Comprehensive warm-up programme to prevent injuries in young female footballers: cluster randomised controlled trial

Planning injury prevention training for youth handball players: application of the generalisable six-step intervention development process

Background

Youth handball players are vulnerable to injuries. Because there is no available injury prevention training specifically developed for youth handball players targeting both upper and lower limbs or incorporating psychological aspects of injury, we undertook the ‘Implementing injury Prevention training ROutines in TEams and Clubs in youth Team handball (I-PROTECT)’ project. We used an ecological participatory design incorporating the perspectives of multiple stakeholders (health beneficiaries, programme deliverers and policy makers). The aim of this paper was to describe the process of developing the I-PROTECT model, featuring injury prevention training and an accompanying implementation strategy.

Design

We used the generalisable six-step intervention development process, outlined to guide researchers when developing implementable, evidence-based sports injury prevention interventions, to develop the I-PROTECT model. The six-step process involves establishing a research–stakeholder collaborative partnership to (1) identify and synthesise research evidence and clinical experience; (2) consult with relevant experts; (3) engage end users to ensure their needs, capacity and values are considered; (4) test the feasibility and acceptability of the intervention; (5) evaluate the intervention against theory; and (6) obtain feedback from early implementers. Two community handball clubs in southern Sweden, offering organised training for youth male and female players, and the district handball federation, participate in the intervention development. Drafts of the I-PROTECT model will be developed and revised with key stakeholder advice and input throughout all six steps.

Conclusion

The I-PROTECT model described will be an end user-driven intervention, including evidence-based, theory-informed and context-specific injury prevention training for youth handball, and an associated implementation strategy.

Prevention of severe knee injuries in men's elite football by implementing specific training modules

PURPOSE

Injury prevention of knee injuries by means of training and warm-up exercises has been investigated in several studies in amateur football. However, the number of investigations in elite football is limited despite the currently higher injury incidence of severe knee injuries. Therefore, the purpose of this study was to investigate whether specifically adapted preventive training modules may reduce severe knee injuries in elite football.

METHODS

In a prospective controlled cohort study of elite football players in Germany, an injury prevention programme with 5 modules was implemented in the season of 2015-2016. The training modules were specifically adapted to this skill level and based on scientific evidence, team coach preferences, and the specific environment of this playing level. Of the 62 teams taking part in this study, 26 used the new trainings modules and 36 continued their standard programme as a control group. Success of the programme was documented by means of an injury report over one season. The primary outcome was reduction in severe knee injuries.

RESULTS

A pre-seasonal investigation had identified five modules to be implemented in the training routine. Postural stability, mobilisation of lower extremity joints, leg and trunk stabilisation, jumping, and landing exercises as well as agility movements were incorporated into the programme to prevent severe knee injuries in elite football. Over the season, the study group (529 players) with the adapted training modules had sustained 52 severe knee injuries (incidence: 0.38 per 1000 h football exposure; prevalence: 9.8%) compared to 108 severe knee injuries in the control group (601 players) using the standard programme (incidence: 0.68 per 1000 h football exposure; prevalence: 18.0%; p < 0.05). The overall injury incidence for any other type of injury was comparable between the two groups (3.3 vs. 3.4 in h 1000 football, n.s.).

CONCLUSION

Appropriate preventive training modules reduce severe knee injuries in elite football significantly. The key for the sustainability of preventive training measures are programmes specifically adapted to the demands of the playing level and to the preferences of the coaches LEVEL OF EVIDENCE: II.

Forty-five per cent lower acute injury incidence but no effect on overuse injury prevalence in youth floorball players (aged 12-17 years) who used an injury prevention exercise programme: two-armed parallel-group cluster randomised controlled trial

Objective

To study whether an injury prevention exercise programme would reduce the number of injuries in youth floorball players.

Methods 

81 youth community level floorball teams (48 clusters=clubs) with female and male players (12–17 years) were cluster-randomised into an intervention or control group. Intervention group coaches were instructed to use the Swedish Knee Control programme and a standard running warm-up before every training session, and the running warm-up before every match, during the season. Control teams continued usual training. Teams were followed during the 2017/2018 competitive season (26 weeks). Player exposure to floorball and occurrence of acute and overuse injuries were reported weekly via a web-based player survey using the Oslo Sports Trauma Research Centre Questionnaire.

Results 

17 clusters (301 players) in the intervention group and 12 clusters (170 players) in the control group were included for analyses. There were 349 unique injuries in 222 players. The intervention group had a 35% lower incidence of injuries overall than the control group (adjusted incidence rate ratio (IRR) 0.65, 95% CI 0.52 to 0.81). The absolute risk reduction was 6.6% (95% CI 3.2 to 10.0), and the number needed to treat was 152 hours of floorball exposure (95% CI 100 to 316). Intervention group teams had a 45% lower incidence of acute injuries (adjusted IRR 0.55, 95% CI 0.37 to 0.83). There was no difference in the prevalence of overuse injuries (adjusted prevalence rate ratio 0.96, 95% CI 0.73 to 1.26).

Conclusion 

The Knee Control injury prevention programme reduced acute injuries in youth floorball players; there was no effect on overuse injuries.

Trial registration number

Clinical Trials NCT03309904.

The 11+ Kids warm-up programme to prevent injuries in young Iranian male high-level football (soccer) players: A cluster-randomised controlled trial

OBJECTIVE

To assess the effectiveness of the 11+ Kids warm-up programme regarding injury reduction in male high-level children's football players.

