Injury patterns differ with age in male youth football: a four-season prospective study of 1111 time-loss injuries in an elite national academy

A systematic review and network meta-analysis on the effectiveness of exercise-based interventions for reducing the injury incidence in youth team-sport players. Part 2: an analysis by movement patterns

The objectives of this network meta-analysis were: (a) to estimate and compare the pooled effects of some injury prevention programs (IPPs) whose exercise-based components were categorized using a movement pattern-specific taxonomy on reducing overall and some specific body regions (lower extremity, thigh, knee, and ankle) injury incidences in youth team sport athletes and (b) to explore the individual effects of these components on the injury incidence rates (IIRs) previously mentioned. Searches were performed in PubMed, Web of Science, SPORTDiscus, and Cochrane Library. Eligible criteria were: exercise-based interventions comprised of exercises involving athletic motor skill competencies and evaluated against a control group, overall IIRs were reported, and youth (≤19 years old) team sport players. For the current analysis, a taxonomy based on movement patterns was employed for exercise component identification (upper body pushing and pulling; lower body concentric and eccentric; core; mechanics; acceleration; and lower body stability). Pooled effects were calculated by frequentist random effects pairwise and network meta-analyses. Nineteen studies were included. Most of the IPPs exhibit risk reduction when compared to their control groups on overall, lower extremity, and ankle injuries. Interventions comprised of lower body concentric and eccentric, core, mechanics, and lower body stability exercises were the most effective measures for reducing these injuries. None of the IPPs demonstrated to be effective for reducing thigh injuries, and contradictory results were found for knee injuries. Individual analysis at component level revealed that the lower body (bilateral and unilateral, concentric, and eccentric) component was the only one associated with a significant reduction on overall injuries. Indirect evidence suggests that interventions incorporating lower body concentric and eccentric, core, mechanics, and lower body stability exercises might be the most effective for reducing overall, lower extremity, and ankle injuries in youth team sports.

An injury burden heat map of all men's and women's teams of a professional football club over a decade

The aim was to present a descriptive 10-season summary of injury data from all teams of a professional football club using a heat map approach. Injuries and exposure time were registered according to the FIFA consensus in all men's and women's teams from Athletic Club over 10 seasons. A team-by-injury table was created, showing the incidence, median severity, and burden in each cell. Cells were coloured based on the injury burden value using a green - yellow-red gradient (lowest to highest). The highest overall injury burden was found in the women's 2nd and 1st teams and the men's U(under)17 team (>200 days lost/1000 h). Muscle injury burden demonstrated an increasing pattern with age. Knee joint/ligament injuries, particularly anterior cruciate ligament ruptures, had the highest impact on women's teams, followed by the men's 2nd team. In comparison, ankle joint/ligament injuries had a relatively low injury burden in most teams. Growth-related injuries were the most impactful injuries in the men's U15 and younger teams, and the women's U14 team. In conclusion, epidemiological data on injuries can inform and guide injury management processes. New and improved visualization methods might be important assets when presenting injury data to key decision-makers.

Overuse Injury of the Epiphyseal Primary Physis

Year-round participation in youth sport that involves high levels of repetitive movement fosters an environment in which overuse injuries are likely to occur. Epiphyseal primary physeal stress injuries (PSIs), unique to skeletally immature athletes, are a particular concern, given their potential for growth disturbance. Initially observed in Little League baseball players, these injuries are now known to affect the long bones around the shoulder, elbow, wrist, hand, knee, ankle, and foot of skeletally immature athletes involved in a variety of sport activities.This article offers an epidemiological and radiologic perspective on the extent and distribution of epiphyseal PSIs in youth sport. We also review a novel framework for understanding the pathophysiologic mechanisms causing these injuries. This information is essential for the early identification of epiphyseal PSIs and devising preventive measures that can reduce a delayed diagnosis and long-term morbidity. Preventing and reducing injury to the epiphyseal growth plates is essential because impairment and dysfunction can result in lifelong morbidity and a risk of premature osteoarthritis.

Epidemiology of football-related injuries in young male football players. An additional analysis of data from a cluster-randomised controlled trial

Football carries a high risk of injury for youth players. The aim of this study was to investigate the epidemiology of football-related injuries in young male players. The data stems from a previously conducted cluster-randomised controlled trial that investigated the efficacy of 'FUNBALL', a new injury prevention programme. This study contains the data of the 503 players of the control arm. The players belonged to 22 football teams of the Under-(U)15, U17 and U19 age groups. The time-loss injuries were recorded during the season 2021-2022 according to the Football Consensus Statement. An analysis on the injury incidence (IR, calculated per 1000 hours of exposure), location, severity, category, and type was performed. Incidence rate ratios (IRRs) were used to compare the variables between the specific age groups. 187 injuries (96 in training and 91 in matches) occurred during 52 938 hours of exposure. The overall IR was 3.53 injuries/1000 h (95% confidence intervals (CI) 3.06 to 4.07). The training IR was 2.16 injuries/1000 h (95% CI 1.17 to 2.64). The match IR was 10.50 injuries/1000 h (95% CI 8.55 to 12.89). In the U19s, the overall IRR was higher compared to the U17s (IRR 1.57, CI 1.12 to 2.19; p = 0.008) and compared to the U15s (IRR 1.82, 95% CI 1.25 to 2.62; p = 0.001). The thigh was the most commonly affected body region (IR 0.92/1000 h, 95% CI 0.69 to 1.22). Muscle injuries were the most common injury type (IR 1.05/1000 h, 95% CI 0.81 to 1.37). Injury burden was 74 lost days/1000 h. The findings of this study indicate a lower injury incidence in youth players than in adult ones. We observed a higher injury incidence towards the older age groups.

