Karen G. Roos

Epidemiology of Overuse Injuries in Collegiate and High School Athletics in the United States

Background: Overuse injuries result from microtrauma due to repetitive loading combined with insufficient tissue recovery time and can result in both immediate and long-term time loss from sports. Hypothesis: Overuse injury rates and patterns differ across college and high school populations, sport, and sex. Study Design: Descriptive epidemiology study. Methods: Surveillance data for 16 sports from the National Collegiate Athletic Association’s Injury Surveillance System (NCAA ISS; 2004-2005 through 2008-2009) and 14 sports from High School Reporting Information Online (High School RIO; 2006-2007 through 2012-2013) were analyzed. All reported injuries had an injury mechanism of overuse/gradual onset (college) or overuse/chronic (high school). Overuse injury incidence rates were calculated, and rate ratios with 95% CIs were used to compare subgroups. Results: The rate of overuse injury was 3.28 times higher in college than high school sports (95% CI, 3.12-3.44). The rate of overuse injury among sex-comparable sports was higher in female than male athletes in both populations (college rate ratio, 1.25; 95% CI, 1.16-1.35; high school rate ratio, 1.55; 95% CI, 1.43-1.68). The lower extremity was the most commonly injured body site (college, 69.4%; high school, 70.4%). A larger proportion of overuse injuries among college athletes resulted in time loss of more than 21 days (college, 20.4%; high school, 7.7%) and surgery (college, 5.2%, high school, 2.5%). Conclusion: Overuse injuries can impose a significant burden on college and high school athletes. Interventions addressing prevention of overuse injury are needed.

Definition and Usage of the Term “Overuse Injury” in the US High School and Collegiate Sport Epidemiology Literature: A Systematic Review

BackgroundA number of epidemiologic and surveillance-based studies of sports injury provide statistics on, and sometimes discussion of, overuse injuries. However, there is no consensus on the definition of “overuse.” Some studies consider “overuse” as a mechanism of injury while others use a diagnosis-based definition.ObjectiveThe objective of this study was to describe variation between studies in the definition and use of the term “overuse.”MethodsPubMed and SPORTDiscus databases were searched between May and November 2012 to find articles published or online ahead of printing pertaining to US high school or collegiate athletics, which were epidemiologic in nature. Inclusion criteria required that the article present data collected on athlete exposure and provided statistics pertaining to overuse injuries. PRISMA guidelines were adhered to, to the best ability of the authors.ResultsThe initial search resulted in 5,182 articles with potential for inclusion. After review of titles or abstracts where appropriate, 232 studies were read in entirety to determine if they were appropriate for inclusion. Of the 35 articles included, 13 used data from the National Collegiate Athletics Association’s Injury Surveillance System, 12 used data from the High School Reporting Information Online (RIO) injury surveillance system, and one used data from both of these systems. The remaining nine articles used data from distinct surveillance systems or prospectively collected data. All of these articles included data on overuse injuries, although not all provided definitions for overuse. A major finding from the literature is that the term “overuse” has been used both as a mechanism of injury and as an injury diagnosis (or a category of diagnoses). Specifically, of 35 articles, 14 used “overuse” as a mechanism of injury, seven used it as a category of injury diagnoses, eight used it as both a category of injury diagnoses and a mechanism of injury, and it was unclear in one how the term is used. Only one of the 35 articles provided a biomechanical definition for overuse injuries. Twelve of 35 articles combined “overuse” with other terms such as “chronic,” “gradual onset,” and “repetitive stress.” Use of the term “no contact” was investigated in relation to “overuse.” Four of 35 articles define overuse in the context of no contact injuries. Only one of 35 articles define “no contact” as a specific acute mechanism of injury, while all other mentions of “no contact” do not specifically distinguish whether “no contact” was limited to acute injuries only, or has potential to include “overuse” injuries.ConclusionThere is a great deal of inconsistency in the use of the term “overuse” both within and between data sources. This is further complicated by the multiple uses of the term “no contact.” We recommend that the term “overuse” only be used in regard to the mechanism of injury in order to enhance interpretation and understanding of the literature regarding overuse injuries and enhance the ability to compare results between studies. We also recommend the adoption of a common working definition of overuse injuries within injury surveillance. This definition should emphasize that overuse injuries are characterized by (1) a mechanism of gradual onset, and (2) an underlying pathogenesis of repetitive microtrauma.