DESIGN

Cluster-randomised controlled trial.

METHOD

Male youth football teams of Iran's high-level football schools were invited to participate. Inclusion criteria were: teams are competing in the highest league of their province; players are between 7 and 14 years old; regular training takes place at least twice per week. Teams were excluded if they used an injury prevention measure. Participating clubs were randomised to an intervention (INT, N = 20 teams) and a control group (CON, N = 22 teams), stratified by the number of teams and the age group. The groups were blinded against each other. The follow-up period was one season (9 months). INT replaced their warm-up by 11+ Kids. CON performed a standard warm-up programme. The primary outcome was the injury incidence density (injuries per 1000 h of football exposure), compared between groups by incidence rate ratios (RR).

RESULTS

In total, 64,047 h of football exposure of 962 players (INT = 443 players, 31,934 h of football, CON = 519 players, 32,113 h of football) were recorded. During the study, 90 (INT = 30; CON = 60) injuries occurred. The overall injury incidence density in INT was reduced by 50% compared to CON (RR 0.50; 95%-CI 0.32, 0.78). No injuries occurred during the execution of the intervention exercises.

CONCLUSIONS

The 11+ Kids reduces injuries in high-level children's football players, thus supporting player health and potentially performance and player development.

How do the new Olympic sports compare with the traditional Olympic sports? Injury and illness at the 2018 Youth Olympic Summer Games in Buenos Aires, Argentina

OBJECTIVE

To describe injuries and illnesses across traditional and new sports among the participating athletes of the Buenos Aires 2018 Youth Olympic Summer Games (BA YOG) (6-18 October 2018).

METHODS

We recorded the daily number of athlete injuries and illnesses (1) through the reporting of all National Olympic Committee (NOC) medical teams and (2) in the polyclinic and medical venues manned by the BA YOG 2018 medical staff.

RESULTS

In total, 3.984 athletes from 206 NOCs were observed. NOCs and BA YOG 2018 medical staff reported 619 injuries and 334 illnesses, equalling 15.5 injuries and 8.4 illnesses per 100 athletes over the 13-day period. The eight new sports on the Youth Olympic programme (futsal, beach handball, karate, roller speed skating, kitesurfing, BMX freestyle, climbing and break dancing) fell in between the other sports with respect to injury and illness risk. Injury incidence was highest in rugby (43% of all rugby players), followed by boxing (33%) and badminton (24%), and lowest in swimming, archery, roller speed skating, equestrian, climbing and rowing (<5%). The highest incidences of illness were recorded in golf (20%), followed by triathlon (16%), beach volleyball and diving (both 14%). Of the illnesses, 50% affected the respiratory system and 15% the gastrointestinal system. Injury and illness incidences varied between continents with athletes representing Europe having significantly fewer injuries and illnesses compared with other continents, apart from a similar illness incidence to Asian athletes.

CONCLUSION

The overall injury incidence of 15.5 injuries per 100 athletes was higher, while the overall illness incidence of 8.4 illnesses per 100 athletes was similar to previous youth and Olympic Games. The new sports did not differ significantly compared with the other sports with respect to injury and illness risk.

Exercise interventions to prevent hamstring injuries in athletes: A systematic review and meta-analysis

The aim of this meta-analysis was to assess the effectiveness of exercise-based interventions for prevention of hamstring injuries in sport. PubMed, Cochrane Central Register of Controlled Trials, Web of Science, ResearchGate, CINAHL, PEDro, ScienceDirect and Google Scholar databases were searched for randomized controlled trials and prospective cohort studies exploring the effects of exercise interventions on hamstring injury incidence. Subgroup analyses were performed to determine effects of several independent variables related to the interventions. Altogether, 17 studies were included. Exercise interventions decreased hamstring injury risk (RR = 0.49; 95%CI = 0.40-0.59; p < 0.001). There were similar effects found for interventions performed ≤2 times per week (RR = 0.35; 95%CI = 0.15-0.82) and the interventions performed >2 times per week (RR = 0.44; 95%CI = 0.31-0.61). Similarly, there were similar effects found for the interventions with progressive increase in load (RR = 0.53; 95%CI = 0.37-0.74) and the interventions with constant loads (RR = 0.46; 95%CI = 0.36-0.58). Other subgroup analyses (intervention supervision, sport type, inclusion of Nordic hamstring exercise and type of the trial) also showed no indications on specific characteristics of the interventions, that increase the preventive effects. Our findings showed that hamstring injury incidence can be decreased with exercise-based interventions, and that weekly frequency and load progression are not among the most important variables to consider in prevention programmes design.

