Injuries in Physical Education Teacher Students: Differences between Sex, Curriculum Year, Setting, and Sports

Background Injury risk is high in Physical Education Teacher Education (PETE) students. Insights into specific injury locations per sex, setting, sports, and curriculum year are needed to develop preventive measures. Purpose To compare injury distributions by body locations in PETE students and how these distributions differ by sex, type, onset, curriculum year, settings, or sports. Methods In a historical cohort study over 14 years, data from 2899 students (male 76.2%, n = 1947) enlisted in the first three years of a PETE curriculum were analysed. Injuries reported at the institution's medical facility were categorised per sex, body location, onset, type, setting, sports, and curriculum year. Results Forty-three percent (n = 1247) of all students (female 54.9%, n = 523, male 37.2%, and n = 429) reported a total of 2129 injuries (freshmen 56.4%; 2nd year 28.2%; 3rd year 15.5%). The most prevalent sudden onset injury locations (63.4% of all injuries) were the ankle (32.5%) and knee (16.6). The most prevalent gradual onset injuries were the lower leg (27.8%) and knee (25.2%). Joint/ligament injuries (45.8%) and muscle/tendon injuries (23.4%) were the most prevalent injury types. Proportions for injury locations and injury types differed significantly between curriculum years. Injury prevalence per setting and sport differed significantly between the sexes. Injury locations differed significantly between sports and between the sexes per sport. Conclusion A differential approach per injury location, onset, type, sex, setting, sports, and curriculum year is needed to develop adequate preventive measures in PETE studies. The engagement of precurricular, intracurricular, and extracurricular stakeholders is needed in the development of these measures.


Introduction
Students in education for sports-related professions are subjected to high cumulative sports loads over a prolonged period.Consequently, they are at high risk of sustaining an injury during their study period [1][2][3][4][5][6].In the short term, sports injuries negatively impact sports performance [7].In the long term, injuries can lead to arthritis, decreased levels of physical activity and quality of life, and work disability [8][9][10].In the Netherlands, physical education teacher education (PETE) students participate in more than 250 hours of intracurricular (i.e., part of the PETE curriculum) sports classes per year during the frst three years of their curriculum.Most PETE students also participate in extracurricular sports (i.e., leisure time or competitive sports outside the PETE curriculum) as well (262 min/wk on average) [2].Although in a recent study in Flemish freshman PETE students, a multifactorial preventive program showed promising results in some injury categories, the overall efect was nonsignifcant [11].A better understanding of the relationship between risk groups or activities and their injuries could help develop targeted injury prevention measures.Intracurricular sports with high injury risks are track and feld athletics, gymnastics, and team ball sports [2,6,12].Most extracurricular injuries occur in soccer [2,6].A recent study over the frst 3 years of the PETE curriculum shows that injury risk is highest during the freshman year and that female students have signifcantly higher injury odds for overall and intracurricular injuries [12].Knowledge of the prevalence of injury locations, types, and onset, as well as the diferences between sexes, curriculum years, and sports types is needed.Specifc risk factors for the most frequently reported injuries and sports types could then be investigated in this population.Based on these risk factors and (sport-specifc) injury mechanisms, targeted prevention strategies can be developed or applied for specifc injuries and sports [13].Recent studies on injuries in PETE students have focused on (semesters in) the freshman year only [1,2,4,5,14].Injury locations and sports types from this period might not represent the whole curriculum.Terefore, an investigation of all three curriculum years (the fourth year consists mainly of internships) is needed to provide full insight into the prevalence of injuries in PETE students.Furthermore, studies on single cohorts with relatively low injury counts cannot differentiate injury distributions between subgroups.For this study, data on the prevalence of sports injuries by body locations, injury types, onset by sex, curriculum year, setting, and sports types were analysed over 14 years.Te primary question was "Which body locations and injury characteristics are most prevalent in sports injuries of male and female PETE students during the frst three years of the PETE curriculum?" Te secondary question was "How do distributions of injury locations and characteristics during the PETE study difer between sex, curriculum years, settings, or sports types?"

Methods
In a historical cohort study [15], all new injuries reported at the medical facility of Te Hague School for Sports Studies (HSSS) between August 2000 and June 2014 were analysed.
Data from injury or student records were used anonymously with permission from the institution and following European privacy legislation [16].
2.1.Subjects.All students enlisted in physical education teacher education at the HSSS between August 2000 and June 2014 were included in this study.Since the fourth year of the PETE curriculum consists mainly of internships, fourth-year students were excluded from the analyses.