Efficacy of a new injury prevention programme (FUNBALL) in young male football (soccer) players: a cluster-randomised controlled trial

OBJECTIVES

To evaluate the efficacy of a new multicomponent, exercise-based injury prevention programme in football players 13-19 years old.

METHODS

Two-arm cluster-randomised controlled trial with clubs as the unit of randomisation. 55 football teams from Kosovo of the under 15, under 17 and under 19 age groups were randomly assigned to the intervention (INT; 28 teams) or the control group (CON; 27 teams) and were followed for one football season (August 2021-May 2022). The INT group performed the 'FUNBALL' programme after their usual warm-up at least twice per week, while the CON group followed their usual training routine. The primary outcome measure was the overall number of football-related injuries. Secondary outcomes were region-specific injuries of the lower limbs (hip/groin, thigh, knee, lower leg, ankle and foot) and injury severity.

RESULTS

319 injuries occurred, 132 in the INT and 187 in the CON group. The INT group used the 'FUNBALL' programme in 72.2% of all training sessions, on average 2.2 times per week. There was a significantly lower incidence in the INT group regarding the overall number of injuries (incidence rate ratio (IRR) 0.69, 95% CI 0.55 to 0.87), the number of thigh injuries (IRR 0.62, 95% CI 0.39 to 0.98), of moderate (time loss between 7 and 28 days) (IRR 0.65, 95% CI 0.44 to 0.97) and of severe injuries (time loss >28 days) (IRR 0.51, 95% CI 0.28 to 0.91).

CONCLUSION

The 'FUNBALL' programme reduced the incidence of football-related injuries among male adolescent football players, and its regular use for injury prevention in this population is recommended.

TRIAL REGISTRATION NUMBER

NCT05137015.

Exploring the true burden of a time-loss injury: full vs partial time-loss in elite academy football (soccer)

In football, the number of days without full participation in training/competition is often used as a surrogate measure for time-loss (TL) caused by injury. However, injury management and return-to-play processes frequently include modified participation, which to date has only been recorded through self-reports. This study aims to demonstrate the differentiation between 'full' (no participation in team football) and 'partial' (reduced/modified participation in team football) burden. Injury and exposure data were collected from 118 male elite footballers (U13-U18) over 3 consecutive seasons according to the Football Consensus Statement. TL injury burden was calculated separately as the number of total, 'full' and 'partial' days lost per 1000 h of exposure. Injury burden (137.2 days lost/1000 h, 95% CI 133.4-141.0) was comprised of 23% (31.9 days lost/1000 h, 95% CI 30.1-33.8) partial TL and 77% (105.3 days lost/1000 h, 95% CI 102.0-108.6) full TL burden. Injuries of moderate severity (8-28 days lost) showed 40% of partial TL. TL injury incidence rate (6.6 injuries/1000 h, 95% CI 5.8-7.5), the number of severe injuries (16%), and the distribution of TL and non-TL injuries (56% and 44%) were comparable to other reports in elite youth footballers. Almost one-quarter of the TL injury burden showed that injured players were still included in some team football activities, which, for injuries with TL >7 days, was likely related to the return to play process. Therefore, reporting on partial TL provides insight into the true impact of injury on participation levels.

Differences in Lumbopelvic Alignment in Adolescent Male Soccer Players With Bilateral and Unilateral Lumbar Bone Stress Injuries: An MRI Evaluation

Background

Differences in the physical characteristics of bilateral and unilateral lumbar bone stress injuries (BSIs) are unknown.

Purpose

To compare bilateral and unilateral lumbar BSIs in adolescent male soccer players, with a focus on lumbopelvic alignment.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

A total of 78 players (age range, 12-15 years) from a local soccer club who had magnetic resonance imaging (MRI) evaluations were included in the study. Lumbopelvic alignment and lumbar BSI were evaluated using short-tau inversion recovery and 3-dimensional LAVA on 3-T MRI; lumbar BSI was defined as the presence of bone marrow edema and/or the complete and incomplete fracture in the pars region on the MRI. Pelvic tilt (PT) and pelvic outflare angles were assessed on the kicking and pivoting sides, and asymmetry for each parameter was calculated by subtracting the kicking side from the pivoting side. In addition, the lumbar lordosis (LL), sacral slope (SS), and SS relative to LL (calculated by subtracting LL from the SS) were assessed. One-way analysis of variance was performed to compare lumbopelvic alignment in players with bilateral BSI, unilateral BSI, or no abnormal findings (controls).

Results

No significant differences were found regarding lumbopelvic alignment between the players with bilateral versus unilateral lumbar BSI. PT asymmetry was significantly greater in both players with bilateral lumbar BSI and unilateral lumbar BSI compared with controls (P = .018 and P = .016, respectively). In addition, SS relative to LL was significantly greater in players with bilateral lumbar BSI compared with controls (P < .001).

Conclusion

Although there were no significant lumbopelvic alignment differences between bilateral and unilateral BSI, players with bilateral BSI exhibited increased sacral anterior tilt relative to the LL, and the pelvis was more posterior on the pivoting side than on the kicking side in both players with bilateral BSI and unilateral BSI. Our results suggest that lumbopelvic alignment assessment may contribute to the management strategy for players with lumbar BSI and to the identification of players at high risk of lumbar BSI.

