Robert C. Lynall

Concussion-Related Protocols and Preparticipation Assessments Used for Incoming Student-Athletes in National Collegiate Athletic Association Member Institutions

CONTEXT National Collegiate Athletic Association (NCAA) legislation requires that member institutions have policies to guide the recognition and management of sport-related concussions. Identifying the nature of these policies and the mechanisms of their implementation can help identify areas of needed improvement. OBJECTIVE To estimate the characteristics and prevalence of concussion-related protocols and preparticipation assessments used for incoming NCAA student-athletes. DESIGN Cross-sectional study. SETTING Web-based survey. PATIENTS OR OTHER PARTICIPANTS Head athletic trainers from all 1113 NCAA member institutions were contacted; 327 (29.4%) completed the survey. INTERVENTION(S) Participants received an e-mail link to the Web-based survey. Weekly reminders were sent during the 4-week window. MAIN OUTCOME MEASURE(S) Respondents described concussion-related protocols and preparticipation assessments (eg, concussion history, neurocognitive testing, balance testing, symptom checklists). Descriptive statistics were compared by division and football program status. RESULTS Most universities provided concussion education to student-athletes (95.4%), had return-to-play policies (96.6%), and obtained the number of previous concussions sustained by incoming student-athletes (97.9%). Fewer had return-to-learn policies (63.3%). Other concussion-history-related information (e.g., symptoms, hospitalization) was more often collected by Division I universities. Common preparticipation neurocognitive and balance tests were the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT; 77.1%) and Balance Error Scoring System (46.5%). In total, 43.7% complied with recommendations for preparticipation assessments that included concussion history, neurocognitive testing, balance testing, and symptom checklists. This was due to moderate use of balance testing (56.6%); larger proportions used concussion history (99.7%), neurocognitive testing (83.2%), and symptom checklists (91.7%). More Division I universities (55.2%) complied with baseline assessment recommendations than Division II (38.2%, χ2 = 5.49, P = .02) and Division III (36.1%, χ2 = 9.11, P = .002) universities. CONCLUSIONS National Collegiate Athletic Association member institutions implement numerous strategies to monitor student-athletes. Division II and III universities may need additional assistance to collect in-depth concussion histories and conduct balance testing. Universities should continue developing or adapting (or both) return-to-learn policies.

Head Impact Biomechanics in Women’s College Soccer

INTRODUCTION There are limited nonlaboratory soccer head impact biomechanics data. This is surprising given soccers global popularity. Epidemiological data suggest that female college soccer players are at a greater concussion injury risk than their male counterparts. Therefore, the purposes of our study were to quantify head impact frequency and magnitude during womens soccer practices and games in the National Collegiate Athletic Association and to characterize these data across event type, playing position, year on the team, and segment of game (first and second halves). METHODS Head impact biomechanics were collected from female college soccer players (n = 22; mean ± SD age = 19.1 ± 0.1 yr, height = 168.0 ± 3.5 cm, mass = 63.7 ± 6.0 kg). We employed a helmetless head impact measurement device (X2 Biosystems xPatch) before each competition and practice across a single season. Peak linear and rotational accelerations were categorized based on impact magnitude and subsequently analyzed using appropriate nonparametric analyses. RESULTS Overall, womens college soccer players experience approximately seven impacts per 90 min of game play. The overwhelming majority (~90%) of all head impacts were categorized into our mildest linear acceleration impact classification (10g-20g). Interestingly, a higher percentage of practice impacts in the 20g-40g range compared with games (11% vs 7%) was observed. CONCLUSION Head impact biomechanics studies have provided valuable insights into understanding collision sports and for informing evidence-based rule and policy changes. These have included changing the football kickoff, ice hockey body checking ages, and head-to-head hits in both sports. Given soccers global popularity, and the growing public concern for the potential long-term neurological implications of collision and contact sports, studying soccer has the potential to impact many athletes and the sports medicine professionals caring for them.

