human
***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: Objective : The ThinkFirst Canada Smart Hockey program is an educational injury prevention video that teaches the mechanisms , consequences , and prevention of brain and spinal cord injury in ice hockey . This study evaluates knowledge transfer and behavioural outcomes in 11–12 year old hockey players who viewed the video . Design : R and omized controlled design . Setting : Greater Toronto Minor Hockey League , Toronto Ontario . Subjects : Minor , competitive 11–12 year old male ice hockey players and hockey team coaches . Interventions : The Smart Hockey video was shown to experimental teams at mid-season . An interview was conducted with coaches to underst and reasons to accept or refuse the injury prevention video . Main outcome measures : A test of concussion knowledge was administered before , immediately after , and three months after exposure to the video . The incidence of aggressive penalties was measured before and after viewing the video . Results : The number of causes and mechanisms of concussion named by players increased from 1.13 to 2.47 and from 0.67 to 1.22 respectively . This effect was maintained at three months . There was no significant change in control teams . There was no significant change in total penalties after video exposure ; however , specific body checking related penalties were significantly reduced in the experimental group . Conclusion : This study showed some improvements in knowledge and behaviours after a single viewing of a video ; however , these findings require confirmation with a larger sample to underst and the sociobehavioural aspects of sport that determine the effectiveness and acceptance of injury prevention interventions Background : In a previous prospect i ve study , the risk of concussion and all injury was more than threefold higher among Pee Wee ice hockey players ( ages 11–12 years ) in a league that allows  bodychecking than among those in a league that does not . We examined whether two years of bodychecking experience in Pee Wee influenced the risk of concussion and other injury among players in a Bantam league ( ages 13–14 ) compared with Bantam players introduced to bodychecking for the first time at age 13 . Methods : We conducted a prospect i ve cohort study involving hockey players aged 13–14 years in the top 30 % of divisions of play in their leagues . Sixty-eight teams from the province of Alberta ( n = 995 ) , whose players had two years of bodychecking experience in Pee Wee , and 62 teams from the province of Quebec ( n = 976 ) , whose players had no bodychecking experience in Pee Wee , participated . We estimated incidence rate ratios ( IRRs ) for injury and for concussion . Results : There were 272 injuries ( 51 concussions ) among the Bantam hockey players who had bodychecking experience in Pee Wee and 244 injuries ( 49 concussions ) among those without such experience . The adjusted IRRs for game-related injuries and concussion overall between players with bodychecking experience in Pee Wee and those without it were as follows : injury overall 0.85 ( 95 % confidence interval [ CI ] 0.63 to 1.16 ) ; concussion overall 0.84 ( 95 % CI 0.48 to 1.48 ) ; and injury result ing in more than seven days of time loss ( i.e. , time between injury and return to play ) 0.67 ( 95 % CI 0.46 to 0.99 ) . The unadjusted IRR for concussion result ing in more than 10 days of time loss was 0.60 ( 95 % CI 0.26 to 1.41 ) . Interpretation : The risk of injury result ing in more than seven days of time loss from play was reduced by 33 % among Bantam hockey players in a league where bodychecking was allowed two years earlier in Pee Wee compared with Bantam players introduced to bodychecking for the first time at age 13 . In light of the increased risk of concussion and other injury among Pee Wee players in a league where bodychecking is permitted , policy regarding the age at which hockey players are introduced to bodychecking requires further consideration Objective : To identify specific risk factors for concussion severity among ice hockey players wearing full face shields compared with half face shields ( visors ) .  