The Epidemiology of Lateral Ligament Complex Ankle Sprains in National Collegiate Athletic Association Sports

Background: Ankle sprains are a common injury in collegiate sports. Few studies have examined the epidemiology of individual ligament injuries, specifically the lateral ligament complex (LLC) of the ankle. Purpose: To describe the epidemiology, including the estimated yearly national incidence, of LLC sprains among National Collegiate Athletic Association (NCAA) athletes. Study Design: Descriptive epidemiology study. Methods: Injury surveillance data for 25 sports from the NCAA Injury Surveillance Program (NCAA-ISP) for the academic years 2009-2010 to 2014-2015 were used for analysis. All injuries included for analysis had a diagnosis of an LLC sprain. LLC sprain rates and rate ratios (RRs) with 95% CIs were calculated. From the sample, national estimates of the annual incidence of LLC sprains across the entire student-athlete body from these 25 sports were also calculated. Results: During the 2009-2010 to 2014-2015 academic years, 2429 LLC sprains were reported, for a rate of 4.95 per 10,000 athlete-exposures (AEs). LLC sprains comprised 7.3% of all reported collegiate sports injuries in the NCAA-ISP. Also, an estimated 16,022 LLC sprains occurred annually among the 25 sports. The sports with the highest LLC sprain rates were men’s basketball (11.96/10,000 AEs) and women’s basketball (9.50/10,000 AEs). Most LLC sprains occurred during practices (57.3%); however, the LLC sprain rate was higher in competitions than in practices (RR, 3.29; 95% CI, 3.03-3.56). Also, 11.9% of LLC sprains were identified as recurrent injuries, with the largest proportions of recurrent LLC sprains being found within women’s basketball (21.1%), women’s outdoor track (21.1%), women’s field hockey (20.0%), and men’s basketball (19.1%). In 44.4% of LLC sprains, the athlete returned to play in less than 24 hours; in 3.6%, the athlete required more than 21 days before returning to play (including those who did not return to play at all). Conclusion: LLC sprains were the most commonly reported injury diagnosis among United States collegiate student-athletes. Continued examination of interventions that aim to reduce the incidence, severity, and recurrence of LLC sprains, specifically in women, is warranted.

Epidemiologic Measures for Quantifying the Incidence of Concussion in National Collegiate Athletic Association Sports

CONTEXT Injury rates compare the relative frequency of sport-related concussions across groups. However, they may not be intuitive to policy makers, parents, or coaches in understanding the likelihood of concussion. OBJECTIVE To describe 4 measures of incidence (athlete-based rate, athlete-based risk, team-based rate, and team-based risk) during the 2011-2012 through 2014-2015 academic years. DESIGN  Descriptive epidemiology study. SETTING Aggregate injury and exposure data collected from the National Collegiate Athletic Association Injury Surveillance Program in 13 sports (mens baseball, basketball, football, ice hockey, lacrosse, soccer, and wrestling and womens basketball, ice hockey, lacrosse, soccer, softball, and volleyball). PATIENTS OR OTHER PARTICIPANTS Collegiate student-athletes. MAIN OUTCOME MEASURE(S) Sport-related concussion data from the National Collegiate Athletic Association Injury Surveillance Program during the 2011-2012 through 2014-2015 academic years were analyzed. We calculated concussion rates per 1000 athlete-exposures (AEs), concussion risk, average number of concussions per team, and percentage of teams with at least 1 concussion. RESULTS During the 2011-2012 through 2014-2015 academic years, 1485 concussions were sustained by 1410 student-athletes across 13 sports. Concussion rates ranged from 0.09/1000 AEs in mens baseball to 0.89/1000 AEs in mens wrestling. Concussion risk ranged from 0.74% in mens baseball to 7.92% in mens wrestling. The average ± SD number of concussions per team ranged from 0.25 ± 0.43 in mens baseball to 5.63 ± 5.36 in mens football. The percentage of teams with a concussion ranged from 24.5% in mens baseball to 80.6% in mens football. CONCLUSIONS   Although mens wrestling had a higher concussion rate and risk, mens football had the largest average number of concussions per team and the largest percentage of teams with at least 1 concussion. The risk of concussion, average number of concussions per team, and percentage of teams with concussions may be more intuitive measures of incidence for decision makers. Calculating these additional measures is feasible within existing injury surveillance programs, and this method can be applied to other injury types.