Muscle Activation in Unilateral Barbell Exercises: Implications for Strength Training and Rehabilitation

Mausehund, L, Skard, AE, and Krosshaug, T. Muscle activation in unilateral barbell exercises: Implications for strength training and rehabilitation. J Strength Cond Res 33(7S): S85-S94, 2019-The purpose of the present investigation was to assess lower-body muscle activity and hamstrings-to-quadriceps (HQ) activation ratios during performance of the split squat (SS), single-leg squat (SLS), and rear foot elevated split squat (RFESS), while using the same relative load and performing the exercises to muscular failure. Eleven healthy, moderately strength-trained subjects performed a 6-8 repetition maximum set of each exercise while electromyographic (EMG) activity of the vastus lateralis, biceps femoris, gluteus maximus, and gluteus medius was recorded. The results show that there were no significant differences in EMG peak activity of the gluteus maximus and vastus lateralis between any of the exercises. Gluteus medius activation was significantly (p ≤ 0.05) higher during the SLS (81.9% maximum voluntary isometric contraction [MVIC]), compared with the RFESS (54.9% MVIC) and SS (46.2% MVIC). The RFESS elicited higher (p ≤ 0.05) biceps femoris activity (76.1% MVIC) than the SS (62.3% MVIC), as well as higher (p ≤ 0.05) HQ activation ratios (0.83) than the SS (0.69) and SLS (0.63). During the SLS and the SS, HQ activation ratios increased significantly in the course of the repetition maximum set. In conclusion, although absolute loading differs between exercises, similar training stimuli of the gluteus maximus and quadriceps femoris can be expected for all exercises. The SLS is likely to induce the greatest improvements in gluteus medius strength, whereas the RFESS should be preferred if high hamstring coactivation is desired. To improve validity in EMG studies, strength training exercises should be performed close to failure while using the same relative loading.

Soccer Injuries in Children and Adolescents

Participation in youth soccer in the United States continues to increase steadily, with a greater percentage of preadolescent participants than perhaps any other youth sport. Despite the wide-ranging health benefits of participation in organized sports, injuries occur and represent a threat to the health and performance of young athletes. Youth soccer has a greater reported injury rate than many other contact sports, and recent studies suggest that injury rates are increasing. Large increases in the incidence of concussions in youth soccer have been reported, and anterior cruciate ligament injuries remain a significant problem in this sport, particularly among female athletes. Considerable new research has identified a number of modifiable risk factors for lower-extremity injuries and concussion, and several prevention programs have been identified to reduce the risk of injury. Rule enforcement and fair play also serve an important role in reducing the risk of injury among youth soccer participants. This report provides an updated review of the relevant literature as well as recommendations to promote the safe participation of children and adolescents in soccer.

Using the Rating of Perceived Exertion and Heart Rate to Quantify Training Intensity in Female Soccer Players: Validity and Utility

Costa, JA, Brito, J, Nakamura, FY, Figueiredo, P, and Rebelo, A. Using the rating of perceived exertion and heart rate to quantify training intensity in female soccer players: validity and utility. J Strength Cond Res XX(X): 000-000, 2019-The aims of this study were as follows: (a) to analyze associations between session rating of perceived exertion (sRPE) and training impulse (TRIMP); (b) to verify whether significantly different ranges of percentage of heart rate peak (%HRpeak) would be reached in each discrete RPE category; and (c) to investigate the amount of time spent >90% of HRpeak and associated intraplayer and interplayer variability during soccer technical training sessions with similar contents and duration. This was a single-group observational study that measured the internal training load during 6 weeks of the competitive period in 17 high-level female soccer players. All training sessions started around 9 PM. and lasted on average 94 ± 5 minutes. During each training session, RPE, sRPE, TRIMP, HRex (%HRpeak), and time spent at >90% of HRpeak were assessed. A very large correlation was found between sRPE and TRIMP (r = 0.78; 95% confidence interval: [0.74-0.82]). Significant differences were observed between %HRpeak associated with each RPE value (i.e., RPE = 2 arbitrary unit [68%; 65-69% of %HRpeak]; RPE 3 [72%; 69-75%]; RPE 4 [79%; 76-82%]; RPE 5 [84; 81-87%]; χ = 73.34; df = 3; P < 0.001). Intraplayer and interplayer coefficients of variation for the time spent >90% of HRpeak (∼8% of training time, ∼7 minutes per session) during training sessions were 73 and 92%, respectively. In conclusion, it was confirmed that sRPE and TRIMP displayed good convergent validity, and different %HRpeak were observed for each discrete RPE. However, because of the high variability in the time >90% of HRpeak, careful monitoring of individual exercises should be performed to ensure the desired training stimulus for each player.

Community-based football in men with prostate cancer: 1-year follow-up on a pragmatic, multicentre randomised controlled trial

BACKGROUND

Physical exercise has been shown to be effective in relation to fatigue, aerobic fitness, and lower body strength in men with prostate cancer. However, research into the clinically relevant effects of interventions conducted in heterogeneous patient populations and in real-life clinical practice settings is warranted.

