Why we should focus on the burden of injuries and illnesses, not just their incidence

Injury characteristics in Norwegian male professional football: A comparison between a regular season and a season in the pandemic

The Coronavirus Disease-19 (COVID-19) pandemic forced the Norwegian male premier league football season to reschedule, reducing the fixture calendar substantially. Previous research has shown that a congested match schedule can affect injury rates in professional football. Therefore, we aimed to investigate whether the Norwegian premier league teams suffered more injuries in the more match congested 2020 season than in the regular 2019-season. We invited all teams having participated in both seasons to export their injury data. Only teams that used the same medical staff to register injuries in both seasons were included, and to maximize data comparability between seasons, we applied a time-loss injury definition only. Seven of 13 teams agreed to participate and exported their injury data. Both seasons had 30 game weeks, but the 2020 season was 57 days shorter than the 2019 season. The match injury incidence did not differ significantly [incidence rate ratio 0.76 (0.48-1.20; p = 0.24) in the 2020 season compared to the 2019 season. Furthermore, we found no differences in the number of injuries, days lost to injury, matches missed to injury, or injury severity. We could not detect any differences between the two seasons, suggesting the congested match calendar combined with the safety measures in the 2020 season can be a safe alternative in future seasons.

Contribution of sex, sports and activity types and curriculum load distribution to intracurricular injury risk in physical education teacher education: a cohort study

Objectives

To investigate the influence of sports/activity types and their distribution over the curriculum years on intracurricular injury risk differences between curriculum years and sexes in Physical Education Teacher Education (PETE) studies.

Methods

In a cohort study over 14 years (2000-2014), injuries reported at the medical facility of a Dutch vocational institute by PETE students who completed their full curriculum were registered. Intracurricular injury rates (IR) per 1000 hours and 95% CIs were calculated per sport, sex and curriculum year and compared with injury rate ratios (RR) and 95% CI. Exposure times per sports category per curriculum year were compared with the χ2 test.

Results

Intracurricular IR was highest for gymnastics, team ball sports and track and field (0.76-1.23, 95% CI 0.65 to 1.45). IRs were higher for female compared with male students (RR 2.38, 95% CI 1.97 to 2.87). Comparisons for all individual sports and for all three curriculum years showed the same pattern. IR for the first year was higher than for the second (RR 1.79, 95% CI 1.45 to 2.21) and third year (RR 2.74, 95% CI 2.13 to 3.54) with similar patterns for all sports categories. Over the curriculum years, exposure time distributions per sport showed small differences (p<0.001, Cramer's V=0.07).

Conclusion

Curriculum year, sex and sports types are risk factors to be independently targeted for preventive and rehabilitative measures in PETE studies. The nature and aetiology of injuries in mixed sports, and the adaption to increased loads in first-year and female PETE students, need further investigation.

Data Collection Procedures and Injury Definitions in Badminton: A Consensus Statement According to the Delphi Approach

ABSTRACT

Previous studies involving injury surveillance in badminton players have used nonstandardized injury definitions and data collection methodologies. The purpose of this study was to apply a Delphi method to (1) reach a consensus on an injury definition in badminton and (2) develop a standardized badminton injury report form. An Injury Consensus Group was established under the auspices of the Badminton World Federation, and initial injury definitions and injury report form were developed. An internal panel was formed from the Injury Consensus Group, and an external panel was selected based on a combination of profession, experience in the field, sport-specific knowledge/expertise, and geographical location to obtain a widely representative sample. Through 2 rounds of voting by the external panel, consensus was reached on both the definition of an injury in badminton and a standardized injury report form. The agreed injury definition was "Any physical injury sustained by a player during a match or training regardless if further diagnostic tests were done or if playing time was lost" and the injury report form contained the following 7 sections: Injury record, Diagnosis, Injury mechanism, Regarding pain, Pain and return to play/training after injury, Grade of severity, and Recurrence. We recommend the use of the definitions and methods presented in this consensus statement for the reporting of injury in all international and domestic badminton players. This should make future injury surveillance reports directly comparable and hence more informative in recognizing trends over time and differences between countries.

Monitoring Variables Influence on Random Forest Models to Forecast Injuries in Short-Track Speed Skating

Injuries limit the athletes' ability to participate fully in their training and competitive process. They are detrimental to performance, affecting the athletes psychologically while limiting physiological adaptations and long-term development. This study aims to present a framework for developing random forest classifier models, forecasting injuries in the upcoming 1 to 7 days, to assist the performance support staff in reducing injuries and maximizing performance within the Canadian National Female Short-Track Speed Skating Program. Forty different variables monitored daily over two seasons (2018-2019 and 2019-2020) were used to develop two sets of forecasting models. One includes only training load variables (TL), and a second (ALL) combines a wide array of monitored variables (neuromuscular function, heart rate variability, training load, psychological wellbeing, past injury type, and location). The sensitivity (ALL: 0.35 ± 0.19, TL: 0.23 ± 0.03), specificity (ALL: 0.81 ± 0.05, TL: 0.74 ± 0.03) and Matthews Correlation Coefficients (MCC) (ALL: 0.13 ± 0.05, TL: -0.02 ± 0.02) were computed. Paired T-test on the MCC revealed statistically significant (p < 0.01) and large positive effects (Cohen d > 1) for the ALL forecasting models' MCC over every forecasting window (1 to 7 days). These models were highly determined by the athletes' training completion, lower limb and trunk/lumbar injury history, as well as sFatigue, a training load marker. The TL forecasting models' MCC suggests they do not bring any added value to forecast injuries. Combining a wide array of monitored variables and quantifying the injury etiology conceptual components significantly improve the injury forecasting performance of random forest models. The ALL forecasting models' performances are promising, especially on one time windows of one or two days, with sensitivities and specificities being respectively above 0.5 and 0.7. They could add value to the decision-making process for the support staff in order to assist the Canadian National Female Team Short-Track Speed Skating program in reducing the number of incomplete training days, which could potentially increase performance. On longer forecasting time windows, ALL forecasting models' sensitivity and MCC decrease gradually. Further work is needed to determine if such models could be useful for forecasting injuries over three days or longer.

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.

Relative skeletal maturity status affects injury burden in U14 elite academy football players

Maturation progresses at different times and at different rates between individuals. Thus, differences in maturity status exist among players in the same chronological age-based category, especially in U14 players. The purpose of this prospective study was to describe injury burden according to the relative skeletal maturity status in U14 elite academy football players. From 2011 to 2020 injuries and individual exposure (training and match) were prospectively recorded in 183 male U14 players. Skeletal age (SA) was assessed using the Tanner-Whitehouse 2 method. Relative skeletal maturity status [SA minus chronological age (CA)] was classified as follows: early (SA-CA > 0.5), on-time (SA-CA ± 0.5) and late (SA-CA < -0.5). Overall and specific injury burden (days lost/1000h) and rate ratios for comparisons between groups were calculated. Overall injury burden was 2.8-times higher (3.6-times in training) in early maturers compared with late maturers. Growth-related injuries were the most burdensome injuries in all three groups, but significant differences were not found between groups. Muscle injuries were 4-times more burdensome in early maturers compared with on-time and late maturers. Besides, joint/ligament injuries were 7- and 12- times less burdensome in late maturers than in on-time and late maturers, respectively. Significant differences between groups in overall and specific injury burden were not found in matches. Our results showed different injury patterns in U14 early, on-time and late maturers. Hence, monitoring maturity seems crucial to detect potential injuries that cause the greatest disruption, and facilitate design of targeted injury prevention programs.

Injuries in elite level male beach soccer players: a prospective three year study

OBJECTIVES

The aim of this study was to investigate the incidence and characteristics of match and training injuries in elite-level national male beach soccer players.

METHOD

The incidence, mechanism, location, type, severity, and burden of injuries of the Turkish national beach soccer team were recorded between 2017 and 2019.

