Looking for the evidence: a systematic review of prevention strategies addressing sport and recreational injury among children and youth

Factors Associated with School Sports Injury among Elementary and Middle School Students in Shanghai, China

School sports activity (SSA) is beneficial to gaining and maintaining optimal health among elementary and middle school students but might increase risks for school sports injury (SSI). This cross-sectional study aimed to investigate the incidence and identify risk factors of SSI among Chinese elementary and middle school students in Shanghai. Students in grades 4–5 (elementary) and 7–9 (middle) from three k-12 schools (aged from 9 to 16 years old) in Shanghai selected via the method of cluster random sampling were invited to participate in the study. Information on socio-demography, sleep duration, individual internal and external risk factors, and SSI experiences in the past 12 months was collected. A multivariate logistic regression model was performed to estimate the risk factors of SSI. A total of 1303 participants completed the questionnaires, with an overall SSI incidence rate of 29.5%. Along with boys, elementary school students, and sports team members, students scoring high on internal and external risk factors were at higher risk for SSA. In summary, SSI was prevalent among elementary and middle school students in Shanghai, China, and was associated with several modifiable risk factors. The findings provide insights regarding actions that could be taken to reduce the occurrence of SSI and maximize the benefits of SSA, including improvements in safety education, maintenance of facilities and equipment, and completion of warm-up exercises.

A prospective study of sport injuries in youth females

OBJECTIVES

To examine sports and physical education (PE) injury rates in youth females during a school year and to investigate if an association exists between injury and phase of the menstrual cycle.

DESIGN

Prospective cohort.

SETTING

An online questionnaire was used to record training and competition exposure and self-reported injuries for 30-weeks.

PARTICIPANTS

103 PE students (12-15 years) from a girls' secondary school.

MAIN OUTCOME MEASURES

Injury rates and prevalence of acute, gradual onset/overuse and substantial injuries.

RESULTS

On average, girls trained 3.4 h/week and competed 1 h/week. During the study, 74 participants reported 595 injuries. The average weekly prevalence of all injuries was 20.7% (95% CI: 20.0-21.3), of which 8.6% (95% CI: 8.3-9.0) were acute injuries and 12.0% (95% CI: 11.4-12.6) were gradual onset/overuse injuries. The overall rate of sport and PE injuries was 10.4 injuries/1000 h of exposure. The most common acute injury involved the ankle (35%) while the most common gradual onset/overuse injury involved the knee (51%). There was no significant association between the stage of the menstrual cycle and the likelihood of injury (P = 0.18).

CONCLUSION

The high number of injuries in this population of girls suggests preventative measures, particularly targeting the lower extremity, are needed.

Effects of the '11+ Kids' injury prevention programme on severe injuries in children's football: a secondary analysis of data from a multicentre cluster-randomised controlled trial

BACKGROUND

To assess the effects of the injury prevention programme '11+ Kids' on reducing severe injuries in 7 to 13 year old football (soccer) players.

METHODS

Football clubs (under-9, under-11 and under-13 age groups) from the Czech Republic, Germany, the Netherlands and Switzerland were cluster-randomised (clubs) into an intervention (INT) and a control group (CON). INT replaced their usual warm-up by '11+ Kids' two times a week. CON followed their regular training regime. Match and training exposure and injury characteristics were recorded and injury incidence rates (IRs) and 95% CIs calculated. For the present analysis, only severe injuries (absence from training/match ≥28 days) were considered. Hazard ratios (HR) were calculated using extended Cox models.

RESULTS

The overall IR of severe injuries per 1000 football hours was 0.33 (95% CI 0.25 to 0.43) in CON and 0.15 (95% CI 0.10 to 0.23) in INT. There was a reduction of severe overall (HR 0.42, 95% CI 0.24 to 0.72), match (0.41, 0.17 to 0.95) and training injuries (0.42, 0.21 to 0.86) in INT. The injury types that were prevented the most were: other bone injuries 66%, fractures 49% and sprains and ligament injuries 37%. Severe injuries located at the knee (82%), hip/groin (81%), the foot/toe (80%) and the ankle (65%) were reduced tremendously.

CONCLUSIONS

'11+ Kids' has a large preventive effect on severe injuries by investing only 15 to 20 min per training session. The present results should motivate coaches to implement effective injury prevention programmes such as the '11+ Kids' in children's football.

TRIAL REGISTRATION NUMBER

NCT02222025.