Epidemiology of 3825 injuries sustained in six seasons of National Collegiate Athletic Association men's and women's soccer (2009/2010-2014/2015)

Aim To describe the epidemiology of National Collegiate Athletic Association (NCAA) mens and womens soccer injuries during the 2009/2010–2014/2015 academic years. Methods This descriptive epidemiology study used NCAA Injury Surveillance Program (NCAA-ISP) data during the 2009/2010–2014/2015 academic years, from 44 mens and 64 womens soccer programmes (104 and 167 team seasons of data, respectively). Non-time-loss injuries were defined as resulting in <24 h lost from sport. Injury counts, percentages and rates were calculated. Injury rate ratios (RRs) and injury proportion ratios (IPRs) with 95% CIs compared rates and distributions by sex. Results There were 1554 mens soccer and 2271 womens soccer injuries with injury rates of 8.07/1000 athlete exposures (AE) and 8.44/1000AE, respectively. Injury rates for men and women did not differ in competitions (17.53 vs 17.04/1000AE; RR=1.03; 95% CI 0.94 to 1.13) or practices (5.47 vs 5.69/1000AE; RR=0.96; 95% CI 0.88 to 1.05). In total, 47.2% (n=733) of mens soccer injuries and 47.5% (n=1079) of womens were non-time loss. Most injuries occurred to the lower extremity and were diagnosed as sprains. Women had higher concussion rates (0.59 vs 0.34/1000AE; RR=1.76; 95% CI 1.32 to 2.35) than men. Conclusions Non-time-loss injuries accounted for nearly half of the injuries in mens and womens soccer. Sex differences were found in competition injuries, specifically for concussion. Further study into the incidence, treatment and outcome of non-time-loss injuries may identify a more accurate burden of these injuries.

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.

Epidemiology of Football Injuries in the National Collegiate Athletic Association, 2004-2005 to 2008-2009

Background: Research has found that injury rates in football are higher in competition than during practice. However, there is little research on the association between injury rates and type of football practices and how these specific rates compare with those in competitions. Purpose: This study utilized data from the National Collegiate Athletic Association Injury Surveillance System (NCAA ISS) to describe men’s collegiate football practice injuries (academic years 2004-2005 to 2008-2009) in 4 event types: competitions, scrimmages, regular practices, and walkthroughs. Study Design: Descriptive epidemiological study. Methods: Football data during the 2004-2005 to 2008-2009 academic years were analyzed. Annually, an average of 60 men’s football programs provided data (9.7% of all universities sponsoring football). Injury rates per 1000 athlete-exposures (AEs), injury rate ratios (RRs), 95% CIs, and injury proportions were reported. Results: The NCAA ISS captured 18,075 football injuries. Most injuries were reported in regular practices (55.9%), followed by competitions (38.8%), scrimmages (4.4%), and walkthroughs (0.8%). Most AEs were reported in regular practices (77.6%), followed by walkthroughs (11.5%), competitions (8.6%), and scrimmages (2.3%). The highest injury rate was found in competitions (36.94/1000 AEs), followed by scrimmages (15.7/1000 AEs), regular practices (5.9/1000 AEs), and walkthroughs (0.6/1000 AEs). These rates were all significantly different from one another. Distributions of injury location and diagnoses were similar across all 4 event types, with most injuries occurring at the lower extremity (56.0%) and consisting of sprains and strains (50.6%). However, injury mechanisms varied. The proportion of injuries due to player contact was greatest in scrimmages (66.8%), followed by regular practices (48.5%) and walkthroughs (34.9%); in contrast, the proportion of injuries due to noncontact/overuse was greatest in walkthroughs (41.7%), followed by regular practices (35.6%) and scrimmages (21.9%). Conclusion: Injury rates were the highest in competitions but then varied by the type of practice event, with higher practice injury rates reported in scrimmage. In addition, greater proportions of injuries were reported in regular practices, and greater proportions of exposures were reported in regular practices and walkthroughs. Efforts to minimize injury in all types of practice events are essential to mitigating injury incidence related to both contact and noncontact.