Methods : A prospect i ve cohort study was conducted during one varsity hockey season ( 1997–1998 ) with 642 male ice hockey players ( median age 22 years ) from 22 teams participating in the Canadian Inter-University Athletics Union . Half of the teams wore full face shields , and half wore half shields ( visors ) for every practice and game throughout the season . Team therapists and doctors recorded on structured forms daily injury , participation , and information on face shield use for each athlete . The main outcome measure was any traumatic brain injury requiring assessment or treatment by a team therapist or doctor , categorised by time lost from subsequent participation and compared by type of face shield worn . Results : Players who wore half face shields missed significantly more practice s and games per concussion ( 2.4 times ) than players who wore full face shields ( 4.07 sessions ( 95 % confidence interval ( CI ) 3.48 to 4.74 ) v 1.71 sessions ( 95 % CI 1.32 to 2.18 ) respectively ) . Significantly more playing time was lost by players wearing half shields during practice s and games , and did not depend on whether the athletes were forwards or defence , rookies or veterans , or whether the concussions were new or recurrent . In addition , players who wore half face shields and no mouthguards at the time of concussion missed significantly more playing time ( 5.57 sessions per concussion ; 95 % CI 4.40 to 6.95 ) than players who wore half shields and mouthguards ( 2.76 sessions per concussion ; 95 % CI 2.14 to 3.55 ) . Players who wore full face shields and mouthguards at the time of concussion lost no playing time compared with 1.80 sessions lost per concussion ( 95 % CI 1.38 to 2.34 ) for players wearing full face shields and no mouthguards . Conclusions : The use of a full face shield compared with half face shield by intercollegiate ice hockey players significantly reduced the playing time lost because of concussion , suggesting that concussion severity may be reduced by the use of a full face shield BACKGROUND Concussion is a serious problem in many contact sports , including rugby union football . The study 's primary aim was to measure the efficacy of padded headgear in reducing the rates of head injury or concussion . METHODS A cluster r and omized controlled trial with three arms was conducted with rugby union football teams as the unit of r and omization . Teams consisted of males participating in under 13- , 15- , 18- , and 20-yr age group competitions . The interventions were " st and ard " and " modified " padded headgear .  Headgear wearing and injury were measured for each study team at each game over two seasons . RESULTS Eighty-two teams participated in year 1 and 87 in year 2 . A total of 1493 participants ( 10,040 player hours ) were in the control group , 1128 participants ( 8170 player hours ) were assigned to the st and ard headgear group , and 1474 participants ( 10,650 player hours ) were assigned to the modified headgear group .  The compliance rates were low in all groups , but 46 % of participants wore st and ard headgear . An intention-to-treat analysis showed no differences in the rates of head injury or concussion between controls and headgear arms . Incidence rate ratios for st and ard headgear wearers referenced to controls were 0.95 and 1.02 for game and missed game injuries . Analyses of injury rates based on observed wearing patterns also showed no significant differences . Incidence rate ratios for st and ard headgear wearers referenced to nonwearers were 1.11 and 1.10 for game and missed game injuries . CONCLUSIONS Padded headgear does not reduce the rate of head injury or concussion . The low compliance rates are a limitation . Although individuals may choose to wear padded headgear , the routine or m and atory use of protective headgear can not be recommended Objective —To determine whether protective headgear reduced the incidence of concussion in a pilot study of under 15 rugby union . Methods —Sixteen under 15 rugby union teams were recruited from three interschool competitions in metropolitan Sydney and the adjacent country region . A prospect i ve study was undertaken over a single competitive season . The study had two arms : a headgear arm and a control arm . Headgear wearing rates and injury data were reported to the investigators and verified using spot checks . Results —A total of 294 players participated in the study . There were 1179 player exposures with headgear and 357 without headgear . In the study time frame , there were nine incidences of concussion ; seven of the players involved wore headgear and two did not . There was no significant difference between concussion rates between the two study arms . Conclusions —Although there is some controversy about the desirability of wearing protective headgear in football , this pilot study strongly suggests that current headgear does not provide significant protection against concussion in rugby union at a junior level BACKGROUND : Each year , in the United states , approximately 900 persons die from injuries due to bicycle crashes and over 500,000 persons are treated in emergency departments . Head injury is by far the greatest risk posed to bicyclists , comprising one-third of emergency department visits , two-thirds of hospital admissions , and three-fourths of deaths . Facial injuries to cyclists occur at a rate nearly identical to that of head injuries . Although it makes inherent sense that helmets would be protective against head injury , establishing the real-world effectiveness of helmets is important . A number of case-control studies have been conducted demonstrating the effectiveness of bicycle helmets . Because of the magnitude of the problem and the potential effectiveness of bicycle helmets , the objective of this review is to determine whether bicycle helmets reduce head , brain and facial injury for bicyclists of all ages involved in a bicycle crash or fall . OBJECTIVES : To determine whether bicycle helmets reduce head , brain and facial injury for bicyclists of all ages involved in a bicycle crash or fall . SEARCH STRATEGY : We search ed The Cochrane Controlled Trials Register , MEDLINE , EMBASE , Sport , ERIC , NTIS , Exp and ed Academic Index , CINAHL , PsycINFO , Occupational Safety and Health , and Dissertations Abstract s. We checked reference lists of past review s and review articles , studies from government agencies in the United States , Europe and Australia , and contacted colleagues from the International Society for Child and Adolescent Injury Prevention , World Injury Network , CDC funded Injury Control and Research Centers , and staff in injury research agencies around the world . SELECTION CRITERIA : Controlled studies that evaluated the effect of helmet use in a population of bicyclists who had experienced a crash . We required that studies have complete outcome ascertainment , accurate exposure measurement , appropriate selection of the comparison group and elimination or control of factors such as selection bias , observation bias and confounding . DATA COLLECTION AND ANALYSIS : Five published studies met the selection criteria . Two abstract ors using a st and ard abstract ion form independently abstract ed data . Odds ratios with 95 % CI were calculated for the protective effect of helmet for head and facial injuries . Study results are presented individually . Head and brain injury results were also summarized using meta- analysis techniques . MAIN RESULTS : No r and omized controlled trials were found . This review identified five well conducted case control studies which met our selection criteria . Helmets provide a 63%-88 % reduction in the risk of head , brain and severe brain injury for all ages of bicyclists .  Helmets provide equal levels of protection for crashes involving motor vehicles ( 69 % ) and crashes from all other causes ( 68 % ) . Injuries to the upper and mid facial areas are reduced 65 % . REVIEW ER 'S CONCLUSIONS : Helmets reduce bicycle-related head and facial injuries for bicyclists of all ages involved in all types of crashes including those involving motor vehicles Objective : To evaluate the effect of cervical muscle strength on head impact biomechanics . Design : Prospect i ve cohort . Setting : Field setting . Participants : Thirty-seven volunteer ice hockey players ( age = 15.0 ± 1.0 years , height = 173.5 ± 6.2 cm , mass = 66.6 ± 9.0 kg , playing experience = 2.9 ± 3.7 years ) . Interventions : Participants were equipped with accelerometer-instrumented helmets to collect  head impact biomechanics ( linear and rotational acceleration ) throughout an entire playing season . Before the season , isometric cervical muscle strength was measured for the anterior neck flexors , anterolateral neck flexors , cervical rotators , posterolateral neck extensors , and upper trapezius . Data were analyzed using r and om intercept general mixed linear models , with each individual player as a repeating factor/cluster . Main Outcome Measures : Dependent variables included linear and rotational head accelerations . Cervical strength data were categorized into tertiles , creating groups with high , moderate , and low strength . Strength measures were averaged and normalized to body mass . Results : Significant differences in cervical muscle strength existed across our strength groups ( P < 0.05 ) . No differences were observed in linear or rotational acceleration across strength groups for the anterior neck flexors ( PLin = 0.399 ; PRot = 0.060 ) , anterolateral neck flexors ( PLin = 0.987 ; PRot = 0.579 ) , cervical rotators ( PLin = 0.136 ; PRot = 0.238 ) , posterolateral neck extensors ( PLin = 0.883 ; PRot = 0.101 ) , or upper trapezius ( PLin = 0.892 ; PRot = 0.689 ) 
    Output:
    
agent
Conditional recommendations are made supporting preventive interventions concussion education and rules prohibiting high-risk activity for both pediatric and adult amateur athletes and neck strengthening exercise in adult amateur athletes .
