***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 BACKGROUND Ankle injuries account for 30 to 60 % of all parachuting injuries . This study was design ed to determine if outside-the-boot ankle braces could reduce ankle sprains during Army paratrooper training . METHODS The r and omized trial involved 777 volunteers from the U.S. Army Airborne School , Fort Benning , Ga. Of this group , 745 completed all study requirements ( 369 brace-wearers and 376 non-brace-wearers ) . Each volunteer made five parachute jumps , for a total of 3,674 jumps . RESULTS The incidence of inversion ankle sprains was 1.9 % in non-brace-wearers and 0.3 % in brace-wearers ( risk ratio , 6.9 ; p = 0.04 ) . Other injuries appeared unaffected by the brace . Overall , 5.3 % of the non-brace group and 4.6 % of the brace group experienced at least one injury . The risk ratio for injured individuals was 1.2:1 ( non-brace to brace groups ; p = 0.65 ) . CONCLUSION Inversion ankle sprains during parachute training can be significantly reduced by using an outside-the-boot ankle brace , with no increase in risk for other injuries 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 Proprioceptive training has been shown to reduce the incidence of ankle sprains in different sports . It can also improve rehabilitation after anterior cruciate ligament ( ACL ) injuries whether treated operatively or nonoperatively . Since ACL injuries lead to long absence from sports and are one of the main causes of permanent sports disability , it is essential to try to prevent them . In a prospect i ve controlled study of 600 soccer players in 40 semiprofessional or amateur teams , we studied the possible preventive effect of a gradually increasing proprioceptive training on four different types of wobble-boards during three soccer seasons . Three hundred players were instructed to train 20 min per day with 5 different phases of increasing difficulty . The first phase consisted of balance training without any balance board ; phase 2 of training on a rectangular balance board ; phase 3 of training on a round board ; phase 4 of training on a combined round and rectangular board ; phase 5 of training on a so-called BABS board .  A control group of 300 players from other , comparable teams trained “ normally ” and received  no special balance training . Both groups were observed for three whole soccer seasons , and possible ACL lesions were diagnosed by clinical examination , KT-1000 measurements , magnetic resonance imaging or computed tomography , and arthroscopy . We found an incidence of 1.15 ACL injuries per team per year in the control group and 0.15 injuries per team per year in the proprioceptively trained group ( P<0.001 ) . Proprioceptive training can thus significantly reduce the incidence of ACL injuries in soccer players Background This study was conducted to investigate whether the most common injuries in soccer could be prevented , and to determine if a simple question naire could identify players at increased risk . Hypothesis Introduction of targeted exercise programs to male soccer players with a history of previous injury or reduced function in the ankle , knee , hamstring , or groin will prevent injuries . Study Design R and omized controlled trial ; Level of evidence , 2 . Methods A total of 508 players representing 31 teams were included in the study . A question naire indicating previous injury and /or reduced function as inclusion criteria was used to divide the players into high-risk ( HR ) ( 76 % ) and low-risk ( LR ) groups . The HR players were r and omized individually into an HR intervention group or HR control group . Results A total of 505 injuries were reported , sustained by 56 % of the players . The total injury incidence was a mean of 3.2 ( 95 % confidence interval [ CI ] , 2.5–3.9 ) in the LR control group , 5.3 ( 95 % Cl , 4.6–6.0 ) in the HR control group ( P = .0001 vs the LR control group ) , and 4.9 ( 95 % Cl , 4.3–5.6 ) in the HR intervention group ( P = .50 vs the HR control group ) . For the main outcome measure , the sum of injuries to the ankle , knee , hamstring , and groin , there was also a significantly lower injury risk in the LR control group compared with the 2 other groups , but no difference between the HR intervention group and the HR control group . Compliance with the training programs in the HR intervention group was poor , with only 27.5 % in the ankle group , 29.2 % in the knee group , 21.1 % in the hamstring group , and 19.4 % in the groin defined as having carried out the minimum recommended training volume . Conclusion The players with a significantly increased risk of injury were able to be identified through the use of a question naire , but player compliance with the training programs prescribed was low and any effect of the intervention on injury risk could not be detected Background Effective strategies for the primary prevention of low back pain ( LBP ) remain elusive with few large-scale clinical trials investigating exercise and education