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

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

A new statistical approach to training load and injury risk: separating the acute from the chronic load.

The relationship between recent (acute) training load relative to long-term (chronic) training load may be associated with sports injury risk. We explored the potential for modelling acute and chronic loads separately to address current statistical methodology limitations. We also determined whether there was any evidence of an interaction in the association between acute and chronic training loads and injury risk in football. A men's Qatar Stars League football cohort (1 465 players, 1 977 injuries), where training load was defined as the number of minutes of activity, and a Norwegian elite U-19 football cohort (81 players, 60 injuries), where training load was defined as the session rating of perceived exertion (sRPE). Mixed logistic regression was run with training load on the current day (acute load) and cumulative past training load estimated by distributed lag non-linear models (chronic load) as independent variables. Injury was the outcome. An interaction between acute and chronic training load was modelled. In both football populations, we observed that the risk of injury on the current day for different values of acute training load was highest for players with low chronic load, followed by high and then medium chronic load. The slopes varied substantially between different levels of chronic training load, indicating an interaction. Modelling acute and chronic loads separately in regression models is a suitable statistical approach for analysing the association between relative training load and injury risk in injury prevention research. Sports scientists should also consider the potential for interactions between acute and chronic load.

Fractures in professional footballers: 7-years data from 106 team seasons in the Middle East.

Epidemiological studies on fractures in European professional football (soccer) are in abundance. However, such data are lacking in Middle Eastern professional footballers and information on fracture treatment is scarce. The aim of this study is to describe the epidemiology of fractures across seven seasons in Qatar Stars League (QSL) footballers. A prospective study of fractures in professional male footballers over 7 consecutive seasons (2013 to 2020), involving 3255 players and 106 team' seasons. Time loss and injuries and illnesses were recorded using standardised digital tools in accordance with international consensus procedures. Fractures were recorded according to onset mechanism, location, diagnoses, treatment and return to play. A total of 108 players sustained fractures during 638,247 hours of player exposure (88.9% training and 11.1% matches), representing 2.7% of all time-loss injuries. The incidence was 0.17 fractures per 1000 h of exposure (match and training incidence of 0.9 and 0.07 fractures / 1000 h, respectively), equivalent to an average of one fracture per team per season. Fractures mostly occurred in the feet (28.2%), hands (21.1%), shoulders (11.3%) and head (i.e., face) (9.9%). Mean (median) absence was 71 (47 days), with 4.6% refractures. Only 34.3% of the fractures required surgery and nearly all players (98.1%) returned to play at the professional level. Almost all professional football players with fractures return to play at the same competitive level after an average of 10 weeks of absence (mean absence was 71 ± 81 (median: 47, Inter Quartile Range [14-93]) days). One in ten continue to play with symptoms and one in twenty may refracture. Long-term effects of fractures are still unknown.

Impact of COVID-19 lockdown on injury risk in Qatar's professional football.

OBJECTIVES: To compare injury incidence, burden and characteristics between the pre- and post-COVID-19 lockdown periods in Qatari professional football. DESIGN: Prospective cohort study. METHODS: Injury and exposure data for two post-COVID-19 lockdown periods [early post-lockdown period: short-term ~2 months (54 matches) and late post-lockdown period: long-term 8-months (183 matches)] were compared to the benchmark of the same periods from the three previous seasons (2017/18-2019/20). RESULTS: We observed no difference in overall, training or match incidence between early post-lockdown period and the benchmark reference. However, this short-term period resulted in lower burden for overall- (RR 0.80, P < 0.0001), training- (RR 0.73, P < 0.0001) and match-injuries (RR 0.40, P < 0.0001) compared to the benchmark. During late post-lockdown period match injury incidence (RR 0.72, P = 0.0010) and match injury burden (RR 0.69, P < 0.001) were lower than the benchmark. In contrast, both overall- (RR 1.30, P < 0.001) and training-injury burden (RR 1.65, P < 0.001) were higher. A significant increase in adductor strains in both post-lockdown periods was observed. CONCLUSIONS: Immediately after the COVID-19 lockdown (short-term effect), there was no difference in injury incidence but a lower injury burden compared to benchmark. Moreover, the rapid return to competition for the successive season (long-term effect) was associated with a higher overall- and training-injury burden, but a lower match-injury burden compared to the benchmark.

Knee Osteoarthritis: Clinical and MRI Outcomes After Multiple Intra-Articular Injections With Expanded Autologous Adipose-Derived Stromal Cells or Platelet-Rich Plasma.