Strong recommendations are supported for head protective equipment in both pediatric and adult amateur athletes .
Strong recommendations regarding newer football helmet technology in adult amateur athletes and rules governing the implementation of body-checking in youth ice hockey are supported .
***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: Objective : The ThinkFirst Canada Smart Hockey program is an educational injury prevention video that teaches the mechanisms , consequences , and prevention of brain and spinal cord injury in ice hockey . This study evaluates knowledge transfer and behavioural outcomes in 11–12 year old hockey players who viewed the video . Design : R and omized controlled design . Setting : Greater Toronto Minor Hockey League , Toronto Ontario . Subjects : Minor , competitive 11–12 year old male ice hockey players and hockey team coaches . Interventions : The Smart Hockey video was shown to experimental teams at mid-season . An interview was conducted with coaches to underst and reasons to accept or refuse the injury prevention video . Main outcome measures : A test of concussion knowledge was administered before , immediately after , and three months after exposure to the video . The incidence of aggressive penalties was measured before and after viewing the video . Results : The number of causes and mechanisms of concussion named by players increased from 1.13 to 2.47 and from 0.67 to 1.22 respectively . This effect was maintained at three months . There was no significant change in control teams . There was no significant change in total penalties after video exposure ; however , specific body checking related penalties were significantly reduced in the experimental group . Conclusion : This study showed some improvements in knowledge and behaviours after a single viewing of a video ; however , these findings require confirmation with a larger sample to underst and the sociobehavioural aspects of sport that determine the effectiveness and acceptance of injury prevention interventions Background : In a previous prospect i ve study , the risk of concussion and all injury was more than threefold higher among Pee Wee ice hockey players ( ages 11–12 years ) in a league that allows  bodychecking than among those in a league that does not . We examined whether two years of bodychecking experience in Pee Wee influenced the risk of concussion and other injury among players in a Bantam league ( ages 13–14 ) compared with Bantam players introduced to bodychecking for the first time at age 13 . Methods : We conducted a prospect i ve cohort study involving hockey players aged 13–14 years in the top 30 % of divisions of play in their leagues . Sixty-eight teams from the province of Alberta ( n = 995 ) , whose players had two years of bodychecking experience in Pee Wee , and 62 teams from the province of Quebec ( n = 976 ) , whose players had no bodychecking experience in Pee Wee , participated . We estimated incidence rate ratios ( IRRs ) for injury and for concussion . Results : There were 272 injuries ( 51 concussions ) among the Bantam hockey players who had bodychecking experience in Pee Wee and 244 injuries ( 49 concussions ) among those without such experience . The adjusted IRRs for game-related injuries and concussion overall between players with bodychecking experience in Pee Wee and those without it were as follows : injury overall 0.85 ( 95 % confidence interval [ CI ] 0.63 to 1.16 ) ; concussion overall 0.84 ( 95 % CI 0.48 to 1.48 ) ; and injury result ing in more than seven days of time loss ( i.e. , time between injury and return to play ) 0.67 ( 95 % CI 0.46 to 0.99 ) . The unadjusted IRR for concussion result ing in more than 10 days of time loss was 0.60 ( 95 % CI 0.26 to 1.41 ) . Interpretation : The risk of injury result ing in more than seven days of time loss from play was reduced by 33 % among Bantam hockey players in a league where bodychecking was allowed two years earlier in Pee Wee compared with Bantam players introduced to bodychecking for the first time at age 13 . In light of the increased risk of concussion and other injury among Pee Wee players in a league where bodychecking is permitted , policy regarding the age at which hockey players are introduced to bodychecking requires further consideration Objective : To identify specific risk factors for concussion severity among ice hockey players wearing full face shields compared with half face shields ( visors ) .  