Exploring Growth, Maturity, and Age as Injury Risk Factors in High-Level Youth Football

Rapid somatic growth and biological maturity status may affect injury patterns in youth football, yet firm conclusions cannot be drawn from the existing research. We aimed to explore growth velocity, maturity, and age as injury risk factors in 95 academy players (11.9-15.0 years), using anthropometric (height and body mass), maturity (skeletal age), injury, and football exposure data collected prospectively over three seasons (2016/17-2018/19). We compared the relative quality of mixed-effects logistic regression models with growth velocity for 223 growth intervals (average 113 days) included as fixed effects and adjusted for age (chronological or skeletal) plus load (hours/week). Associations were considered practically relevant based on the confidence interval for odds ratios, using thresholds of 0.90 and 1.11 to define small beneficial and harmful effects, respectively. We observed harmful effects of older age on overall (OR: 2.61, 95% CI: 1.15-5.91) and sudden onset (1.98, 1.17-3.37) injury risk. Significant associations (p<0.05) were observed for higher body mass change and greater maturity on sudden onset injuries, and for higher hours/week on gradual onset, bone tissue, and physis injuries. Future studies should include larger samples, monitoring athletes from pre-adolescence through maturation, to enable within-subject analyses and better understand the relationship between growth, maturation, and injuries.

Injuries in male youth football: a one season prospective cohort study of 223 Danish elite players

Objectives

This study prospectively investigated injury prevalence, incidence, and burden in male elite under-17 football players (N = 223) during a full season.

Methods

The players weekly completed a standardized web-based injury survey (OSTRC-H2) and a physical exposure report throughout the study.

Results

Average weekly response rate was 89.5%. Football exposure accounted for 52.4% of total physical exposure. On average (±SD), the players participated in individual football, strength, and rehabilitation practices for 1.2 ± 1.5, 3.0 ± .2.1, and 1.9 ± 3.4 h/week, respectively. In total, 742 health problems were reported. Mean weekly prevalence of health problems, injuries and illnesses were 20.1%, 16.5% and 3.8%, respectively. The injury incidence per 1,000 h of football exposure, match play and team practice were 8.28 (95% CI: 7.54-9.08), 16.77 (95% CI: 13.65-20.4), and 7.24 (95% CI: 6.5-8.04), respectively. Sudden-onset and gradual-onset injuries accounted for 36.7% and 43.4% of the total proportion of health problems. Hip/groin injuries had the highest incidence (1.58/1,000 h), whereas knee injuries had the highest burden (20.86 days lost/1,000 h). On average, the players experienced 3.33 health problems (average duration: 7.8 days). On average pr. player, 2.7 (95% CI: 2.2-3.3) wks of football exposure were lost.

Conclusion

Sudden and gradual-onset injuries influenced player availability during the season. Health problem prevalence fluctuated markedly, and injury incidence was higher during match play than training. The players had substantial volumes of training beyond football-specific training and matches. Our findings could assist medical and sports science practitioneers in enhancing training and recovery processes to maximize player availability.

How Does Age Affect Injury Characteristics in Young Elite Footballers?-A Prospective Cohort Study of a German Youth Academy

BACKGROUND

Little is known about age-related changes in injury characteristics and burden, and existing data are inconsistent, highlighting the need for new studies on this topic. This study aimed to describe age-related injury risk, severity and burden in a German elite youth football academy.

METHODS

A prospective cohort study was conducted in the 2012/2013 season, reporting 109 time-loss injuries among 138 young athletes playing at an elite football academy in Germany. For the most severe injuries, the injury burden in the different age groups was considered separately.

RESULTS

Athletes missed a total of 2536 days of exposure, resulting in an overall incidence of 2.6 per 1000 h (1.7-3.0; 95% CI) and a burden of 60.6 days lost per 1000 h (40.8-80.3; 95% CI). The incidence and burden of joint sprains and muscle injuries were higher in the older age groups. Physeal injuries peaked in the U14 age group during the pubertal growth spurt. Bone injuries and contusions showed no age trend.

CONCLUSION

Injury characteristics vary with age. The overall incidence, severity and burden of injuries increased with the age of the athletes. To ensure the optimal development of young athletes, it is important to be aware of the differences in injury susceptibility between age groups in order to implement tailored prevention programmes.

Higher age and present injury at the start of the season are risk factors for in-season injury in amateur male and female football players-a prospective cohort study

PURPOSE

To describe the injury prevalence, injury pattern, and potential baseline risk factors for injuries in male and female adolescent and adult amateur football players.

METHODS

This prospective study followed adolescent and adult amateur football players over one season March-October 2020. The study was completed by 462 players (130 men, age 20.0 ± 5.7, 14-46 years) who answered a baseline survey and a weekly web survey during the season. A total of 1456 weekly surveys were registered from males and 5041 from females. Injuries were recorded with the Oslo Sports Trauma Research Center Overuse Injury Questionnaire (OSTRC-O2). Potential baseline risk factors (age, performance of strength/conditioning training, participation in other sports, perceived importance of sporting success, self-rated training and match load, perceived balance between training/match load and recovery, previous/present injury at start of season, and injury beliefs) and their association with injury were analysed with Poisson regressions within each sex.

RESULTS

Males reported 95 injuries (262 injury weeks, weekly prevalence 18.0% (95% CI 16.1-20.1)) and females 350 injuries (1206 injury weeks, weekly prevalence 23.9% (95% CI 22.8-25.1)). Gradual-onset injuries accounted for 57% of the injuries in males and 66% in females. For males, substantial injuries were most common in the hip/groin (weekly prevalence 3.8%), ankle (2.1%), posterior thigh (2.0%), and knee (2.0%); and for females, in the knee (4.3%), ankle (2.5%), and lower leg/Achilles tendon (2.0%). Significant risk factors for injury were higher age (rate ratio males 1.05 per year increase (95% CI 1.02-1.08), females 1.03 (95% CI 1.01-1.05)), and present injury at baseline (males 1.92 (95% CI 1.27-2.89), females 1.58 (95% CI 1.19-2.09)).