OBJECTIVE: To directly compare clinical and MRI outcomes of multiple intra-articular injections of adipose-derived stromal cells (ASCs) or platelet-rich plasma (PRP) in patients with knee osteoarthritis (OA). DESIGN: We retrospectively compared 24-month outcomes in (1) 27 patients receiving 3-monthly intra-articular injections with a total of 43.8 million ASCs and (2) 23 patients receiving 3-monthly injections of 3-ml preparation of PRP. All patients had Kellgren-Lawrence grade 1, 2, or 3 knee OA with failed conservative medical therapy. The Numeric Pain Rating Scale (NPRS) scores; Knee injury and Osteoarthritis Outcome Score (KOOS) at baseline, 6, 12, and 24 months after the first injection; and the MRI Osteoarthritis Knee Score (MOAKS) at 12 and 24 months were considered as outcomes. RESULTS: No major complications occurred in any patient. Both groups significantly improved in pain NPRS score and KOOS at 6 months. At 12- and 24-month evaluations, the ASC group significantly decreased scores to a greater degree (P < 0.001) than the PRP group. MOAKS scores indicated a decrease in disease progression in the ASC group. CONCLUSION: Both ASCs and PRP were safe and resulted in clinical improvement in patients with knee OA at 6 months; however, at 12 and 24 months, ASCs outperformed leukocyte-poor PRP in clinical and radiological outcomes.

Mechanisms of ACL injuries in men's football: A systematic video analysis over six seasons in the Qatari professional league.

To assess the mechanisms of ACL injury in male professional football players in Qatar across multiple seasons using systematic video analysis. 15 ACL injuries occurred in competition among the professional football teams that participated in an injury Surveillance Programme during 6 seasons (2013/2014 to 2018/2019). High-definition broadcast videos of these injuries were analyzed (49 views; 34 slow motion) by five analysts who independently described the injury mechanisms (situation, behavior, biomechanical characteristics) using validated observational tools. A knee valgus mechanism was observed in two-thirds of the cases (1 with direct contact to the knee, 3 with indirect contact (other body parts) and 6 with no contact). No visible valgus was reported in 2 of the direct knee contact injuries, while 3 cases of non-contact and indirect contact injuries were unclear. We observed 4 main categories of injury situation among those (n = 12) classified as non-contact/ indirect contact (multiple combinations were possible): pressing (n = 6), tackling or being tackled (n = 4), blocking (n = 3) and screening (n = 2). Direct contact injuries (n = 3) were suffered by 2 players during tackling and 1 whilst being tackled. Contact injuries represented only 20% of ACL injuries occurring during competition in Qatari professional soccer players. Independent of the playing situation, knee valgus was frequently observed (10/15 cases). Pressing was the most common situation (6/15 cases) leading to injury. Landing after heading was not reported in any of these ACL injuries.

Obstacles and opportunities for injury prevention in professional football in Qatar: exploring the implementation reality.

Background: Research focusing on reducing the risk of injuries has increased over the last two decades showing that prevention implementation in real life is challenging. Objective: To explore the experience and opinions of professional football stakeholders regarding injuries, their prevention and the implementation of preventive measures. Design: Qualitative study. Setting: Technical and medical staff from Qatar's premier football league. Participants: 22 professionals from 6 teams. Main outcome: Semistructured interviews were transcribed verbatim and analysed using the thematic analysis method. Results: All the participants acknowledged the importance of injury prevention. They mentioned teamwork, trust and communication as critical factors for a successful injury prevention implementation. Teams' doctors see themselves mainly involved in the treatment and recovery process, and to a lesser degree, in the prevention process. Physiotherapists defined their primary responsibilities as screening for injury risk and providing individual exercises to players. The participants declared that the fitness coach is responsible for injury prevention implementation. All stakeholders reported that the fitness coach plays a vital role in communication by bridging the head coach and the medical staff. Stakeholders reported that the Qatari football league has a very particular context around the player, such as socioecological factors influencing injury prevention implementation. Conclusions: The fitness coach plays a vital role in the injury prevention implementation system, as one of the key actors for the process, as well as the bridge between the medical team and the head coach, resulting from their better communication with the head coaches. The findings support considering and understanding the contextual factors during the development of preventive strategies in football.

Karatekas educated on injury prevention and supported by fitness coaches are more likely to practise injury prevention.