approaches . The purpose of this trial was to determine whether core stabilization alone or in combination with psychosocial education prevented incidence of low back pain in comparison to traditional lumbar exercise . Methods The Prevention of Low Back Pain in the Military study was a cluster r and omized clinical study with four intervention arms and a two-year follow-up . Participants were recruited from a military training setting from 2007 to 2008 . Soldiers in 20 consecutive companies were considered for eligibility ( n = 7,616 ) . Of those , 1,741 were ineligible and 1,550 were eligible but refused participation . For the 4,325 Soldiers enrolled with no previous history of LBP average age was 22.0 years ( SD = 4.2 ) and there were 3,082 males ( 71.3 % ) . Companies were r and omly assigned to receive traditional lumbar exercise , traditional lumbar exercise with psychosocial education , core stabilization exercise , or core stabilization with psychosocial education , The psychosocial education session occurred during one session and the exercise programs were done daily for 5 minutes over 12 weeks . The primary outcome for this trial was incidence of low back pain result ing in the seeking of health care . Results There were no adverse events reported . Evaluable patient analysis ( 4,147/4,325 provided data ) indicated no differences in low back incidence result ing in the seeking of health care between those receiving the traditional exercise and core stabilization exercise programs . However , brief psychosocial education prevented low back pain episodes regardless of the assigned exercise approach , result ing in a 3.3 % ( 95 % CI : 1.1 to 5.5 % ) decrease over two years ( numbers needed to treat ( NNT ) = 30.3 , 95 % CI = 18.2 to 90.9 ) . Conclusions Core stabilization has been advocated as preventative , but offered no such benefit when compared to traditional lumbar exercise in this trial . Instead , a brief psychosocial education program that reduced fear and threat of low back pain decreased incidence of low back pain result ing in the seeking of health care . Since this trial was conducted in a military setting , future studies are necessary to determine if these findings can be translated into civilian population s . Trial Registration NCT00373009 at Clinical Trials.gov - http:// clinical BACKGROUND Shock-absorbing and biomechanic shoe orthoses are frequently used in the prevention and treatment of back and lower extremity problems . One review concludes that the former is clinical ly effective in relation to prevention , whereas the latter has been tested in only 1 r and omized clinical trial , concluding that stress fractures could be prevented . OBJECTIVES To investigate if biomechanic shoe orthoses can prevent problems in the back and lower extremities and if reducing the number of days off-duty because of back or lower extremity problems is possible . DESIGN Prospect i ve , r and omized , controlled intervention trial . STUDY SUBJECTS One female and 145 male military conscripts ( aged 18 to 24 years ) , representing 25 % of all new conscripts in a Danish regiment . METHOD Health data were collected by question naires at initiation of the study and 3 months later . Custom-made biomechanic shoe orthoses to be worn in military boots were provided to all in the study group during the 3-month intervention period . No intervention was provided for the control group . Differences between the 2 groups were tested with the chi-square test , and statistical significance was accepted at P < .05 . Risk ratio ( RR ) , risk difference ( ARR ) , numbers needed to prevent ( NNP ) , and cost per successfully prevented case were calculated . OUTCOME VARIABLES Outcome variables included self-reported back and /or lower extremity problems ; specific problems in the back or knees or shin splints , Achilles tendonitis , sprained ankle , or other problems in the lower extremity ; number of subjects with at least 1 day off-duty because of back or lower extremity problems and total number of days off-duty within the first 3 months of military service because of back or lower extremity problems . RESULTS Results were significantly better in an actual-use analysis in the intervention group for total number of subjects with back or lower extremity problems ( RR 0.7 , ARR 19 % , NNP 5 , cost 98 US dollars ) ; number of subjects with shin splints ( RR 0.2 , ARR 19 % , NNP 5 , cost 101 US dollars ) ; number of off-duty days because of back or lower extremity problems ( RR 0.6 , ARR < 1 % , NNP 200 , cost 3750 US dollars ) . In an intention-to-treat analysis , a significant difference was found for only number of subjects with shin splints ( RR 0.3 , ARR 18 % , NNP 6 cost 105 US dollars ) , whereas a worst-case analysis revealed no significant differences between the study groups . CONCLUSIONS This study shows that it may be possible to 
    Output:
    
Conclusions Studies that account for compliance demonstrated that compliance significant affects study outcomes .