METHODS AND FINDINGS

We conducted a pragmatic, multicentre, parallel randomised controlled trial in 5 Danish urological departments. Recruitment began in May 2015, the first participant was randomised in June 2015, and the last participant was included in February 2017. In total, 214 men with prostate cancer were randomly assigned to either 6 months of free-of-charge football training twice weekly at a local club (football group [FG]) (n = 109) or usual care (usual care group [UG]) (n = 105), including brief information on physical activity recommendations at randomisation. Participants were on average 68.4 (SD 6.2) years old, 157 (73%) were retired, 87 (41%) were on castration-based treatment, 19 (9%) had received chemotherapy, and 41 (19%) had skeletal metastases at baseline. In this 1-year follow-up study, we evaluated the effects of community-based football training on the following outcomes: primary outcome, quality of life; secondary outcomes: continuation of football after 6 months, hip and lumbar spine bone mineral density (BMD), mental health score, fat and lean body mass, and safety outcomes, i.e., fractures, falls, and hospital admissions. Intention to treat (ITT) and per protocol (PP) analyses were conducted. No statistically significant between-group difference was observed in change in prostate-cancer-specific quality of life (ITT: 1.9 points [95% CI -1.9 to 5.8], p = 0.325; PP: 3.6 points [95% CI -0.9 to 8.2], p = 0.119). A statistically significant between-group difference was observed in change in total hip BMD, in favour of FG (0.007 g/cm2 [95% CI 0.004 to 0.013], p = 0.037). No differences were observed in change in lumbar spine BMD or lean body mass. Among patients allocated to football, 59% chose to continue playing football after the end of the 6-month intervention period. At 1-year follow-up in the PP population, FG participants had more improvement on the Mental Component Summary (2.9 [95% CI 0.0 to 5.7], p = 0.048 points higher) than UG participants, as well as a greater loss of fat mass (-0.9 kg [95% CI -1.7 to -0.1], p = 0.029). There were no differences between groups in relation to fractures or falls. Hospital admissions were more frequent in UG compared to FG (33 versus 20; the odds ratio based on PP analysis was 0.34 for FG compared to UG). There were 3 deaths in FG and 4 in UG. Main limitations of the study were the physically active control group and assessment of physical activity by means of self-report.

CONCLUSIONS

In this trial, participants allocated to football appeared to have improved hip BMD and fewer hospital admissions. Men who played football more than once a week for 1 year lost fat mass and reported improved mental health. Community-based football proved to be acceptable, even when club membership was not subsidised.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02430792.

Implementation of the FIFA 11+ Injury Prevention Program by High School Athletic Teams Did Not Reduce Lower Extremity Injuries: A Cluster Randomized Controlled Trial

BACKGROUND

Lower extremity injuries are common in high school sports and are costly, and some have poor outcomes. The FIFA 11+ injury prevention program has been shown to decrease injuries in elite athletes by up to 72%.

HYPOTHESIS

High schools in which coaches implement the FIFA 11+ injury prevention program in their athletic programs will have a decreased incidence of lower extremity injuries compared with schools using their usual prepractice warm-up.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

Fourteen high schools that employed an athletic trainer were randomly assigned to either the FIFA 11+ group or control group (usual warm-up routine). Exposure to sports and injuries were recorded and used to determine the incidence rates of lower extremity injuries per athlete-exposure (AE). The FIFA 11+ program was implemented by coaches and complicance with the program recorded.

RESULTS

There were 196 lower extremity injuries among 1825 athletes in the FIFA 11+ group and 172 injuries among 1786 athletes in the control group (1.59 and 1.47 injuries per 1000 AEs, respectively; P = .771). The distribution of the types of injury in the 2 groups did not differ, but the body locations where the injuries occurred differed somewhat (P = .051). The FIFA 11+ group had larger proportions of thigh and foot injuries, while the control group had higher proportions of knee and ankle injuries. Group differences in injury rates varied with sport (P = .041 for interaction), but there were no significant differences in injury rates between the FIFA 11+ and control groups by sport, level of play, and sex. In the FIFA 11+ group, 62% of the coaches reported that their teams completed the full FIFA 11+ program at least once a week, and 32% reported that they completed it at least twice a week.

CONCLUSION

This study did not demonstrate a reduction in lower extremity injuries in schools randomized to use the FIFA 11+ program compared with schools using their usual prepractice warm-up program. Coach-reported compliance with performing the FIFA 11+ program at least twice a week was low.

The effect of short period high-intensity circuit training-modified FIFA 11+ program on physical fitness among young football players

BACKGROUND

Studies showed that FIFA 11+, the football injury prevention program, can improve physical fitness components through resistance and neuromuscular exercise. Currently, resistance training using High Intensity Circuit Training (HICT) is considered beneficial in increasing physical fitness component, including maintaining cardiopulmonary fitness. The purpose of this study was to evaluate the effect of HICT modified- FIFA 11+ training on the physical fitness components and cardiovascular (CV) training intensity of young football players.

METHODS

Thirty-nine football players were recruited by purposive random sampling to the football academies in Yogyakarta, Indonesia. The players were randomized into two groups; 20 players were in the experiment (EXP) group and 19 players were in the control (CON) group. The EXP group performed HICT-modified FIFA 11+ exercise and the CON group performed standard FIFA 11+. HICT modification was performed in the EXP group only in part 2 of FIFA 11+ (strength, power, and balance training) while the other parts were regular. Both groups performed the intervention 3 times per week for 4 weeks. All players completed a pre- and post-intervention physical fitness tests comprising the core strength (plank test), leg strength (leg dynamometer) and agility (Illinois test). Heart rate (HR) was monitored in both groups while exercise was being implemented to measure the CV training intensity. Changes in performance (pre- versus post-intervention) of each group were analyzed using paired t-test and Wilcoxon test. Statistical significance was set to P<0.05. Twelve players dropped out in this research.

RESULTS

This study showed that core strength increased significantly in both groups (P=0.00). The EXP group had higher CV training intensity (HR max 91%; mean HR 74%) than the CON group (HR max 90%; mean HR 66%).

CONCLUSIONS

Results suggest that HICT modified FIFA 11+ can be implemented as an alternative program to increase the physical fitness components and also CV training intensity among young football players.

