***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 Female athletes have a higher risk of anterior cruciate ligament injury than their male counterparts who play at similar levels in sports involving pivoting and l and ing . Hypothesis The competitive female basketball players who participated in a sports injury prevention training program  would show better muscle strength and flexibility and improved biomechanical properties associated with anterior cruciate ligament injury than during the pretraining period and than posttraining parameters in a control group . Study Design Controlled laboratory study . Methods A total of 22 high school female basketball players were recruited and r and omly divided into 2 groups ( the experimental group and the control group , 11 participants each ) . The experimental group was instructed in the 6 parts of the sports injury prevention training program and performed it during the first 20 minutes of team practice for the next 8 weeks , while the control group performed their regular training program . Both groups were tested with a rebound-jump task before and after the 8-week period . A total of 21 reflective markers were placed in preassigned positions . In this controlled laboratory study , a 2-way analysis of variance ( 2 × 2 ) experimental design was used for the statistical analysis ( P < .05 ) using the experimental group and a testing session as within and between factors , respectively . Post hoc tests with Sidak correction were used when significant factor effects and /or interactions were observed . Results A comparison of the experimental group 's pretraining and posttraining results identified training effects on all strength parameters ( P = .004 to .043 ) and on knee flexion , which reflects increased flexibility ( P = .022 ) . The experimental group showed higher knee flexion angles ( P = .024 ) , greater interknee distances ( P = .004 ) , lower hamstring-quadriceps ratios ( P = .023 ) , and lower maximum knee extension torques ( P = .043 ) after training . In the control group , no statistical differences were observed between pretraining and posttraining findings ( P = .084 to .873 ) . At pretraining , no significant differences were observed between the 2 groups for any parameter ( P = .067 to .784 ) . However , a comparison of the 2 groups after training revealed that the experimental group had significantly higher knee flexion angles ( P = .023 ) , greater knee distances ( P = .005 ) , lower hamstring-quadriceps ratios ( P = .021 ) , lower maximum knee extension torques ( P = .124 ) , and higher maximum knee abduction torques ( P = .043 ) than the control group . Conclusion The sports injury prevention training program improved the strength and flexibility of the competitive female basketball players tested and biomechanical properties associated with anterior cruciate ligament injury as compared with pretraining parameters and with posttraining parameters in the control group . Clinical Relevance This injury prevention program could potentially modify the flexibility , strength , and biomechanical properties associated with ACL injury and lower the athlete 's risk for injury 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 Background Little is known about the influence of compliance with neuromuscular training ( NMT ) on the  knee injury rate in football . Aim To evaluate team and player compliance with an NMT programme in adolescent female football and to study the association between compliance and acute knee injury rates . Methods Prospect i ve cohort study based on a cluster r and omised controlled trial on players aged 12–17 years with 184 intervention teams ( 2471 players ) and 157 control teams ( 2085 players ) .  Exposure and acute time loss knee injuries were recorded . Team and player compliance was recorded by the coaches on a player attendance form . The intervention group was divided into tertiles of compliance . Injury rates were compared by calculating rate ratios ( RRs ) and 95 % CIs using exact Poisson tests with the low-compliance tertile as reference . Seasonal compliance trends were analysed using linear regression . Results Players in the high-compliance tertile had an 88 % reduction in the anterior cruciate ligament ( ACL ) injury rate ( RR 0.12 , 95 % CI 0.01 to 0.85 ) , whereas the rate in the control group players was not significantly different from those in the low-compliance tertile ( RR 0.77 , 95 % CI 0.27 to 2.21 ) . A significant deterioration occurred in team ( b=−3.0 % per month , 95 % CI −5.2 to −0.8 ) and player ( b=−5.0 % per month , 95 % CI −7.1 to −2.9 ) compliance over the season . Conclusions Players with high compliance with the  NMT programme had significantly reduced ACL injury rate compared with players with low compliance . Significant deterioration in team and player compliance occurred over the season 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 Objectives : The objective of this study was to analyze whether it is more frequent the presence of a decreased range of motion in the hips of recreational athletes with primary injury of the anterior cruciate ligament ( ACL ) than in a control group of volunteers without knee pathology . Methods : We included prospect ively recreational athletes between 18 and 40 years with an acute ACL injury between January 2011 and January 2013 . They were compared with a control group of volunteers recreational athletes without lower limb pathology and in the same range of age . The internal and external rotations