CONCLUSION

At any given week, almost one in five male and one in four female amateur football players reported new or ongoing injuries. Hip/groin injuries were more frequent in males, while female players had a higher prevalence of knee injuries. Older players and those with an existing injury at the start of the season were more prone to new injury during the season. Rehabilitation of pre-season injury and complaints are key to reduce the injury burden in amateur football.

LEVEL OF EVIDENCE

Level II. Trial registration number NCT04272047, Clinical trials.

Growth-related sports injuries among young male professional football players in the Netherlands: a prospective cohort study concerning injury incidence, severity and burden

OBJECTIVES

To investigate the incidence, type and location of growth-related sports injuries (GRSI) in youth professional football in the Netherlands. Secondary, to gain more knowledge on the injury severity and burden of GRSI.

METHODS

In this prospective, longitudinal cohort study, 813 players aged 10-18 are included. Data collection is performed by instructing the medical staff of six professional football club academies to register GRSI by means of standardized forms. Training and match exposure are registered individually on a weekly basis. Injury incidence was calculated as number of GRSI per 1000 hours, injury severity as the median number of days lost in categories and injury burden as the number of days lost per 1000 hours.

RESULTS

A total of 62 GRSI were documented in the football season 2021-2022. The total incidence of GRSI was 0.62/1000 hours football exposure. Morbus Osgood Schlatter and Morbus Sever were most common types of GRSI, both with incidence rates of 0.22/1000 hours exposure. About 58.3% of the documented GRSI were classified as major (>28 days lost). Within this group, the mean severity was 55 days time-loss to football.

CONCLUSIONS

GRSI are relatively common in youth professional football. The most common types are Morbus Sever and Morbus Osgood Schlatter. Morbus Osgood Schlatter has the highest injury severity and burden compared to other types of GRSI.

The effect of progressive and individualised sport-specific training on the prevalence of injury in football and handball student athletes: a randomised controlled trial

Objective

To evaluate the effectiveness of communication and coordination combined with designing a progressive and individualised sport-specific training program for reducing injury prevalence in youth female and male football and handball players transitioning to a sports academy high school. An additional aim was to investigate the characteristics of the reported injuries.

Methods

Forty-two Norwegian athletes were randomised into an intervention or control group. Mean age, height, weight and BMI was 15.5 ± 0.5 years, 178.6 cm ± 6.3 cm, 71.3 ± 9.8 kg, 22.3 ± 2.7 BMI for the intervention group (IG) (n = 23), and 15.4 ± 0.5 years, 175.6 cm ± 6.6 cm, 67.1 ± 9.8 kg, 21.7 ± 2.4 BMI for the control group (CG) (n = 19). During the summer holiday, the intervention group received weekly progressive, individualised sport-specific training programs and weekly follow-up telephone calls from the researchers. All athletes completed a baseline questionnaire and a physical test battery. Training data and injuries were recorded prospectively for 22 weeks using the Oslo Sports Trauma Research Center Questionnaire on Health Problems (OSTRC-H2). A two-way chi-square (χ²) test of independence was conducted to examine the relationship between groups and injury.

Results

Average weekly prevalence of all injuries was 11% (95% CI: 8%-14%) in IG and 19% (95% CI: 13%-26%) in CG. Average weekly prevalence of substantial injuries was 7% (95% CI: 3%-10%) in IG and 10% (95% CI: 6%-13%) in CG. The between-group difference in injuries was significant: χ² (1, N = 375) = 4.865, p = .031, φ = .114, with 1.8 times higher injury risk in CG vs. IG during the first 12 weeks after enrolment.

Conclusions

For student athletes transitioning to a sports academy high school, progressive individualised, sport-specific training programs reduced the prevalence of all-complaint injuries following enrolment. Clubs and schools should prioritise time and resources to implement similar interventions in periods where student athletes have less supervision, such as the summer holidays, to facilitate an optimal transition to a sports academy high school.

Association Between Magnetic Resonance Imaging Findings and Time to Return to Sport After Muscle Injuries in High-Level Youth Athletes

OBJECTIVE

To describe the relationship between magnetic resonance imaging (MRI) findings and time to return to sport (RTS) from muscle injuries in youth athletes.

DESIGN

Prospective collection of injury surveillance data over 6 seasons (2014-2015 to 2019-2020) and reanalysis of MRIs by a radiologist blinded to RTS time after the data collection period.

SETTING

National sports academy and sports medicine hospital.

PARTICIPANTS

Male youth (11-19 years) athletes participating in the football (soccer) or athletics (track and field) programs with a muscle injury.

INDEPENDENT VARIABLES

Magnetic resonance imaging findings (eg, grade and location) in time-loss muscle injuries.

MAIN OUTCOME VARIABLES

Injury incidence, distributions, and RTS time.

RESULTS

In total, 353 time-loss muscle injuries were recorded for 1089 athlete-seasons, of which 85 satisfied our inclusion criteria (MRI within 14 days). Return to sport time was significantly longer for reinjuries compared with index injuries. Associations between MRI findings and RTS time were specific to the muscle group, with significant differences in RTS time observed between categories of structure, location, and grade. The largest number of injuries was to the hamstrings (n = 46), where injuries involving the tendon were more severe than those involving the myotendinous junction and muscle, proximal injuries were more severe than mid-portion and distal, and longer RTS time was observed for higher injury grade ( P < 0.05).

CONCLUSIONS

Muscle injuries in youth are diverse and cannot be treated as a single injury type. Specific injury durations can be expected depending on injury characteristics such as reinjury, location, structure, and grade.