Adolescent female soccer players' soccer-specific warm-up effects on performance and inter-limb asymmetries

No studies have assessed whether changes in physical performance and inter-limb asymmetries (ILA) can be achieved with the FIFA 11+ prevention programme in adolescent female soccer players. The aim of this study was to assess the effect of the FIFA 11+ programme compared with a standard warm-up on physical performance and ILA in adolescent female soccer players. Thirty-six adolescent female soccer players were randomly assigned to an experimental (EG; n = 19) or a control group (CG; n = 17). Unilateral/bilateral countermovement jump (CMJ), drop jump (DJ) and horizontal jump tests, two different change of direction tests, an ankle dorsiflexion test, the Y-Balance test (YBT) and inter-limb asymmetries were measured before and after 10 weeks of training. The results revealed no significant group-by-time interactions in the vast majority of variables (p>0.05). Paired t-test revealed significant improvements of the right [effect size (ES):0.56] and left (ES:0.49) CMJ, right (ES:0.74) and left (ES:0.54) DJ (ES:0.74), right (ES:1.27) and left (ES:1.26) posteromedial direction and right (ES:0.89) and left (ES:0.84) posterolateral direction in the YBT in the EG (p < 0.05). Right anterior direction in the YBT and V-cut test were significantly improved in both groups (p<0.05). For inter-limb asymmetry variables, no significant group-by-time interactions (ES:0 to 0.93) and an improvement between pre- and post-tests (ES:-0.76 to 0.49) were observed. Therefore, the FIFA 11+ programme led to improved unilateral jumping, dynamic balance and reduced lower extremity symmetries of several tests in adolescent female soccer players.

General versus sports-specific injury prevention programs in athletes: A systematic review on the effects on performance

INTRODUCTION

Injury prevention programs (IPPs) are an inherent part of training in recreational and professional sports. Providing performance-enhancing benefits in addition to injury prevention may help adjust coaches and athletes' attitudes towards implementation of injury prevention into daily routine. Conventional thinking by players and coaches alike seems to suggest that IPPs need to be specific to one's sport to allow for performance enhancement. The systematic literature review aims to firstly determine the IPPs nature of exercises and whether they are specific to the sport or based on general conditioning. Secondly, can they demonstrate whether general, sports-specific or even mixed IPPs improve key performance indicators with the aim to better facilitate long-term implementation of these programs?

METHODS

PubMed and Web of Science were electronically searched throughout March 2018. The inclusion criteria were randomized control trials, publication dates between Jan 2006 and Feb 2018, athletes (11-45 years), injury prevention programs and included predefined performance measures that could be categorized into balance, power, strength, speed/agility and endurance. The methodological quality of included articles was assessed with the Cochrane Collaboration assessment tools.

RESULTS

Of 6619 initial findings, 22 studies met the inclusion criteria. In addition, reference lists unearthed a further 6 studies, making a total of 28. Nine studies used sports specific IPPs, eleven general and eight mixed prevention strategies. Overall, general programs ranged from 29-57% in their effectiveness across performance outcomes. Mixed IPPs improved in 80% balance outcomes but only 20-44% in others. Sports-specific programs led to larger scale improvements in balance (66%), power (83%), strength (75%), and speed/agility (62%).

CONCLUSION

Sports-specific IPPs have the strongest influence on most performance indices based on the significant improvement versus control groups. Other factors such as intensity, technical execution and compliance should be accounted for in future investigations in addition to exercise modality.

Can Backward Sled Towing Potentiate Sprint Performance?

Monaghan, DJ and Cochrane, DJ. Can backward sled towing potentiate sprint performance? J Strength Cond Res 34(2): 345-354, 2020-The objectives of this study were to determine whether backward sled towing can elicit a postactivation potentiation response to enhance forward 5-m sprint performance and to determine whether sled loading through a reduction in velocity can elicit an improvement in 5-m sprint performance. A randomized design was used to examine the effects of forward and backward sled tow loading of 35 and 55% reduction of individual's maximal velocity (rVelmean) on 5-m sprint performance. Eighteen well-trained male subjects performed 4 intervention sessions (55% rVelmean backward; 55% rVelmean forward; 35% rVelmean backward; and 35% rVelmean forward) separated by a minimum of 24 hours. Intervention sessions included baseline unresisted 5-m sprints, followed by 3 loaded sled tows over a distance of 3.2 m or 5 m for heavy and light loads, respectively. An unresisted 5-m sprint was completed after 6 and 12 minutes of rest. Mean sprint velocity, electromyography, sprint kinematic, and temporal data were collected during each session. Sled towing, irrespective of load or rest period, produced no significant change in 5-m sprint velocity (p > 0.05). In addition, there were no significant changes in electromyography, kinetic, and temporal data; however, current findings support previous research of confirming muscle activation and vertical force production during sprint acceleration. It is unclear whether individualizing a reduction in velocity is a superior method to percent body mass for optimizing sled loading in well-trained male subjects.

Inter-rater Reliability in Assessing Exercise Fidelity for the Injury Prevention Exercise Programme Knee Control in Youth Football Players

BACKGROUND

To receive maximum benefits from injury prevention exercise programmes (IPEP) such as Knee Control, players need to perform the exercises as prescribed. But, exercise fidelity in IPEPs is seldom evaluated. We developed a checklist to assess exercise fidelity in the Knee Control IPEP, and the primary aim was to evaluate its inter-rater reliability. The secondary aim was to study Knee Control exercise fidelity in youth football players and compare sex differences.