Comparison of Indiana High School Football Injury Rates by Inclusion of the USA Football “Heads Up Football” Player Safety Coach

Background: In Indiana, high school football coaches are required to complete a coaching education course with material related to concussion awareness, equipment fitting, heat emergency preparedness, and proper technique. Some high schools have also opted to implement a player safety coach (PSC). The PSC, an integral component of USA Football’s Heads Up Football (HUF) program, is a coach whose primary responsibility is to ensure that other coaches are implementing proper tackling and blocking techniques alongside other components of the HUF program. Purpose: To compare injury rates in Indiana high school football teams by their usage of a PSC or online coaching education only. Study Design: Cohort study; Level of evidence, 2. Methods: Athletic trainers (ATs) evaluated and tracked injuries at each practice and game during the 2015 high school football season. Players were drawn from 6 teams in Indiana. The PSC group, which used the PSC component, was comprised of 204 players from 3 teams. The “education only” group (EDU), which utilized coaching education only, was composed of 186 players from 3 teams. Injury rates and injury rate ratios (IRRs) were reported with 95% confidence intervals (CIs). Results: During 25,938 athlete-exposures (AEs), a total of 149 injuries were reported, of which 54 (36.2%) and 95 (63.8%) originated from the PSC and EDU groups, respectively. The practice injury rate was lower in the PSC group than the EDU group (2.99 vs 4.83/1000 AEs; IRR, 0.62; 95% CI, 0.40-0.95). The game injury rate was also lower in the PSC group than the EDU group (11.37 vs 26.37/1000 AEs; IRR, 0.43; 95% CI, 0.25-0.74). When restricted to concussions only, the rate was lower in the PSC group (0.09 vs 0.73/1000 AEs; IRR, 0.12; 95% CI, 0.01-0.94), although only 1 concussion was reported in the PSC group. No differences were found in game concussion rates (0.60 vs 4.39/1000 AEs; IRR, 0.14; 95% CI, 0.02-1.11). Conclusion: Findings support the PSC as an effective method of injury mitigation in high school football. Future research should seek to replicate this study using larger samples from additional states.

Prevention and Management of Physical and Social Environment Risk Factors for Sports-Related Injuries

An understanding of the environmental factors that contribute to injury risk will allow for the optimization of athletic performance and minimize morbidity. The purpose of this review is to discuss the physical and social environments of sport that affect injury risk, and to review the strategies that sports medicine professionals (eg, clinicians, certified athletic trainers) can implement to prevent injury. Searches using the PubMed, Cochrane, and Google Scholar databases were used to identify injury risk factors pertaining to the physical and social environment of athletics. Physical environmental risk factors identified include weather, air quality, playing surface, and the presence of sports medicine professionals. Social environmental factors include parents, teammates, coaches, media, policy/legislation, and sports medicine professionals. Sports medicine professionals seeking effective prevention and care strategies will benefit from (1) education about the physical and social environmental risk factors that place athletes at risk for injury and (2) a holistic approach that recognizes that physical and social factors are as important as individual risk factors in determining injury risk.

Epidemiology of Shoulder Dislocations in High School and Collegiate Athletics in the United States: 2004/2005 Through 2013/2014

Background: Shoulder dislocations occur frequently in athletes across a variety of sports. This study provides an updated descriptive epidemiological analysis of shoulder dislocations among high school and college athletes and compares injury rates and patterns across these age groups. Hypothesis: There would be no difference in injury rates/patterns between high school and college athletes. Study Design: Descriptive epidemiology study. Level of Evidence: Level 3. Methods: Shoulder dislocation data from the High School Reporting Information Online (RIO) and the National Collegiate Athletic Association (NCAA) Injury Surveillance Program (ISP) databases were analyzed from the 2004/2005 through 2013/2014 (NCAA) or 2005/2006 through 2013/2014 (RIO) academic years in 11 different sports. Rate ratios (RRs) and injury proportion ratios (IPRs) were calculated to make comparisons between age groups. Results: During the study period, 598 shoulder dislocations were reported during 29,249,482 athlete-exposures (AEs) among high school athletes, for an overall shoulder dislocation rate of 2.04 per 100,000 AEs; 352 shoulder dislocations were reported during 13,629,533 AEs among college athletes, for an overall injury rate of 2.58 per 100,000 AEs. College athletes had a higher rate of shoulder dislocation than high school athletes (RR, 1.26; 95% CI, 1.11-1.44). However, the injury rate in football was lower in collegiate than high school athletes (RR, 0.52; 95% CI, 0.43-0.62). Surgery was performed to correct 28.0% of high school and 29.6% of college shoulder dislocations. Shoulder dislocations resulted in longer return-to-play times than other shoulder injuries. Conclusion: Overall, shoulder dislocation rates were higher among collegiate than high school athletes. This may be due to greater contact forces involved in sports at higher levels of play, although the increased rate in high school football warrants additional research. Clinical Relevance: Higher shoulder dislocation rates within collegiate athletics are likely due to the higher level of intensity at this level of play, with stronger and faster athletes resulting in more forceful collisions.