Return to sport following low-risk and high-risk bone stress injuries: a systematic review and meta-analysis

OBJECTIVE

Bone stress injuries (BSIs) are classified in clinical practice as being at low- or high-risk for complication based on the injury location. However, this dichotomous approach has not been sufficiently validated. The purpose of this systematic review was to examine the prognostic role of injury location on return-to-sport (RTS) and treatment complications after BSI of the lower extremity and pelvis.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, Web of Science, Cochrane CENTRAL and Google Scholar databases were searched from database inception to December 2021.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Peer-reviewed studies that reported site-specific RTS of BSIs in athletes.

RESULTS

Seventy-six studies reporting on 2974 BSIs were included. Sixteen studies compared multiple injury sites, and most of these studies (n=11) described the anatomical site of injury as being prognostic for RTS or the rate of treatment complication. Pooled data revealed the longest time to RTS for BSIs of the tarsal navicular (127 days; 95% CI 102 to 151 days) and femoral neck (107 days; 95% CI 79 to 135 days) and shortest duration of time for BSIs of the posteromedial tibial shaft (44 days, 95% CI 27 to 61 days) and fibula (56 days; 95% CI 13 to 100 days). Overall, more than 90% of athletes successfully returned to sport. Treatment complication rate was highest in BSIs of the femoral neck, tarsal navicular, anterior tibial shaft and fifth metatarsal; and lowest in the fibula, pubic bone and posteromedial tibial shaft.

CONCLUSION

This systematic review supports that the anatomical site of BSIs influences RTS timelines and the risk of complication. BSIs of the femoral neck, anterior tibial shaft and tarsal navicular are associated with increased rates of complications and more challenging RTS.

PROSPERO REGISTRATION NUMBER

CRD42021232351.

Efficacy of Multi-Component Exercise-Based Injury Prevention Programs on Injury Risk Among Footballers of All Age Groups: A Systematic Review and Meta-analysis

BACKGROUND

Playing football is associated with a high risk of injury. Injury prevention is a priority as injuries not only negatively impact health but also potentially performance. Various multi-component exercise-based injury prevention programs for football players have been examined in studies.

OBJECTIVE

We aimed to investigate the efficacy of multi-component exercise-based injury prevention programs among footballers of all age groups in comparison to a control group.

METHODS

We conducted a systematic review and meta-analysis of randomized and cluster-randomized controlled trials. CINAHL, Cochrane, PubMed, Scopus, and Web of Science databases were searched from inception to June 2022. The following inclusion criteria were used for studies to determine their eligibility: they (1) include football (soccer) players; (2) investigate the preventive effect of multi-component exercise-based injury prevention programs in football; (3) contain original data from a randomized or cluster-randomized trial; and (4) investigate football injuries as the outcome. The risk of bias and quality of evidence were assessed using the Cochrane Risk of Bias Tool and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE), respectively. The outcome measures were the risk ratio (RR) between the intervention and the control group for the overall number of injuries and body region-specific, contact, and non-contact injuries sustained during the study period in training and match play.

RESULTS

Fifteen randomized and cluster-randomized controlled trials with 22,177 players, 5080 injuries, and 1,587,327 exposure hours fulfilled the inclusion criteria and reported the required outcome measures. The point estimate (RR) for the overall number of injuries was 0.71 (95% confidence interval [CI] 0.59-0.85; 95% prediction interval [PI] 0.38-1.32) with very low-quality evidence. The point estimate (RR) for lower limb injuries was 0.82 (95% CI 0.71-0.94; 95% PI 0.58-1.15) with moderate-quality evidence; for hip/groin injuries, the RR was 0.56 (95% CI 0.30-1.05; 95% PI 0.00-102.92) with low-quality evidence; for knee injuries, the RR was 0.69 (95% CI 0.52-0.90; 95% PI 0.31-1.50) with low-quality evidence; for ankle injuries, the RR was 0.73 (95% CI 0.55-0.96; 95% PI 0.36-1.46) with moderate-quality evidence; and for hamstring injuries, the RR was 0.83 (95% CI 0.50-1.37) with low-quality evidence. The point estimate (RR) for contact injuries was 0.70 (95% CI 0.56-0.88; 95% PI 0.40-1.24) with moderate-quality evidence, while for non-contact injuries, the RR was 0.78 (95% CI 0.55-1.10; 95% PI 0.25-2.47) with low-quality evidence.

CONCLUSIONS

This systematic review and meta-analysis indicated that the treatment effect associated with the use of multi-component exercise-based injury prevention programs in football is uncertain and inconclusive. In addition, the majority of the results are based on low-quality evidence. Therefore, future high-quality trials are needed to provide more reliable evidence.

CLINICAL TRIAL REGISTRATION

PROSPERO CRD42020221772.

Risk Factors for Symptomatic Bilateral Lumbar Bone Stress Injury in Adolescent Soccer Players: A Prospective Cohort Study

BACKGROUND

Lumbar bone stress injury (BSI) is a high-risk long time-loss injury for adolescent soccer players. However, the risk factors for lumbar BSI are unclear.

PURPOSE

To identify the risk factors for bilateral lumbar BSI for adolescent soccer players.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Adolescent soccer players underwent orthopaedic examination, whole-body dual energy x-ray scan, lumbar magnetic resonance imaging (MRI), and muscle tightness testing at baseline. Lumbar lordosis (LL), sacral slope, maturity stage of lumbar vertebral body, and bone marrow edema (BME) at the L5 were examined via MRI. In addition, bone mineral density and content; trunk lean body mass via dual energy x-ray scan; and bilateral muscle tightness including the iliopsoas, hamstrings, and quadriceps were measured. Lumbar BSI was diagnosed as positive bilateral BME and extension-based lumbar pain. All participants were examined twice, one at 6 months and one at 1 year, after the baseline examination. Multivariate logistic regression analysis was performed to identify the risk factors for bilateral lumbar BSI.