Injury Defnition and Registration.
Te defnition of injury for this study was "Any new musculoskeletal complaint related to sports participation for which medical advice was sought at the medical facility of the HSSS."Tis complies with the medical attention injury defnition for multisports events [17].At the medical facility of the HSSS, voluntary free medical consultation was provided twice a week.Injuries were diagnosed by the same sports physical therapist and sports physician over the complete period of 14 years.Advice was given on treatment options or restrictions regarding sports participation.Students were obliged to report injuries at this facility to be excused from (active) participation in sports classes or exams if necessary.Data from student and injury records were collected as previously described [12].In short, from all new musculoskeletal complaints reported at the medical facility, injury location, type, onset, sports, setting, and curriculum year were collected.During the study period, no specifc injury prevention program was introduced.

Data Analysis.
For each student included in the study, their age at the start of the curriculum (in years) and sex were recorded.For students who sustained more than one new injury, all injuries were used for analysis.All injury data from the frst three curriculum years were recoded to injury locations, types, mode of onset (sudden or gradual), and time loss categories as proposed by Fuller et al. [18].Te reported setting (intracurricular or extracurricular) and sports activity were categorised.Incomplete injury records were used only if they could be traced to an individual student.For these records, missing data were categorised as unknown.
Demographic data of PETE students were calculated in mean and standard deviation (sd) for age (in years), as well as frequencies and percentages for sex.Te mean ages were compared by sex using the independent T-test.For injuries, frequencies and percentages for time loss (yes, no, unknown) and duration of symptoms before consultation (<1 week, 1 week-4 weeks, >4 weeks, and unknown) were calculated as previously described [12] and compared by sex using χ 2 analyses.Overall and subgroup frequencies and percentages for injuries were reported with 95% confdence intervals (95% CI).Proportions were compared for body locations, injury types and onset (sudden/gradual) by sex, curriculum year, setting (intracurricular or extracurricular), and sports using χ 2 analyses or the Fisher-Freeman-Halton exact test.
For all analyses, α was set at 0.05.Statistical Package for the Social Sciences (SPSS) version 27 (IBM, Chicago) was used for all analyses.

Injury Locations, Onset, and Types by Curriculum Year.
Of all registered injuries, 56.4% were freshman injuries, 28.2% were 2 nd year injuries, and 15.5% were 3 rd year injuries (Figure 1).Distributions per sex were not signifcantly diferent.Comparisons of proportions of injury locations by

Translational Sports Medicine
Table 1: Injury prevalence and proportions per injury location per sex and curriculum year for all injuries.Proportions (and 95% confdence intervals) are calculated as percentage of total injuries per sex per curriculum year.For 37 injuries, the exact injury location was unknown.) and most other gradual onset injuries.In sudden onset injuries, the diferences between curriculum years were less obvious (Figure 1).Comparison between curriculum years for injury types showed signifcant diferences compatible with those found in gradual onset injuries.Te contribution of fractures and bone stress injuries (predominantly lower leg injuries) was more than twice as high during the freshman year (15.7% and 95% CI 13.6-17.7%)compared to the 2 nd and 3 rd year (7.3%, 95% CI 5.2%-9.4% and 8.5%, 95% CI 5.5%-11.5%,respectively).In contrast, joint and ligament injuries increased from 41.9% (95% CI 39.1%-44.7%) in the freshman year to 51.2% (95% CI 47.2%-55.2%)and 50.5% (95% CI 45.1%-55.9%) in the 2 nd and 3 rd years.
Figure 3 shows analysis of most common injury locations by sport that showed signifcant diferences between injury locations overall and per sex.In all injury locations, the proportion of soccer injuries was higher in male students, whereas this was higher in female students for other team sports.Apart from that, ankle injuries also occurred frequently in gymnastics and thigh injuries occurred predominantly in track and feld.Most lower leg injuries occurred in multiple sports.Te other injury locations showed more diverse distributions but with specifc patterns by sex and sports.