METHODS

This observational study included 11 teams with male and female youth players (11-18 years). On average, the players trained with the Knee Control IPEP for 7 weeks (SD 1.4, range 6-10 weeks). After the training period, two physiotherapists attended a team training session to observe players executing exercises and individually assessed their performance of these exercises as correct or incorrect based on standardised criteria set in the fidelity checklist. Agreement between observers was assessed using Cohen's kappa coefficient.

RESULTS

The observers agreed on 144 out of 160 (90%) observations (Kappa = 0.80, substantial agreement). Both observers agreed on correct exercise performance for 69 out of 144 observations (exercise fidelity 48%). Exercise fidelity was higher in females (56%) than males (40%), but the difference was not statistically significant (p = 0.18).

CONCLUSION

The Knee Control exercise fidelity checklist had high inter-rater reliability with substantial agreement. The exercise fidelity was low, which could hamper the preventive effects of an IPEP. Understanding the reasons for low exercise fidelity is important and more effort should focus on increasing exercise fidelity alongside the implementation of IPEPs.

Core-Muscle Training and Neuromuscular Control of the Lower Limb and Trunk

CONTEXT

Comprehensive injury-prevention training (plyometric, agility, balance, and core-stability exercises) has been shown to decrease sport-related injury. The relationship between trunk control and sport-related injury has been emphasized; however, the isolated effects of core-muscle training are unclear.

OBJECTIVE

To investigate the effect of a simple 8-week core-muscle-training program on the neuromuscular control of the lower limb and trunk during jump landing and single-legged squatting.

DESIGN

Controlled laboratory study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

Seventeen female collegiate basketball players were randomly divided into training (n = 9; age = 19.7 ± 0.9 years) and control (n = 8; age = 20.3 ± 2.5 years) groups.

INTERVENTION(S)

The training group completed the core-muscle-training program in addition to daily practice, and the control group performed only daily practice. Kinematic and kinetic data during a drop-jump test and single-legged squat were acquired using a 3-dimensional motion-analysis system.

MAIN OUTCOME MEASURE(S)

Three-dimensional hip, knee, and trunk kinematics; knee kinetics; and isokinetic muscle strength were measured at the pretraining and posttraining phases.

RESULTS

For the drop-jump test, the maximal trunk-flexion angle increased (P = .008), and peak knee-valgus moment (P = .008) decreased in the training group. For the single-legged squat, the peak trunk-flexion angle increased (P = .04), and the total amount of trunk lateral-inclination angle (P = .02) and peak knee-valgus moment (P = .008) decreased in the training group. We observed no changes in the control group.

CONCLUSIONS

A consecutive 8-week core-muscle-training program improved lower limb and trunk biomechanics. These altered biomechanical patterns could be favorable to preventing sport-related injuries.

Evidence-Based Best-Practice Guidelines for Preventing Anterior Cruciate Ligament Injuries in Young Female Athletes: A Systematic Review and Meta-analysis

BACKGROUND

Injury prevention neuromuscular training (NMT) programs reduce the risk for anterior cruciate ligament (ACL) injury. However, variation in program characteristics limits the potential to delineate the most effective practices to optimize injury risk reduction.

PURPOSE

To evaluate the common and effective components included in ACL NMT programs and develop an efficient, user-friendly tool to assess the quality of ACL NMT programs.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

Study inclusion required (1) a prospective controlled trial study design, (2) an NMT intervention aimed to reduce incidence of ACL injury, (3) a comparison group, (4) ACL injury incidence, and (5) female participants. The following data were extracted: year of publication, study design, sample size and characteristics, and NMT characteristics including exercise type and number per session, volume, duration, training time, and implementer training. Analysis entailed both univariate subgroup and meta-regression techniques using random-effects models.

RESULTS

Eighteen studies were included in the meta-analyses, with a total of 27,231 participants, 347 sustaining an ACL injury. NMT reduced the risk for ACL injury from 1 in 54 to 1 in 111 (odds ratio [OR], 0.51; 95% CI, 0.37-0.69]). The overall mean training volume was 18.17 hours for the entire NMT (24.1 minutes per session, 2.51 times per week). Interventions targeting middle school or high school-aged athletes reduced injury risk (OR, 0.38; 95% CI, 0.24-0.60) to a greater degree than did interventions for college- or professional-aged athletes (OR, 0.65; 95% CI, 0.48-0.89). All interventions included some form of implementer training. Increased landing stabilization and lower body strength exercises during each session improved prophylactic benefits. A meta-regression model and simple checklist based on the aforementioned effective components (slope = -0.15, P = .0008; intercept = 0.04, P = .51) were developed to allow practitioners to evaluate the potential efficacy of their ACL NMT and optimize injury prevention effects.

CONCLUSION

Considering the aggregated evidence, we recommend that ACL NMT programs target younger athletes and use trained implementers who incorporate lower body strength exercises (ie, Nordic hamstrings, lunges, and heel-calf raises) with a specific focus on landing stabilization (jump/hop and hold) throughout their sport seasons.

CLINICAL RELEVANCE

Clinicians, coaches, athletes, parents, and practitioners can use the developed checklist to gain insight into the quality of their current ACL NMT practices and can use the tool to optimize programming for future ACL NMT to reduce ACL injury risk.