Injury incidence in a Premier League youth soccer academy using the consensus statement: a prospective cohort study

Background

There is an established risk of injury to young athletes exposed to high training loads. Identifying and monitoring injury risk is essential to aid prevention. The aim of this study was to use the consensus statement to determine the incidence and pattern of injury in 1 English Premier League soccer academy during 1 season.

Methods

A prospective cohort study included 181 elite academy soccer players during the 2012–2013 season. Players were divided into 5 age groups between 9 and 18 years. The number, type and incidence of injuries were recorded during matches and training. Incidence was calculated per 1000 hours of exposure.

Results

127 injuries occurred during 29 346 hours of soccer exposure. 72% of injuries were non-contact related. Under (U)18 players sustained the highest number of match injuries. U12–14 players sustained the highest number of training injuries and injuries overall. U16 players sustained the highest number of severe injuries, and U18 players sustained the highest number of moderate injuries. U18 players sustained the highest number of injuries/1000 hours of training and overall. U15 players sustained the highest number of injuries/1000 hours of matches, the highest number of recurrent injuries and the highest incidence of recurrence. The most common injuries were muscle injuries in U15 and U18 players. The most common injury location was the anterior thigh, with the majority of these occurring in training.

Conclusions

Using the consensus statement, this study used a repeatable method to identify the injury profile of elite academy-level soccer players.

The Effects of Individualized Resistance Strength Programs on Knee Muscular Imbalances in Junior Elite Soccer Players

The purpose of this study was to investigate the effects of a resistance training program on the muscular strength of soccer players' knees that initially presented unilateral and bilateral differences. For this study, a team of 24 male well-trained junior soccer players was divided into two strength program training groups: a Resistance Training Control Group (RTCG) composed of 10 players that did not have muscular imbalances and a Resistance Training Experimental Group (RTEG) composed of 14 players that had muscular imbalances. All players followed a resistance training program for six weeks, two times per week, during the transition period. The program of individualized strength training consisted of two parts. The first part, which was identical in terms of the choice of training loads, was intended for both training groups and contained two series of exercises including upper and lower body exercises. The second part of the program was intended only for RTEG and consisted of two additional series for the groups of muscles that had identified unilateral and bilateral differences. The applied program showed various directions in the isokinetic profile of changes. In the case of RTCG, the adaptations related mainly to the quadriceps muscle (the peak torque (PT) change for the dominant leg was statistically significant (p < 0.05)). There were statistically significant changes in RTEG (p < 0.05) related to PT for the hamstrings in both legs, which in turn resulted in an increase in the conventional hamstring/quadriceps ratio (H/Q). It is interesting that the statistically significant (p < 0.05) changes were noted only for the dominant leg. No statistically significant changes in bilateral differences (BD) were noted in either group. These results indicate that individualized resistance training programs could provide additional benefits to traditional strength training protocols to improve muscular imbalances in post-adolescent soccer players.

Exercise-based injury prevention in child and adolescent sport: a systematic review and meta-analysis

BACKGROUND

The promotion of sport and physical activity (PA) for children is widely recommended to support a healthy lifestyle, but being engaged in sport bears the risk of sustaining injuries. Injuries, in turn, can lead to a reduction in current and future involvement in PA and, therefore, may negatively affect future health as well as quality of life. Thus, sports injury prevention is of particular importance in youth.

OBJECTIVE

The aim of this systematic review was to quantify the effectiveness of exercise-based injury prevention programs in child and adolescent sport in general, and with respect to different characteristics of the target group, injury prevention program, and outcome variables.

DATA SOURCES

An Internet-based literature search was conducted in six databases (CINAHL, Cochrane, EMBASE, ISI Web of Science, PubMed, SPORTDiscus) using the following search terms with Boolean conjunction: (sport injur* OR athletic injur* OR sport accident*) AND (prevent* OR prophylaxis OR avoidance) AND (child* OR adolescent OR youth).

STUDY SELECTION

Randomized controlled trials and controlled intervention studies in organized sport, published in English in a peer-reviewed journal, analyzing the effects of an exercise-based injury prevention program in athletes younger than 19 years of age.

DATA EXTRACTION

Two reviewers evaluated eligibility and methodological quality. Main outcome extracted was the rate ratio (RR). Statistical analyses were conducted using the inverse-variance random effects model.