RESULTS

A total of 136 injuries occurred during the study period. Total injury incidence was 238.9 injuries/1,000 match hours (MHs) and 37.7 injuries/1,000 training hours (THs) (p < 0.001). Twenty-seven injuries led to time-loss, and the incidences for match and training injuries were 36.7 and 7.9 per 1,000 hours, respectively. Of medical attention injuries (MAI) caused by trauma, 54.6% (n = 53) were due to another player and, 60.9% (n = 14) of time-loss injuries (TLI) caused by trauma were due to non-contact trauma (p < 0.001). While 82% (n = 91) of training injuries occurred in lower extremities, 29% (n = 9) of match injuries occurred in the head/neck region (p < 0.001). Head injury incidence was 45.9 per 1,000 match hours. Of MAI, 50% (n = 57) were contusion, and 32.1% (n = 9) of TLI were strain (p < 0.001). Also, the most common injury subtype was foot/toe contusion during match and training (19.4%; n = 6, 27.9%; n = 31, respectively). The majority of injuries 91.9% (n = 125) had slight severity.

CONCLUSION

Head trauma, tendon injury, and foot/toe contusion are important for clinical practice in beach soccer. Protective measures (rule regulation, use of protective equipment, etc.) should be considered to prevent these injuries.

Prevalence and burden of health problems in top-level football referees

BACKGROUND

Top-level football referees take decisions during strenuous physical activity, and often under great mental pressure. Despite their central role in a football match, little is known about referees' health problems, particularly in female referees.

AIM

To investigate the prevalence and burden of health problems in female and male top-level referees.

STUDY DESIGN

Prospective cohort study.

METHOD

Fifty-five Norwegian male and female top-level referees reported health problems (injuries and illnesses) in pre-season and during the 2020 competitive season, using the Oslo Sports Trauma Research Center Questionnaire on Health Problems (OSTRC-H2).

RESULTS

We recorded data for 49 weeks with a compliance of 98%. On average, 34% (95% CI 31-36%) of referees reported at least one health problem each week, and 20% (95% CI 19-22%) reported substantial health problems. Female referees reported more health problems than male referees, and on-field referees reported more health problems than assistant referees. Gradual-onset injuries were most prevalent and caused the greatest absence from training and matches, whereas illnesses represented only a small portion to the overall burden of health problems. The injury incidence was three injuries per athlete-year (95% CI 2.5-3.5) and 11 injuries per 1000 match hours (95% CI 7-18). The illness incidence was 1.4 illnesses per athlete-year (95% CI 1.1-1.8). Injuries to the lower legs and feet represented the highest burden of health problems.

CONCLUSION

Top-level referees, especially females, reported a high prevalence of health problems. Gradual-onset injuries to the lower leg and foot represented the highest injury burden.

Between-Limb Symmetry in ACL and Tibiofemoral Contact Forces in Athletes After ACL Reconstruction and Clearance for Return to Sport

Background:

Current return-to-sport (RTS) criteria after anterior cruciate ligament (ACL) reconstruction (ACLR) include demonstrating symmetry in functional and strength tests. It remains unknown if at the time that athletes are cleared to RTS, they exhibit between-limb symmetry in ACL and tibiofemoral contact forces or if these forces are comparable with those in uninjured athletes.

Purposes:

To (1) examine ACL and tibiofemoral contact forces in athletes who underwent ACLR and were cleared to RTS and (2) compare the involved leg to the healthy contralateral leg and healthy controls during functional tasks.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

A total of 26 male athletes who underwent ACLR were tested at the time of RTS during tasks that included single-leg vertical, horizontal, and side jumps; cutting maneuvers; and high-intensity running. We used an electromyography-constrained musculoskeletal modeling workflow to estimate ACL and tibiofemoral contact forces and compared the results with those of 23 healthy male participants.

Results:

The ACLR group presented no differences in peak tibiofemoral contact forces in the involved limb compared with the control group. However, there were significant between-limb differences mainly due to higher contact forces in the uninvolved (healthy) limb of the ACLR group compared with the control group. In the ACLR group, ACL forces were significantly higher in the uninvolved limb compared with the involved limb during cutting and running. Lateral contact forces were lower in the involved compared with the uninvolved limb, with large effect sizes during cutting (d = 1.14; P < .001) and running (d = 1.10; P < .001).

Conclusion:

Current discharge criteria for clearance to RTS after ACLR did not ensure the restoration of symmetric loading in our cohort of male athletes. ACL force asymmetry was observed during cutting and running, in addition to knee loading asymmetries on several tasks tested.

Early versus delayed lengthening exercises for acute hamstring injury in male athletes: a randomised controlled clinical trial

Background

To evaluate the efficacy of early versus delayed introduction of lengthening (ie, eccentric strengthening) exercises in addition to an established rehabilitation programme on return to sport duration for acute hamstring injuries in a randomised controlled superiority trial.

Methods

90 male participants (age: 18–36 years, median 26 years) with an MRI-confirmed acute hamstring injury were randomised into an early lengthening (at day 1 of rehabilitation) group or a delayed lengthening (after being able to run at 70% of maximal speed) group. Both groups received an established rehabilitation programme. The primary outcome was time to return to sport (ie, time from injury to full unrestricted training and/or match play). The secondary outcome was reinjury rate within 12 months after return to sport. Other outcomes at return to sport included the Askling H-test, hamstring strength, clinical examination and readiness questions.

Results

The return to sport in the early lengthening group was 23 (IQR 16–35) days and 33 (IQR 23–40) days in the delayed lengthening group. For return to sport (in days), the adjusted HR for the early lengthening group compared with the delayed lengthening group was 0.95 (95% CI 0.56 to 1.60, p=0.84). There was no significant difference between groups for reinjury rates within 2 months (OR=0.94, 95% CI 0.18 to 5.0, p=0.94), from 2 to 6 months (OR=2.00, 95% CI 0.17 to 23.3, p=0.58), and 6 to 12 months (OR=0.57, 95% CI 0.05 to 6.6, p=0.66).

Conclusion

Accelerating the introduction of lengthening exercises in the rehabilitation of hamstring injury in male athletes did not improve the time to return to sport nor the risk of reinjury.

Use of GPS to measure external load and estimate the incidence of muscle injuries in men's football: A novel descriptive study

Measurement of external load in players provides objective information to optimise the weekly balance between training and recovery to improve performance and prevent injuries. Our aim was to evaluate the incidence of sports-related muscle injuries of the lower limb in relation to external load, measured by global positioning system (GPS), in football players. A descriptive study was carried out. Data were collected from 71 professional male football players (30 professionals and 41 youth players) from an elite football club competing in the Spanish and European League in the 2017-2018 season. As external load variables, we measured High Metabolic Load Distance (HMLD), High Speed Running (HSR), Player Load (PL), and Total Distance (TD) through GPS. Injury rate (IR) was calculated both in relation to such GPS load metrics and to load exposure time. We considered categories (youth and professional), playing positions (centre back, full back, midfielder, and forward), and training day with respect to match-day (-4MD, -3MD, -2MD, -1MD, MD, +1MD, +2MD). The GPS load metrics HMLD, HSR, PL, and TD showed very similar patterns across categories and positions, but varied according to training session or MD. The highest loads were observed on MD and three days prior to the match (-3MD). Similarly, the overall IR, both calculated per load exposure time and per GPS load metrics, was highest on MD and -3MD. Again, no differences were observed between youth and professional players. Midfielders demonstrated the highest IR in all metrics, followed by the forwards. In conclusion, this study suggests that external load and incidence of muscle injuries are directly proportional. Therefore, the measurement of more external load variables other than load exposure time, such as the GPS metrics HMLD, HSR, PL, and TD may help to describe the pattern and magnitude of injuries. Future studies based on ours may help to further improve the understanding of the incidence of muscle injuries on the basis of external loads measurements in different football teams.

Symmetry in Triple Hop Distance Hides Asymmetries in Knee Function After ACL Reconstruction in Athletes at Return to Sports

BACKGROUND

After anterior cruciate ligament reconstruction (ACLR), a battery of strength and hop tests is frequently used to determine the readiness of an athlete to successfully return to sports. However, the anterior cruciate ligament reinjury rate remains alarmingly high.

PURPOSE

To evaluate the lower limb function of athletes after ACLR at the time when they had been cleared to return to sports (RTS). We aimed to evaluate if passing discharge criteria ensures restoration of normal lower limb biomechanics in terms of kinematics, kinetics, work, and percentage work contribution during a triple hop for distance.

STUDY DESIGN

Controlled laboratory study.