Implementation of the Adductor Strengthening Programme: Players primed for adoption but reluctant to maintain - A cross-sectional study

Groin injuries represent a considerable problem in male football, accounting for 4%‐19% of all time‐loss injuries. The Adductor Strengthening Programme is the first groin‐specific prevention program shown to reduce the risk of groin problems. We aimed to use the RE‐AIM framework to examine the players’ experiences with the implementation of the program and player attitude toward groin injury prevention in football. Of the 632 players involved in the trial examining the effect of the Adductor Strengthening Programme, 501 agreed to participate in a survey at the end of the season. Most players thought that footballers are at moderate to high risk for groin injuries (87%) and that there is a need for preventive measures (96%). They also believed that a preventive program with strengthening exercises would reduce the risk of groin injuries (91%). Majority of the players reported using <5 minutes to complete the program (73%), and only 11% wanted additional exercises. However, only 46% reported to have performed the program as recommended, and an even smaller proportion (31%) planned to continue using it as recommended the next season. Our results suggest that footballers believe that prevention of groin injuries is needed. Attitude toward implementation of the Adductor Strengthening Programme was positive, and the single‐exercise approach was considered an important facilitator. However, in future dissemination of the program, the players’ reluctance to maintain the exercise protocol may be a potential barrier to implementation that should be addressed.

Prevention of Lateral Ankle Sprains

CONTEXT

Given the frequency of ankle sprains, especially in the athletic population, prevention is a primary task of athletic trainers and other sports health care professionals.

OBJECTIVE

To discuss the current evidence as it relates to prophylactic programs for the prevention of ankle sprains and to provide critical interpretation of the evidence supporting and refuting the implementation of preventive programs.

CONCLUSIONS

External prophylactic supports and preventive exercise programs are effective for reducing the risk of ankle sprains in both uninjured and previously injured populations. Ankle bracing appears to offer the best outcomes in terms of cost and risk reduction. However, there remains a paucity of well-designed, prospective randomized controlled trials relevant to the primary prevention of lateral ankle sprains, especially across a range of sport settings.

The effect of the NetballSmart Dynamic Warm-up on physical performance in youth netball players

OBJECTIVES

To investigate the efficacy of the NetballSmart Dynamic Warm-up in improving physical performance measures in New Zealand secondary school netball players.

DESIGN

Cluster randomised controlled trial.

SETTING

A seven-week intervention study in secondary school netball.

PARTICIPANTS

81 youth netball players (Intervention group, n = 45; Control group, n = 36).

MAIN OUTCOME MEASURES

Performance measures included prone hold, change of direction, sprint, vertical and horizontal jump, Y-balance and time-to-stabilisation. Mixed effects models and t-tests were used to determine significant differences of pre and post measures between groups.

RESULTS

Significant improvements in prone hold (β = 20.46 s; p = 0.01) and vertical jump (β = 6.73 cm; p = 0.01) were found in the intervention group compared to the control group, while horizontal jump was found to significantly decrease (β = -9.86 cm; p = 0.03) in comparison to the control group.

CONCLUSIONS

The results of this study show the NetballSmart Dynamic Warm-up can improve some physical performance measures in youth netball players. It is recommended that coaches should consider implementing the warm-up in their netball programmes.

Application of a Preventive Training Program Implementation Framework to Youth Soccer and Basketball Organizations

CONTEXT

Preventive training programs (PTPs) can reduce injury rates and improve neuromuscular control and sport performance. However, PTPs must be implemented correctly and consistently over time for athletes to benefit. Coaches represent the best long-term option for implementing PTPs. Youth athletes are at the optimal age for developing good habits before maturation. Although frameworks have been proposed to guide implementation efforts, little is known regarding the feasibility and real-world context of PTP implementation at the youth sport level.

OBJECTIVE

To evaluate the application of the 7-Step framework for promoting implementation of a preseason PTP workshop.

DESIGN

Descriptive epidemiology study.

SETTING

Youth soccer and basketball organizations.

PATIENTS OR OTHER PARTICIPANTS

Organizations with at least 1 team of athletes aged 8 to 14 years were invited to participate in a free preseason coaches' education workshop on PTP implementation.

INTERVENTION(S)

The 7-Step framework was used to guide PTP education and implementation for each organization. Personnel at organizations that agreed to participate attended a single preseason workshop for coaches. Research staff were available as a resource throughout the season but did not actively implement or monitor the PTPs.

MAIN OUTCOME MEASURE(S)

Retrospective evaluation of each organization's completion of steps 1 through 5 of the 7-Step framework.

RESULTS

A total of 62 youth soccer (n = 40) and basketball (n = 22) organizations were invited to participate. Twelve organizations completed steps 1 through 4 and steps 5a through 5d. The highest drop-off rate occurred during step 1, "Establishing Administrative Support." No organization completed all components of steps 1 through 5.

CONCLUSIONS

To better understand how to successfully promote PTP adoption, we must identify the implementation steps that may present the most challenges. Because the highest drop-off rate was seen during the initial step, establishing administrative support and strengthening initial engagement are necessary to improve PTP implementation.

Effects of Warm-Up, Post-Warm-Up, and Re-Warm-Up Strategies on Explosive Efforts in Team Sports: A Systematic Review

BACKGROUND

In team sports, it is imperative that the warm-up improves acute explosive performance. However, the exact strategies, methods, and consequences of different warm-up practices remain unclear. A time delay between the warm-up and match and during half-time could negate the positive metabolic effects of the warm-up.