To determine the current perceptions and practices of top-level karate athletes concerning risk factors and injury prevention programme (IPP) implementation in training and competition. Out of 90 eligible countries (933 athletes) participating in the karate World Senior Championships (WSC) in Madrid 2018, 50 countries (55.6%) represented by 137 athletes (14.7%; 52 females and 85 males) responded to a structured questionnaire. Of the athletes responding, 45% reported that their national team did not conduct any measures to reduce injury risk (43% among females and 47% among males; p = 0.68). Kumite athletes (51%) were more likely to practise injury prevention compared to kata athletes (25%; p = 0.016). Of the respondents, 69%, 60%, 60% and 34% reported having no team doctor, fitness coach, massage therapist and physiotherapist, respectively. A greater proportion of athletes who had access to a fitness coach (part-time or full-time) engaged in injury prevention strategies (67% and 51%, respectively) than those who did not (35%; p = 0.031). Athletes who had received previous advice about injury prevention were more likely to practise injury prevention (58%) compared to the rest (21%; p < 0.001). The current study revealed that: i) almost half of the karatekas already benefited from an injury prevention programme, ii) injury prevention programmes were practised more frequently when there was a fitness coach among their coaching staff, iii) karatekas who had received education about injury prevention were more likely to practise injury prevention programmes.

Training Practices of Football Players During the Early COVID-19 Lockdown Worldwide.

The COVID-19 lockdown challenged the training options of athletes worldwide, including players from the most popular sport globally, football/soccer. PURPOSE: The authors explored the training practices of football players worldwide during the COVID-19 lockdown. METHODS: Football players (N = 2482, 30% professional, 22% semipro, and 48% amateur) completed an online survey (May-July 2020) on their training practices before versus during lockdown (March-June 2020). Questions were related to training frequency and session duration, as well as training knowledge and attitudes. RESULTS: Before lockdown, more professional (87%) than semipro (67%) and amateur (65%) players trained ≥5 sessions/wk, but this proportion decreased during the lockdown to 55%, 35%, and 42%, respectively. Players (80%-87%) trained ≥60 minutes before lockdown, but this proportion decreased to 45% in professionals, 43% in amateurs, and 36% in semipros during lockdown. At home, more than two-thirds of players had training space (73%) and equipment (66%) for cardiorespiratory training, while availability of equipment for technical and strength training was <50% during lockdown. Interactions between coach/trainer and player were more frequent (ie, daily) among professional (27%) than amateur (11%) and semipro (17%) players. Training load monitoring, albeit limited, was mostly performed by fitness coaches, more so with professionals (35%) than amateurs (13%) and semipros (17%). The players' training knowledge and attitudes/beliefs toward training were relatively modest (50%-59%). CONCLUSION: COVID-19 lockdown negatively affected training practices of football players worldwide, especially amateurs and semipros, for example, in training frequency, duration, intensity, technical, recovery, and other fitness training and coaching-related aspects. During lockdown-like situations, players should be monitored closely and provided appropriate support to facilitate their training.

Ramadan intermittent fasting induced poorer training practices during the COVID-19 lockdown: A global cross-sectional study with 5529 athletes from 110 countries.

Ramadan intermittent fasting during the COVID-19 lockdown (RIFL) may present unique demands. We investigated training practices (i.e., training load and training times) of athletes, using pre-defined survey criteria/questions, during the 'first' COVID-19 lockdown, comparing RIFL to lockdown-alone (LD) in Muslim athletes. Specifically, a within-subject, survey-based study saw athletes (n = 5,529; from 110 countries/territories) training practices (comparing RIFL to LD) explored by comparative variables of: sex; age; continent; athlete classification (e.g., world-class); sport classification (e.g., endurance); athlete status (e.g., professional); and level of training knowledge and beliefs/attitudes (ranked as: good/moderate/poor). During RIFL (compared to LD), athlete perceptions (ranges presented given variety of comparative variables) of their training load decreased (46-62%), were maintained (31-48%) or increased (2-13%). Decreases (≥ 5%, p < 0.05) affected more athletes aged 30-39 years than those 18-29 years (60 vs 55%); more national than international athletes (59 vs 51%); more team sports than precision sports (59 vs 46%); more North American than European athletes (62 vs 53%); more semi-professional than professional athletes (60 vs 54%); more athletes who rated their beliefs/attitudes 'good' compared to 'poor' and 'moderate' (61 vs 54 and 53%, respectively); and more athletes with 'moderate' than 'poor' knowledge (58 vs 53%). During RIFL, athletes had different strategies for training times, with 13-29% training twice a day (i.e., afternoon and night), 12-26% at night only, and 18-36% in the afternoon only, with ranges depending on the comparative variables. Training loads and activities were altered negatively during RIFL compared to LD. It would be prudent for decision-makers responsible for RIFL athletes to develop programs to support athletes during such challenges.