Discussion
Tis study aimed to identify the most prevalent injury locations and characteristics in PETE students and to compare their distributions between sexes, curriculum years, settings, and sports types.Our study showed that over the frst three curriculum years, both in male and female Dutch PETE students, injuries to the knee, ankle, lower leg, shoulder, and back/pelvis were most prevalent.Joint and ligament injuries were most prevalent in both sexes, followed by muscle and tendon injuries, fractures, and bone stress injuries.Whereas knee and ankle injuries were most prevalent over all curriculum years, the proportion of (gradual onset) lower leg injuries decreased after the freshman year.Most injuries occurred in soccer (predominantly male extracurricular), other team ball sports (both intracurricular and extracurricular), intracurricular gymnastics, and track and feld.Overall and location-specifc injury distributions per sport were signifcantly diferent between the sexes.
Te results of our study shed new light on injury characteristics in PETE students over their full curriculum.Recent studies on injury characteristics in PETE students investigated freshman students only [1,2,4,5].Our study's distribution of injury locations is compatible with earlier  * For 110 injuries, the onset was unknown. 6 Translational Sports Medicine studies but showed a higher proportion of knee and ankle injuries during the freshman year and overall, especially compared to lower leg injuries [1,2,4,6].Te majority of these lower leg injuries were gradual onset injuries.In our registration of medical attention injuries, possibly only more persistent lower leg injuries were registered, compared to other studies with prospective registration of all injuries [1,2,4,6].Intercultural diferences in student ftness or curriculum load might also be of infuence.In Flemish PETE studies, the curriculum starts with 12 weeks of sports classes, whereas in Dutch PETE studies, periods of 6 or 7 weeks of sports classes are followed by a 3-week or 4-week period without practical classes.Although a serious problem in freshman students [8,16], the percentage of gradual onset lower leg injuries in our study dropped during the 2 nd and 3 rd years.Tese results are compatible with the decrease of new lower leg injuries after the frst trimester, found in freshman students [14].Whether these injuries have dissolved in later years, students learn to cope with them, or they do not report them anymore, needs further investigation.Te increase in the proportion of gradual onset knee injuries over the years in our study indicates that more prolonged/sustained preventive measures over all curriculum years are needed for these injuries.Tis holds for acute knee and ankle injuries.
Comparison between sexes showed a signifcant but relatively small diference in distribution by injury location.However, female athletes sustained a signifcantly larger part of their injuries (64.6%) during intracurricular activities than male students (48.2%).Tis is in line with the higher overall intracurricular injury risk we found for females compared to male PETE students (rate ratio female to male: 2.38, 95% CI 1.97 to 2.87) who completed their full curriculum [19].In Flemish freshman PETE students, a comparable but nonsignifcant higher intracurricular injury risk was found for female students, whereas in extracurricular injuries, it was the other way around [4].A possible bias for the higher extracurricular prevalence we found in male students is a larger cumulative exposure time to extracurricular sports activities in male students [4].Furthermore, the attribution of injuries to a certain setting or sport difers between studies.In one study, unsupervised training in the context of curricular sports is categorised as an extracurricular activity [4].Like in the study of Twellaar et al. [6], we included both sudden and gradual onset injuries in our distribution between settings and sports because this classifcation was closest to the original injury registration and best represented the students' perceptions of the onset of their injuries.According to the students, more than 50% of injuries attributed to multiple sports were associated with intracurricular sports.How these Translational Sports Medicine perceptions must be interpreted needs further investigation.In extracurricular sports, students compete at their own level of play and training.In many intracurricular sports that are new to students, extensive repetitions of new sports techniques might lead to gradual onset injuries.On top of that, the diferences in physical capacities between sexes might explain the higher percentage of intracurricular injuries in female students compared to male students [20].A comparison of injuries by sports types showed that team ball sports were most frequently (32.5%) reported.Te higher contribution of (predominantly extracurricular) soccer (22.6%) in male students compared to female (6.5%) students could be explained by the popularity of male soccer in the Netherlands [21].Other team ball sports were more frequently reported in female (20.8%) compared to male (14.4%) students, but for both sexes, most of these injuries (58% and 59%, respectively), were sustained during intracurricular sports activities.Gymnastic and track and feld athletics injuries were also predominantly (more than 88%) sustained during intracurricular activities.Tese results align with contemporary results in Dutch freshman PETE students [2].
Te found distributions by sex and sports implicate that for soccer injuries (male students) and other extracurricular team sports (both sexes), risk factors should be derived from sports representative of extracurricular activities.For intracurricular team sports, gymnastics, and track and feld athletics, risk factors should be investigated in intracurricular activities.Teir risk factors and injury mechanisms might be more related to mistakes in technique and high repetitive loads due to new motor skills that have to be acquired in sports unfamiliar to PETE students.Te higher injury rates for practice sessions than for sports classes found in earlier studies confrm this assumption [6,11].In frst-year students, one third of all injuries are gradual onset noncontact injuries, and during curricular practices, 44% of injury mechanisms are noncontact [22].To develop tailor-made injury prevention programs for PETE students, the distribution of these mechanisms for specifc injury locations and sports needs further investigation.
Goossens et al. found a nonsignifcant (p � 0.061) 20% reduction in injury rates after implementing a combined programme of injury awareness and preventive strategies in their regular PETE programme.Teir program showed a signifcant reduction in extracurricular injury risk but not in intracurricular injury risk [23].Considering the higher proportion of intracurricular injuries than extracurricular injuries, enhanced prevention strategies are needed.Compared to extracurricular injuries, a more diferentiated approach for intracurricular activities might help reduce the risk of intracurricular injury.Te specifc injury profles per injury location, setting, and sports per sex found in this study could help specify preventive measures further.For most ankle injuries, wearing an ankle brace could reduce the risk of injury by more than half [24].Both for knee and ankle injuries, neuromuscular training has shown to be efective in team sports players [24,25].To reduce the number of thigh  Translational Sports Medicine injuries, besides strength training interventions [26], load management of fatigued students in track and feld and team sports is warranted [27].Considering the already high load on PETE students and related high injury risk in the frst year of their curriculum [12], extrinsic risk factors such as rapid increases in training load [28] also need to be considered in gradual onset injuries in general and specifcally of the lower leg and knee.A precurricular neuromuscular training program for novice PETE students could address (sex specifc) risks factors for specifc injuries.Such training programs can improve landing kinematics related to both sudden and gradual onset knee injuries in female athletes [29,30].Te addition of basic exercises to get familiar with new techniques in gymnastics and other (new) intracurricular sports could further help novice (female) students to adapt to new physical loads before the curriculum starts.Reducing the overall physical load of the curriculum for female (freshmen) students could help minimize the risk diference between sexes for all intracurricular sports, irrespective of specifc injury locations.
Te strength of our study was the prospective registration of injuries over all curriculum years over 14 years by the same sports medical professionals.Te resulting high number of registered injuries enabled subanalyses that helped get more insight into the injuries in PETE students.Te interpretation of the results of our study also needs to consider the weaker points.Te registration of injuries at the HSSS was initiated before the publication of the consensus statement of Fuller et al. [18], and injury locations and categories were categorised retrospectively.According to the student, the registered sport/setting during which an injury occurred is not always the sport/setting responsible for that injury.In sudden and gradual onset injuries, the accumulative load from earlier activities can contribute to an injury event [31].Our study was conducted in a single institution on Dutch PETE students, but our results align with those from other studies on Dutch PETE students [1,2].However, interpretation of our results in other countries should consider intercultural diferences in sports participation and curriculum load [2][3][4][5].

