Abstract
BACKGROUND: We compared injury incidence and mechanisms among youth, high school (HS), and National Collegiate Athletic Association (NCAA) boys’ and men’s lacrosse athletes for the 2014–2015 to 2016–2017 lacrosse seasons.
METHODS: Multiple injury surveillance systems were used to capture 21 youth boys’, 22 HS boys’, and 20 NCAA men’s lacrosse team-seasons of data during the 2014–2015 to 2016–2017 seasons. Athletic trainers reported game and practice injuries and athlete exposures (AEs). Injuries included those occurring during a game and/or practice and requiring evaluation from an athletic trainer and/or physician. Injury counts, rates per 1000 AEs, and injury rate ratios (IRRs) with 95% confidence intervals (CIs) were calculated.
RESULTS: The injury rate in youth was higher than those reported in HS (10.3 vs 5.3 per 1000 AEs; IRR = 2.0; 95% CI: 1.6–2.4) and the NCAA (10.3 vs 4.7 per 1000 AEs; IRR = 2.2; 95% CI: 1.9–2.5). When considering time loss injuries only (restricted participation of ≥24 hours), the injury rate in youth was lower than those reported in HS (2.0 vs 2.9 per 1000 AEs; IRR = 0.7; 95% CI: 0.5–0.95) and the NCAA (2.0 vs 3.3 per 1000 AEs; IRR = 0.6; 95% CI: 0.4–0.8). The concussion rate in youth was higher than those in HS (0.7 vs 0.3 per 1000 AEs; IRR = 2.4, 95% CI: 1.1–5.2) and the NCAA (0.7 vs 0.3 per 1000 AEs; IRR = 2.1, 95% CI: 1.2–3.7). Injuries at the youth, HS, and NCAA levels were most commonly associated with stick contact, inflammatory conditions (including bursitis, tendonitis, and other unspecified inflammation), and noncontact mechanisms, respectively.
CONCLUSIONS: Although the time loss injury rate was lowest in youth boys’ lacrosse, the concussion rate was the highest. Injury prevention approaches should be specific to the mechanisms associated with each level of play (eg, equipment skill development in youth).
- AE —
- athlete exposure
- HS —
- high school
- IRR —
- injury rate ratio
- ISP —
- Injury Surveillance Program
- IST —
- Injury Surveillance Tool
- LADM —
- Lacrosse Athlete Development Model
- NATION —
- National Athletic Treatment, Injury, and Outcomes Network
- NCAA —
- National Collegiate Athletic Association
What’s Known on This Subject:
Researchers have yet to compare injury incidence across youth boys’, high school boys’ and college men’s lacrosse using the same methodologies. Such comparisons would help elucidate how level of play may be associated with injury risk and tailor prevention interventions.
What This Study Adds:
This study is the first to compare lacrosse injury incidence across 3 levels of play. Youth boys’ lacrosse had the lowest time loss injury rate and highest all-injury and concussion rates. Equipment contact-related injuries were more likely among youth boys.
In the past decade, lacrosse has been 1 of the fastest growing sports in the United States.1 As of 2016, an estimated 292 695 youth boys <14 years of age, 180 399 high school (HS) boys, and 25 365 college men participated in lacrosse.1 HS and National Collegiate Athletic Association (NCAA) participation data suggest that steady increases occurred within the past decade.2,3
Boys’ and men’s lacrosse injury surveillance data are available at the youth,4,5 HS,6 and college7,8 levels. Yet, researchers have yet to compare injury incidence across these levels using the same methodologies. Such comparisons would help elucidate how level of play may be associated with injury risk and help tailor injury prevention interventions to each setting.
This surveillance study is used to describe the epidemiology of sport-related injury among male lacrosse players at the youth, HS, and NCAA levels. We hypothesized that injury rates would be higher in higher levels of play. Sports injury surveillance for youth boys’ lacrosse was developed, with resulting data from the 2014–2015 to 2016–2017 seasons compared with data from the National Athletic Treatment, Injury, and Outcomes Network (NATION) and the NCAA Injury Surveillance Program (ISP).