METHODS

Integrated 3-dimensional motion analysis was performed in 24 male athletes after ACLR when cleared to RTS and 23 healthy male controls during the triple-hop test. The criteria for RTS were (1) clearance by the surgeon and the physical therapist, (2) completion of a sports-specific on-field rehabilitation program, and (3) limb symmetry index >90% after quadriceps strength and hop battery tests. Lower limb and trunk kinematics, as well as knee joint moments and work, were calculated. Between-limb differences (within athletes after ACLR) and between-group differences (between ACLR and control groups) were evaluated using mixed linear models.

RESULTS

Although achieving 97% limb symmetry in distance hopped and displaying almost 80% symmetry for knee work absorption in the second rebound and third landing, the ACLR cohorts demonstrated only 51% and 66% limb symmetry for knee work generation in the first and second rebound phases, respectively. During both work generation phases of the triple hop, the relative contribution of the involved knee was significantly smaller, with a prominent compensation from the hip joint (P < .001, for all phases) as compared with the uninvolved limb and the controls. In addition, patients deployed a whole body compensatory strategy to account for the between-limb differences in knee function, mainly at the hip, pelvis, and trunk.

CONCLUSION

Symmetry in the triple hop for distance masked important deficits in the knee joint work. These differences were more prominent during work generation (concentric-propulsive) than work absorption (eccentric-landing).

CLINICAL RELEVANCE

Symmetry in hop distance during the triple hop test masked significant asymmetries in knee function after ACLR and might not be the appropriate outcome to use as a discharge criterion. Differences between limbs in athletes after ACLR were more prominent during the power generation than the absorption phase.

Part 2 of the 11+ as an effective home-based exercise programme in elite academy football (soccer) players: a one-club matched-paired randomised controlled trial

Background:Although the 11+ is known to reduce injuries and improve performance in adolescent footballers, its duration presents a notable barrier to implementation. Hence, this study investigated injury and performance outcomes when 65 elite male academy footballers either performed Part 2 3x/week at training (TG) or at home (HG).Methods:Time to stabilisation (TTS), eccentric hamstring strength (EH-S) and countermovement jump height (CMJ-H) were collected 4 times during the 2019 football season. Linear mixed models were used to evaluate main and interaction effects of group and time. Bonferroni post-hoc tests were used to account for multiple comparisons. Differences in time loss and medical attention injuries were determined using a two-tailed Z test for a comparison of rates.Results:Relative to baseline, EH-S (HG 4.3 kg, 95% CI 3 to 5.7, p < 0.001; TG 5.5 kg, 95% CI 4.3 to 6.6, p < 0.001) and CMJ-H (HG 3.5 cm, 95% CI 2.2 to 4.7, p < 0.001; TG 3.2 cm, 95% CI 2.2 to 4.3, p < 0.001) increased, with no difference between groups observed at the end of the season. All injury outcomes were similar.Conclusion: Rescheduling Part 2 did not affect performance or increased injury risks in academy footballers.

Epidemiology of injuries in elite male and female futsal: a systematic review and meta-analysis

The main purpose of this study was to conduct a systematic review and meta-analysis quantifying the incidence of injuries in futsal players. A systematic search was conducted using MEDLINE, PubMed, Web of Science and Scopus databases and subsequently, six studies (14 cohorts) were selected. Separate meta-analyses for male and female players were conducted using a Poisson random-effect regression model approach. The overall and match incidence rates in elite male futsal players were 6.8 (95% CI = 0.0-15.2) and 44.9 (95% CI = 17.2-72.6) injuries/1000 hours of exposure. Pooled training injury rate in male players was not calculated due to the lack of studies reporting training injuries in this cohort. For females, an overall, training and match incidence rates of 5.3 (95% CI = 3.5-7), 5.1 (95% CI = 2.7-7.6) and 10.3 (95% CI = 0.6-20.1) injuries/1000 hours of exposure were reported. In males, match incidence rate in International tournaments was 8.5 times higher than in national leagues (77.2 [95% CI = 60.0-94.5] vs 9.1 [95% CI = 0.0-19.3] for international tournaments and national leagues, respectively). Elite male and female futsal players are exposed to a substantial risk of sustaining injuries, especially during matches.

Perceived Social Support, Reinjury Anxiety, and Psychological Readiness to Return to Sport in Soccer Players

The burden of sports injury in soccer is high, and return to sport outcomes following injury are often poor. This is compounded by a current lack of understanding surrounding the factors that may optimize psychological readiness to return to sport. Consequently, in the present study, we aim to further our understanding of these issues by examining the role of perceived social support in predicting psychological readiness to return to sport. In doing so, we extend previous research by examining whether reinjury anxiety is a mediating factor in this relationship. A sample of 150 previously injured soccer players (mean age = 25.32 y) completed measures of perceived social support, reinjury anxiety during rehabilitation, and psychological readiness to return to sport. Mediation analyses showed that reinjury anxiety partly accounted for the positive relationship between perceived social support and psychological readiness to return to sport. These findings suggest that injured soccer players with higher perceptions of social support will experience less reinjury anxiety during rehabilitation and, as a consequence, will be more psychologically ready upon return to sport.

Injuries in elite-level women's football-a two-year prospective study in the Irish Women's National League

We investigated the pattern of injuries in elite-level women's football in Ireland, during a two-season prospective injury surveillance study in the Women's National League (WNL). Seven out of the eight clubs (271 players) in the WNL were followed prospectively during the 2018 and 2019 seasons. The injury incidence rate in matches (19.2/1000 h) was 7.5 times higher than in training (2.5/1000 h). Players, on average, sustained 0.69 injuries per season (266 injuries/383 player seasons), which equates to 15 time-loss injuries per season for a squad of 22 players. The majority of the injuries sustained by players were lower extremity injuries (85%), of which, 46% had a non-contact injury mechanism. Muscle, ligament, and contusion injuries were the most common injury types, while the ankle, knee, and thigh were the most commonly injured body sites. The most common injuries sustained over the two seasons were lateral ankle sprains (13.9%), hamstring strains (12.4%), knee meniscus/cartilage injuries (7.5%), adductor strains (6%), quadriceps strains (4.5%), and ankle contusions (4.5%). The injuries with the highest injury burden were ACL injuries (59 days lost/1000 h), knee meniscus/cartilage injuries (23/1000 h), lateral ankle sprains (21/1000 h), hamstring strains (12/1000 h), MCL sprains (11/1000 h), and quadriceps strains (11/1000 h). There were 8 ACL tears documented over the 2 seasons, which accounted for 28% of all time lost to injury with a mean days lost per injury of 247. We recommend that clubs in the WNL in Ireland should implement injury risk mitigation strategies, with a particular focus on injuries with a high injury burden.

Illness and injury among Norwegian Para athletes over five consecutive Paralympic Summer and Winter Games cycles: prevailing high illness burden on the road from 2012 to 2020

OBJECTIVE

To describe the illness and injury pattern of Norwegian Para athletes over five consecutive Paralympic Summer and Winter Games cycles and to identify which health problems should be targeted in risk management plans with respect to impairment types.

METHODS

We monitored athletes from 12 to 18 months prior to each Game using a weekly online questionnaire (Oslo Sports Trauma Research Center-H2 (OSTRC-H2)). We asked them to report all health problems they had experienced in the preceding 7 days, irrespective of their consequences on their sports participation or performance and whether they had sought medical attention.

RESULTS

Between 2011 and 2020, 94 candidate athletes were included in this monitoring programme and prepared to represent Norway; of these, 66 (71%) were finally selected for multiple Paralympic Games. The overall response rate to the weekly questionnaires was 87%. At any given time during the five observation cycles, 37% of the athletes (95% CI 36% to 38%) reported having at least one health problem. Athletes with neurological impairments (n=51) lost 10 days per year due to respiratory problems (95% CI 9 to 11) compared with 9 days (8-10) among those with musculoskeletal impairments (n=37). Gastrointestinal problems caused a time loss of on average 4 days per year in athletes with neurological impairments versus 1 day in athletes with musculoskeletal impairments (mean difference 2.7 days, 2.1-3.3). Musculoskeletal injuries generated a high burden for both athlete groups, in particular, to the elbow, shoulder and lumbosacral regions.