Methods : A prospect i ve cohort study was conducted during one varsity hockey season ( 1997–1998 ) with 642 male ice hockey players ( median age 22 years ) from 22 teams participating in the Canadian Inter-University Athletics Union . Half of the teams wore full face shields , and half wore half shields ( visors ) for every practice and game throughout the season . Team therapists and doctors recorded on structured forms daily injury , participation , and information on face shield use for each athlete . The main outcome measure was any traumatic brain injury requiring assessment or treatment by a team therapist or doctor , categorised by time lost from subsequent participation and compared by type of face shield worn . Results : Players who wore half face shields missed significantly more practice s and games per concussion ( 2.4 times ) than players who wore full face shields ( 4.07 sessions ( 95 % confidence interval ( CI ) 3.48 to 4.74 ) v 1.71 sessions ( 95 % CI 1.32 to 2.18 ) respectively ) . Significantly more playing time was lost by players wearing half shields during practice s and games , and did not depend on whether the athletes were forwards or defence , rookies or veterans , or whether the concussions were new or recurrent . In addition , players who wore half face shields and no mouthguards at the time of concussion missed significantly more playing time ( 5.57 sessions per concussion ; 95 % CI 4.40 to 6.95 ) than players who wore half shields and mouthguards ( 2.76 sessions per concussion ; 95 % CI 2.14 to 3.55 ) . Players who wore full face shields and mouthguards at the time of concussion lost no playing time compared with 1.80 sessions lost per concussion ( 95 % CI 1.38 to 2.34 ) for players wearing full face shields and no mouthguards . Conclusions : The use of a full face shield compared with half face shield by intercollegiate ice hockey players significantly reduced the playing time lost because of concussion , suggesting that concussion severity may be reduced by the use of a full face shield BACKGROUND Concussion is a serious problem in many contact sports , including rugby union football . The study 's primary aim was to measure the efficacy of padded headgear in reducing the rates of head injury or concussion . METHODS A cluster r and omized controlled trial with three arms was conducted with rugby union football teams as the unit of r and omization . Teams consisted of males participating in under 13- , 15- , 18- , and 20-yr age group competitions . The interventions were " st and ard " and " modified " padded headgear .  Headgear wearing and injury were measured for each study team at each game over two seasons . RESULTS Eighty-two teams participated in year 1 and 87 in year 2 . A total of 1493 participants ( 10,040 player hours ) were in the control group , 1128 participants ( 8170 player hours ) were assigned to the st and ard headgear group , and 1474 participants ( 10,650 player hours ) were assigned to the modified headgear group .  The compliance rates were low in all groups , but 46 % of participants wore st and ard headgear . An intention-to-treat analysis showed no differences in the rates of head injury or concussion between controls and headgear arms . Incidence rate ratios for st and ard headgear wearers referenced to controls were 0.95 and 1.02 for game and missed game injuries . Analyses of injury rates based on observed wearing patterns also showed no significant differences . Incidence rate ratios for st and ard headgear wearers referenced to nonwearers were 1.11 and 1.10 for game and missed game injuries . CONCLUSIONS Padded headgear does not reduce the rate of head injury or concussion . The low compliance rates are a limitation . Although individuals may choose to wear padded headgear , the routine or m and atory use of protective headgear can not be recommended Objective —To determine whether protective headgear reduced the incidence of concussion in a pilot study of under 15 rugby union . Methods —Sixteen under 15 rugby union teams were recruited from three interschool competitions in metropolitan Sydney and the adjacent country region . A prospect i ve study was undertaken over a single competitive season . The study had two arms : a headgear arm and a control arm . Headgear wearing rates and injury data were reported to the investigators and verified using spot checks . Results —A total of 294 players participated in the study . There were 1179 player exposures with headgear and 357 without headgear . In the study time frame , there were nine incidences of concussion ; seven of the players involved wore headgear and two did not . There was no significant difference between concussion rates between the two study arms . Conclusions —Although there is some controversy about the desirability of wearing protective headgear in football , this pilot study strongly suggests that current headgear does not provide significant protection against concussion in rugby union at a junior level BACKGROUND : Each year , in the