Methods
In this study, we used surveillance data from samples of youth boys’, HS boys’, and NCAA men’s lacrosse athletes during the 2014–2015 to 2016–2017 seasons. HS and NCAA data originated from NATION and NCAA ISP, respectively, with methods for each having been previously described.9,10 The youth lacrosse surveillance program was modeled after NATION and NCAA ISP and is similar to previous youth football surveillance efforts.11,12 The youth lacrosse surveillance and NATION protocols were approved by the Western Institutional Review Board (Puyallup, WA); the NCAA ISP protocol was approved by the NCAA Research Review Board (Indianapolis, IN).
Study Sample
Youth lacrosse data originated from 10 youth boys’ lacrosse leagues (with ages ranging from 9 to 15 years) in 5 states providing 21 league-seasons of data over the 3-year period. NATION included 20 HS boys’ lacrosse programs providing 22 team-seasons of data. The NCAA ISP included 15 NCAA men’s lacrosse programs providing 20 team-seasons of data.
Data Collection
On-site athletic trainers reported injury data from games and practices into an electronic medical record. NCAA athletic trainers were employed by their college or university. HS athletic trainers were either employed by their HS or provided by outreach entities (university or hospital system). All youth athletic trainers were employed by outreach entities.
At the youth level, all athletic trainers were provided with and trained to use an electronic medical record called the Injury Surveillance Tool (IST) (Datalys Center, Indianapolis, IN). The IST was initially created for use with the NCAA ISP but was later updated to be compatible for other systems. At the HS and NCAA levels, lacrosse athletic trainers could use the IST or their institution’s electronic medical record application.9,10 Athletic trainers were trained by Datalys Center staff to use their electronic medical records in the context of surveillance.
For all systems, an athlete exposure (AE) was defined as 1 player participating in 1 game or 1 practice. An injury was defined as occurring during a game or practice that required evaluation from an athletic trainer or physician. A time loss injury restricted participation for ≥24 hours from injury onset. Athletic trainers completed detailed reports on each injury, including information on event type (ie, practice or competition), body part injured, injury mechanism, and diagnosis. Athletic trainers also noted whether body checking was a primary factor associated with the injury. After initially inputting injury data, athletic trainers could return to update the data as needed within a season, such as when an athlete returned to sports participation. Data went through automated verification procedures to prevent invalid data and were also checked by Datalys Center staff who worked with athletic trainers to resolve any pertinent issues.
Statistical Analyses
Data were analyzed using SAS software (version 9.4; SAS Institute, Inc, Cary, NC). Frequencies, injury rates per 1000 AEs, and injury distributions were calculated for all injuries and time loss injuries only. Injury distributions for body part were presented with categories for head, face, and/or neck, upper extremity, trunk, lower extremity, and other (including systemic ailments such as heat illness); frequencies for subcategories within the upper and lower extremities were also calculated. Injury mechanism categories included player contact, surface contact, equipment contact (with subcategories for ball contact and stick contact), out-of-bounds object contact, noncontact, overuse, illness or infection, and other. We also computed the percentage of injuries associated with body checking. Diagnosis categories were concussion, contusion, fracture, inflammatory condition (including bursitis, tendonitis, and other unspecified inflammation), sprain, strain, and other.
Injury rate ratios (IRRs) with 95% confidence intervals (CIs) were used to compare injury rates across levels of play. IRRs were not calculated when a level of play category had <10 injuries nor for subcategories within the upper and lower extremities or equipment contact. IRRs with a 95% CI not including 1.00 were considered statistically significant.
Results
Injury Frequencies and Rates
In youth boys’ lacrosse, athletic trainers reported 268 injuries during 26 070 AEs (all-injury rate of 10.3 per 1000 AEs; 95% CI: 9.0–11.5; Table 1). With 51 injuries (19.0%) being time loss, the time loss injury rate was 2.0 per 1000 AEs (95% CI: 1.4–2.5). In HS boys’ lacrosse, athletic trainers reported 191 injuries during 36 315 AEs (all-injury rate of 5.3 per 1000 AEs; 95% CI: 4.5–6.0). With 104 injuries (54.5%) being time loss, the time loss injury rate was 2.9 per 1000 AEs (95% CI: 2.3–3.4). In NCAA men’s lacrosse, athletic trainers reported 544 injuries during 114 719 AEs (all-injury rate of 4.7 per 1000 AEs; 95% CI: 4.3–5.1). With 377 injuries (69.3%) being time loss, the time loss injury rate was 3.3 per 1000 AEs (95% CI: 3.0–3.6).