CONCLUSION

At any given time, nearly two out of five elite Norwegian Para athletes reported at least one health problem. Respiratory tract and other infections; gastrointestinal problems, injuries to the shoulder, elbow and lumbosacral regions represented the greatest health burden. Our findings can help guide the allocation of clinical resources, which should include a broad network of medical specialists, together with dieticians and physiotherapists, to meet the health challenges in Para athletes.

Prevalence and Burden of Self-Reported Health Problems in Junior Male Elite Ice Hockey Players: A 44-Week Prospective Cohort Study

BACKGROUND

Little is known about the burden of overuse injuries and illnesses in junior elite ice hockey.

PURPOSE

To describe the prevalence and burden of all health problems in junior male elite ice hockey players in Norway during 1 school year.

STUDY DESIGN

Descriptive epidemiological study.

METHODS

A total of 206 junior male ice hockey players (mean age, 17 years; range, 15-20 years) attending specialized sports academy high schools in Norway reported all health problems, acute injuries, overuse injuries, and illnesses, weekly during the 2018-2019 school year (44 weeks). The players self-reported injuries and illnesses using the Oslo Sports Trauma Research Center Questionnaire on Health Problems.

RESULTS

Of the players included, 25% (95% CI, 23%-27%) reported at least 1 health problem at any given time, while 16% (95% CI, 14%-17%) experienced health problems with a substantial negative effect on training and performance. Of the total burden of health problems, acute injuries accounted for 44%, overuse injuries 31%, and illnesses 25%. For acute injuries, the greatest burden was caused by injuries to the ankle, knee, and hand, whereas for overuse injuries the most burdensome location was the hip/groin and knee.

CONCLUSION

This study documented that while acute injuries did represent the greatest problem among junior elite ice hockey players, overuse injuries, especially to the knee and hip/groin, also had a substantial effect.

Characterization of Rookie Season Injury and Illness and Career Longevity Among National Basketball Association Players

IMPORTANCE

There is limited research investigating injury and illness among professional basketball players during their rookie season. By improving the understanding of injury incidence and risk specific to rookie players, sports medicine clinicians may be able to further individualize injury mitigation programs that address the unique needs of rookie players.

OBJECTIVE

To compare incidence and rate ratio (RR) of injury and illness among professional National Basketball Association (NBA) players in their rookie season with veteran players and to explore the association of sustaining an injury rookie season with career longevity.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study used an online data repository and extracted publicly available data about NBA players between the 2007 and 2008 season to the 2018 and 2019 season. Available data for initial injury and all subsequent injuries were extracted during this time frame.

EXPOSURES

Injury and illness based on injury status during the rookie season of professional NBA players.

MAIN OUTCOMES AND MEASURES

Injury and illness incidence and RR. Association of injury during the rookie season with career longevity was assessed via Poisson regressions.

RESULTS

Of the 12 basketball seasons analyzed, 904 NBA players were included (mean [SD] age, 24.6 [3.9] years; body mass index, 24.8 [1.8]). The injury and illness incidence for rookie players was 14.28 per 1000 athlete game exposures (AGEs). Among all body regions, ankle injuries had the greatest injury incidence among players injured during their rookie season (3.17 [95% CI, 3.15-3.19] per 1000 AGEs). Rookie athletes demonstrated higher RR compared with veterans across multiple regions of the body (ankle: 1.32; 95% CI, 1.12 to 1.52; foot/toe: 1.29; 95% CI, 0.97 to 1.61; shoulder/arm/elbow: 1.43; 95% CI, 1.10 to 1.77; head/neck: 1.21; 95% CI, 0.61 to 1.81; concussions: 2.39; 95% CI, 1.89 to 2.90; illness: 1.14; 95% CI, 0.87 to 1.40), and demonstrated a higher rate of initial injuries compared with veteran players (1.41; 95% CI, 1.29 to 1.53). Players who sustained an injury rookie season demonstrated an unadjusted decrease in total seasons played (-0.4 [95% CI, -0.5 to -0.3] log years; P < .001), but this decrease was not observed within adjusted analysis (0.1 [95% CI, -0.1 to 0.2] log years; P = .36).

CONCLUSIONS AND RELEVANCE

In this study, rookie athletes demonstrated the highest injury incidence at the ankle and increased RR across multiple regions. These findings may reflect differences in preseason conditioning or load variables impacting rookie athletes and warrant further investigation. Future research is needed to determine the association of cumulative injury burden vs a singular injury event on career longevity.

The Burden and Risk Factors of Patellar and Achilles Tendinopathy in Youth Basketball: A Cohort Study

This study aimed at evaluating the burden and risk factors of patellar and Achilles tendinopathy among youth basketball players. Patellar and Achilles tendinopathy were prospectively monitored in 515 eligible male and female youth basketball players (11–18 years) through a competitive season. Overall, the season prevalence of patellar tendinopathy was 19.0% (95% CI: 15.7–22.7%), 23.2% (95% CI: 18.6–28.2%) in males and 12.5% (95% CI: 8.3–17.9%) in females. The season prevalence of Achilles tendinopathy was 4.3% (95% CI: 2.7–6.4%), 4.1% (95% CI: 2.2–7.0%) in males and 4.5% (95% CI: 2.1–8.4%) in females. Median proportion of symptoms duration was 83% of average total weeks of basketball exposure for patellar tendinopathy and 75% for Achilles tendinopathy. Median time to patellar tendinopathy onset was 8 weeks for male players and 6 weeks for female players. Higher odds of patellar tendinopathy risk were seen in males (OR: 2.23, 95% CI: 1.10–4.69) and players with previous anterior knee pain had significantly elevated odds (OR: 8.5, 95% CI: 4.58–16.89). The burden and risk of patellar tendinopathy is high among competitive youth basketball players. Risk factors include sex and previous anterior knee pain. These findings provide directions for practice and future research.

Injury profiles of Australian football players across five, women's and girls' competition levels

OBJECTIVES

To describe injury profiles of Australian football players and explore trends across five, women's and girls' competition levels.

DESIGN

Prospective cohort study.

METHODS

Injuries were prospectively recorded by team personnel across one or two seasons of Australian football (2017-18 and/or 2018-19) including five, women's and girls' competition levels (elite senior, non-elite senior, high-level junior, non-elite junior (14-17 years), and non-elite junior (10-13 years)). Injury incidence rates were calculated per 1000 h and injury prevalence calculated for pre-season, early-season, mid-season, and late-season. Descriptive statistics present injury profiles according to activity, body region, pathology, mechanism, and severity.

RESULTS

From the 392 included players, 760 injuries were recorded. Overall injury incidence was 20.9 injuries per 1000 h. Injury prevalence was highest during pre-season (64.1%). Most injuries were to the lower extremity (n = 440; 58.0%). Ligament/joint sprain injuries were common (n = 147, 19.3%). Several injuries resulted from contact mechanisms (n = 314, 61.4%), with many due to contact with another player (n = 131, 52.8%). Injuries resulting in time lost from participation were common (n = 444, 58.9%). Competition level injury trends were observed, with elite senior (125.1 injuries per 1000 h) and high-level junior (116.9 injuries per 1000 h) players having greater match injury incidence compared to their non-elite counterparts (15.5-41.4 injuries per 1000 h).

CONCLUSIONS

This study provides preliminary insight into injury profiles of Australian football players in women's and girls' competitions. These findings can drive future injury risk reduction research specific to this population across the developmental pathway.

Short and Long-Term Effects of a Simple-Strength-Training Program on Injuries Among Elite U-19 Soccer Players

Purpose: The aim of this study was to examine the short and long-term effects of a simple strength training program on muscle injury prevention in soccer players. Methods: Twenty-seven U-19 elite male soccer players participated in the study. The investigation was conducted over two consecutive and similar seasons (e.g., the same staff, players, weekly training schedule), the first being the control and the second the experimental season. The strength program was carried out 2 times per week, for 10 weeks, during part of the preseason and in-season. Injury incidence and absence days were compared between both seasons, according to the injury rate ratio (IRR), with 95% CI and the Z test. Results: A lower number of total and hamstring injuries were recorded during the experimental (9 and 2, respectively) compared to the control (15 and 7, respectively) period. During the 10 weeks intervention period, the injury rate ratio (IRR) was lower in the experimental season than in the control season (IRR = 8.12; 95% CI: 1.00-66.03; effect size (ES) = 3.30, large). In addition, there was a decline in absence days per injury and in the number of absence days/1000 h (IRR = 2.44; 95% CI: 1.90-3.14; ES = 1.12) during the experimental season. Conclusion: The results of this study suggest that this simple strength-training program could reduce the muscle injury incidence during its application period in young soccer players.

