Characterization of Throwing Track and Field Injuries in Adolescent and Young Adult Participants Resulting in Emergency Department Visits: An Analysis of the National Electronic Injury Surveillance System

Introduction: Track and field throwing event injuries in the United States has not been well characterized for the adolescent and young adult population. In a sport where athletes’ bodies are subject to repetitive actions with substantial biomechanical demands, a more thorough understanding of common injuries is crucial. This information would allow coaches and parents to not only mitigate risk of injury


Introduction
Track and field is among the most popular sports in the United States.It was the most popular high school girls' sport and second most popular boys' sport with 1,093,621 U.S. high school athletes participating in outdoor track and field during the 2018-2019 academic year [1].Rates of injury have steadily paralleled the growing popularity of the sport, with the estimated incidence of adult track and field injuries increasing from 0.72 injuries per 100,000 U.S. population in 2004 to 2.09 injuries per 100,000 U.S. population in 2015 [2].
to December 31, 2021 were evaluated.The patient population was restricted to adolescents and young adults (ages 10 to 22).Narratives were further evaluated by one reviewer to include only track and field injuries involving throwing events, as defined by USA Track and Field (USATF) [14].Fastidious efforts were made to exclude ED events with narratives describing injuries not specifically related to track and field participation as the primary cause of injury.All analyses were conducted on the final study sample of 434 ED visits and an estimated weighted total of 16,218 ED visits.
Injury incidence rates were determined based on annual U.S. census estimates by sex and age [15].Variables of interest included age, sex, date of injury (by year), injury diagnosis, body region injured, mechanism of injury, and event.Age was stratified into 3 age groups: 10 to 13 years, 14 to 17 years, and 18 to 22 years, representing middle school, high school, and college aged participants, respectively.Injury diagnosis and body part injuries were categorized consistent with previous NEISS research methodology (Supplementary Table S1) [2].Mechanism of Injury (MOI) was assessed using narratives in the NEISS data.Data was categorized and coded into 6 categories: 'Overuse' for injuries caused by body stressing or overuse; 'Falls' for injuries caused by falls, slips, or trips; 'Contact' for injuries caused by contact with self, other living entities, moving objects, or stationary objects; 'Abnormal Positioning' for injuries caused by abnormal body positioning, such as inversion or eversion of feet, hyperextension of limbs, or twisting of joints; 'Unspecified' for injuries listed without a MOI.Additionally, observations were categorized by event.Event categories were 'Shotput', 'Discus', 'Javelin', and 'Other' for unspecified or other throwing events, such as hammer throw.
Analysis of the distribution of injuries across age groups, sex, and event type was done using chi-squared analysis.Z-test column proportion post-hoc analysis with Bonferroni adjustments was used to analyze significant individual differences between groups.P-values less than 0.05 were considered statistically significant and incidence rates were calculated with 95% confidence intervals.Analysis was performed using Microsoft Excel (Microsoft Corporation), Stata (Version 16.1, StataCorp), and SPSS (Version 28, IBM).

Results
Between January 1 st , 2002 and December 31 st , 2021, an estimated total of 16,218 track and field throwing event related injuries among track and field participants 10 to 22-years-old presented at emergency departments in the United States.The highest injury incidence rate was in 2002, with 2.27 injuries per 100,000 people (95% CI: 1.37-3.17),and the lowest injury incidence rate was in 2020, with 0.03 injuries per 100,000 people (95% CI: 0-0.09).Overall, females (8,294; 95% CI: 7,087-9,502) Despite the popularity of track and field, limited research has investigated this population at large.Many studies have instead focused on National Collegiate Athletic Association (NCAA) or elite level athletes specifically [3][4][5][6].Even less research has focused on throwing event injury patterns.One previous study examined running event differences in NEISS adolescent data, but contained no analyses on field events [7].
Another study included all track and field events in high school athletes, but was restricted to high schools with athletic trainers with National Athletic Trainers' Association membership and had little emphasis on throwing events [8].
Throwing athletes are particularly susceptible to rotator cuff injury due to repetitive periods of heavy stress on the glenohumeral joint.Maximum leg extensor forces can reach as high as 4,954 N in elite shot-putters [9].Hyperextension and powerful rotation of the trunk leave athletes vulnerable to lumbar spine injury as well [10].This unique combination of mechanisms is used in each throwing event, highlighting the need to further examine injury patterns between events in order to allow for targeted prevention and recommendations to reduce injury risk.The purpose of this study was to use comprehensive population data to determine the epidemiology of throwing track and field related injuries in adolescent and young adult participants presenting to EDs in the United States and to characterize throwing track and field injuries and trends with regard to event type, mechanism of injury, body region, and sex.