The relationship between clinically measured hip rotational motion and shoulder biomechanics during the pitching motion

OBJECTIVES To examine how clinically measured hip motion is related to shoulder biomechanics during the pitching motion. DESIGN Cross-sectional. METHODS Bilateral hip rotational range of motion was measured clinically among 34 collegiate baseball pitchers. External rotation torque and maximum horizontal adduction range of motion of the throwing shoulder were measured using a three-dimensional, high speed video capture system. RESULTS Separate standard multiple regression analyses showed that the total hip rotational range of motion of the lead leg had a significant relationship with shoulder external rotation torque during the throwing motion (r=0.56, P=0.003). Both lead leg hip external rotation range of motion (r=-0.39, P=0.02) and internal rotation range of motion (r=0.42, P=0.009) made significant contributions to this dependent variable. Lead leg external rotation range of motion also had a significant negative relationship with shoulder horizontal adduction range of motion (r=-0.36, P=0.04). The total rotational range of motion of the trail leg had a significant relationship with shoulder horizontal adduction range of motion (r=0.43, P=0.04). However, trail leg external rotation range of motion was the only significant contributor to this relationship (r=-0.35, P=0.04). No other significant relationships were noted (r<0.37, P>0.11). CONCLUSIONS Our results demonstrate that altered hip rotational range of motion, measured clinically, has a direct effect on the amount of external rotation torque and horizontal adduction range of motion of the shoulder during the throwing motion.

Effect of the mandible on mouthguard measurements of head kinematics.

Wearable sensors are becoming increasingly popular for measuring head motions and detecting head impacts. Many sensors are worn on the skin or in headgear and can suffer from motion artifacts introduced by the compliance of soft tissue or decoupling of headgear from the skull. The instrumented mouthguard is designed to couple directly to the upper dentition, which is made of hard enamel and anchored in a bony socket by stiff ligaments. This gives the mouthguard superior coupling to the skull compared with other systems. However, multiple validation studies have yielded conflicting results with respect to the mouthguard׳s head kinematics measurement accuracy. Here, we demonstrate that imposing different constraints on the mandible (lower jaw) can alter mouthguard kinematic accuracy in dummy headform testing. In addition, post mortem human surrogate tests utilizing the worst-case unconstrained mandible condition yield 40% and 80% normalized root mean square error in angular velocity and angular acceleration respectively. These errors can be modeled using a simple spring-mass system in which the soft mouthguard material near the sensors acts as a spring and the mandible as a mass. However, the mouthguard can be designed to mitigate these disturbances by isolating sensors from mandible loads, improving accuracy to below 15% normalized root mean square error in all kinematic measures. Thus, while current mouthguards would suffer from measurement errors in the worst-case unconstrained mandible condition, future mouthguards should be designed to account for these disturbances and future validation testing should include unconstrained mandibles to ensure proper accuracy.

Division I College Football Concussion Rates Are Higher at Higher Altitudes

STUDY DESIGN Retrospective cohort. BACKGROUND Participating in sports at high altitude may have a protective effect on the brain, according to research studies. Research using validated data-collection methods in a previously unexplored cohort may better estimate the association between concussion injury risk and altitude. OBJECTIVES To determine the association between concussion rates and altitude during college football games. METHODS Athletic trainers from 21 Division I football programs provided exposure and injury data to the National Collegiate Athletic Association (NCAA) Injury Surveillance Program (ISP) from the 2009-2010 to 2013-2014 academic years. The elevation of each stadium was determined. Concussion rates per 1000 athlete-exposures (AEs) were compared in 2 ways, based on the sample of stadium elevations: (1) median split (elevation higher than 178 m or lower than 178 m), and (2) quartile split. Rate ratios (RRs), rate differences, and 95% confidence intervals (CIs) were computed. RESULTS One hundred sixty-nine concussions were reported over 49 040 AEs (3.45/1000 AEs). Using the median split, the concussion rate above 178 m (RR = 4.18/1000 AEs) was 1.47 times the concussion rate below 178 m (RR = 2.84/1000 AEs; 95% CI: 1.09, 2.00; P = .01). The concussion rate at the highest altitude quartile (higher than 284 m; RR = 5.01/1000 AEs) was 1.67 times greater than the concussion rate at the lowest altitude quartile (lower than 43 m; RR = 3.00/1000 AEs; 95% CI: 1.13, 2.48; P = .01). CONCLUSION College football game concussion rates appear to increase at higher altitudes. The clinical significance of this relatively small increase is unknown. Future research should explore potential physiologic underpinnings associated with concussion risk at relatively higher and lower altitudes. LEVEL OF EVIDENCE Prognosis, level 2b.