Follicular phase of menstrual cycle is related to higher tendency to suffer from severe injuries among elite female futsal players

OBJECTIVE

To describe the injury incidence according to each phase of menstrual cycle (MC) in professional futsal players along two consecutive season and, secondly, to compare the injury incidence and frequency between different phases of the MC.

DESIGN

Prospective cohort study.

SETTINGS

Elite futsal players.

PARTICIPANTS

179 players.

MAIN OUTCOME MEASURE

Players were registered along two consecutive seasons.

RESULTS

191 injuries were reported throughout both seasons. The injury incidence was 30.63 days-off during the follicular phase, 23.6 during ovulatory phase and 17.59 days-off in luteal phase, showing higher incidence during the follicular phase. No statistical differences (p > 0.05) were reported for any variable comparing among the three phases of MC.

CONCLUSIONS

This study suggests the relevance to track the MC, but reduces its possible relationship or influence on the injury distribution during each phase of the MC. The knowledge of injury incidence, burden and etiology is a key factor to design injury prevention programs with the focus on the most common injuries, where MC could be included as a complementary factor.

Immediate and 6-week effects of wearing a knee sleeve following anterior cruciate ligament reconstruction: a cross-over laboratory and randomised clinical trial

BACKGROUND

Rehabilitation following anterior cruciate ligament (ACL) reconstructions is based mainly on comprehensive progressive exercise programmes using a multi-dimensional approach. Elastic knee sleeves may be useful adjuncts to rehabilitation. The aim of this study was to determine the immediate and 6-week effects of wearing a knee sleeve on person-reported outcomes and function in participants who had undergone an ACL reconstruction and who had residual self-reported functional limitations.

METHODS

Individuals with ACL reconstruction in the previous 6 months to 5 years were recruited. Immediate effects of a commercially-available elastic knee sleeve on single-leg horizontal hop distance were explored using a cross-over design. Following this first session, participants were randomised into a Control Group and a Sleeve Group who wore the sleeve for 6 weeks, at least 1 h daily. Outcome measures for the randomised clinical trial (RCT) were the International Knee Documentation Classification Subjective Knee Form (IKDC-SKF) score, the single-leg horizontal hop distance, and isokinetic quadriceps and hamstring peak torque. Linear mixed models were used to determine random effects. Where both limbs were measured at multiple time points, a random measurement occasion effect nested within participant was used.

RESULTS

Thirty-four individuals (16 women) with ACL reconstruction completed the cross-over trial. Hop distance for the injured side during the sleeve condition increased by 3.6 % (95 % CI 0.4-6.8 %, p = 0.025). There was no evidence of differential changes between groups for the IKDC-SKF (Sleeve Group n = 15; Control Group n = 16; p = 0.327), or relative improvement in the injured side compared to the uninjured side for the physical performance measures (Sleeve Group n = 12, Control Group n = 12; three-way interaction p = 0.533 [hop distance], 0.381 [quadriceps isokinetic peak torque], and 0.592 [hamstring isokinetic peak torque]).

CONCLUSIONS

Single-leg hop distance of the ACL reconstructed side improved when wearing a knee sleeve. Wearing the knee sleeve over 6 weeks did not lead to enhanced improvements in self-reported knee function, hop distance and thigh muscle strength compared to the control group.

TRIAL REGISTRATION

The trial was prospectively registered with the Australia New Zealand Clinical Trials Registry No: ACTRN12618001083280 , 28 June 2018.

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

OBJECTIVES

To describe age group patterns for injury incidence, severity and burden in elite male youth football.

METHODS

Prospective cohort study capturing data on individual exposure and time-loss injuries from training and matches over four seasons (2016/2017 through 2019/2020) at a national football academy (U13-U18; age range: 11-18 years). Injury incidence was calculated as the number of injuries per 1000 hours, injury severity as the median number of days lost and injury burden as the number of days lost per 1000 hours.

RESULTS

We included 301 players (591 player-seasons) and recorded 1111 time-loss injuries. Overall incidence was 12.0 per 1000 hours (95% CI 11.3 to 12.7) and burden was 255 days lost per 1000 hours (252 to 259). The mean incidence for overall injuries was higher in the older age groups (7.8 to 18.6 injuries per 1000 hours), while the greatest burden was observed in the U16 age group (425 days; 415 to 435). In older age groups, incidence and burden were higher for muscle injuries and lower for physis injuries. Incidence of joint sprains and bone stress injuries was greatest for players in the U16, U17 and U18 age groups, with the largest burden observed for U16 players. No clear age group trend was observed for fractures.

CONCLUSION

Injury patterns differed with age; tailoring prevention programmes may be possible.

Days until return-to-play differ for sub-categories of acute respiratory tract illness in Super Rugby players: A cross-sectional study over 5 seasons (102,738 player-days)

OBJECTIVES

To document incidence rate and severity of specific sub-categories of respiratory tract illness (RTill) in rugby players during the Super Rugby tournament.

DESIGN

Cross-sectional study.

METHODS

Team physicians completed daily illness logs in 537 professional male rugby players from South African teams participating in the Super Rugby Union tournaments (2013-2017) (1141 player-seasons, 102,738 player-days). The incidence rate (IR: illness episodes/1000 player-days) and severity [%RTill resulting in time-loss, illness burden (IB: days lost to illness/1000 player-days) and days until return-to-play (DRTP)/single illness (mean: 95% Confidence Intervals)] are reported for the following specific sub-categories of RTill: non-infective respiratory tract illness (RTnon-inf), respiratory tract infections (RTinf), influenza-like illness, infective sinusitis, upper respiratory tract infections (URTinf), lower respiratory tract infections (LRTinf).

RESULTS

The overall IR of RTill was 2.9 (2.6-3.3). IR was higher for RTinf (2.5; 2.2-2.9) vs. RTnon-inf (0.4; 0.3-0.6) (p < 0.001). For sub-categories the highest IR was in URTinf (1.9; 1.7-2.2), while the % illness causing time-loss was influenza-like illness (100%), LRTinf (91.7%), infective sinusitis (55.6%), and URTinf (49.0%). IB was highest for URTinf (2.0; 1.6-2.5), and the DRTP/single illness was highest for LRTinf (3.2; 2.3-4.4), and influenza-like illness (2.1; 1.6-2.8).

CONCLUSIONS

RTinf accounted for >57% of all illness during the Super Rugby tournament, and mostly URTinf. Influenza-like illness. LRTinf caused time-loss in >90% cases. URTinf, LRTinf and influenza-like illness resulted in the highest burden of illness and LRTinf caused the highest DRTP. Prevention strategies should focus on mitigating the risk of RTinf, specifically URTinf, LRTinf and influenza-like illness.

Injuries in Irish male and female collegiate athletes

OBJECTIVE

To understand the incidence and burden of injury of student-athletes in four of the most popular collegiate sports.

DESIGN

Prospective cohort study.

SETTING

Collegiate sport.

PARTICIPANTS

Gaelic football, hurling/Camogie, soccer and Rugby (n = 672; male = 416, female = 256) student-athletes.

MAIN OUTCOME MEASURE

Injury incidence, burden of injury and total, match and training injury rates, and their 95% confidence intervals were calculated. The frequencies and proportions were also calculated. An injury was defined as any physical condition that prevents a student-athlete from full participation for a period greater than 24 h.

