Youth have very high participation and injury rates in sport. Sport is the leading cause of injury in youth. Sport injury reduces future participation in physical activity which adversely affects future health. Sport injury may lead to overweight/obesity and post-traumatic osteoarthritis. The objective of the systematic review and meta-analysis was to evaluate the efficacy of injury prevention neuromuscular training strategies in youth sport. Three electronic databases were systematically searched up to September 2014. Studies selected met the following criteria: original data; analytic prospective design; investigated a neuromuscular training prevention strategy intervention(s) and included outcomes for injury sustained during sport participation. Two authors assessed the quality of evidence using Downs and Black (DB) criteria. Meta-analyses including randomised controlled trials only (RCTs) to ensure study design homogeneity were completed for lower extremity and knee injury outcomes. Of 2504 potentially relevant studies, 25 were included. Meta-analysis revealed a combined preventative effect of neuromuscular training in reducing the risk of lower extremity injury (incidence rate ratio: IRR=0.64 (95% CI 0.49 to 0.84)). Though not statistically significant, the point estimate suggests a protective effect of such programmes in reducing the risk of knee injury (IRR=0.74 (95% CI 0.51 to 1.07)). There is evidence for the effectiveness of neuromuscular training strategies in the reduction of injury in numerous team sports. Lack of uptake and ongoing maintenance of such programmes is an ongoing concern. A focus on implementation is critical to influence knowledge, behaviour change and sustainability of evidence informed injury prevention practice.

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Background: Ice hockey has one of the highest sport participation and injury rates in youth in Canada. Body checking (BC) is the predominant mechanism of injury in leagues in which it is permitted. The objectives of this study were to determine whether the incidence and types of physical contact differ for Bantam players (aged 13–14 years) who were exposed to BC at Pee Wee level (aged 11–12 years) in Calgary, Alberta versus Bantam players who were not exposed to BC at Pee Wee level in Québec City, Québec. All teams were exposed to BC at bantam level; Methods: A cohort study was conducted in Québec City and Calgary. Sixteen games for Calgary and 15 for Québec City were randomly selected and analysed with a validated observation system to quantify five intensities of physical contact and to observe different types of physical contact such as slashing and holding; Results: A total of 5610 incidences of physical contact with the trunk and 3429 other types of physical contact were observed. Very light intensity trunk contact was more frequent in Calgary (adjusted incidence RR (ARR): 1.71; 95% CI: 1.28–2.29). Holding (ARR: 1.04; 95% CI: 1.02–1.07) and slashing (ARR: 1.38; 95% CI: 1.07–1.77) were more frequent in Calgary; Conclusion: Results suggest that players’ physical contacts differ between Bantam leagues in which BC was permitted at Pee Wee level and leagues in which it was not permitted until Bantam level.

a) Objective. We explored relationships between male mortality and the sex ratio. (b) Methods. We tested relationships across 142 societies and in longitudinal data from Scotland. (c) Results. A male-biased sex ratio was associated with reduced mortality by intentional self-harm across 142 societies. This was replicated in longitudinal Scottish data, and men were less likely to die by suicide and assault when there were more men in the population only when levels of unemployment were low. (d) Conclusion. We argue that this is consistent with a theoretical model in which men increase investment in relationships and offspring as 'competition' under a male-biased sex ratio, and that the conflicting results of previous work may stem from divergent effects of the sex ratio on mortality depending upon relative deprivation.

BackgroundParticipation and injury rates in youth ice hockey are high. Results of recent studies show that for 11 and 12 years old players the risk of injury is significantly higher in leagues where body checking (BC) is permitted compared to leagues where it is not. The objective of this research was to determine whether the incidence and types of body contact differ for 13 and 14 years old players in leagues where BC commenced at age 11 (Calgary) versus 13 and 14 years old players in leagues where BC was delayed until age 13 (Québec City).MethodsA cohort study was conducted in Québec City and Calgary. Sixteen games for Calgary and fifteen for Québec City were randomly selected and retrospectively analysed. Games were videotaped and analysed with a validated observation system allowing quantification of the intensity of physical contacts (PC). Five levels of intensity were coded. Level 1 represents the lowest intensity, and level 5 the highest. Different types of PC such as slashing and hooking were also observed. Multivariate Poisson’s regression analyses were performed to compare games between the two cohorts. The results provided a body contact incidence rate per team game. Rates were adjusted for the game period, rink zone, and score difference.ResultsA total of 5,610 incidences of body contact with the trunk and 3,429 other types of body contact were observed. Very light intensity (Level 1) trunk contact was more frequent in Québec City (adjusted incidence RR [ARR]: 1.71; 95% CI: 1.28–2.29). Hooking (ARR: 2.18; 95% CI: 1.42–3.32) and slashing (ARR: 3.35; 95% CI: 1.31–8.58) were more frequent in Calgary. Body contacts were made more often by defensive players (ARR: 1.28; 95% CI: 1.03–1.58) and on puck carriers (ARR: 1.47; 95% CI: 1.02–2.12) in Calgary.ConclusionsResults suggest that players’ behaviours differ between players in leagues in which BC was permitted at age 11 compared to leagues in which BC was delayed until age 13.