High School Football Injury Rates and Services by Athletic Trainer Employment Status

CONTEXT Reported injury rates and services in sports injury surveillance may be influenced by the employment setting of the certified athletic trainers (ATs) reporting these data. OBJECTIVE To determine whether injury rates and the average number of AT services per injury in high school football varied by AT employment status. DESIGN Cross-sectional study. SETTING We used data from the National Athletic Treatment, Injury and Outcomes Network and surveyed ATs about their employment setting. PATIENTS OR OTHER PARTICIPANTS Forty-four responding ATs (37.9% of all National Athletic Treatment, Injury and Outcomes Network participants) worked at high schools with football programs and were included in this study. Fourteen ATs were full-time employees of the high school, and 30 ATs were employed as outreach ATs (i.e., full-time and part-time ATs from nearby clinics, hospitals, and graduate school programs). MAIN OUTCOME MEASURE(S) We calculated injury rates per 1000 athlete-exposures and average number of AT services per injury. RESULTS Reported injury rates and services per injury were greater among full-time school employees compared with outreach ATs. However, injury rates did not differ when restricted to time-loss injuries only. CONCLUSIONS Our findings suggest that ATs who are full-time school employees may be able to identify and care for more patients with injuries.

Epidemiology of National Collegiate Athletic Association men's and women's tennis injuries, 2009/2010–2014/2015

Background This study describes the epidemiology of mens and womens tennis injuries reported by the National Collegiate Athletic Association (NCAA) Injury Surveillance Program (ISP) during the 2009/2010–2014/2015 academic years. Methods Injuries and athlete-exposure (AE) data originated from 19 varsity mens programmes (38 team-seasons); womens tennis data originated from 25 varsity programmes (52 team-seasons). Injury rates, injury rate ratios (IRRs) and injury proportions ratios (IPRs) were reported with 95% CIs. Results The ISP captured 181 and 227 injuries for mens and womens tennis, respectively, for injury rates of 4.89 and 4.88/1000 AE for men and women, respectively. There were 32.2% and 63.9% reductions in mens and womens tennis practice injury rates between 2009/2010–2011/2012 and 2012/2013–2014/2015, but no reductions in competition injury rates. Competition injury rates were higher than practice injury rates in mens (IRR=2.32; 95% CI 1.72 to 3.13) and womens tennis (IRR=1.77; 95% CI 1.35 to 2.33). Most injuries in mens and womens tennis occurred to the lower extremities (47.0% and 52.4%, respectively), compared with the trunk (16.6% and 17.6%, respectively) and upper extremities (23.8 and 23.8, respectively). Conclusions Injury rates in NCAA mens and womens tennis were similar overall. Practice injury rates in mens and womens tennis have declined, although competition rates have not changed. These findings may help inform injury prevention programmes in the future.

Reliability and validity of the protokinetics movement analysis software in measuring center of pressure during walking

Our purpose was to determine the validity and test-retest reliability of the Protokinetics Movement Analysis Software (PKMAS) in measuring center of pressure (COP) during walking as compared to a force plate gold standard. Twenty-five healthy participants (14 females, 11 males; age 20.0±1.5years) completed 2 testing sessions approximately 5days apart (mean=5.5±1.1 days). In each session, participants completed 16 total trials across a 6m walkway: 8 trials walking on a ProtoKinetics Zeno Walkway using PKMAS and 8 trials walking over 2 force plates arranged in an offset tandem pattern. COP path length (cm) and speed (cm/s) were calculated from data averaged across the 8 trials on a given device for a given foot. Intraclass correlation coefficients (ICC 2, k) were computed to determine between session reliability. Pearson correlation coefficients (r) and Bland-Altman plots were produced between the PKMAS and force plate outcomes for session 1 to determine validity. The PKMAS demonstrated excellent reliability (ICC 2, k≥0.962) for all COP measures. Pearson correlation coefficients between PKMAS and force plates were ≥0.75 for all outcome variables. Bland-Altman plots and 95% levels of agreement revealed a bias where the PKMAS appeared to underestimate COP path length and speed by approximately 4cm and 6cm/s, respectively. After correcting for bias, our findings suggest the PKMAS is a reliable tool to measure COP in healthy people during gait. Using the PKMAS with the ProtoKinetics Zeno Walkway may allow for more efficient investigation of dynamic balance variables during functional movement tasks.

