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 .
Background Awareness of the magnitude of contact sports-related concussions has risen exponentially in recent years .
Our objective is to conduct a prospect ively registered systematic review of the scientific evidence regarding interventions to prevent contact sports-related concussions .
Influence of the limited interchange rule on injury rates in sub-elite Rugby League players.
This study investigated the incidence of injury in sub-elite Rugby League players before and after the introduction of the limited interchange rule .  The incidence of injury was prospect ively studied in one sub-elite Rugby League club over three competitive seasons . Two seasons were played under the unlimited interchange rule , while the third season was played under the limited interchange rule .  Players participated in 91 matches under the unlimited interchange rule and 44 matches under the limited interchange rule .  Injury was defined as any pain , disability or injury that occurred as a result of a competition game that caused the player to miss a subsequent game . The relative risk ( RR ) of injury significantly decreased ( RR = 0.70 [ 0.65 to 0.75 ] , P<0.05 ) following the introduction of the limited interchange rule , with the incidence of injury decreasing from 72.5 ( 58.2 to 86.8 ) per 1000 playing hr under the unlimited interchange rule to 51.0 ( 33.8 to 68.1 ) per 1000 playing hr under the limited interchange rule . The risk of sustaining thigh and calf injuries ( RR= 0.27 [ 0.12 to 0.59 ] , P < 0.05 ) , muscular strains ( RR= 0.23 10.17 to 0.31 ] . , P<0.05 ) , and high intensity running injuries ( RR= 0.16 [ 0.04 to 0.691 , P<0.05 ) was significantly reduced following the introduction of the limited interchange rule . These findings demonstrate that the risk of injury in sub-elite Rugby League players is significantly reduced following the introduction of the limited interchange rule . The reduced injury risk may reflect a fatigue-induced reduction in match speed and impact forces associated with physical collisions and tackles
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 .
Background Awareness of the magnitude of contact sports-related concussions has risen exponentially in recent years .
Our objective is to conduct a prospect ively registered systematic review of the scientific evidence regarding interventions to prevent contact sports-related concussions .