Injury Counts and Rates per 1000 AEs With 95% CIs in Youth Boys’, HS Boys’, and NCAA Men’s Lacrosse (2014–2015 to 2016–2017 Seasons)
The all-injury rate in youth was higher than those in HS (IRR = 2.0; 95% CI: 1.6–2.4) and the NCAA (IRR = 2.2; 95% CI: 1.9–2.5). However, the time loss injury rate in youth was lower than those in HS (IRR = 0.7; 95% CI: 0.5–0.95) and the NCAA (IRR = 0.6; 95% CI: 0.4–0.8). No differences were found in injury rates between HS and the NCAA (all-injury IRR = 1.1; 95% CI: 0.9–1.3; time loss injury IRR = 0.9; 95% CI: 0.7–1.1).
Injury Distributions
Injury distributions and rates are presented for all injuries by body part injured (all injuries: Table 2; time loss injuries only: Table 3), injury mechanism (all injuries: Table 4; time loss injuries only: Table 5), and diagnosis (all injuries: Table 6; time loss injuries only: Table 7). Table 8 presents the most common specific injuries at each level. The following section summarizes the key findings.
Injury Counts and Rates per 1000 AEs With 95% CIs in Youth Boys’, HS Boys’, and NCAA Men’s Lacrosse, by Body Part (2014–2015 to 2016–2017 Seasons)
Time Loss Injury Counts and Rates per 1000 AEs With 95% CIs in Youth Boys’, HS Boys’, and NCAA Men’s Lacrosse, by Body Part (2014–2015 to 2016–2017 Seasons)
Injury Counts and Rates per 1000 AEs With 95% CIs in Youth Boys’, HS Boys’, and NCAA Men’s Lacrosse, by Injury Mechanism (2014–2015 to 2016–2017 Seasons)
Time Loss Injury Counts and Rates per 1000 AEs With 95% CIs in Youth Boys’, HS Boys’, and NCAA Men’s Lacrosse, by Injury Mechanism (2014–2015 to 2016–2017 Seasons)
Injury Counts and Rates per 1000 AEs With 95% CIs in Youth Boys’, HS Boys’, and NCAA Men’s Lacrosse, by Diagnosis (2014–2015 to 2016–2017 Seasons)
Time Loss Injury Counts and Rates per 1000 AEs With 95% CIs in Youth Boys’, HS Boys’, and NCAA Men’s Lacrosse, by Diagnosis (2014–2015 to 2016–2017 Seasons)
Most Common Injuries in Youth Boys’, HS Boys’, and NCAA Men’s Lacrosse (2014–2015 to 2016–2017 Seasons)
Across all 3 levels, most injuries occurred to the lower extremity (Table 2). All-injury rates were generally highest in youth across most body parts. Also, the time loss head, face, and/or neck injury rate in youth was higher than those in HS (IRR = 1.9; 95% CI: 1.01–3.6) and the NCAA (IRR = 2.3; 95% CI: 1.4–3.9). However, the time loss lower extremity injury rate in the NCAA was higher than those in youth (IRR = 2.8; 95% CI: 1.8–4.4) and HS (IRR = 1.3; 95% CI: 1.02–1.8); the time loss lower extremity injury rate was also higher in HS than that in youth (IRR = 2.1; 95% CI: 1.3–3.4).
Nearly half of all youth injuries were due to equipment contact (49.6%), with the majority being from stick contact (35.8% of all injuries), followed by ball contact (13.8% of all injuries; Table 4). Equipment contact comprised the largest proportion of HS injuries (26.2%) but only 8.6% of NCAA injuries. Equipment contact was associated with 52.8%, 42.9%, and 16.7% of all head, face, and/or neck injuries in youth, HS, and the NCAA, respectively. When comparing all-injury rates across levels by injury mechanism, injury rates were generally the highest in youth. The exceptions were noncontact injury rates, which were the highest in the NCAA, and overuse injury rates, which were the highest in HS.