The effect of head impact location on day of diagnosed concussion in college football

INTRODUCTION Scientists and clinicians have attempted to identify and understand biomechanical factors that influence concussion likelihood. The effect of impact frequency to a given head location before the concussion has not been evaluated. The purpose of this study was to compare the frequency of impacts to a given head location on days of diagnosed concussion to the frequency of impacts to a given head location before kinematically matched nonconcussive impacts. METHODS Head impact data were gathered from 33 Division I National Collegiate Athletic Association football players. Twenty-four concussions were identified and matched with impacts of similar kinematic and injury criterion values (linear acceleration, rotational acceleration, Gadd severity index, and head injury criterion) that occurred during the same event type (game, practice, or scrimmage). In addition, these same matching criteria were used to match all players to the closest kinematic/same player group. All impacts within a session before the impact of interest (concussive or matched impact) were analyzed. RESULTS On days of diagnosed concussion, the concussive group sustained a lower percentage of impacts to the front of the head (34.5%) and a greater frequency of impacts to the sides (19.6%) and top (18.9%) of the head (χ(3) = 10.23, P = 0.017) as compared with the matched nonconcussive group (front = 42.5%, sides = 16.6%, top = 14.0%). No significant difference in frequency was found in impacts to the back of the head. CONCLUSION It may be more difficult to mitigate concussive forces sustained in impacts to the top and sides of the head than the front of the head. These findings fall in line with previous research demonstrating that reduced impact magnitudes may lessen concussion risk. Studying appropriate training paradigms to develop safer playing techniques on the field is warranted.

Lower Extremity Musculoskeletal Injury Risk After Concussion Recovery in High School Athletes

CONTEXT   Although an association between concussion and musculoskeletal injury has been described in collegiate and professional athletes, no researchers have investigated an association in younger athletes. OBJECTIVE   To determine if concussion in high school athletes increased the risk for lower extremity musculoskeletal injury after return to activity. DESIGN   Observational cohort study. SETTING   One hundred ninety-six high schools across 26 states. PATIENTS OR OTHER PARTICIPANTS   We used data from the National Athletic Treatment, Injury and Outcomes Network surveillance system. Athletic trainers provided information about sport-related concussions and musculoskeletal injuries in athletes in 27 sports, along with missed activity time due to these injuries. MAIN OUTCOME MEASURE(S)   Three general estimating equations were modeled to predict the odds of sustaining (1) any lower extremity injury, (2) a time-loss lower extremity injury, or (3) a non-time-loss lower extremity injury after concussion. Predictors were the total number of previous injuries, number of previous concussions, number of previous lower extremity injuries, number of previous upper extremity injuries, and sport contact classification. RESULTS   The initial dataset contained data from 18 216 athletes (females = 39%, n = 6887) and 46 217 injuries. Lower extremity injuries accounted for most injuries (56.3%), and concussions for 4.3% of total injuries. For every previous concussion, the odds of sustaining a subsequent time-loss lower extremity injury increased 34% (odds ratio [OR] = 1.34; 95% confidence interval [CI] = 1.13, 1.60). The number of previous concussions had no effect on the odds of sustaining any subsequent lower extremity injury (OR = 0.97; 95% CI = 0.89, 1.05) or a non-time-loss injury (OR = 1.01; 95% CI = 0.92, 1.10). CONCLUSIONS   Among high school athletes, concussion increased the odds of sustaining subsequent time-loss lower extremity injuries but not non-time-loss injuries. By definition, time-loss injuries may be considered more severe than non-time-loss injuries. The exact mechanism underlying the increased risk of lower extremity injury after concussion remains elusive and should be further explored in future research.