***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 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 Female soccer players are three times more likely to suffer a non-contact anterior cruciate ligament ( ACL ) tear compared with male soccer players . Several ACL injury prevention programs have been developed and are used to reduce injury risk . However , to date there is limited information on how such programs affect physical performance . The aim of this r and omized controlled study was to investigate the effects of the Prevent Injury Enhance Performance ( PEP ) program in adolescent female soccer players . Four soccer teams were r and omly assigned to an intervention ( PEP ) or control ( CON ) group and assessed at baseline , 6 weeks , and 12 weeks on  linear sprinting , countermovement jump ( CMJ ) , and two agility tests . A mixed model factorial ANOVA with repeated measures was used to assess for treatment effects on the dependent variables . Improvements in 27.3 and 36.6 m sprint times ( < 0.10 s ) were evident during the first 6 weeks for PEP , but reverted back to baseline values by 12 weeks ; there were no changes for 9.1 or 18.2 m sprint times in either group . There was no change in the CMJ height for PEP ; however , there was a decrement at 6 and 12 weeks compared with baseline in CON . Performance on the Illinois and pro-agility tests declined in both groups . Our findings demonstrate that improvements in linear sprint performance were small and transient in adolescent female soccer players , and that there was no benefit of the PEP program on CMJ or agility performance . ACL injury prevention programs design ed as a structured warm-up routine seem to lack the necessary stimulus to enhance athletic performance The main purpose of this study was to analyse the training effects of the FIFA 11 + and Harmoknee on several parameters of physical performance measures in youth amateur football players . 41 adolescent players were r and omised within each team into 2 groups ( team 1 : control vs. FIFA 11 + ; team 2 : control vs. Harmoknee ) . The FIFA 11 + and Harmoknee groups performed the program 3 times a week for 4 weeks ; the control groups completed their usual warm-up routines . 13 physical performance measures ( joint range of motion , dynamic postural control , single legged hop limb symmetry , sprint time , jumping height and agility ) were assessed . All physical performance parameters were compared via a magnitude-based inference analysis . Significant between-group differences ( in favour of the FIFA 11 + players ) were found for dynamic postural control ( anterior [ 2.5 % ] and posteromedial [ 7.2 % ] distances ) , single legged hop limb symmetry ( side-to-side symmetry during a triple hop test [ 8.3 % ] ) , 10 ( 8.4 % ) and 20 ( 1.8 % ) m sprint times and jumping height ( 9.1 % ) neuromuscular outcomes . For the Harmoknee , significant differences ( in comparison to its paired control group ) were found only for 10 ( 2.7 % ) and 20 ( 2.9 % ) m sprint times and jumping height ( 9.7 % ) . Therefore , the main findings of this study suggest exchanging traditional warm-up programmes for the FIFA 11 + in male youth soccer players based on its superior effects on some neuromuscular parameters ( sprinting , jumping and stability ) of physical performance Purpose The objective of the present r and omised controlled trial was to study the effect of a neuromuscular warm-up programme on performance tests in youth female football . Methods Four youth female football teams with players aged 12–16 years were r and omised into an intervention group and control group . The intervention was a 15-min neuromuscular warm-up programme carried out twice a week during the 11-week study period . Baseline and follow-up measurements of performance were made indoors and included the star excursion balance test , a countermovement jump test , a triple-hop for distance test , a modified Illinois agility test , and 10- and 20-m sprint tests . Results Fifty-two players ( intervention 28 ; control 24 ) took part in baseline measurements , and after dropout , 41 players ( intervention 23 ; control 18 ) were included for analysis . Minor positive changes were seen in the control group compared to the intervention group for a sub-score of the star excursion balance test ( P < 0.05 ) and in the modified Illinois agility test ( P < 0.05 ) . No improvement was seen in the intervention group from baseline to follow-up . Conclusions The study showed that a neuromuscular warm-up programme carried out during 11 weeks did not improve performance in youth female football . This could indicate that the programme does not contain sufficient stimulus to improve performance . A low player attendance at training sessions , and low specificity between exercises in the warm-up programme and the evaluated performance tests may also contribute to the lack of effect . Level of evidence 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 DiStefano , LJ , Padua , DA , Blackburn , JT , Garrett , WE , Guskiewicz , KM , and Marshall , SW . Integrated injury prevention program improves balance and vertical jump height  in children . J Strength Cond Res 24(2 ) : 332 - 342 ,  
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Conclusion : Multimodal IPP beneficially affect neuromuscular performance .
These improvements may substantiate the preventative efficacy of IPP and may support the wide-spread implementation and dissemination of IPP .