There were 14 checking-related injuries in youth (5.2%), 9 in HS (4.7%), and 10 in the NCAA (1.8%). Of these, only 2 HS and 3 NCAA were time loss injuries. Youth had the highest checking-related all-injury rate (0.5 per 1000 AEs; 95% CI: 0.3–0.8); this rate was significantly higher than that in the NCAA (IRR = 6.2; 95% CI: 2.7–13.9).
The most common injury was contusions in youth (52.6%) and HS (25.1%; Table 6), of which most were to the arm and/or elbow (youth = 22.9%; HS = 15.6%) and the trunk (youth = 20.8%; HS = 20.8%). Strains and sprains were the most common diagnoses in the NCAA (27.4% and 23.3%, respectively). Most strains were to the thigh and/or upper leg (49.0%) and hip and/or groin (20.1%), whereas most sprains were to the ankle (48.8%) and knee (26.0%).
Few concussions were reported in youth and HS (17 and 10, respectively); 36 concussions were reported in the NCAA. Concussions comprised 35.4%, 47.6%, and 66.7% of all head, face, and/or neck injuries in youth boys’, HS boys’, and NCAA men’s lacrosse, respectively. Most concussions were due to player contact (youth: 58.8%; HS: 50.0%; NCAA: 77.8%). However, 29.4% (n = 5) of concussions in youth were due to stick contact, and 30.0% (n = 3) of concussions in HS were due to ball contact. Youth had the highest concussion rate (0.7 per 1000 AEs; 95% CI: 0.3–1.0). It was significantly higher than those in HS (IRR = 2.4; 95% CI: 1.1–5.2) and the NCAA (IRR = 2.1; 95% CI: 1.2–3.7).
Discussion
We hypothesized that injury rates would be the highest among NCAA men and lower in HS and youth. In actuality, our data revealed that youth boys had the highest all-injury rate but the lowest time loss injury rate. Differences in injury rates and distributions across the 3 levels may highlight variations in what injuries present to pediatricians. Likewise, prevention efforts must be cognizant of level-specific variations in player skill, rules, and game play. Pediatricians should encourage parents to consult them before their children’s lacrosse participation to ensure they are aware about injury risk.
Injury Rates
The variations in all-injury and time loss injury rates among the 3 levels are likely due to the focus of youth lacrosse on skill acquisition, whereas HS and NCAA lacrosse may be more focused on competition. Skill acquisition often results in less severe injuries because of the emphasis on learning specific movement patterns rather than full-contact game situations, which often lead to the relatively more severe time loss injuries.11,12 With our results, we highlight this as the proportion of injuries that were time loss increased from youth (19.0%) to HS (54.5%) to the NCAA (69.3%). This shift in injury severity by level of play has been seen in both football and wrestling.13,14 Other theories include athletes at higher levels play more competitively and aggressively,13–17 and older players have greater body mass and speed, which has been associated with increased injury risk in other contact sports.18–20
Although our study was focused on time loss injuries, it is important to acknowledge the presence of non–time loss injuries (ie, injuries resulting in participation restriction time <24 hours) along time loss injuries. Reporting and documenting practices among athletes and athletic trainers may vary by level of play. Younger athletes may seek care more often for non–time loss injuries than athletes at higher levels of play21 (hence the lower proportions of time loss injuries at higher levels of play). Reporting practices among athletic trainers may also vary.22,23 Ultimately, medical professionals can only treat and document those injuries that are reported; therefore, the reporting practices of the athletes themselves cannot be discounted. All injuries regardless of participation restriction time should receive proper care to mitigate prolonged recovery and prevent reinjury.24–26 Injury documentation will also help ensure physicians have a more complete injury history as athletes continue participation.
League adoption and proper enforcement of age-appropriate rules by officials may limit injuries.27 Similarly, coaching certification and education programs may assist in teaching young athletes lacrosse-specific skills,28 particularly related to stick use, or using neuromuscular control exercises.29,30 Although we did not examine its use or effectiveness, a focus on developmentally appropriate sport and skill acquisition (eg, Lacrosse Athlete Development Model [LADM])31 may limit initial injuries and have a preventive effect later in an athletic career. The initial stages of the LADM occur at the youth level, with latter stages being focused on the HS and collegiate levels. Possibly, the success of the LADM relies on its adoption across multiple levels and settings for lacrosse.
