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Background Not all anterior cruciate ligament (ACL) injuries are preventable. While some ACL injuries are unavoidable such as those resulting from a tackle, others that occur in non-contact situations like twisting and turning in the absence of external contact might be more preventable. Because ACL injuries commonly occur in team ball-sports that involve jumping, landing and cutting manoeuvres, accurate information about the epidemiology of non-contact ACL injuries in these sports is needed to quantify their extent and burden to guide resource allocation for risk-reduction efforts. Objective To synthesize the evidence on the incidence and proportion of non-contact to total ACL injuries by sex, age, sport, participation level and exposure type in team ball-sports. Methods Six databases (MEDLINE, EMBASE, Web of Science, CINAHL, Scopus and SPORTDiscus) were searched from inception to July 2021. Cohort studies of team ball-sports reporting number of knee injuries as a function of exposure and injury mechanism were included. Results Forty-five studies covering 13 team ball-sports were included. The overall proportion of non-contact to total ACL injuries was 55% (95% CI 48–62, I2 = 82%; females: 63%, 95% CI 53–71, I2 = 84%; males: 50%, 95% CI 42–58, I2 = 86%). The overall incidence of non-contact ACL injuries was 0.07 per 1000 player-hours (95% CI 0.05–0.10, I2 = 77%), and 0.05 per 1000 player-exposures (95% CI 0.03–0.07, I2 = 97%). Injury incidence was higher in female athletes (0.14 per 1000 player-hours, 95% CI 0.10–0.19, I2 = 40%) than male athletes (0.05 per 1000 player-hours, 95% CI 0.03–0.07, I2 = 48%), and this difference was significant. Injury incidence during competition was higher (0.48 per 1000 player-hours, 95% CI 0.32–0.72, I2 = 77%; 0.32 per 1000 player-exposures, 95% CI 0.15–0.70, I2 = 96%) than during training (0.04 per 1000 player-hours, 95% CI 0.02–0.07, I2 = 63%; 0.02 per 1000 player-exposures, 95% CI 0.01–0.05, I2 = 86%) and these differences were significant. Heterogeneity across studies was generally high. Conclusion This study quantifies several key epidemiological findings for ACL injuries in team ball-sports. Non-contact ACL injuries represented over half of all ACL injuries sustained. The proportion of non-contact to total ACL injuries and injury incidence were higher in female than in male athletes. Injuries mostly occurred in competition settings.

Background A comprehensive examination of the sport-specific activities and circumstances being performed at the time of injury is important to hypothesise mechanisms, develop prevention strategies and inform future investigations. Results reported in the literature are inconsistent because inciting activities are reported using different classifications. Hence the aim was to develop a standardised system for the reporting of inciting circumstances. Methods The system was developed using a modified Nominal Group Technique. The initial panel included 12 sports practitioners and researchers from four continents with respectively ≥ 5 years of experience working in professional football and/or conducting injury research. The process consisted of six phases: idea generation, two surveys, one online meeting and two confirmations. For answers to the closed questions, consensus was deemed achieved if ≥ 70% of respondents agreed. Open-ended answers were qualitatively analysed and then introduced in subsequent phases. Results Ten panellists completed the study. The risk of attrition bias was low. The developed system includes a comprehensive range of inciting circumstances across five domains: contact type, ball situation, physical activity, session details, contextual information. The system also distinguishes between a core set (essential reporting) and an optional set. The panel deemed all the domains to be important and easy to use both in football and in research environments. Conclusion A system to classify inciting circumstances in football was developed. Given the extent of reporting inconsistency of inciting circumstances in the available literature, this can be used while further studies evaluate its reliability.

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 hours of exposure. Injury burden (137.2 days lost/1000h, 95% CI 133.4 - 141.0) was comprised of 23% (31.9 days lost/1000h, 95% CI 30.1 - 33.8) partial TL and 77% (105.3 days lost/1000h, 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/1000h, 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 TL7 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.

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 Conclusion: Rescheduling Part 2 did not affect performance or increased injury risks in academy footballers.

