***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background A protective effect on injury risk in youth sports through neuromuscular warm-up training routines has consistently been demonstrated . However , there is a paucity of information regarding the quantity and quality of coach-led injury prevention programmes and its impact on the physical performance of players . Objective The aim of this cluster-r and omised controlled trial was to assess whether different delivery methods of an injury prevention programme ( FIFA 11 + ) to coaches could improve player performance , and to examine the effect of player adherence on performance and injury risk . Method During the 2011 football season ( May – August ) , coaches of 31 tiers 1–3 level teams were introduced to the 11 + through either an unsupervised website or a coach-focused workshop with and without additional on-field supervisions . Playing exposure , adherence to the 11 + , and injuries were recorded for female 13-year-old to 18-year-old players . Performance testing included the Star Excursion Balance Test ( SEBT ) , single-leg balance , triple hop and jumping-over-a-bar tests . Results Complete preseason and postseason performance tests were available for 226 players ( 66.5 % ) . Compared to the unsupervised group , single-leg balance ( OR=2.8 ; 95 % CI 1.1 to 4.6 ) and the anterior direction of the SEBT improved significantly in the onfield supervised group of players ( OR=4.7 ; 95 % CI 2.2 to 7.1 ) , while 2-leg jumping performance decreased ( OR=−5.1 ; 95 % CI −9.9 to −0.2 ) . However , significant improvements in 5 of 6 reach distances in the SEBT were found , favouring players who highly adhered to the 11 + . Also , injury risk was lower for those players ( injury rate ratio , IRR=0.28 , 95 % CI 0.10 to 0.79 ) . Conclusions Different delivery methods of the FIFA 11 + to coaches influenced players ’ physical performance minimally . However , high player adherence to the 11 + result ed in significant improvements in functional balance and reduced injury risk Objective To evaluate the effectiveness of neuromuscular training in reducing the rate of acute knee injury  in adolescent female football players . Design Stratified cluster r and omised controlled trial with clubs as the unit of r and omisation . Setting 230 Swedish football clubs ( 121 in the intervention group , 109 in the control group ) were followed for one season ( 2009 , seven months ) . Participants 4564 players aged 12 - 17 years ( 2479 in the intervention group , 2085 in the control group ) completed the study . Intervention 15 minute neuromuscular warm-up programme ( targeting core stability , balance , and proper knee alignment ) to be carried out twice a week throughout the season . Main outcome measures The primary outcome was rate of anterior cruciate ligament injury ; secondary outcomes were rates of severe knee injury ( > 4 weeks ’ absence ) and any acute knee injury . Results Seven players ( 0.28 % ) in the intervention group , and 14 ( 0.67 % ) in the control group had an anterior cruciate ligament injury . By Cox regression analysis according to intention to treat , a 64 % reduction in the rate of anterior cruciate ligament injury was seen in the intervention group ( rate ratio 0.36 , 95 % confidence interval 0.15 to 0.85 ) . The absolute rate difference was −0.07 ( 95 % confidence interval −0.13 to 0.001 ) per 1000 playing hours in favour of the intervention group . No significant rate reductions were seen for secondary outcomes . Conclusions A neuromuscular warm-up programme significantly reduced the rate of anterior cruciate ligament injury in adolescent female football players . However , the absolute rate difference did not reach statistical significance , possibly owing to the small number of events . Trial registration Clinical trials NCT00894595 Background Participants ' compliance , attitudes and beliefs have the potential to influence the efficacy of an intervention greatly . Objective To characterise team and player compliance with a comprehensive injury prevention warm-up programme for football ( The 11 + ) , and to assess attitudes towards injury prevention among coaches and their association with compliance and injury risk . Study Design A prospect i ve cohort study and retrospective survey based on a cluster-r and omised controlled trial with teams as the unit of r and omisation . Methods Compliance , exposure and injuries were registered prospect ively in 65 of 125 football teams ( 1055 of 1892 female Norwegian players aged 13–17 years and 65 of 125 coaches ) throughout one football season ( March – October 2007 ) . St and ardised telephone interviews were conducted to assess coaches ' attitudes towards injury prevention . Results Teams completed the injury prevention programme in 77 % ( mean 1.3 sessions per week ) of all training and match sessions , and players in 79 % ( mean 0.8 sessions per week ) of the sessions they attended . Compared with players with intermediate compliance , players with high compliance with the programme had a 35 % lower risk of all injuries ( RR 0.65 , 95 % CI 0.46 to 0.91 , p=0.011 ) . Coaches who had previously utilised injury prevention training coached teams with a 46 % lower risk of injury ( OR 0.54 , 95 % CI 0.33 to 0.87 , p=0.011 ) . Conclusions Compliance with the injury prevention programme was high , and players with high compliance had significantly lower injury risk than players with intermediate compliance . Positive attitudes towards injury prevention correlated with high compliance and lower injury risk Background Injury prevention programme delivery on adherence and injury risk , specifically involving regular supervisions with coaches and players on programme execution on field , has not been examined . Aim The objective of this cluster-r and omised study was to evaluate different delivery methods of an effective injury prevention programme ( FIFA 11 + ) on adherence and injury risk among female youth football teams . Method During the 4-month 2011 football season , coaches and 13-year-old to 18-year-old players from 31 tier 1–3 level teams were introduced to the 11 + through either an unsupervised website ( ‘ control ’ ) or a coach-focused workshop with ( ‘ comprehensive ’ ) and without ( ‘ regular ’ ) additional supervisions by a physiotherapist .  Team and player adherence to the 11 + , playing exposure , history and injuries were recorded . Results Teams in the comprehensive and regular intervention groups demonstrated adherence to the 11 + programme of 85.6 % and 81.3 % completion of total possible sessions , compared to 73.5 % for teams in the control group . These differences were not statistically significant , after adjustment for cluster by team , age , level and injury history . Compared to players with low adherence , players with high adherence to the 11 + had a 57 % lower injury risk ( IRR 0.43 , 95 % CI 0.19 to 1.00 ) . However , adjusting for covariates , this between-group difference was not statistically significant ( IRR=0.44 , 95 % CI 0.18 to 1.06 ) . Conclusion Following a coach workshop , coach-led delivery of the FIFA 11 + was equally successful with or without the additional field involvement of a physiotherapist . Proper education of coaches during an extensive preseason workshop was more effective in terms of team adherence than an unsupervised delivery of the 11 + programme to the team . Trial registration IS RCT N67835569 Purpose We aim ed to investigate the effect of FIFA 11 + ( 11 + ) and HarmoKnee injury preventive warm-up programs on conventional strength ratio ( CSR ) , dynamic control ratio ( DCR ) and fast/slow speed ratio ( FSR ) in young male professional soccer players . These ratios are related to the risk of injury to the knee in soccer players . Methods Thirty-six players were divided into 3 groups ; FIFA 11 + , HarmoKnee and control ( n = 12 per group ) . These exercises were performed 3 times per week for 2 months ( 24 sessions ) . The CSR , DCR and FSR  were measured before and after the intervention . Results After training , the CSR and DCR of knee muscles in both groups were found to be lower than the published normal values ( 0.61 , 0.72 , and 0.78 during 60 ° .s−1 , 180 ° .s−1 and 300 ° .s−1 , respectively ) . The CSR ( 60 ° .s−1 ) increased by 8 % and FSR in the quadriceps of the non-dominant leg by 8 % in the 11 + . Meanwhile , the DCR in the dominant and non-dominant legs were reduced by 40 % and 30 % respectively in the 11 + . The CSR ( 60 ° .s−1 ) in the non-dominant leg showed significant differences between the 11 + , HarmoKnee and control groups ( p = 0.02 ) . As for the DCR analysis between groups , there were significant differences in the non-dominant leg between both programs with the control group ( p = 0.04 ) . For FSR no significant changes were found between groups . Conclusions It can be concluded that the 11 +  improved CSR and FSR , but the HarmoKnee program did not demonstrate improvement . We suggest adding more training elements to the HarmoKnee program that aim ed to enhance hamstring strength ( CSR , DCR and FSR ) . Professional soccer players have higher predisposition of getting knee injuries because hamstring to quadriceps ratio were found to be lower than the average values . It seems that the 11 + have potentials to improve CSR and FSR as well as prevent knee injuries in soccer players Background