Concussion Incidence
Concussion rates were the highest in youth boys’ lacrosse, which differs from similar tackle football-related research across competition levels.32 Concussion counts were low (youth = 17; HS = 10; NCAA = 36) and yielded rate estimates with wide CIs. Still, the high concussion incidence in youth highlights the need to ensure medical care is accessible to youth athletes. Alongside some HS sport settings,33 on-site medical coverage is often limited in youth settings, which may result in parents of concussed children seeking medical services from their primary care pediatricians34 and/or urgent care physicians or not seeking medical evaluation. Compared with previously estimated concussion rates in youth, HS, and NCAA football (range of 0.8–1.0 per 1000 AEs), our concussion rates in lacrosse were lower.32 Still, pediatricians should be aware of the potential concussion risk in lacrosse and ensure they and the parents with whom they work are well educated on concussion management.
Although concussion-related policy and legislation exist within the NCAA35 and at the state level,36 HS-level compliance may vary,37,38 and youth sports-related policy and legislation may not be fully implemented or even exist. Concussion prevention needs to consider multiple levels of influence.39 For example, because most concussions occurred from player contact across all 3 levels, prevention can be focused on skill acquisition at an early age that is then further validated at older levels of play, with emphasis placed on “heads up, eyes up play” alongside greater open field collision anticipation. Pediatricians working with youth sports can serve as advocates for such prevention incorporated into skill development.
Lower Extremity Injuries
Large proportions of lower extremity injuries were found across all 3 levels. However, injury rates at this body region generally increased as level of play increased, similar to previous lacrosse research.6,15,17,40–42 Pediatricians could recommend the use of neuromuscular control exercises because these have been suggested to be effective in other settings.29,30
US Lacrosse has developed a warm-up and exercise program known as LaxPrep that incorporates dynamic warm-ups and emphasizes core strength, balance, and proper landing techniques.43 Although LaxPrep has yet to be scientifically evaluated, it is important to consider how its use may vary by level. For example, LaxPrep may have a smaller impact in youth settings in which noncontact injuries were relatively rare. In contrast, LaxPrep may be most effective at the NCAA level for which noncontact injury rates were the highest. At the HS level, for which overuse injury rates were the highest, LaxPrep may also need to consider the more time-intensive and rigorous practice schedules that are aimed to improve skill. Such scheduling may induce fatigue, which may have adverse effects on lower extremity biomechanics and thus increase injury risk.44,45
Contact-Related Injury Mechanisms
Youth boys’ lacrosse had the highest equipment contact (ie, stick- and ball-related) injury rate, and 4 of the 5 most common injuries were associated with stick contact. Pediatricians working with lacrosse athletes should encourage appropriate stick type and well-fitted safety equipment.46 As younger players learn the technical aspects of the game, such as body positioning and stick game play, they may be predisposed to injury given having less experience. As they develop their skills, injury risk may decrease, which is illustrated by the decreasing equipment contact injury rate from youth to HS to the NCAA. Continued emphasis on skills development is needed, but all stakeholders within a lacrosse setting, including the pediatricians that serve athletes, should advocate for age-appropriate training and game play. US Lacrosse resources, such as the LADM31 and rule books used to outline developmentally appropriate game play, are available for use. Also, to mitigate injury risk and severity, US Lacrosse introduced a new ball in 2017 that had a 40% reduction in energy transfer and was posited to provide safer game play.47 Evaluating the effectiveness of these US Lacrosse initiatives is needed.
Checking-related injuries were low in count among all 3 levels of play. Despite body checking not being permitted below the U14 division, youth had the highest checking-related injury rate. Also, 1 in 5 injuries in youth were due to player contact. Rules prohibiting checking may not be adopted appropriately, with rules from higher levels of play possibly being used instead. Additional information is needed to elucidate specific details related to how contact was initiated and whether it was appropriate to the expectations of youth boys’ rules and regulations.