This study aimed to examine differences in sleep and perceived wellness between a group of adolescent academy football (soccer) players from sport high schools (SHS) and regular high schools (RHS) during different phases of the year, with a secondary focus on their school physical activity (s-PA) levels. Data were collected from 51 adolescent football players from one youth Australian academy in two blocks of two weeks (four weeks total). Subjective sleep quantity and quality, wellness and s-PA were assessed through validated daily questionnaires and weekly surveys. MANOVAs and ANOVAs for repeated measures were conducted to assess sleep and wellness variables across different weeks (school vs. holidays, early vs. late season) and between groups (SHS vs. RHS). No differences in sleep or muscle pain were found between players at SHS and RHS (p > 0.05). No effect of week (school vs. holidays, early season vs. late season) on sleep quality or wellness was found, nor did hours of s-PA affect sleep duration (all p > 0.05). Total sleep time was within recommended guidelines and significantly longer sleep times were experienced during the holidays compared to school term (p = 0.002). Overall, adolescent academy football players reported sleep quantities within recommended ranges and had greater sleep volumes during the holidays rather than during school. School type (SHS vs. RHS) and hours of s-PA had no effect on the players sleep within our cohort. Additionally, it appears perceptual wellness in this population is unaffected by time of season, or school compared to holidays.

Objectives To explore the usage and awareness of the FIFA 11 + (11 + ) across multiple stakeholders involved with amateur football. Methods Coaches, players, non-coaching staff and medical personnel in New South Wales (NSW), Australia, were invited to complete a cross-sectional online survey, which was disseminated using a targeted email to two Football NSW member organisations and a social media campaign. Categorical data (including age-groups and sex) are presented as counts and percentages and analysed using a Chi-square or Fisher's exact test. A significance level of 0.05 was used for all analyses. Results In total 328 players, 55 coaches, 37 non-coaching staff and 16 medical personnel completed the survey (n = 436). Awareness of the 11 + was lowest among non-coaching staff (16.2%) and players (32.6%) but higher among coaches (52.7%) and medical personnel (93.8%). Once aware of the 11 + , 75.8% of all respondents used the program although 89.5% of them did so with modifications. In addition, only 40.0% of players reported completing all three parts of the 11 + program. Veteran players were less likely to complete any type of warm-up compared with junior players (63.7% vs. 96.3%, respectively). Conclusions Although awareness of the 11 + varied amongst survey respondents, 3 out of 4 respondents who were aware of the 11 + adopted the program. However, respondents reported modifying the 11 + and not completing the program as intended, which suggests modification guidance is required to maintain the efficacy of the 11 + .

To systematically evaluate the literature and estimate the prevalence, incidence, and burden of gradual-onset knee injuries in team ball-sports.Systematic review with meta-analysis.Six databases (MEDLINE, EMBASE, Web of Science, CINAHL, SPORTDiscus, SCOPUS) were searched from inception to June 2021. Cohort studies of team ball-sports reporting the number of gradual-onset knee injuries were included. Study quality was assessed using a modified Newcastle-Ottawa scale. Studies were pooled using a Freeman-Tukey Double arcsine transformation (prevalence) and a Poisson random effects regression model (incidence, burden).Forty-nine studies that captured gradual-onset knee injuries (unclassified, patellofemoral pain, tendinopathies, and iliotibial band friction syndrome) across 15 team ball-sports were included. For unclassified gradual-onset knee injuries, prevalence was 4 % (95 % Confidence Interval (CI) 2 % to 7 %, IEstimates of prevalence, incidence and burden generated from this systematic review quantify the extent of gradual-onset knee injuries in team ball-sports. Further research is required to assess whether age, sport, and participation level are predictors of gradual-onset knee injuries.

To determine the prevalence and impact of non-time loss injuries in semi-professional football. 218 players completed the Oslo Sports Trauma Research Centre (OSTRC) Questionnaire on Health Problems...

Brown, GA, Veith, S, Sampson, JA, Whalan, M, and Fullagar, HHK. Influence of training schedules on objective measures of sleep in adolescent academy football players. J Strength Cond Res 34(9): 2515-2521, 2020-Football academy settings may pose risks to adolescent athletes achieving sufficient sleep because of the contextual challenges these players face (e.g., psychosocial pressure, changes in training, competition, and academic stress). Given the importance of sleep to overall health as well as physical athletic development and injury risk, this study aimed to investigate whether differences in training schedules (morning vs. evening training sessions) affected objective measures of sleep in adolescent academy football (soccer) players. Twelve academy players (mean age 14.18 ± 1.36 years) wore an ActiGraph accelerometer on nights before, and nights of, training days in 2 separate weeks where morning (09:00-11:00 hours) and evening (18:00-20:00 hours) training occurred. Objective sleep parameters and training load data were collected. Night-time sleep periods were categorized as sleep preceding morning training, preceding evening training, or after evening training. One-way univariate and multivariate analyses of variance for repeated measures were performed to determine the impact of the training schedule on sleep. Significance levels were set at p < 0.05. The total sleep time was below the recommended guidelines (