RESULTS

A total of 69 (26.3%) players were diagnosed with bilateral lumbar BSI. Asymptomatic BME (odds ratio [OR], 4.260; 95% CI, 2.153-8.431), apophyseal stage of the lumbar vertebral body (OR, 3.438; 95% CI, 1.698-6.959), sacral slope relative to LL ≥5° (OR, 4.067; 95% CI, 2.021-8.181), and hamstring tightness ≥50° (OR, 3.221; 95% CI, 1.385-7.489) were significantly associated with bilateral lumbar BSI.

CONCLUSION

The incidence of bilateral lumbar BSI was common at 26.2%. Asymptomatic BME, sacral anterior tilt relative to LL, immature lumbar epiphyses, and hamstring tightness were found to be risk factors for bilateral lumbar BSI. The results of this study suggest that regular MRI examination could facilitate the early detection of BME, and improvement in hamstring flexibility and lumbosacral alignment may prevent bilateral lumbar BSI in young athletes.

Horseback Riding-Related Injuries in Portugal and Prevention Strategies

CONTEXT

Horse riding (HR) has gain popularity in Portugal, thereby increasing the number of related injuries. This study identifies frequently occurring injuries in Portuguese riders, the conditions under which they occur, and preventive measures.

DESIGN

A retrospective cohort study.

METHODS

We included 216 Portuguese riders practicing HR at the time of the study with ≥1 year of experience. Data were obtained from a questionnaire that characterized first and second rider injuries; we opted for a systematic method to assess the riders' injuries, in a temporal order. Questions regarding demographic data, sports-related background, systematic training workload, number and characteristics of the first 2 injuries, and the need for treatment were included in the questionnaire.

RESULTS

Most first and second injuries were musculoskeletal, occurred from falling off the horse during training, and primarily affected the lower limb. Rehabilitation was required in almost 50% of all cases. The occurrence of injury was significantly associated with the number of days of training per week, years of experience, height and weight of the rider, and practice of another sport. Riding different horses was also significantly associated with the number of injuries.

CONCLUSIONS

The most frequently occurring injuries during HR are musculoskeletal and in the extremities. Injury prevention is essential in HR, as most riders have at least one injury while practicing. Rehabilitation should involve a physiatrist and core strengthening exercises.

Why Median Severity and Ordinal Scale Severity Values should not be used for Injury Burden Results: A Critical Review

Injury burden is a composite measure of injury incidence and mean severity; this parameter has been reported as an output measure from injury surveillance studies in rugby for over 20 years. The benefits of reporting injury burden results have, more recently, been recognised in other sports. This wider use of injury burden as an output measure from injury surveillance studies has, however, highlighted misunderstandings about how to calculate, present and interpret injury burden data. The aim of this critical review is to explain why median severity and ordinal severity scales should not be used to calculate and report injury burden results in injury surveillance studies. Equations are presented to show how injury burden results should be calculated, and graphs and tables are presented to explain the errors that are introduced when median severity and ordinal scales of severity are used instead of mean severity. This critical review is intended to highlight the correct procedures for calculating, reporting and interpreting injury burden results in order to avoid incorrect results, conclusions and injury prevention recommendations being published.

Peak Height Velocity Affects Injury Burden in Circa-PHV Soccer Players

Growth and maturation are potential risk factors for soccer injuries. This research sought to describe how peak height velocity (PHV) affects overall and specific injury burden in circa- and post-PHV elite academy soccer players. Injuries and growth data collected from 2000 to 2020 were studied retrospectively. Longitudinal height records for 124 players were fitted with the Super-Imposition by Translation and Rotation model to calculate PHV (cm/year) and age at PHV. Players were classified according to PHV percentile (fast:≥75th; average: 25-75th; slow:≤25th) and maturity status (circa- or post-PHV). Overall and specific injury burden (days lost/player-season) and rate ratios for comparisons between groups were calculated based on zero-inflated negative binomial models. Confidence intervals were calculated at the 95% confidence level (CI) and the significance level was set at<0.05. In circa-PHV, players with fast PHV had 2.6 (CI: 1.4-4.8)- and 3.3 (CI:1.3-6.7)-times higher overall burden and 2.9 (CI:1.1-7.1)- and 4.1 (CI: 1.4-15.2)-times higher for growth-related injury burden compared to players with average and slow PHV, respectively. Regular monitoring of growth seems important to detect players at higher risk for being disrupted by growth-related injuries.

Growth, maturation and injuries in high-level youth football (soccer): A mini review

Understanding the challenges football (soccer) players face during adolescence is fundamental to avoid disruptions in their development due to injury. This mini review will describe basic concepts of somatic growth and biological maturity, examine data from 53 prospective epidemiological studies on high-level youth football players and discuss how age, growth and maturity may affect the injury patterns observed. Based on the existing evidence, at least every third player sustains an injury during a football season. The thigh (median for studies of boys: 25%, median for girls: 21%), ankle (b: 18%, g: 30%), knee (b: 17%, g: 18%) and hip/groin (b: 14%, g: 10%) are the body parts injured most often, while muscle strains (b: 31%, g: 25%), sprains (b: 20%, g: 27%) and contusions (b: 17%, g: 16%) are the most common injury types. Injury trends are, however, not consistent throughout adolescence, and players' age, maturity status and position relative to peak height velocity (PHV) have shown to influence the number, type and location of injuries sustained. Despite a high volume of observational injury studies published on high-level youth players, girls (7 studies) and settings outside of Europe (included in 23% of studies) are underrepresented and should receive extra attention in the future. Based on the available epidemiological data, tailored injury reduction programmes can be considered in youth football, alongside application of general training principles such as progression, variation and individualization which may be especially important during vulnerable phases such as the adolescent growth spurt.