Methods
A retrospective cross-sectional study of track and field injuries was conducted using the National Electronic Injury Surveillance System (NEISS).The NEISS is a publicly available, deidentified database not requiring IRB approval maintained by the United States Consumer Product Safety Commission (CPSC) [11][12][13].This database is a nationally represented probability model constructed using all-injury data from emergency department visits at a stratified sample of 100 hospitals in the United States and its territories.Each year the CPSC creates a new 100 hospital sample, selected from both children's and adult hospitals, trauma centers and community hospitals from both rural and urban communities, to ensure year to year accuracy of the sample.Each documented case is assigned a weighted values based in the inverse probability of being selected to estimate the total number of cases throughout the United States each year.Data on pertinent demographics (age, sex, and race), injury information (diagnosis, disposition, injury location, and product(s) involved), and a short narrative describing the details surrounding the event are included in the database.

Discussion
Despite the popularity of track and field, there is currently a paucity of data on throwing track and field injuries.This study sought to characterize the throwing track and field related injury patterns in adolescent and young adult aged participants.Our analysis found unique injury patterns between age groups.The youngest age cohort, middle school aged patients, had the significantly highest proportion of strains/sprains.Through long-term systemic training and higher load resistance exercises, experienced throwers have previously been found to have a higher bone mineral density, which allows for the and high school aged participants (14-17 years-old) (10,788; 95% CI: 9,517-12,058) had the most injuries (Table 1).
With regards to diagnosis differences, males had significantly higher proportions of lacerations (17.3%, z-test for proportions with Bonferroni correction p < 0.05) and fractures/dislocations (12.5%, z-test for proportions with Bonferroni correction p < 0.05), while females had significantly higher proportions of soft tissue injuries (23.2%, z-test for proportions with Bonferroni correction p < 0.05) and strains/sprains (33.0%, z-test for proportions with Bonferroni correction p < 0.05).Across body areas, men had a significantly higher proportion of head/neck injuries (29.2%, z-test for proportions with Bonferroni correction p < 0.05) and trunk injuries (14.3%, z-test for proportions with Bonferroni correction p < 0.05) while women had significantly higher proportion of upper extremity (30.8%, z-test for proportions with Bonferroni correction p < 0.05) and lower extremity injuries (32.4%, z-test for proportions with Bonferroni correction p < 0.05).Males also had a significantly higher proportion of injuries caused by falls (4.1%, z-test for proportions with Bonferroni correction p < 0.05) and abnormal positioning (16.9%, z-test for proportions with Bonferroni correction p < 0.05) while females had significantly higher proportion of overuse (19.0%, z-test for proportions with Bonferroni correction p < 0.05) and contact injuries (48.2%, z-test for proportions with Bonferroni correction p < 0.05).shotput had similar injury patterns, with wrist and shoulder being the most common while javelin had a more unique injury pattern with shoulder and elbow being the most common.This may be explained by the more similar mechanisms used for discus and shotput, with both requiring the transfer of rotational kinetic energy from the lower limbs and trunk to the upper limbs for release of the implement while the javelin throw more mimics an overhead baseball pitching motion [10].Similar to baseball pitchers, javelin throwers have also been found to have increased risk for shoulder and elbow/UCL injuries [17,18].Javelin was found to have a significantly higher proportion of lacerations, likely due to the risk of impalement by the implement.The proportion of lower extremity, falling, and abnormal body positioning injuries were also significantly higher in javelin participants compared to discus and shotput.These findings may be explained by the longer sprint and exertion in the approaching phase.A study by Schleichardt, et al. examined force-velocity profiles in track and field throwing athletes, finding female javelin throwers to generate the highest leg extensor velocities of all throwers (1.47 m/s) [9].Taken together, these findings suggest more targeted lower extremity ability to resist and generate larger forces [16].The lack of experience and strength development of younger participants might explain the larger proportion of such injuries.