passively prior to the point at which the pelvis movement contributes were observed . The results were statistically analyzed using t test for related sample s to the hips of patients with ACL injury and t test for independent variables for comparison with the control group . Results : 48 patients with ACL injury and 53 healthy volunteers were evaluated . The ACL group was composed of 32 males and 16 females with an average age of 29.3 years . In the control group 26 males and 27 females were studied with a mean age of 26.6 years . Internal ( IR ) and external ( ER ) rotation in the LCA group was 22,9º and 55,5º respectively in the ipsilateral hip and 27,9º and 57,7º in the contralateral . In the control group a 35,9º of IR and 55,2º of ER was observed . The analysis showed an association between ACL injury and hypomotility of the hip further expense of a decrease in internal rotation . The analysis showed an association between ACL injury and hypomotility of the hip at the expense to a greater decrease in internal rotation . Conclusion : We found a statistically significant difference in the mobility of the hips in patients with ACL injury predominantly due to internal rotation , pattern that allows us to interpret this injury not only as an intrinsic etiology of the knee but also of the adjacent joints . We consider very importance to incorporate prevention activities and screening of risk factors regarding to at least high performance athletes Background Anterior cruciate ligament ( ACL ) injury prevention programs show promising results with changing movement ; however , little information exists regarding whether a program design ed for an individual 's movements may be effective or how baseline movements may affect outcomes . Hypothesis A program design ed to change specific movements would be more effective than a “ one-size-fits-all ” program . Greatest improvement would be observed among individuals with the most baseline error . Subjects of different ages and sexes respond similarly . Study Design R and omized controlled trial ; Level of evidence , 1 . Methods One hundred seventy-three youth soccer players from 27 teams were r and omly assigned to a generalized or stratified program . Subjects were videotaped during jump-l and ing trials before and after the program and were assessed using the  L and ing Error Scoring System ( LESS ) , which is a valid clinical movement analysis tool . A high LESS score indicates more errors . Generalized players performed the same exercises , while the stratified players performed exercises to correct their initial movement errors . Change scores were compared between groups of varying baseline errors , ages , sexes , and programs . Results Subjects with the highest baseline LESS score improved the most ( 95 % CI , −3.4 to −2.0 ) . High school subjects ( 95 % CI , −1.7 to −0.98 ) improved their technique more than pre – high school subjects ( 95 % CI , −1.0 to −0.4 ) . There was no difference between the programs or sexes . Conclusions Players with the greatest amount of movement errors experienced the most improvement . A program 's effectiveness may be enhanced if this population is targeted Background : The Fédération Internationale de Football Association ( FIFA ) 11 + program has been shown to be an effective injury prevention program in the female soccer cohort , but there is a paucity of research to demonstrate its efficacy in the male population . Hypothesis : To examine the efficacy of the FIFA 11 + program in men ’s collegiate United States National Collegiate Athletic Association ( NCAA ) Division I and Division II soccer . Study Design : R and omized controlled trial ; Level of evidence , 1 . Methods : Before the commencement of the fall 2012 season , every NCAA Division I and Division II men ’s collegiate soccer team ( N = 396 ) was solicited to participate in this research study . Human ethics review board approval was obtained through Quorum Review IRB . Sixty-five teams were r and omized : 34 to the control group ( CG ; 850 players ) and 31 to the intervention group ( IG ; 675 players ) . Four teams in the IG did not complete the study , reducing the number for analysis to 61 . The FIFA 11 + injury prevention program served as the intervention and was utilized weekly . Athlete-exposures ( AEs ) , compliance , and injury data were recorded using a secure Internet-based system . Results : In the CG , 665 injuries ( mean ± SD , 19.56 ± 11.01 ) were reported for 34 teams , which corresponded to an incidence rate ( IR ) of 15.04 injuries per 1000 AEs . In the IG , 285 injuries ( mean ± SD , 10.56 ± 3.64 ) were reported for 27 teams , which corresponded to an IR of 8.09 injuries per 1000 AEs . Total days missed because of injury were significantly higher for the CG ( mean ± SD , 13.20 ± 26.6 days ) than for the IG ( mean ± SD 
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RESULTS The best practice features of an IPP have the following six components : ( 1 ) lower extremity and core strengthening ; ( 2 ) plyometrics ; ( 3 ) continual feedback to athletes regarding proper technique ; ( 4 ) sufficient dosage ; ( 5 ) minimal-to-no additional equipment ; and ( 6 ) balance training to help prevent injuries .
Exercises focused on preventing ankle sprains , hamstring injuries and lateral trunk movements are important .
Balance training alone does not significantly reduce injuries , but is beneficial with other exercises .
Not enough evidence to recommend stretching and agility exercises , with no ill effects identified .