Epidemiology of injuries in male and female youth football players: A systematic review and meta-analysis

BACKGROUND

To conduct a systematic review and meta-analysis of epidemiological data of injuries in male and female youth football players.

METHODS

Searches were performed in MEDLINE/PubMed, Web of Science, Cochrane Library, and SPORTDiscus databases. Studies were considered if they reported injury incidence rate in male and female youth (≤19 years old) football players. Two reviewers (FJRP and ALV) extracted data and assessed trial quality using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement and the Newcastle Ottawa Scale. The Grading of Recommendations Assessment, Development, and Evaluation approach determined the quality of evidence. Studies were combined using a Poisson random effects regression model.

RESULTS

Forty-three studies were included. The overall incidence rate was 5.70 injuries/1000 h in males and 6.77 injuries/1000 h in females. Match injury incidence (14.43 injuries/1000 h in males and 14.97 injuries/1000 h in females) was significantly higher than training injury incidence (2.77 injuries/1000 h in males and 2.62 injuries/1000 h in females). The lower extremity had the highest incidence rate in both sexes. The most common type of injury was muscle/tendon for males and joint/ligament for females. Minimal injuries were the most common in both sexes. The incidence rate of injuries increased with advances in chronological age in males. Elite male players presented higher match injury incidence than sub-elite players. In females, there was a paucity of data for comparison across age groups and levels of play.

CONCLUSION

The high injury incidence rates and sex differences identified for the most common location and type of injury reinforce the need for implementing different targeted injury-risk mitigation strategies in male and female youth football players.

Incidence, burden, and pattern of injuries in Spanish male youth soccer players: A prospective cohort study

OBJECTIVES

To explore the incidence, burden, and pattern of injuries in Spanish male youth soccer players during a 9-month competitive season (from September to May-June).

DESIGN

Prospective cohort study.

PARTICIPANTS

314 young (10-19 years) soccer players.

MAIN OUTCOME MEASURES

Incidence, burden, location, type, severity, mechanism, and circumstance of injuries, as well as potential differences by tactical position, month of the year, age group, and maturity status.

RESULTS

A total of 146 time-loss injuries were sustained by 101 different players. This resulted in an overall injury incidence of 3.1 injuries per 1000 h, a training injury incidence of 1.8 injuries per 1000 h, and a match injury incidence of 11.2 injuries per 1000 h. The probability of injury over the season was 34%. Most of the injuries affected the lower extremity and were classified as muscle/tendon injuries, with hamstring muscle injuries representing the most burdensome diagnosis. The incidence of injuries increased with age and maturation, but a heightened risk of overuse injuries during periods around peak height velocity was also identified.

CONCLUSIONS

These findings suggest a need for implementing specific injury prevention measures. Due to the high burden shown, these measures should mainly focus on reducing the number and severity of hamstring muscle injuries.

Players with high physical fitness are at greater risk of injury in youth football

The aim of this study was to investigate physical fitness, football-specific skills, and their association with injury risk in youth football. Altogether 447 male and female players aged 9-14 years (median 12 years) participated in performance tests and prospective follow-up. The physical fitness tests included five-jump test for distance, 30-m sprint, football-specific figure of eight agility, countermovement jump, and Yo-Yo intermittent endurance test level 1. The football-specific skill tests included dribbling and passing tests. Injuries and exposure were registered during the 20-week follow-up. Our candidate risk factors were low/high level of physical fitness measured with a composite score of physical fitness tests and low/high level of football-specific skills measured with a composite score of dribbling and passing tests. Secondarily, we investigated performance in individual tests and their association with injury risk. During the follow-up, players reported 565 injuries (264 acute and 301 overuse injuries). High level of physical fitness was associated with increased rate of all injuries (age-, sex-, and mean team exposure-adjusted IRR: 1.28, 95% CI: 1.04-1.58). The level of football-specific skills had no influence on the overall injury rate. Burden of overuse injuries, but not acute injuries was significantly higher in most fit players compared with the players in the reference group (IRR: 2.09, 95% CI: 1.04-4.24). In conclusion, most fit players were at greater risk of sustaining injuries in youth competitive football.

Epidemiology of Campus Football Injuries in Ningxia, China: Occurrence, Causes, and Management

Objective

By 2022, the Chinese government intends to have more than 30 million primary-, middle- and high-school children and adolescents regularly participate in campus football. In contrast, epidemiology of campus football injuries is completely missing. The goal of this descriptive epidemiological study was to determine the current state of campus football injuries and then to recommend appropriate prevention and management strategies.

Methods

This retrospective epidemiological study conducted a survey of students, physical education and football teachers in primary, middle and high schools in the Ningxia Autonomous Region to determine the campus football injuries that occurred throughout the preceding 12-month period. The survey comprised questions on demographic characteristics, the occurrence, causes, and management of campus football injuries.

Results

A total of 1,285 students and 200 teachers returned eligible surveys. 25.7% of students had encountered injury accidents while participating in campus football activities. 31.3% of high school students, 23.8% of middle school students, and 19.2% of primary school students have sustained injuries. Football competition, accounting for 45.4% of all injuries, is the leading cause of injury. Football class teaching, which accounted for 3.0% of all injuries, had the lowest injury rate of any campus football activity. Students and teachers reported that a lack of safety awareness and injury prevention education were the primary causes of injuries. Only 18.7% and 11.4% of students are familiar with first aid basics and cardiopulmonary resuscitation, respectively. 10.6% and 7.5% of students lack any first aid basics and skills, respectively. 43.9% of students lack insurance coverage for athletic injuries. 62.5% and 38.5% of teachers reported that schools lack first aid training and an emergency plan for injuries, respectively.

