***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 
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    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 : Sport is the leading cause of injury requiring medical attention among adolescents . We studied the effectiveness of a home-based balance-training program using a wobble board in improving static and dynamic balance and reducing sports-related injuries among healthy adolescents . Methods : In this cluster r and omized controlled trial , we r and omly selected 10 of 15 high schools in Calgary to participate in the fall of 2001 . We then recruited students from physical education classes and r and omly assigned them , by school , to either the intervention ( n = 66 ) or the control ( n = 61 ) group . Students in the intervention group participated in a daily 6-week and then a weekly 6-month home-based balance-training program using a wobble board .  Students at the control schools received testing only . The primary outcome measures were timed static and dynamic balance , 20-m shuttle run and vertical jump , which were measured at baseline and biweekly for 6 weeks . Self-reported injury data were collected over the 6-month follow-up period . Results : At 6 weeks , improvements in static and dynamic balance were observed in the intervention group but not in the control group ( difference in static balance 20.7 seconds , 95 % confidence interval [ CI ] 10.8 to 30.6 seconds ; difference in dynamic balance 2.3 seconds , 95 % CI 0.7 to 4.0 seconds ) . There was evidence of a protective effect of balance training in over 6 months ( relative risk of injury 0.2 , 95 % CI 0.05 to 0.88 ) . The number needed to treat to avoid 1 injury over 6 months was 8 ( 95 % CI 4 to 35 ) . Interpretation : Balance training using a wobble board is effective in improving static and dynamic balance and reducing sports-related injuries among healthy adolescents BACKGROUND The aim of this study was to investigate stability of physical activity  from childhood and adolescence to adulthood in multiple age cohorts , and analyze how well adult physical activity can be predicted by various physical activity variables measured in childhood and adolescence . METHODS The data were drawn from the Cardiovascular Risk in Young Finns Study . The study was started in 1980 , when cohorts of r and omly sample d boys and girls aged 3 , 6 , 9 , 12 , 15 , and 18 years ( total of 2309 subjects ) were examined for the first time . The measurements were repeated in 1983 , 1986 , 1989 , 1992 , and 2001 . In 2001 , the subjects ( n = 1563 , 68 % ) were aged 24 , 27 , 30 , 33 , 36 , and 39 years , respectively .  Physical activity  was measured by means of a short self-report question naire that was administered individually in connection with a medical examination . On the basis of a question naire , a physical activity index ( PAI ) was calculated . There were no significant differences in the 1980 PAI between participants and dropouts in 2001 . RESULTS Spearmans rank order correlation coefficients for the 21-year tracking period varied from 0.33 to 0.44 in males , and from 0.14 to 0.26 in females . At shorter time intervals the correlation was higher . On average , the tracking correlation was lower in females than in males . Persistent physical activity , defined as a score in the most active third of the PAI in two or three consecutive measurements , increased the odds that an individual would be active in adulthood . Odds ratios for 3-year continuous activity versus continuous inactivity varied from 4.30 to 7.10 in males and 2.90 to 5.60 in females . The corresponding odds ratios for 6-year persistence were 8.70 to 10.80 and 5.90 to 9.40 . CONCLUSIONS It was concluded that a high level of physical activity at ages 9 to 18 , especially when continuous , significantly predicted a high level of adult physical activity . Although the correlations were low or moderate , we consider it important that school-age physical activity appears to influence adult physical activity , and through it , the public health of the general population Young female players in European h and ball have a very high injury incidence , up to 50 injuries per 1000 hours of game . More than half of these injuries happen without any external cause . The aim of the study was to investigate the effect of an intervention programme design ed to reduce the number of injuries in young female players in European h and ball , with special emphasis on injuries in the lower extremities . The programme was created using elite athlete training programmes and those design ed for rehabilitation of injured athletes with functional instability of their ankles and rupture of the anterior cruciate ligament . It included the use of an ankle disk for 10 - 15 min at all practice sessions , for one 10-month season ( August 1995-May 1996 ) . Twenty-two teams participated in the study , and were r and omly assigned to the intervention or control group . Eleven teams with 111 players were r and omised to the intervention group and 11 teams with 126 players to the control group . Data were analysed using a t-test for continuous variables , chi2- analysis and Fisher 's exact test for dichotomous variables and multivariate methods to determine odds-ratios . The results indicated that using the intervention programme decreased the numbers of both traumatic and overuse injuries significantly . The differences in injuries between the groups were 80 % during games and 71 % during practice . In addition , the players in the control group had a 5.9 times higher risk of acquiring an injury than the players in the intervention group OBJECTIVE To study the effects of a school-based injury prevention program on physical activity injury incidence and severity . DESIGN Cluster r and omized controlled trial performed from January 1 , 2006 , through July 31 , 2007 . SETTING Forty Dutch primary schools . PARTICIPANTS A total of 2210 children ( aged 10 - 12 years ) . INTERVENTION Schools were r and omized to receive either the regular curriculum or an intervention program that targeted physical activity injuries . OUTCOME MEASURES Incidence and severity of physical activity injuries per 1000 hours of physical activity participation . RESULTS A total of 100 injuries in the intervention group and 104 injuries in the control group were registered . Nonresponse at baseline or follow-up was minimal ( 8.7 % ) . The Cox regression analyses adjusted for clustering showed a small nonsignificant intervention effect on total ( HR , 0.81 ; 95 % confidence interval [ CI ] , 0.41 - 1.59 ) , sports club ( 0.69 ; 0.28 - 1.68 ) , and leisure time injuries ( 0.75 ; 0.36 - 1.55 ) . However , physical activity appeared to be an effect modifier . In those who were less physically active , the intervention had a larger effect . The intervention reduced the total and leisure time injury incidence ( HR , 0.47 ; 95 % CI , 0.21 - 1.06 ; and 0.43 ; 0.16 - 1.14 ; respectively ) . Sports club injury incidence was significantly reduced ( HR , 0.23 ; 95 % CI , 0.07 - 0.75 ) . CONCLUSION We found a substantial and relevant reduction in physical activity injuries , especially in children in the low active group , because of the intervention . This school-based injury prevention program is promising , but future large-scale research is needed To prospect ively evaluate the effect of neuromuscular training on the incidence of knee injury in female athletes , we monitored two groups of female athletes , one trained before sports participation and the other not trained , and a group of untrained male athletes throughout the high school soccer , volleyball , and basketball seasons . Weekly reports included the number of practice and competition exposures and mechanism of injury . There were 14 serious knee injuries in the 1263 athletes tracked through the study . Ten of 463 untrained female athletes sustained serious knee injuries ( 8 noncontact ) , 2 of 366 trained female athletes sustained serious kne 
    Output:
    
Conclusions The results provide good evidence and clearly demonstrate beneficial effects of exercise-based injury prevention programs in youth sports as they can result in statistically significant and practically relevant injury reduction .
In particular , multimodal programs including jumping/plyometric exercises can be recommended .