United states , approximately 900 persons die from injuries due to bicycle crashes and over 500,000 persons are treated in emergency departments . Head injury is by far the greatest risk posed to bicyclists , comprising one-third of emergency department visits , two-thirds of hospital admissions , and three-fourths of deaths . Facial injuries to cyclists occur at a rate nearly identical to that of head injuries . Although it makes inherent sense that helmets would be protective against head injury , establishing the real-world effectiveness of helmets is important . A number of case-control studies have been conducted demonstrating the effectiveness of bicycle helmets . Because of the magnitude of the problem and the potential effectiveness of bicycle helmets , the objective of this review is to determine whether bicycle helmets reduce head , brain and facial injury for bicyclists of all ages involved in a bicycle crash or fall . OBJECTIVES : To determine whether bicycle helmets reduce head , brain and facial injury for bicyclists of all ages involved in a bicycle crash or fall . SEARCH STRATEGY : We search ed The Cochrane Controlled Trials Register , MEDLINE , EMBASE , Sport , ERIC , NTIS , Exp and ed Academic Index , CINAHL , PsycINFO , Occupational Safety and Health , and Dissertations Abstract s. We checked reference lists of past review s and review articles , studies from government agencies in the United States , Europe and Australia , and contacted colleagues from the International Society for Child and Adolescent Injury Prevention , World Injury Network , CDC funded Injury Control and Research Centers , and staff in injury research agencies around the world . SELECTION CRITERIA : Controlled studies that evaluated the effect of helmet use in a population of bicyclists who had experienced a crash . We required that studies have complete outcome ascertainment , accurate exposure measurement , appropriate selection of the comparison group and elimination or control of factors such as selection bias , observation bias and confounding . DATA COLLECTION AND ANALYSIS : Five published studies met the selection criteria . Two abstract ors using a st and ard abstract ion form independently abstract ed data . Odds ratios with 95 % CI were calculated for the protective effect of helmet for head and facial injuries . Study results are presented individually . Head and brain injury results were also summarized using meta- analysis techniques . MAIN RESULTS : No r and omized controlled trials were found . This review identified five well conducted case control studies which met our selection criteria . Helmets provide a 63%-88 % reduction in the risk of head , brain and severe brain injury for all ages of bicyclists .  Helmets provide equal levels of protection for crashes involving motor vehicles ( 69 % ) and crashes from all other causes ( 68 % ) . Injuries to the upper and mid facial areas are reduced 65 % . REVIEW ER 'S CONCLUSIONS : Helmets reduce bicycle-related head and facial injuries for bicyclists of all ages involved in all types of crashes including those involving motor vehicles Objective : To evaluate the effect of cervical muscle strength on head impact biomechanics . Design : Prospect i ve cohort . Setting : Field setting . Participants : Thirty-seven volunteer ice hockey players ( age = 15.0 ± 1.0 years , height = 173.5 ± 6.2 cm , mass = 66.6 ± 9.0 kg , playing experience = 2.9 ± 3.7 years ) . Interventions : Participants were equipped with accelerometer-instrumented helmets to collect  head impact biomechanics ( linear and rotational acceleration ) throughout an entire playing season . Before the season , isometric cervical muscle strength was measured for the anterior neck flexors , anterolateral neck flexors , cervical rotators , posterolateral neck extensors , and upper trapezius . Data were analyzed using r and om intercept general mixed linear models , with each individual player as a repeating factor/cluster . Main Outcome Measures : Dependent variables included linear and rotational head accelerations . Cervical strength data were categorized into tertiles , creating groups with high , moderate , and low strength . Strength measures were averaged and normalized to body mass . Results : Significant differences in cervical muscle strength existed across our strength groups ( P < 0.05 ) . No differences were observed in linear or rotational acceleration across strength groups for the anterior neck flexors ( PLin = 0.399 ; PRot = 0.060 ) , anterolateral neck flexors ( PLin = 0.987 ; PRot = 0.579 ) , cervical rotators ( PLin = 0.136 ; PRot = 0.238 ) , posterolateral neck extensors ( PLin = 0.883 ; PRot = 0.101 ) , or upper trapezius ( PLin = 0.892 ; PRot = 0.689 ) 
    Output:
    