Conclusion

Students in Ningxia's campus football programs have a high injury risk. Injury prevention and management strategies lag significantly behind the mainstream nationwide promotion of campus football in China.

Elite professional goalkeepers report high rate of sport resumption after shoulder surgery

PURPOSE

The aim of this study is to evaluate the return to sport after surgical treatment of shoulder injuries in professional goalkeepers in relationship with the mechanism of injury and the pattern of related shoulder lesions.

METHODS

Twenty-six shoulders in nineteen elite male professional soccer goalkeepers were retrospectively analyzed considering multiple diseases (instability, rotator cuff, biceps or other tendon injuries). Data was collected for injury modality and context, pathological findings, surgical procedures, time, level of return to sport, and complications.

RESULTS

The mechanism of injury was "mild trauma without contact" in 46% of the cases and 54% of injuries happened during training. 11 patients (42%) reported multiple pattern lesions and 9 patients (35%) classic anterior instability lesions. The mean time for return to differentiated training and unrestricted sport activity was 14 and 20.2 weeks, respectively. 15 athletes (62.5%) reported 100% return to sport, 4 (16.7%) to 90%, 1 (4.2%) to 85%, 3 (12.5%) to 80% and 1 athlete to 50%, stopping professional activity. 21% of the cases reported the persistence of some shoulder symptoms. 3 cases experienced a new injury. Patients with classic anterior instability had significantly lower age (30.7 vs 19.8 years, P = 0.001), experienced injury in different context and reported symptoms more frequently compared to multiple lesion patients (4/8 vs 0/10, P = 0.011).

CONCLUSION

Professional elite goalkeepers which required shoulder surgery for different causes demonstrated high-rate level of return to play despite the persistence of mild symptoms. The high frequency of multiple lesions, patients' characteristics, injury context and mechanism, increase the concern for injuries in overstressed shoulder for this category of sport.

LEVEL OF EVIDENCE

IV.

Primary Periphyseal Stress Injuries in Young Athletes: A Systematic Review

BACKGROUND

Overuse injuries are common in sporting children and adolescents. These injuries are a particular concern when they involve the epiphyseal-physeal-metaphyseal (EPM) complex given their potential to disturb skeletal growth. Specifically, the limits of mechanical tolerance of the EPM complex to repetitive stress may be exceeded by the intense and continuous training characteristic of many youth sports today.

OBJECTIVE

This article describes the present status of knowledge on the occurrence and outcome of primary periphyseal stress injuries (PPSIs) affecting the EPM complex in the extremities of children and adolescents involved in youth sports.

METHODS

A comprehensive review of the sports medicine literature was conducted to determine the nature and extent of PPSIs affecting the EPM complex of the extremities among youth sports participants and the potential for consequent skeletal growth disturbance and resultant limb deformity associated with these injuries.

RESULTS

Our initial search uncovered 128 original published scientific articles reporting relevant data on PPSIs. There were 101 case reports/series, 19 cross-sectional, 1 case-control, and 7 cohort studies with relevant data. The case reports/series studies reported 448 patients with PPSIs involving the extremities. Children and adolescents representing a variety of high impact repetitive youth sports activities-including baseball, badminton, climbing, cricket, dance, gymnastics, rugby, soccer, swimming, tennis, and volleyball-may sustain PPSIs involving the shoulder, elbow, hand and wrist, knee, and ankle and foot. Although incidence data from prospective cohort studies are lacking, data arising from cross-sectional studies suggest that PPSIs may be common in select groups of youth athletes-including the shoulder in baseball players (0-36.6%), wrist in gymnasts (10-83%) and platform divers (52.6%), and fingers in rock climbers (5-58%). Notably, not all stress-related skeletal changes detected on imaging were symptomatic in these studies. When diagnosed and treated with an appropriate period of rest and rehabilitation, most patients studied were able to return to their sport activities. However, our data also show that 57/448 PPSIs (12.7%) produced growth disturbance, and that 28/448 patients (6.2%) underwent surgery for their injuries. Absence of treatment, delayed presentation and diagnosis, and non-compliance with a rest regimen were common in cases that produced growth disturbance.

CONCLUSIONS

PPSIs may affect the extremities of children and adolescents engaged in a variety of youth sports, especially at advanced levels of training and competition. Most skeletally immature patients with PPSIs respond well to timely treatment; however, in extreme cases, PPSIs can progress to produce skeletal growth disruption which may necessitate surgical intervention. Clearly, establishing the early diagnosis of PPSIs and providing timely treatment of these injuries are needed to ensure the skeletal health of youth sports participants. Rigorous prospective longitudinal epidemiological and imaging studies designed to provide incidence rates of PPSIs and to determine the effect of PPSIs on long-term skeletal health are also necessary.

Ankle Injuries in Soccer Players: A Narrative Review

Soccer is one of the most popular sport, with many describing it as the "king of sports." In recent years, increased global participation in soccer has led to an inevitable increase in injury rates, especially in the lower extremities. Consequently, there is an increase in the epidemiology of soccer injuries, both in professionals and amateur athletes. The cause of an injury is multifactorial and depends on psychosocial, predisposing, intrinsic, and extrinsic factors. Also, contact with another player and non-contact injuries seem to be the most widespread mechanisms of injuries. The most common injuries recorded in soccer are ankle sprains and hamstrings injuries. More specifically, many studies have shown a correlation between the previous injury in lower extremities, weakness of abductors muscle, and psychosocial factors with the ankle sprain. Additionally, according to study results, injuries in adult men, adolescent men, and women during a match are higher than injuries during training. This narrative review aims to record the epidemiology of ankle injuries, risk factors, and the relationship between circadian rhythm, sleep, and injuries.