RESULTS

Over a quarter (0.266) of student-athletes sustained an injury in the academic season. Male student-athletes had a higher injury rate than females (21.6 vs 11.3 injuries/1000 h). Rugby (20.8 injuries/1000 h) had the highest injury rates with hurling/Camogie (6.3 injuries/1000 h) the lowest. Lower extremity injuries were predominant (68.8%) with ankle sprains demonstrating a large burden for all sports (20.6-280.2 days absent/1000 h). Hamstring strains (13.7-118.4 days absent/1000 h) had a large burden for all sports except male Rugby. Knee sprains had a large burden on the female Gaelic footballer (84.8 days absent/1000 h). Sprinting (27.4%) and the tackle (20.1%) were the most common mechanism of injury. Injuries were predominantly moderate (8-28 days) or severe (>28 days) (84.7%).

CONCLUSION

Injury reduction needs to be prioritised in the student-athlete, particularly in males. Specific focus is required on the lower extremity, especially in the hamstring muscles and ankle joint owing to the large burden of injury.

Methods, challenges and benefits of a health monitoring programme for Norwegian Olympic and Paralympic athletes: the road from London 2012 to Tokyo 2020

OBJECTIVE

To describe the implementation of a health monitoring programme for Norwegian Paralympic and Olympic candidates over five consecutive Olympic and Paralympic Games cycles (London 2012, Sochi 2014, Rio de Janeiro 2016, PyeongChang 2018 and Tokyo 2020).

METHODS

Athletes were monitored for 12-18 months preparing for the games using a weekly online questionnaire (OSTRC-H2) with follow-up by physicians and physiotherapists, who provided clinical care and classified reported problems.

RESULTS

Between 2011 and 2020, 533 Olympic and 95 Paralympic athletes were included in the monitoring programme, with an overall response of 79% to the weekly questionnaire and a total observation period of 30 826 athlete weeks. During this time, 3770 health problems were reported, with a diagnosis rate of 97%. The average prevalence of health problems at any given time was 32% among Olympic athletes and 37% among Paralympic athletes. Acute traumatic injuries represented the greatest burden for Olympic team sport athletes, and illnesses represented the greatest burden for Olympic endurance and Paralympic athletes. On average, Olympic athletes lost 27 days and Paralympic athletes lost 33 days of training per year due to health problems.

CONCLUSION

Conducting long-term health monitoring of Olympic and Paralympic athletes is challenging, particularly because athletes travel frequently and often relate to many medical providers. This programme has been implemented and improved within Team Norway for five Olympic and Paralympic cycles and during this time we believe it has helped protect our athletes' health.

Injury Profile in Professional Handball Players During 4 Consecutive Seasons According to Playing Positions: A Longitudinal Study

BACKGROUND

The injury profile of each playing position in handball is a key factor in being able to improve the injury risk management process. Therefore, the aim of this study was to longitudinally analyze the differences in professional handball players' injury profile according to their playing position (ie, goalkeeper, back, wing, and line).

HYPOTHESIS

Injury incidence and burden would be higher in back players compared with the other playing positions, while ligament and knee would be the most common injury type and location.

STUDY DESIGN

Prospective cohort design.

LEVEL OF EVIDENCE

Level 4.

METHODS

Sixty-eight male handball players belonging to the same professional team participated in this study over 4 consecutive seasons. Injury incidence and injury burden were recorded as well as the severity, type, and location following the International Olympic Committee consensus statement.

RESULTS

Although nonsignificant differences in injury incidence were found according to playing position (rate ratios [RRs] from 0.43 to 2.47; P > 0.05), back players reported the highest burden (60.65 absence days/1000 h; RR from 0.12 to 7.75;P < 0.05), with wing players showing a greater burden (54.29 absence days/1000 h; RR from 0.09 to 4.91; P < 0.05) in comparison with goalkeepers (12.19 absence days/1000 h) and line players (13.10 absence days/1000 h). Muscle/tendon injuries and sprains presented higher incidence and burden than other type of injuries, and a greater incidence and burden was reported for knee injuries in all playing positions.

CONCLUSION

The highest injury incidence and injury burden is in back players in professional handball.

CLINICAL RELEVANCE

This study provides comprehensive information on the injury profile of professional handball players, which can be useful for strength and conditioning coaches when developing specific injury risk management programs.

A qualitative investigation into the individual injury burden of amateur rugby players

OBJECTIVE

To examine the individual experiences of injury burden in amateur Rugby players across the onset of injury, rehabilitation, and return to play.

DESIGN

Qualitative.

SETTING

Irish amateur Rugby clubs.

PARTICIPANTS

Three male and two female Rugby players who sustained a severe injury that resulted in a time loss of at least 28 days.

MAIN OUTCOME MEASURES

Semi-structured interviews were used to explore the injury burden experienced during the three phases of injury.

RESULTS

Hierarchical content analysis revealed 36 codes representing individual injury burden, which were clustered into seven themes across personal (emotional reaction; impact on performance or involvement; lack of knowledge; severity of injury and incapacitation) and situational (exposure to others playing; negative experiences with treatment or rehabilitation; societal burden) dimensions.

CONCLUSIONS

The findings indicate that individual injury experiences can affect a player's recovery and rehabilitation outcome, potentially extending the injury process and affecting player availability for the team. As such, injury management should focus on alleviating any injury-related burden experienced by players, as well as burden placed on the team, to maximise rehabilitation outcomes.

Evaluation of stoppage time due to field injuries in professional football games: do players really need medical help so often?

This study aimed to identify the incidence of stoppage time due to field injuries in professional football (soccer) games and to evaluate if the players involved really need medical care and whether team physicians deal with fake injuries. A total of 893 injury time-outs occurred leading to 956 treatments during 266 matches included in the study. The mean stoppage time was 88.7 ± 34.4 seconds. Less than one fifth of the injuries (17.4%) resulted in an impossibility to complete the game. The overall time-loss injury incidence which led players to miss the next game was 9.1/1000 match-hours (n = 80, 8.4% of all injuries). The players on teams in the lead at the time of the incident had significantly higher injury time-out incidence than players on teams who were losing (p < 0.05). Increasing the knowledge of team physicians, coaches, referees, and rule-makers about the medical needs of players during the game will help to identify the behaviour pattern of players.

Machine learning methods in sport injury prediction and prevention: a systematic review

PURPOSE

Injuries are common in sports and can have significant physical, psychological and financial consequences. Machine learning (ML) methods could be used to improve injury prediction and allow proper approaches to injury prevention. The aim of our study was therefore to perform a systematic review of ML methods in sport injury prediction and prevention.

METHODS

A search of the PubMed database was performed on March 24th 2020. Eligible articles included original studies investigating the role of ML for sport injury prediction and prevention. Two independent reviewers screened articles, assessed eligibility, risk of bias and extracted data. Methodological quality and risk of bias were determined by the Newcastle-Ottawa Scale. Study quality was evaluated using the GRADE working group methodology.

RESULTS

Eleven out of 249 studies met inclusion/exclusion criteria. Different ML methods were used (tree-based ensemble methods (n = 9), Support Vector Machines (n = 4), Artificial Neural Networks (n = 2)). The classification methods were facilitated by preprocessing steps (n = 5) and optimized using over- and undersampling methods (n = 6), hyperparameter tuning (n = 4), feature selection (n = 3) and dimensionality reduction (n = 1). Injury predictive performance ranged from poor (Accuracy = 52%, AUC = 0.52) to strong (AUC = 0.87, f1-score = 85%).

CONCLUSIONS

Current ML methods can be used to identify athletes at high injury risk and be helpful to detect the most important injury risk factors. Methodological quality of the analyses was sufficient in general, but could be further improved. More effort should be put in the interpretation of the ML models.

Single leg hop for distance symmetry masks lower limb biomechanics: time to discuss hop distance as decision criterion for return to sport after ACL reconstruction?

Background

We evaluated the lower limb status of athletes after anterior cruciate ligament reconstruction (ACLR) during the propulsion and landing phases of a single leg hop for distance (SLHD) task after they had been cleared to return to sport. We wanted to evaluate the biomechanical components of the involved (operated) and uninvolved legs of athletes with ACLR and compare these legs with those of uninjured athletes (controls).

Methods

We captured standard video-based three-dimensional motion and electromyography (EMG) in 26 athletes after ACLR and 23 healthy controls during SLHD and calculated lower limb and trunk kinematics. We calculated lower limb joint moments and work using inverse dynamics and computed lower limb muscle forces using an EMG-constrained musculoskeletal modelling approach. Between-limb (within ACLR athletes) and between-group differences (between ACLR athletes and controls) were evaluated using paired and independent sample t-tests, respectively.

