. Methods: 22 patients underwent a subpectoral biceps tenodesis and were evaluated at least 6 months following the procedure. We evaluated range of motion, strength, and scapular kinematics. Measures included glenohumeral abduction, internal and external rotation, elbow flexion and extension, internal and external rotation strength, and scapular kinematics. Subjects also completed the DASH questionnaire. Results: The average DASH score was 5.3 +/- 6.3 following surgery. The post-surgical shoulder showed a significant 8.3 degree decrease (p = 0.003) in glenohumeral abduction external rotation compared to the uninvolved shoulder. However, there were no significant differences in other measurements of glenohumeral motion or strength. Kinematic data revealed significantly increased scapular internal rotation (p = 0.02) and anterior tipping (p = 0.019) while reaching for the contralateral shoulder. Conclusion: The majority of outcome measures were equivalent when comparing the post-surgical and uninvolved shoulder function and biomechanics. Significant findings include a loss of glenohumeral abduction external rotation after surgery as well as anterior scapular tipping and rotation while reaching for the contralateral shoulder. Overall, subjects expressed minimal disability following surgery, as evidenced by their DASH scores. Nonetheless, we recommend a vigilant focus on regaining external rotation following open subpectoral biceps tenodesis in an attempt to limit or prevent loss of shoulder motion.