Although the 11+ program has been shown to reduce injuries in sub-elite football, program compliance is typically poor, suggesting that strategies to optimize delivery are necessary. This study investigated the effect of rescheduling Part 2 of the three-part 11+ program on program effectiveness. Twenty-five semi-professional football clubs were randomly allocated to either a Standard-11+ (n = 398 players) or P2post group (n = 408 players). Both groups performed the 11+ program at least twice a week throughout the 2017 football season. The Standard-11+ group performed the entire 11+ program before training activities commenced, whereas the P2post group performed Parts 1 and 3 of the 11+ program before and Part 2 after training. Injuries, exposure, and individual player 11+ dose were monitored throughout the season. No significant between group difference in injury incidence rate (P2pos t vs Standard-11+ = 11.8 vs 12.3 injuries/1000 h) was observed. Severe time loss injuries > 28 days (33 vs 58 injuries; P < .002) and total days lost to injury (4303 vs 5815 days; P < .001) were lower in the P2post group. A higher 11+ program dose was observed in the P2post (29.1 doses; 95% CI 27.9-30.1) versus Standard-11+ group (18.9 doses; 95% CI 17.6-20.2; P < .001). In semi-professional football, rescheduling Part 2 of the 11+ program to the end of training maintained the effectiveness of the original 11+ program to reduce injury incidence. Importantly, rescheduling Part 2 improved player compliance and reduced the number of severe injuries and total injury burden, thereby enhancing effectiveness of the 11+ program.

Background The association between movement quality and injury is equivocal. No soccer-specific movement assessment has been prospectively investigated in relation to injury risk. Objectives To investigate the association between a soccer-specific movement-quality assessment and injury risk among semiprofessional soccer players. Methods In this prospective cohort study, semiprofessional soccer players (n = 306) from 12 clubs completed the Soccer Injury Movement Screen (SIMS) during the preseason period. Individual training/match exposure and noncontact time-loss injuries were recorded prospectively for the entirety of the 2016 season. Relative risks were calculated, and presented with 90% confidence intervals, for the SIMS composite and individual subtest scores from generalized linear models with Poisson distribution offset for exposure. Results When considering noncontact time-loss lower extremity injuries (primary level of analysis), there was a most likely trivial association with the SIMS composite score. Similarly, the SIMS composite score demonstrated most likely to likely trivial associations with all injury categories included in the secondary level of analysis (noncontact time-loss hip/groin, thigh, knee, and ankle injuries). When considering hamstring strains and ankle sprains specifically (tertiary level of analysis), the SIMS composite score demonstrated very likely trivial associations. A total of 262 noncontact time-loss injuries were recorded. The overall (training and match exposure combined) incidence of noncontact time-loss injury was 12/1000 hours. Conclusion The SIMS composite score demonstrated no association with any of the investigated categories of soccer-related injury. The SIMS composite score should not be used to group players into high- or low-risk groups. Level of Evidence Prognosis, level 4. J Orthop Sports Phys Ther 2018;48(8):630-636. Epub 8 May 2018. doi:10.2519/jospt.2018.8037.

Objectives This study aimed to conduct the first injury surveillance study in sub-elite football in Australia, using methods from the international football consensus statement. Design Descriptive epidemiological study. Methods 1049 sub-elite football players were recruited during the 2016 season. Injury and exposure data was collected by trained Primary Data Collectors (PDCs) who attended every training session and match. Results There were 1041 time loss injuries recorded during 52,127 h of exposure resulting in an injury incidence rate of 20 injuries/1000 h (95% Confidence Interval [CI]: 15.9–23.3). The injury burden (days lost to injury relative to exposure) was 228 days lost/1000 h. Muscle and ligament injuries were the most prevalent (41% and 26%) and incurred the highest injury burden (83 and 80 days lost/1000 h, respectively). The most common injuries were observed at the thigh (22%) and ankle (17%), with hamstring (13%) the highest reported muscle injury. The profile of injury severity was: mild — 35%; minor — 29%; moderate — 28% and severe — 8%. Recurrent injuries accounted for 20% of all injuries. Conclusions By addressing issues identified with injury recording in sub-elite football, this study found that the injury incidence was twice that observed in previous research in elite and sub-elite football cohorts. Injury burden was also twice that of the elite setting, with similar injuries associated with the highest burden. The results highlight the need for investment into medical provision, facilities, coach education and injury mitigation programmes to reduce healthcare costs to sub-elite players in Australia.