RESULTS

Twenty-one trials, conducted on a total of 27,561 athletes (median age 16.7 years [range 10.7-17.8]), were included. The overall RR was 0.54 (95% CI 0.45-0.67) [p < 0.001]. Girls profited more from injury prevention than boys (p = 0.05). Both prevention programs with a focus on specific injuries (RR 0.48 [95% CI 0.37-0.63]) and those aiming at all injuries (RR 0.62 [95% CI 0.48-0.81]) showed significant reduction effects. Pre-season and in-season interventions were similarly beneficial (p = 0.93). Studies on programs that include jumping/plyometric exercises showed a significant better (p = 0.002) injury preventive effect (RR 0.45 [95% CI 0.35-0.57], Z = 6.35, p < 0.001) than studies without such exercises (RR 0.74 [95% CI 0.61-0.90], Z = 3.03, p = 0.002).

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. However, there is a considerable lack of data for children (under 14 years of age) and for individual sports in general. Future research should include these groups and focus on the effect of specific exercises and compliance.

Interventions to prevent sports related injuries: a systematic review and meta-analysis of randomised controlled trials

BACKGROUND

The effects of methods to prevent injuries have been studied in several systematic reviews. However, no meta-analysis taking into account all randomised controlled intervention trials aiming at the prevention of sports injuries has been published.

OBJECTIVE

To summarise the effects of sports injury prevention interventions.

DESIGN

Systematic review and meta-analysis of randomised controlled trials.

DATA SOURCES

PubMed, MEDLINE, SPORTDiscus, the Cochrane Central Register of Controlled Trials, CINAHL, PEDro, and Web of Science, searched in September 2013. The reference lists of retrieved articles and reviews were hand searched.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

To be selected articles had to examine the effects of any preventive intervention on sports injuries, be randomised/quasi-randomised and controlled trials, published in a peer-reviewed journal. The outcome of the trial had to be injury rate or the number of injured individuals.

RESULTS

Of the 5580 articles retrieved after a search of databases and the relevant bibliography, 68 randomised controlled trials were included in the systematic review and 60 trials were included in the meta-analysis. Insoles (OR 0.51, 95% CI 0.32-0.81), external joint supports (OR 0.40, 95% CI 0.30-0.53), and specific training programmes (OR 0.55, 95% CI 0.46-0.66) appeared to be effective in reducing the risk of sports injuries. Stretching (OR 0.92, 95% CI 0.80-1.06), modified shoes (OR 1.23, 95% CI 0.81-1.87), and preventive videos (OR 0.86, 95% CI 0.44-1.68) seemed not to be effective.

CONCLUSIONS

This meta-analysis showed that certain interventions can reduce the risk of sports injuries. There were limitations regarding the quality of the trials, generalisability of the results, and heterogeneity of the study designs. In future, the mechanisms behind effective methods and the most beneficial elements of preventive training programmes need to be clarified.

Unintentional Injuries among School-Aged Children in Palestine: Findings from the National Study of Palestinian Schoolchildren (HBSC-WBG2006)

Purpose. This study describes the nonfatal injuries among adolescents in Palestine. Methods. The 2006 Palestinian Health Behaviour in School-aged Children (HBSC) is a cross-sectional survey. Students of grades 6, 8, 10, and 12 completed a modified version of the international HBSC questionnaire, resulting in 15,963 students (47.3% boys and 52.7% girls) included in this study (56.9% from the West Bank and 43.1% from Gaza). Results. Of the total 15,963 adolescents, 47.6% were injured, with boys (53.5%) being statistically higher than girls (42.1%) (P<0.001). The prevalence of those injured more than once decreased by age and was also found significantly higher in boys than in girls (27.3% and 17.9%, resp.) (P<0.001). Children living in low FAS families showed significantly lower ratios of injuries than those living in moderate and high FAS families (P<0.001). Injuries while biking were significantly higher among boys (46.3%) than girls (41.7%) (P<0.001), and injuries while walking/running were more prevalent among girls (32.5%) than boys (28.0%) (P<0.001). Conclusion. Despite these considerably high rates, injury remains relatively underappreciated. Results of this study are useful to develop a national injury prevention program aimed at enhancing the safety of Palestinian adolescents.

Effectiveness of interventions to reduce aggression and injuries among ice hockey players: a systematic review

BACKGROUND

The increasing incidence of injuries related to playing ice hockey is an important public health issue. We conducted a systematic review to evaluate the effectiveness of interventions designed to reduce injuries related to aggressive acts in ice hockey.