Results

Significant differences in kinematics (effect sizes ranging from 0.42 to 1.56), moments (0.39 to 1.08), and joint work contribution (0.55 to 1.04) were seen between the involved and uninvolved legs, as well as between groups. Athletes after ACLR achieved a 97%±4% limb symmetry index in hop distance but the symmetry in work done by the knee during propulsion was only 69%. During landing, the involved knee absorbed less work than the uninvolved, while the uninvolved knee absorbed more work than the control group. Athletes after ACLR compensated for lower knee work with greater hip work contribution and by landing with more hip flexion, anterior pelvis tilt, and trunk flexion.

Conclusion

Symmetry in performance on a SLHD test does not ensure symmetry in lower limb biomechanics. The distance hopped is a poor measure of knee function, and largely reflects hip and ankle function. Male athletes after ACLR selectively unload the involved limb but outperform controls on the uninvolved knee.

Does lower-limb asymmetry increase injury risk in sport? A systematic review

OBJECTIVE

The aim of this review was to synthesize the current understanding relating to the risks of lower body functional asymmetry with injury in athletic populations.

METHODS

An iterative data mining and sampling approach was used to construct a search phrase from key words, which were used to identify studies within SPORTdiscus, Medline and Academic Search Complete databases. Additional references were sourced from the reference lists of these articles.

RESULTS

After screening, 31 papers were reviewed, from an initial search identifying 302 possible studies. A total of 6228 participants were involved in the studies, of which soccer players were the most observed sporting demographic (n = 2171). Of the 31 studies reviewed eight found no statistical association between lower limb asymmetry and injury risk, 10 studies provided partial statistically significant evidence and a further 10 provided statistically significant statistical links.

CONCLUSION

Overall moderate to lower quality evidence for functional asymmetry as a risk factor for injury in sport was observed. While the possibility of a relationship between lower limb functional asymmetry and injury risk cannot be ruled out, further higher quality investigations, adopting standardised methodologies, is required.

Injury Trends in Irish Amateur Rugby: An Epidemiological Comparison of Men and Women

Background:

Rugby union is a physically demanding sport that carries an inherent risk of injury. Despite being a popular and widely played team sport, little is known about injuries occurring across the male and female amateur game.

Purpose:

To establish and compare injury incidence, nature, and severity in male and female Irish amateur rugby union.

Study Design:

Prospective cohort study.

Level of Evidence:

Level 3.

Methods:

Data were collected prospectively from 25 male teams (959 players) and 8 female teams (234 players) over 2 full seasons. Both time-loss (24-hour time-loss injury definition) and non-time-loss match injury reports were collected, alongside match exposure data.

Results:

Time-loss match injury incidence rates were 49.1/1000 and 35.6/1000 player-hours for male and female players, respectively. Concussion and ankle ligament sprains were the most common diagnoses for male (5.6/1000 and 4.4/1000 player-hours, respectively) and female players (5.5/1000 and 3.9/1000 player-hours, respectively). Anterior cruciate ligament injuries presented the highest injury burden for male and female players with 200.3 and 307.2 days of absence per 1000 player-hours, respectively. In female players, 83% of noncontact injuries occurred in the fourth quarter of match play.

Conclusion:

While female players had a lower overall injury incidence rate compared with male players, concussion and ankle ligament injuries were the most common injuries in both cohorts. In female players, a high rate of noncontact injuries in the second half points to the need for strength and conditioning training programs to reduce fatigue-related injuries.

Clinical Relevance:

Establishing the incidence and burden of rugby-related injuries is an essential step in minimizing injury risk. This epidemiological information will aid the development of future reduction strategies, including education and coaching strategies and strength and conditioning programs, informed by the most common injuries observed and the mechanism of injury.

Training load characteristics and injury and illness risk identification in elite youth ski racing: A prospective study

PURPOSE

The study aimed to investigate the role of training load characteristics and injury and illness risk in youth ski racing.

METHODS

The training load characteristics as well as traumatic injuries, overuse injuries, and illnesses of 91 elite youth ski racers (age = 12.1 ± 1.3 years, mean ± SD) were prospectively recorded over a period of 1 season by using a sport-specific online database. Multiple linear regression analyses were performed to monitor the influence of training load on injuries and illnesses. Differences in mean training load characteristics between preseason, in-season, and post-season were calculated using multivariate analyses of variance.

RESULTS

Differences were discovered in the number of weekly training sessions (p = 0.005) between pre-season (4.97 ± 1.57) and post-season (3.24 ± 0.71), in the mean training volume (p = 0.022) between in-season (865.8 ± 197.8 min) and post-season (497.0 ± 225.5 min) and in the mean weekly training intensity (Index) (p = 0.012) between in-season (11.7 ± 1.8) and post-season (8.9 ± 1.7). A total of 185 medical problems were reported (41 traumatic injuries, 12 overuse injuries, and 132 illnesses). The weekly training volume and training intensity was not a significant risk factor for injuries (p > 0.05). Training intensity was found to be a significant risk factor for illnesses in the same week (β = 0.348; p = 0.044; R² = 0.121) and training volume represents a risk factor for illnesses in the following week (β = 0.397; p = 0.027; R² = 0.157).

CONCLUSION

A higher training intensity and volume were associated with increased illnesses, but not with a higher risk of injury. Monitoring training and ensuring appropriate progression of training load between weeks may decrease incidents of illness in-season.

Drill design using the 'control-chaos continuum': Blending science and art during return to sport following knee injury in elite football

Establishing the level of risk, planning and adapting the return to sport (RTS) process following a complex knee injury involves drawing on a combination of relevant high-quality evidence and practitioner experience. On-pitch rehabilitation is a critical element of this process, providing an effective transition from rehabilitation to team training. The 'control-chaos continuum' (CCC) is an adaptable framework for on-pitch rehabilitation moving from high control to high chaos, progressively increasing running load demands and incorporating greater perceptual and neurocognitive challenges within sport-specific drills. Drills are a key element of the CCC, and are designed to ensure specificity, ecological validity and maintaining player interest. We showcase drill progression through the phases of the CCC, highlighting the use of constraints to create drills that incorporate the physical, technical, tactical and injury-specific needs of the player. We also provide recommendations to help practitioners create training session content using the CCC to help replicate the demands of team training within their own environment.

The burden of injury in field hockey: A secondary analysis of prospective cohort data

Most studies report injuries based upon their incidence rate, or the number of injuries which occur in a sport per unit of time. While this is recommended across numerous consensus statements on reporting injury data in sport, it may be of benefit to consider injury burden also. Reporting injuries as the duration of injury per 1000 exposure hours highlights those injuries which will likely cause greater disruption within a team. Therefore, the primary aim of this study was to report the burden of injury in field hockey. This secondary analysis of epidemiological data employed two methods of data collection: self-reported through an online reporting software, and through contact with the team physiotherapist. Athletes reported injury-related symptoms for 4170 days in total, giving rise to an injury burden of 121.0/1000 h, of which 61.4/1000 h were days lost through injury. Injuries to the hamstring, as well as muscle strain injuries, caused the most significant injury burden in athletes (22.6 and 35.8/1000 h respectively). Reporting injuries as the duration of injuries per 1000 hours highlights those injuries which cause the most significant disruption within a squad. Future injury prevention strategies in field hockey should prioritize the injuries which are most burdensome.

Injury rates decreased in men's professional football: an 18-year prospective cohort study of almost 12 000 injuries sustained during 1.8 million hours of play

BACKGROUND

The UEFA Elite Club Injury Study is the largest and longest running injury surveillance programme in football.

OBJECTIVE

To analyse the 18-season time trends in injury rates among male professional football players.

METHODS

3302 players comprising 49 teams (19 countries) were followed from 2000-2001 through 2018-2019. Team medical staff recorded individual player exposure and time-loss injuries.