Perspective.
Compared to previous studies on freshman students [1,2,4,5], our analyses of 2129 injuries from three curriculum years allow for enhanced recommendations for research on risk factors and preventive measures in PETE students [11,23].For intracurricular sports that students are unfamiliar with, novice athletes' risk factors and injury mechanisms should be targeted.A precurricular preventive program aimed at these sports could help (female) students adapt to the high curricular load before the freshman year.Including Nordic hamstring exercises in precurricular preventive programs could reduce the high number of thigh injuries in sprint-related sports [26].For these thigh injuries and for (knee and lower leg) gradual onset injuries, the efect of load management and distribution over the curriculum years needs investigation.Te higher injury risk for female students [12,19], irrespective of injury location, could further be targeted with a reduction of their physical load compared to male students.Te high contribution of (extracurricular) team sports to acute ankle and knee injuries implies the need to investigate existing sports-specifc preventive programs in PETE students [11,24,25].Tese programs should be implemented in extracurricular sports, adjusted to students' individual extracurricular playing levels.Te preventive efect of ankle braces during intracurricular and extracurricular team sports and gymnastics should be investigated [24].To tackle the diverse nature and distribution of injuries over the curriculum in PETE students, a diferentiated multisetting approach including precurricular, intracurricular, and extracurricular stakeholders is needed.

Figure 1 :
Figure 1: Prevalence of injury locations by onset in percentage (and 95% confdence intervals) of all injuries per sex per curriculum year.*For 110 injuries, the onset was unknown.

Table 2 :
Prevalence of injury locations and 95% confdence intervals (95% CI) for intracurricular and extracurricular injuries and for injuries sustained in multiple settings.* For 35 injuries, no exact body location was registered.* * For 69 injuries, the setting was unknown.
Figure 2: Prevalence of injuries per sport as percentage (and 95% confdence intervals) of all injuries per sex per setting.* Another 137 injuries were sustained during activities in multiple settings.