Football in Times of COVID-19: A Recapitulation of Preventive Measures and Infection Control Policies Aiming at a Safe Game Environment.

Coronavirus disease 2019 (COVID-19) resulted in sporting event suspensions and cancellations, affecting competition calendars worldwide during 2020 and 2021. This challenged high-performance athletes' capacity to complete physical, technical, or tactical training during restricted movement measures (lockdown). With the Football World Cup organized in the last quarter of 2022, the past period of training and match disturbances challenged footballers concerning their performance and potential higher risk of injury at official matches' resumption. There has been considerable debate about the management of resuming professional football (soccer) during the COVID-19 pandemic. Governing bodies worldwide implemented measures to ensure a safe resumption of football. These precautionary measures aimed to protect the health of players, their support staff, and officials around the pitch and ensure the enjoyment of the event by spectators in the football stadiums. We have therefore narratively reviewed scientific papers about how football has resumed on the pitch and in the stands with special focus on the COVID-19 infection control strategies allowing footballers to perform again and supporters to enjoy the game after the 2020 global stop to sport.

High-speed running during match-play before and after return from hamstring injury in professional footballers.

Hamstring injuries constitute the single largest cause of lost playing time in professional football. While restoring high-speed running ability is paramount for rehabilitation from these injuries, little evidence exists regarding the extent of return to sport running performance after hamstring injury in football. We examined medical and match performance data available from a sample of 38 professional soccer players competing in the Qatar Stars League (N = 1426 observations) to describe high-speed running performance during match-play prior and subsequent to a hamstring strain injury. Multivariable-adjusted random-effects generalized additive models estimated post- versus pre-hamstring injury differences in maximal speed (km/h), high-speed running (>20 km/h), and sprinting (>25 km/h) distance. Mean effects and uncertainty (95% confidence interval, CI) were interpreted against the estimated random match-to-match variability in maximal sprinting speed, high-speed running distance, and sprinting running distance of ±1.67 km/h (95% CI, 1.62-1.72 km/h), ±102 m (95% CI, 99-105 m), and ±60 m (95% CI, 58-61 m), respectively. The estimated post- versus pre-hamstring injury mean differences in maximal sprinting speed, high-speed running distance, and sprinting running distance primary outcomes were -0.25 km/h (95% CI, -0.38 to -0.12 km/h), -43 m (95% CI, -56 to -30 m), and -22 m (95% CI, -29 to -16 m). Players returning to football match-play after hamstring strain injury experienced reductions in high-speed match physical performance that were well within normal match-to-match variation in performance.

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.

Shedding light on incidence and burden of physeal injuries in a youth elite football academy: A 4-season prospective study.

INTRODUCTION: Physeal injuries have been overlooked in epidemiological research in youth sports. Our prospective study investigated the incidence, severity, and burden of physeal injuries in a youth elite football academy. METHODS: In total, 551 youth male football players from under-9 to under-19 were included and observed over four consecutive seasons. Injuries involving the physis were diagnosed and recorded according to type, location, and diagnosis. Injury incidence (II), severity (days lost), and injury burden (IB) were calculated per squad per season (25 players/squad). RESULTS: There were 307 physeal injuries: 262 apophyseal (85%), 26 physeal (9%), 2 epiphyseal (1%), and 17 other physeal injuries (5%) with 80% (n=245) causing time-loss. The overall mean incidence of time-loss physeal injuries was 6 injuries/squad-season, leading to a total of 157 days lost/squad-season. The U-16s had the highest burden with 444 days lost per squad-season [median: 20 (95% CI: 12-30) days; II: 10 (95% CI: 7.3.1-13.4)]. Apophyseal injuries of the hip-pelvis resulted in the greatest burden [median: 13 (95% CI: 10-17); II: 2.5 (95% CI: 2.1-3.0)]. Peak apophyseal injury incidence per body parts occurred in U-11 for foot-ankle (II: 2.4; 95% CI: 1.0-4.9), U-14 for knee (II: 4.5; 95% CI: 2.7-7.1), and U-17 for hip-pelvis (II: 6.4; 95% CI: 4.2-9.3). CONCLUSION: Physeal injuries accounted for a quarter of all-time loss with the largest injury burden in U-16. Most physeal injuries involved the lower limb and affected the apophysis. Physeal and apophyseal injuries incidence, burden, and pattern vary substantially depending on age. Hip-pelvic apophyseal injuries accounted for the largest injury burden.