METHODS

We identified relevant articles by searching electronic databases from their inception through July 2012, by using Internet search engines, and by manually searching sports medicine journals, the book series Safety in Ice Hockey and reference lists of included articles. We included studies that evaluated interventions to reduce aggression-related injuries and reported ratings of aggressive behaviour or rates of penalties or injuries.

RESULTS

We identified 18 eligible studies. Most involved players in minor hockey leagues. Of 13 studies that evaluated changes in mandatory rules intended to lessen aggression (most commonly the restriction of body-checking), 11 observed a reduction in penalty or injury rates associated with rule changes, and 9 of these showed a statistically significant decrease. The mean number of penalties decreased by 1.2-5.9 per game, and injury rates decreased 3- to 12-fold. All 3 studies of educational interventions showed a reduction in penalty rates, but they were not powered or designed to show a change in injury rates. In 2 studies of cognitive behavioural interventions, reductions in aggressive behaviours were observed.

INTERPRETATION

Changes to mandatory rules were associated with reductions in penalties for aggressive acts and in injuries related to aggression among ice hockey players. Effects of educational and cognitive behavioural interventions on injury rates are less clear. Well-designed studies of multifaceted strategies that combine such approaches are required.

Youth injuries in British Columbia: type, settings, treatment and costs, 2003-2007

In this study, the types and costs of unintentional injuries among adolescents transitioning to adulthood are examined to provide age-appropriate prevention strategies. The data were collected in 2003, 2005 and 2007, in which a total of 273 (41%), 228 (39%) and 176 (33%) youths, respectively, reported to be having at least one serious injury. The leading types of injuries were sprains/strains, broken bones and bruises. Most injuries occurred while playing sports, falling/tripping, biking or rollerblading, mainly in recreation centres (>12-15%), schools (<27-9%), and workplaces (>2-14.5%). Most injuries were treated at emergency departments, walk-in clinics and health professional's offices (68-84%). Prevention included: doing nothing; being more careful; giving up the activity and rarely, rehabilitation or physiotherapy. The total direct cost of treatment was $471,498, (Canadian) at a mean direct cost of $775 per injury. Improved sports training and educational strategies targeted at subgroups of adolescents are needed to reduce the human and economic burden of injury.

Reproducibility of impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) classification: a systematic review

BACKGROUND

The classifications of impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) represent glucose levels above normal, but below the decision threshold for diabetes. We sought to determine what the reproducibility of these classifications was when repeat tests were performed by conducting a systematic review of the literature.

METHODS

All primary studies published in English of any study design were included. Studies were excluded if they did not follow the World Health Organization or American Diabetes Association diagnostic criteria, used whole blood as the specimen type, a glucose meter for analysis, or performed repeat testing greater than 8 weeks apart.

RESULTS

Five papers had reproducibility data for IGT or IFG, two of which where from the same population but sampled differently. The kappa coefficients, indicating agreement between repeat tests that exceeded chance, indicated poor to fair agreement for IGT (0.04, 0.22, 0.38, 0.42) and moderate agreement for IFG (0.44 and 0.56). Similarly, the observed reproducibility was slightly lower for IGT (33%, 44%, 47%, 48%) compared to IFG (51%, 64%). In two studies for which data were available for both IGT and IFG, the average reproducibility was lower (49%) for the prediabetes group compared to the diabetes group (73%) or the normal group (93%).

CONCLUSIONS

Poor reproducibility of IGT and IFG classification suggests caution should be exercised when interpreting a single test result.

Annual incidence and relative risk of diabetes in people with various categories of dysglycemia: a systematic overview and meta-analysis of prospective studies

BACKGROUND

Several estimates of the risk of progression to diabetes in people with impaired fasting glucose (IFG) or impaired glucose tolerance (IGT) have been reported.

OBJECTIVE

To provide an estimate of the risk of progression to diabetes and regression to normoglycemia in these populations.

DESIGN

Systematic overview and meta-analysis of prospective cohort studies published from 1979 until 2004.

SETTING

Global cohort studies.

PATIENTS

People with IFG or IGT detected by a screening oral glucose tolerance test.

MEASUREMENTS

Fasting and post-load plasma glucose levels.

RESULTS

The absolute annual incidence of diabetes in individuals with various categories of IFG or IGT varied from 5 to 10%. Compared to normoglycemic people the meta-analyzed relative risk and 95% confidence interval for diabetes was: 6.35 (4.87-7.82) in people with IGT; 5.52 (3.13-7.91) in people with isolated IGT; 4.66 (2.47-6.85) in people with IFG; 7.54 (4.63-10.45) in people with isolated IFG; and 12.13 (4.27-20.00) in people with both IFG and IGT. People with IGT were 0.33 times as likely to be normoglycemic after 1 year compared to people with normal glucose tolerance (95% CI 0.23-0.43).