Comparing across age groups, middle school aged patients had the significantly highest proportion of
Shotput participants had the significantly highest proportion of strains/sprains and upper extremity injuries.Broken down to specific upper extremity diagnoses, shotput participants also had the most wrist, hand, and finger injuries (21.0% of shotput injuries).The shotput is the heaviest implement used in track and field, ranging from approximately 6 to 16 pounds.Previous literature has hypothesized that shot-putters might be at increased risk for wrist injuries, since the sport requires rapid transition from wrist extension to flexion against the weight of the shot put [10].This exertion against resistance in combination with the repetitive demands of practice and competition likely explains the higher proportion of overuse injuries in shotput participants.These findings highlight the need for better strengthening and injury prevention exercises specific to the distal upper extremities for shotput participants.
Among the upper extremity injuries, discus and

Conclusion
In this study, we have demonstrated that there are significant differences in the injury mechanisms and types of injuries across events in adolescent and young adult throwing track and field participants.Among these differences, shotput participants had a higher proportion of injuries related to the higher forces necessary for the event, with significantly higher overuse, upper extremity, and truncal injuries.Javelin participants had the highest proportion of lower extremity, falling, and abnormal positioning injuries, unique to the longer approach phase and higher running velocities of javelin participants.Discus participants had a higher proportion of contact and head/neck injuries.Moreover, younger track throwing participants had a higher proportion of strains/sprains.These results can hopefully serve as an initial study for further research into more targeted care recommendations and prevention techniques to better guide providers, coaches, and athletes in reducing adolescent and young adult throwing track and field related injuries.

Funding
No funding was received for this study.
strengthening exercises with an emphasis on core and lower extremity structural balance would be highly beneficial for javelin participants.Furthermore, discus was found to have a significantly higher proportion of soft tissue and head/neck injuries related to contact.Future prevention could focus on education and better netting and safety barriers.
Given the unique injury patterns across track and field throwing event types, further research into targeted prevention programs and increased barriers to injury is necessary.Previous initiatives have been proven to reduce severe injury risk in the past.A targeted 8 week physical therapy routine in javelin throwers found improvements in rotator cuff strength, flexibility, and core stability [19].In France, the Athletics Injury Prevention Programme (AIPP), which included 8 exercises for core stability, hamstring, leg and pelvic muscle stretching, and balance strengthening, was found to significantly reduce risk of injury in the short term for inter-regional and national level track and field athletes [20].Another example to improve injury prevention was rule changes made in pole vault in 2003 mandated by the NCAA, National Federation of State High Schools (NFHS), and USA Track and Field which included increasing the minimum dimensions of the landing pad behind the vault box.These regulation changes markedly reduced catastrophic and fatal injuries caused by pole vault [21].Similar regulation changes for throwing caging and netting might minimize risk for contact injuries.
The one major limitation of this study is that the NEISS database is limited to emergency department data.Injuries presenting at other settings, such as urgent care, primary care providers, or outpatient care, are not included, likely underestimating the true incidence of track and field-related injuries.In addition, due to the NEISS dataset's publicly available design and deidentified nature, does not provide a way to identify patients who present to the ED more than once nor follow patients after an initial injury to observe if there is an increased chance of secondary injury.With the heavy forces exerted on track and field athletes, it's likely that injury rates are higher on those who have already experiences an injury.Furthermore, analyses were limited by the narratives provided with this dataset.Although most narratives provided enough information to identify the event type and MOI, an estimated 410 (2.5%) of ED visits either could not be further specified into a distinct event type or included multiple event types and 2,815 (17.3%) of ED visits were categorized with an 'unspecified' MOI.Despite these limitations, the NEISS database is a nationally representative database that reflects the American population, allowing this study to be uniquely comprehensive within the existing literature.In addition, this study provides more detailed examinations of throwing track and field event-based and age-based differences in injury risk and mechanisms

Table 1 :
Estimated counts of patient demographics.
a Data reported as national estimates, which were calculated by applying statistical weights provided by the US Consumer Product Safety Commission's National Electronic Injury Surveillance System to actual case counts; b Some categories are not equal to 100%, due to rounding.CI: Confidence interval

Table 2 :
Estimated counts of injury characteristics by diagnosis, body area, and MOI by event.