Hamstring Injury Prevention for Elite Soccer Players: A Real-World Prevention Program Showing the Effect of Players' Compliance on the Outcome.

ABSTRACT: Chebbi, S, Chamari, K, Van Dyk, N, Gabbett, T, and Tabben, M. Hamstring injury prevention for elite soccer players: A real-world prevention program showing the effect of players' compliance on the outcome. J Strength Cond Res 36(5): 1383-1388, 2022-The aim of this study was to determine the effect of implementing the Nordic hamstring exercise (NHE) to prevent hamstring injuries in soccer. A professional team was followed by the same medical team during 5 successive seasons (2012/2013 through 2016/2017). During the first and last seasons (2012/2013 and 2016/2017), no hamstring preventive action was implemented. For the seasons 2013/2014, 2014/2015, and 2015/2016, a noncompulsory (few players refusing to participate) NHE prevention program was implemented with accurate recording of the players' training and match exposure and attendance to the prevention sessions. The first 10 weeks of the season were used to progressively increase the volume and intensity of the NHE exercises, and at the end of the season, players were split in low-, moderate-, and high-attendance groups to the prevention sessions. Overall, 35 time-loss hamstring strain injuries were accounted for. The injury incidence was 0.30 per player per season, and the injury rate was 0.95 injury/1000 hour of exposure. A nonstatistically significant higher risk of hamstring injury was observed in the control, low, and moderate attendance groups compared with the high-attendance group. The greatest risk of hamstring injury was observed in the low-attendance group (odds ratio 1.77, confidence interval 0.57-5.47, p = 0.32). Implementing a NHE prevention program has a positive effect on the injury rate in a soccer team; however, the compliance of players with such interventions may be critical for its success.

Organising football matches with spectators during the COVID-19 pandemic: What can we learn from the Amir Cup Football Final of Qatar 2020? A call for action.

The COVID-19 pandemic is a potential threat to professional sporting events when they eventually return to their usual calendar with spectators' capacity of football stadiums usually exceeding 40,000 seats for important events. Hence, a strategy for safe return to sporting events is needed in the COVID-19 pandemic to pave the way towards a new normalcy. We reviewed the guidelines and policies implemented in organising the Amir Cup Football Final of Qatar, which hosted about 20,000 fans. The authors evaluated the publicly available information on the official websites of the various organizations involved and highlight the importance and usefulness of the Covid-19 Rapid Antigen Assay-Kit as a tool for screening sports spectators as well as the importance of a rigorous spectator pathway, including their accurate traceability thanks to a specific mobile phone application. Despite the surging of COVID-19 all over the world, a big football event with around 20,000 spectators in the same stadium has been hosted under strongly controlled preventative measures. These preventative measures show that it is possible to organize a major football match held outdoors, with the presence of thousands of supporters. This article is a call for action for the organisers of such events where the supporters' health status is traceable to provide the scientific community with actual data of post-event infection rates. Therefore, it is suggested to consider using procedures like the ones described in the present article as a potential model in the process of organizing big sporting events with spectators in times of COVID-19.

The dominant leg is more likely to get injured in soccer players: systematic review and meta-analysis.

In soccer (football), dominant limb kicking produces higher ball velocity and is used with greater frequency than the non-dominant limb. It is unclear whether limb dominance has an effect on injury incidence. The purpose of this systematic review with meta-analysis is to examine the relationship between limb dominance and soccer injuries. Studies were identified from four online databases according to PRISMA guidelines to identify studies of soccer players that reported lower extremity injuries by limb dominance. Relevant studies were assessed for inclusion and retained. Data from retained studies underwent meta-analyses to determine relative risk of dominant versus non-dominant limb injuries using random-effects models. Seventy-four studies were included, with 36 of them eligible for meta-analysis. For prospective lower extremity injury studies, soccer players demonstrated a 1.6 times greater risk of injury to the dominant limb (95% CI [1.3-1.8]). Grouped by injury location, hamstring (RR 1.3 [95% CI 1.1-1.4]) and hip/groin (RR 1.9 [95% CI 1.3-2.7]) injuries were more likely to occur to the dominant limb. Greater risk of injury was present in the dominant limb across playing levels (amateurs RR 2.6 [95% CI 2.1-3.2]; youths RR 1.5 [95% CI 1.26-1.67]; professionals RR 1.3 [95% CI 1.14-1.46]). Both males (RR 1.5 [95% CI 1.33-1.68)] and females (RR 1.5 [95% CI 1.14-1.89]) were more likely to sustain injuries to the dominant limb. Future studies investigating soccer injury should adjust for this confounding factor by using consistent methods for assigning limb dominance and tracking use of the dominant versus non-dominant limb.