RESULTS

A total of 11 820 time-loss injuries were recorded during 1 784 281 hours of exposure. Injury incidence fell gradually during the 18-year study period, 3% per season for both training injuries (95% CI 1% to 4% decrease, p=0.002) and match injuries (95% CI 2% to 3% decrease, p<0.001). Ligament injury incidence decreased 5% per season during training (95% CI 3% to 7% decrease, p<0.001) and 4% per season during match play (95% CI 3% to 6% decrease, p<0.001), while the rate of muscle injuries remained constant. The incidence of reinjuries decreased by 5% per season during both training (95% CI 2% to 8% decrease, p=0.001) and matches (95% CI 3% to 7% decrease, p<0.001). Squad availability increased by 0.7% per season for training sessions (95% CI 0.5% to 0.8% increase, p<0.001) and 0.2% per season for matches (95% CI 0.1% to 0.3% increase, p=0.001).

CONCLUSIONS

Over 18 years: (1) injury incidence decreased in training and matches, (2) reinjury rates decreased, and (3) player availability for training and match play increased.

Prevalence and burden of health problems in competitive adolescent distance runners: A 6-month prospective cohort study

To describe all health problems (injuries and illnesses) in relation to type, location, incidence, prevalence, time loss, severity, and burden, in competitive adolescent distance runners in England. Prospective observational study: 136 competitive adolescent distance runners (73 female athletes) self-reported all health problems for 24-weeks between May and October 2019. Athletes self-reported health problems using the Oslo Sports Trauma Research Centre Questionnaire on Health Problems. The incidence of running-related injury per 1,000 hours of exposure was markedly higher, compared to previous research. At any time, 24% [95% Confidence Intervals (CI): 21-26%] of athletes reported a health problem, with 11% [95% CI: 9-12%] having experienced a health problem that had substantial negative impact on training and performance. Female athletes reported noticeably more illnesses, compared to male athletes, including higher prevalence, incidence, time loss, and severity. The most burdensome health problems, irrespective of sex, included lower leg, knee, and foot/toes injuries, alongside upper respiratory illnesses. The mean weekly prevalence of time loss was relatively low, regardless of health problem type or sex. Competitive adolescent distance runners are likely to be training and competing whilst concurrently experiencing health problems. These findings will support the development of injury and illness prevention measures.

Employing Standardised Methods to Compare Injury Risk Across Seven Youth Team Sports

Injury surveillance systems seek to describe injury risk for a given sport, in order to inform preventative strategies. This often leads to comparisons between studies, although these inferences may be inappropriate, considering the range of methods adopted. This study aimed to describe the injury epidemiology of seven youth sports, enabling valid comparisons of injury risk. Consistent methods were employed across seven sports [male American football, basketball, soccer, rugby league, rugby union; female soccer and rugby union] at a high school in England. A 24-hour time-loss injury definition was adopted. Descriptive statistics and injury incidence (/1000 match-hours) are reported. In total, 322 injuries were sustained by 240 athletes (mean age=17.7±1.0) in 10 273 player-match hours. American football had a significantly greater injury incidence (86/1000 h; 95% CI 61-120) than all sports except female rugby union (54/1000 h; 95% CI 37-76). Concussion was the most common injury (incidence range 0.0-26.7/1000 h), while 59% of injuries occurred via player contact. This study employed standardized data collection methods, allowing valid and reliable comparisons of injury risk between youth sports. This is the first known study to provide epidemiological data for female rugby union, male basketball and American football in an English youth population, enabling the development of preventative strategies.

Injury and illness epidemiology in professional Asian football: lower general incidence and burden but higher ACL and hamstring injury burden compared with Europe

BACKGROUND

While football injury and illness epidemiology surveillance at professional club level in Europe is available, epidemiological data from other continents are lacking.

PURPOSE

Investigating injury and illness epidemiology in professional Asian football.

STUDY DESIGN

Descriptive prospective study.

METHODS

Professional teams from the Asian Football Confederation (AFC) league were followed prospectively for three consecutive AFC seasons (2017 through 2019, 13 teams per season, 322 team months). Time-loss injuries and illnesses in addition to individual match and training exposure were recorded using standardised digital tools in accordance with international consensus procedures.

RESULTS

In total, 232 665 hours of exposure (88.6% training and 11.4% matches) and 1159 injuries were recorded; 496 (42.8%) occurred during matches, 610 (52.6%) during training; 32 (2.8%) were reported as 'not applicable' and for 21 injuries (1.8%) information was missing. Injury incidence was significantly greater during match play (19.2±8.6 injuries per 1000 hours) than training (2.8±1.4, p<0.0001), resulting in a low overall incidence of 5.1±2.2.The injury burden for match injuries was greater than from training injuries (456±336 days per 1000 hours vs 54±34 days, p<0.0001). The two specific injuries causing the greatest burden were complete ACL ruptures (0.14 injuries (95% CI 0.9 to 0.19) and 29.8 days lost (29.1 to 30.5) per 1000 hours) and hamstring strains (0.86 injuries (0.74 to 0.99) and 17.5 days (17.0 to 18.1) lost per 1000 hours).Reinjuries constituted 9.9% of all injuries. Index injuries caused 22.6±40.8 days of absence compared with 25.1±39 for reinjuries (p=0.62). The 175 illnesses recorded resulted in 1.4±2.9 days of time loss per team per month.

CONCLUSION

Professional Asian football is characterised by an overall injury incidence similar to that reported from Europe, but with a high rate of ACL ruptures and hamstring injury, warranting further investigations.

Low knee-related quality of life and persistent physical asymmetries in participants up to 10 years post-ACL reconstruction - A cross-sectional study

OBJECTIVE

To compare self-report and functional outcomes between participants with anterior cruciate ligament reconstruction (ACLR) with age and activity matched controls.

DESIGN

Cross-sectional study.

SETTING

University laboratory-based study.

PARTICIPANTS

Twenty-five participants (30.8 ± 9.7 years; 13 women), two to ten years post anterior cruciate ligament reconstruction; 24 controls (31.0 ± 10 years, 13 women).

MAIN OUTCOME MEASURES

Knee Osteoarthritis and Injury Outcome Score (KOOS), Tegner, Marx Activity and Fear of Re-injury scales, and SF-12; isokinetic quadriceps and hamstring peak torque and single-leg hop distance.

RESULTS

There were no between-groups differences for the Tegner and the Marx Activity Scales. The ACLR group had lower KOOS dimensions (p < 0.001), SF-12 Physical Component Scores (p = 0.008), and higher Fear of Reinjury Scores (<0.001) than the controls. No significant differences were found for physical performance measures between the ACLR and the control groups. Significant between-side differences for the ACLR group were evident for concentric quadriceps (p < 0.001) and concentric hamstring peak torque (p = 0.002), and hop distance (p < 0.001).

CONCLUSION

Knee-specific symptoms and function, activity and quality of life were lower, and fear of re-injury was higher for participants with ACLR than controls. Side-to-side thigh muscle strength and hop distance deficits were evident for the ACLR group.

Illness and infection in elite full-contact football-code sports: A systematic review

OBJECTIVES

Full-contact football-code team sports offer a unique environment for illness risk. During training and match-play, players are exposed to high-intensity collisions which may result in skin-on-skin abrasions and transfer of bodily fluids. Understanding the incidence of all illnesses and infections and what impact they cause to time-loss from training and competition is important to improve athlete care within these sports. This review aimed to systematically report, quantify and compare the type, incidence, prevalence and count of illnesses across full-contact football-code team sports.

DESIGN/METHODS

A systematic search of Cochrane Library, MEDLINE, SPORTDiscus, PsycINFO and CINAHL electronic databases was performed from inception to October 2019; keywords relating to illness, athletes and epidemiology were used. Studies were excluded if they did not quantify illness or infection, involve elite athletes, investigate full-contact football-code sports or were review articles.

RESULTS

Twenty-eight studies met the eligibility criteria. Five different football-codes were reported: American football (n=10), Australian rules football (n=3), rugby league (n=2), rugby sevens (n=3) and rugby union (n=9). One multi-sport study included both American football and rugby union. Full-contact football-code athletes are most commonly affected by respiratory system illnesses. There is a distinct lack of consensus of illness monitoring methodology.

CONCLUSIONS

Full-contact football-code team sport athletes are most commonly affected by respiratory system illnesses. Due to various monitoring methodologies, illness incidence could only be compared between studies that used matching incidence exposure measures. High-quality illness surveillance data collection is an essential component to undertake effective and targeted illness prevention in athletes.