Limitations
Data originated from samples of male youth, HS, and NCAA players in the United States that comprised a small proportion of their respective populations. Thus, findings may not be generalizable to the entire lacrosse population, particularly settings without on-site athletic trainers to provide medical care. Specifically, future research should be used to examine girls’ and women’s lacrosse because different rules and protective equipment standards exist. Because lacrosse is an emerging sport in many areas, including those included in our sample, caution in interpretation must be taken. Also, injury underreporting may have occurred if players opted not to seek on-site care or experienced delayed onset of symptoms after leaving the lacrosse setting. However, athletic trainers are experienced health care professionals trained to accurately detect injury and each received the same study protocol training. With our study, we were unable to directly examine other factors that may contribute to injury incidence across and within levels of play, including game-based components (eg, equipment size, game lengths), geographic location (eg, newness of the sport within area), league (eg, rules allowing some degree of body checking and enforcement, type of athletic trainer coverage), and team (eg, coaching strategies, skill development techniques, proper use of protective equipment).
Conclusions
Findings suggest that pediatricians may see variations in the types of injuries presenting from these populations. Although youth boys’ lacrosse had the lowest time loss injury rate, it also had the highest all-injury, concussion, and checking-related injury rates. Equipment contact-related injuries were more likely among youth boys. HS lacrosse players experience the majority of time loss injuries in competitions, whereas NCAA players experience them in practices. Age-appropriate rules, coach training, and proper rules enforcement may help to further reduce injury risk across all 3 levels of play. Youth boys’ lacrosse should be focused on skill development to mitigate the risk of equipment-related contact injuries. At the HS level, skill development should continue in addition to consideration of modifying scheduling to ensure rest and/or recovery and mitigating risk of overuse injury. At the NCAA level, focus should be placed on preventing noncontact injuries. Surveillance is an important contributor to injury prevention that can help evaluate preventive efforts.48,49 However, more in-depth examinations may require external researchers to assist in acquiring additional information so that surveillance staff and data collectors are not overburdened.
Acknowledgments
The content of this article is solely the responsibility of the authors and does not necessarily represent the official views of the study’s sponsors. We thank the many athletic trainers who volunteered their time and efforts to submit data to the NCAA ISP, NATION, and youth lacrosse surveillance programs. Their efforts are greatly appreciated and have had a tremendously positive effect on the safety of athletes.
Footnotes
- Accepted March 22, 2019.
- Address correspondence to Zachary Y. Kerr, PhD, MPH, Department of Exercise and Sport Science, The University of North Carolina at Chapel Hill, 313 Woollen Gym, CB#8700, Chapel Hill, NC 27599-8700. E-mail: zkerr{at}email.unc.edu
FINANCIAL DISCLOSURE: The authors have indicated they have no financial relationships relevant to this article to disclose.
FUNDING: This study, inclusive of the youth lacrosse surveillance component, was funded by the National Operating Committee on Standards for Athletic Equipment. National Operating Committee on Standards for Athletic Equipment is an independent, nonprofit 501(c)(3) organization funded primarily through licensing fees that it charges to equipment manufacturers who want to have their equipment certified or recertified to National Operating Committee on Standards for Athletic Equipment standards. Its board of directors serves without compensation and includes representation from organizations such as the American Academy of Pediatrics. The funding received from National Operating Committee on Standards for Athletic Equipment did not solely originate from lacrosse equipment manufacturers. The National Collegiate Athletic Association Injury Surveillance Program data were provided by the Datalys Center for Sports Injury Research and Prevention. The Injury Surveillance Program was funded by the National Collegiate Athletic Association. The National Athletic Treatment, Injury, and Outcomes Network was funded by the National Athletic Trainers’ Association Research and Education Foundation and the Central Indiana Corporate Partnership Foundation in cooperation with BioCrossroads. The content of this report is solely the responsibility of the authors and does not necessarily represent the official views of the funding organizations.
POTENTIAL CONFLICT OF INTEREST: The authors have indicated they have no potential conflicts of interest to disclose.
References
- Copyright © 2019 by the American Academy of Pediatrics
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