Expanded adipose derived mesenchymal stromal cells are effective in treating chronic insertional patellar tendinopathy: clinical and MRI evaluations of a pilot study.

PURPOSE: Effect of ultrasound guided injections of autologous ASCs in chronic recalcitrant patellar tendinopathy. METHODS: Fourteen patients (16 knees, 12/2 males/females) with chronic, recalcitrant (unsuccessfully treated with nonoperative treatments) insertional PT underwent clinical evaluation and magnetic resonance imaging (MRI) before intervention. Stromal vascular fraction cells (SVF) were expanded by in-vitro culture and characterized by flow cytometry. Players were injected with three bi-weekly injections of ASCs followed by physiotherapy. They underwent serial clinical evaluations during a 12-month period with repeated MRI at 6-month post-injection. RESULTS: Victorian Institute of sports assessment-patellar tendon questionnaire (VISA-P) scores improved from 43.8 ± 4.9 at baseline to 58.1 ± 7.1, 70.3 ± 7.9 and 78.7 ± 7.5 at 3, 6, and12months follow-up, respectively. (p = 0.0004 comparing each variable with the previous one). Mean Visual analogue pain in sports (VAS-sport) score during practice significantly decreased from 7.4 ± 0.5 at baseline to 5.2 ± 1.5 9 (p = 0.0005), 3.3 ± 1.1 (p = 0.0004) and 1.5 ± 0.7 (P = 0.0004) at 3, 6, and 12 months, respectively. Mean Tegner-scores for patients were 8.0 ± 0.8 before injury and 2.3 ± 0.9 before treatment, thereafter, improving to 4.8 ± 0.8 and 7.2 ± 0.7 at 6- and 12- months, respectively (p = 0.0001). MRI assessed tendon width' did not change over the first 6 months post-intervention. Significant changes were observed for: tendon thickness (12.8 ± 1.1 to 10.9 ± 0.7, P = 0.0001); tear length (9.3 ± 1.3 to 2.3 ± 0.7, P = 0.0001), tear width (6.3 ± 0.8 to 3.4 ± 0.4, P = 0.0001), and tear thickness (4.6 ± 0.4 to 2.6 ± 0., P = 0.0001) at baseline and 6 months, respectively. CONCLUSION: Patients with recalcitrant insertional PT showed significant clinical improvement and structural repair at the patellar insertional tendinopathy after injections of autologous ASCs. Results of this study are promising and open a new biological therapeutic modality to treat PT.

Severe knee injuries among karate athletes ranking towards the Tokyo Olympic Games: a retrospective study.

BACKGROUND: Injury prevention strategies should be built upon data about the more frequent injuries in each specific sport. Therefore, this study aimed to describe the lifetime prevalence and characteristics of severe knee injuries among world-class karatekas. METHODS: A retrospective study based on a face-to-face survey was conducted. Participants were athletes who competed in World Karate Senior Championships in Madrid 2018, which was a tournament with the highest value to rank athletes to the Tokyo Olympic Games. A questionnaire was used to collect retrospective information on the prevalence and characteristics of severe knee injuries that occurred along elite karatekas sport careers. Odds Ratio (OR) were calculated to identify the association of sex and karate modality (kata / kumite) with severe knee injury risk. RESULTS: Out of the 293 athletes surveyed (23.4±4.0 years; 137 female), 71 (24.2%) had suffered a serious knee injury at some point of their careers, without a statistically significant difference between male and female athletes. There was no difference between the percentage of injuries that took place during training (54.9%) or during competition (45.1%) both in male and female athletes. Kumite athletes suffered more knee injuries during competition than training. The most common injury mechanism for both genders was a pivoting or dodging movement (36.4% in males and 39.5% in females). CONCLUSIONS: The information presented in this study about the prevalence and characteristics (mechanism, anatomical location, moment, time off) of the severe knee injuries in elite karatekas could be useful to design prevention programs to be implemented among karate athletes.