The incidence rate of soccer injuries is among the highest in sports , particularly for adult male soccer players . Purpose To investigate the effect of the ‘ The11 ’ injury prevention programme on injury incidence and injury severity in adult male amateur soccer players . Study design Cluster-r and omised controlled trial . Methods Teams from two high-level amateur soccer competitions were r and omly assigned to an intervention ( n=11 teams , 223 players ) or control group ( n=12 teams , 233 players ) . The intervention group was instructed to perform The11 in each practice session during one soccer season . The11 focuses on core stability , eccentric training of thigh muscles , proprioceptive training , dynamic stabilisation and plyometrics with straight leg alignment . All participants of the control group continued their practice sessions as usual . Results In total , 427 injuries were recorded , affecting 274 of 456 players ( 60.1 % ) .  Compliance with the intervention programme was good ( team compliance=73 % , player compliance=71 % ) . Contrary to the hypothesis , injury incidences were almost equal between the two study groups : 9.6 per 1000 sports hours ( 8.4–11.0 ) for the intervention group and 9.7 ( 8.5–11.1 ) for the control group . No significant differences were found in injury severity , but a significant difference was observed in the location of the injuries : players in the intervention group sustained significantly less knee injuries . Conclusions This study did not find significant differences in the overall injury incidence or injury severity between the intervention and control group of adult male soccer players . More research is recommended , focusing on injury aetiology and risk factors in adult male amateur soccer players Purpose The study investigated the effects of FIFA 11 + and HarmoKnee , both being popular warm-up programs , on proprioception , and on the static and dynamic balance of professional male soccer players . Methods Under 21 year-old soccer players ( n = 36 ) were divided r and omly into 11 + , HarmoKnee and control groups . The programs were performed for 2 months ( 24 sessions ) . Proprioception was measured bilaterally at 30 ° , 45 ° and 60 ° knee flexion using the Biodex Isokinetic Dynamometer  . Static and dynamic balances were evaluated using the stork st and test and Star Excursion Balance Test ( SEBT ) , respectively . Results The proprioception error of dominant leg significantly decreased from pre- to post-test by 2.8 % and 1.7 % in the 11 + group at 45 ° and 60 ° knee flexion , compared to 3 % and 2.1 % in the HarmoKnee group . The largest joint positioning error was in the non-dominant leg at 30 ° knee flexion ( mean error value = 5.047 ) , ( p<0.05 ) . The static balance with the eyes opened increased in the 11 + by 10.9 % and in the HarmoKnee by 6.1 % ( p<0.05 ) . The static balance with eyes closed significantly increased in the 11 + by 12.4 % and in the HarmoKnee by 17.6 % . The results indicated that static balance was significantly higher in eyes opened compared to eyes closed ( p = 0.000 ) . Significant improvements in SEBT in the 11 + ( 12.4 % ) and HarmoKnee ( 17.6 % ) groups were also found . Conclusion Both the 11 + and HarmoKnee programs were proven to be useful warm-up protocol s in improving proprioception at 45 ° and 60 ° knee flexion as well as static and dynamic balance in professional male soccer players . Data from this research may be helpful in encouraging coaches or trainers to implement the two warm-up programs in their soccer teams Objective To examine the effect of a comprehensive warm-up programme design ed to reduce the risk of injuries in female youth football . Design Cluster r and omised controlled trial with clubs as the unit of r and omisation . Setting 125 football clubs from the south , east , and middle of Norway ( 65 clusters in the intervention group ; 60 in the control group ) followed for one league season ( 
    Output:
    
The FIFA 11 + has demonstrated how a simple exercise program completed as part of warm-up can decrease the incidence of injuries in amateur football players .
In addition , players with high compliance to the FIFA 11 + program had an estimated risk reduction of all injuries by 35 % and show significant improvements in components of neuromuscular and motor performance when participating in structured warm-up sessions at least 1.5 times/week .
Given the large number of people who play football at amateur level and the detrimental impact of sports injuries on a personal and societal level , the FIFA 11 + can be considered as a fundamental tool to minimize the risks of participation in a sport with substantial health benefits