LIMITATIONS

Studies that used differing criteria for IFG and IGT were included, and participants were classified on the basis of only one test.

CONCLUSION

IFG and IGT are associated with similar, high relative risk for incident diabetes. The combined abnormality of IFG plus IGT is associated with the highest relative risk.

Safe and healthy school environments

Children spend much of their waking time at school. Many of the factors in the school environment can be improved with careful planning and allocation of resources. The pediatrician, as a child advocate, is in an excellent position to influence the allocation of school resources to improve the educational outcome. This article summarizes some of the current understanding gathered from applying an environmental health approach to the school setting and provides a basis for the interested physician and other child advocate to learn more and get involved.

Injury prevention in child and adolescent sport: whose responsibility is it?

OBJECTIVE

Sport and recreational injuries are a leading cause of morbidity in youth. There is a significant body of literature on risk factors for sport-related injuries and a growing body of research supporting the effectiveness of sport-specific prevention strategies in youth. Given the predictability and preventability of injuries in youth sport, the purpose of this article is to develop a model that considers societal responsibility for injury prevention in youth sport, and to discuss the evidence that supports this model.

DATA SOURCES/SYNTHESIS

Previously published papers have provided a basis for expert opinion to discuss an approach to examining the shared societal responsibility for implementing countermeasures to reduce the risk of injury to youth during sports.

RESULTS

Based on a historical perspective, broad conceptual framework, and specific evidence for prevention strategies in youth sport, the authors have developed and supported a theoretical model that defines a responsibility hierarchy in preventing injuries in youth sport. An argument has been made for a hierarchy of responsibility, with the lowest level of responsibility assigned to the child, and the highest level to those organizations or groups with the potential to effect the most change. The justification for this approach has been discussed in the context of the desirability of passive prevention strategies, the limited evidence for the effectiveness of strategies relying solely on behavior change in children and parents, and the level of perceptual and cognitive development in children that inadequately prepares them to take primary responsibility for their own safety in sport.

CONCLUSIONS

The development of effective programs to reduce the burden of sport injury among youth necessitates a scientific approach, the identification of key risk factors for injury, a thorough examination of how factors interact to affect risk, and the identification of potential barriers to the effectiveness of injury-prevention programs.

Emergency department visits among pediatric patients for sports-related injury: basic epidemiology and impact of race/ethnicity and insurance status

OBJECTIVES

(1) To characterize the demographics and external causes of pediatric sports injury-related visits (SIRVs) to emergency departments (EDs). (2) To analyze the effect of race/ethnicity and insurance on SIRVs to EDs.

METHODS

A stratified random-sample cross-sectional survey of EDs in the National Hospital Ambulatory Medical Care Survey was conducted from 1997-2001; for patients younger than 19 years, we used all visits [n = 33,654; injury-related visits (IRVs) = 13,496, SIRVs = 2990]. We examined both the external cause codes and the actual verbatim text of all IRVs. National estimates of pediatric IRVs were obtained using the assigned patient visit weights in the National Hospital Ambulatory Medical Care Survey databases and SUDAAN 9.1 software (SAS Institute, Inc., Cary, NC).

RESULTS

Sports injuries resulted in 2.5 million visits annually, or 23% of ED IRVs. Male sex, older age (6-18 years), and white race/ethnicity are associated with higher rates of SIRVs. Cycling, basketball, playground injuries, and football resulted in the largest numbers of ED SIRVs. Leading diagnoses for SIRVs included fractures and dislocations, sprains and strains, open wounds, and contusions. Hispanic race/ethnicity was associated with lower rates of SIRVs across all insurance types. After controlling for demographic factors and insurance, Hispanic children were less likely to have an SIRV than white children (odds ratio, 0.7; 95% confidence interval, 0.6-0.9).

CONCLUSIONS

Sports and recreation are the leading causes of pediatric ED IRVs. Hispanic children, regardless of insurance status, had lower rates of SIRVs than white children, which helps explain the lower rate of nonfatal IRVs to EDs among Hispanic youth.

Interventions to prevent softball related injuries: a review of the literature

OBJECTIVES

To examine the published evidence on interventions to prevent softball related injuries among adults, and to encourage more epidemiologic research as a foundation for future softball injury prevention efforts.

METHODS

The authors reviewed literature identified from six electronic databases for studies on softball related injuries. The search was limited to studies written in the English language, published between 1970 and 2002, and involving adult populations. Research was excluded that evaluated baseball ("hard ball") related injuries or was aimed at injury treatment. Identified studies were categorized by study design. Intervention/prevention papers were evaluated further and described in detail.

RESULTS

The search strategy identified 39 studies specifically related to softball. Most studies were case reports/case series (n=13) or descriptive studies (n=11); only four were analytic or intervention/prevention studies. Studies collected data in a variety of ways, often without denominator data to permit calculation of injury rates. Studies also did not differentiate between slow or fast pitch softball activities and most did not mention the type of softball that was used.

CONCLUSIONS

Surprisingly few studies exist on interventions to reduce injuries during softball, one of the most popular recreational sports in the US. Of the existing literature, much attention has been on sliding related injuries, which comprise only a segment of softball injuries. Basic epidemiologic studies describing the nature, severity, and risk factors for softball injuries in a variety of populations are needed, followed by additional intervention evaluation studies aimed at modifiable risk factors.

Promoting respect for the rules and injury prevention in ice hockey: evaluation of the fair-play program

OBJECTIVE

To reduce the number of transgressions to the rule, the occurrence of violent acts and to prevent injuries, Hockey Québec adopted the Fair-Play Program (FPP). The objective of the present study was to evaluate the effectiveness of the FPP.

METHODS

52 Bantam (14-15 years) teams participated in this cohort study. In total, 49 games (13 with the FPP, 36 without FPP) were systematically assessed for transgressions to the rule. Body checking was allowed in all games. Transgressions to the rule data were obtained using a real time observation system in a natural setting, while injury data were collected through a self-administered questionnaire. Data were analysed using generalised linear models with generalised estimating equations accounting for potential team effect.

RESULTS

The number of penalties per game was significantly lower (p < 0.01) for games played with the FPP. Overall, no difference was noted in the number of transgressions observed during games played with or without the FPP. Players in leagues where the FPP was used held their opponents more frequently (p < 0.0001). On the other hand, players in leagues without the FPP shoved and hit more (p = 0.05). No difference was noted in the injury rate for games played with or without the FPP.

CONCLUSIONS

This study showed that the FPP is one of the tools available to help those in the hockey world promote fair play values. Moreover, this project clearly showed the importance of program evaluation and the value of direct observation in a natural setting.

Assessment of lower limb neuromuscular control in prepubescent athletes

BACKGROUND

Although neuromuscular indices have been extensively studied in adolescents and adults, limited data exist for prepubescent children.

HYPOTHESIS

No differences exist between prepubescent boys and girls in lower limb strength, symmetry on single-legged hop testing, and limb alignment during drop-jump testing.

STUDY DESIGN

Cross-sectional study (prevalence); Level of evidence, 1.

METHODS

The authors tested 27 female and 25 male athletes who were aged 9 to 10 years and matched for both body mass index and years of organized sports participation. In a drop-jump screening test, the distance between the right and left hips, knees, and ankles was measured as an indicator of lower limb axial alignment in the coronal plane. The distance between the knees and ankles was normalized by the hip separation distance. Quadriceps and hamstrings strengths were measured isokinetically at 180 deg/s. Lower limb symmetry was determined from 2 single-legged hop function tests.

RESULTS

Boys demonstrated greater mean absolute and normalized knee and ankle separation distances on the drop-jump test. Even so, 76% of boys had a normalized knee separation distance of 60% or less of the hip separation distance, as did 93% of girls, indicating a distinctly valgus alignment. There were no differences between the sexes in quadriceps and hamstrings peak torques, hamstrings/quadriceps ratio, time to peak torque, total work, or lower limb symmetry values.

CONCLUSIONS

A high percentage of the prepubescent athletes studied had a distinctly valgus lower limb alignment during the drop-jump test and a lack of lower limb symmetry during the hop tests. These same indices have been hypothesized to increase the risk for knee ligament injuries in older athletes. Neuromuscular training may be needed to address these issues in children.

Craniomaxillofacial injury in sport: a review of prevention research

Current decision making in prevention of sport related craniomaxillofacial injury is based on available data derived from surveillance and attitude based studies. The literature on this type of injury prevention lacks the high quality scientific design and evidence on which mandatory interventions can be based. Currently available prevention methodology can provide a better understanding of injury mechanisms and produce valid interventions.