OBJECTIVES

We conducted a systematic review to synthesize and analyze the potential effects of strategies during a warm-up (before match), post-warm-up (time between the end of warm-up and the start of a match), and re-warm-up (half-time break within a match) on explosive performance in team sports. Furthermore, we examined optimal warm-up strategies based on the included studies.

METHODS

We performed a search of four databases (Web of Science, Scopus, PubMed, and ScienceDirect) for original research articles published between January 1981 and August 2017. A total of 30 articles met the inclusion criteria, and the Cochrane risk of bias tool was used to assess the risk of bias. The results of the included studies were recalculated to determine effect sizes using Cohen's d.

RESULTS

A warm-up comprising 8 sets of 60-m sprints (- 2.19%, d = 1.20) improved sprint performance. Additionally, 7 min of dynamic exercises after 5 min of jogging improved sprint (- 7.69%, d = 1.72), jumping (8.61%, d = 0.61), and agility performance (- 6.65%, d = 1.40). The use of small-sided games also seems to be a valid strategy, especially for jumping performance (6%, d = 0.8). These benefits resulted from the warm-up strategies combined with some passive rest (between 2 and 10 min) before the main performance. In this post-warm-up period, the use of heated garments could result in better outcomes than simple rest (- 0.89%, d = 0.39). However, if the transition was longer than 15 min, before entering the match, performing a re-warm-up with short-term explosive tasks to reactivate was the most effective approach (- 1.97%, d = - 0.86). At half-time, heated garments maintained better sprint (- 1.45%, d = 2.21) and jumping performance (3.13%, d = 1.62).

CONCLUSION

Applying properly structured strategies in the warm-up and avoiding a long rest in the post-warm-up improves explosive performance. Studies tend to recommend a short active warm-up strategy (10-15 min), gradually increasing intensity (~ 50-90% of maximum heart rate), and the use of heated garments soon after the warm-up to maintain muscle temperature. However, 2 min of active re-warm-up with short-term sprints and jumps should be needed for transitions longer than 15 min (~ 90% of maximum heart rate). Last, at the half-time re-warm-up, combining heated garments to maintain muscle temperature and performing an active strategy, with explosive tasks or small-sided games for 5 min before re-entering the game, resulted in better explosive performance than 15 min of resting.

Desempenho isocinético de atletas de futsal sub-13 após a prática do protocolo Fifa 11+

RESUMO O objetivo deste estudo foi avaliar o desempenho isocinético da musculatura flexora e extensora do joelho de jogadores de futsal sub-13 após a prática de 18 semanas do protocolo Fifa 11+. Participaram 14 jogadores de futsal do sexo masculino com idade média de 12,58±0,66 anos. A avaliação da força foi realizada através do dinamômetro isocinético (Biodex System Pro 4™), nas velocidades de 60°/s, 180°/s e 300°/s, pré e pós-intervenção. O protocolo Fifa 11+ foi aplicado antes do início de cada treino regular, duas vezes por semana, durante 18 semanas, com duração aproximada de 25 minutos. Na análise pré-intervenção foi encontrada uma diferença entre o membro dominante e o não dominante superior a 10% no pico de torque de flexores e extensores a 60°/s e 180°/s, respectivamente. Já na análise pós-intervenção não foram encontradas tais assimetrias. Houve um aumento da relação agonista/antagonista no lado dominante na velocidade de 60°/s, pós-intervenção, aproximando-se do valor ideal proposto pela literatura (de 60%). Houve, ainda, aumento do desempenho isocinético dos atletas após a intervenção. Neste sentido, conclui-se que a aplicação de 18 semanas do protocolo Fifa 11+ promoveu uma melhora do desempenho isocinético das musculaturas extensoras e flexoras de joelho, além de diminuir as assimetrias musculares entre os membros em jovens atletas de futsal.

Including the Nordic hamstring exercise in injury prevention programmes halves the rate of hamstring injuries: a systematic review and meta-analysis of 8459 athletes

Research question

Does the Nordic hamstring exercise (NHE) prevent hamstring injuries when included as part of an injury prevention intervention?

Design

Systematic review and meta-analysis.

Eligibility criteria for selecting studies

We considered the population to be any athletes participating in any sporting activity, the intervention to be the NHE, the comparison to be usual training or other prevention programmes, which did not include the NHE, and the outcome to be the incidence or rate of hamstring injuries.

Analysis

The effect of including the NHE in injury prevention programmes compared with controls on hamstring injuries was assessed in 15 studies that reported the incidence across different sports and age groups in both women and men.

Data sources

MEDLINE via PubMed, CINAHL via Ebsco, and OpenGrey.

Results

There is a reduction in the overall injury risk ratio of 0.49 (95% CI 0.32 to 0.74, p=0.0008) in favour of programmes including the NHE. Secondary analyses when pooling the eight randomised control studies demonstrated a small increase in the overall injury risk ratio 0.52 (95% CI 0.32 to 0.85, p=0.0008), still in favour of the NHE. Additionally, when studies with a high risk of bias were removed (n=8), there is an increase of 0.06 in the risk ratio to 0.55 (95% CI 0.34 to 0.89, p=0.006).

Conclusions

Programmes that include the NHE reduce hamstring injuries by up to 51%. The NHE essentially halves the rate of hamstring injuries across multiple sports in different athletes.

Trial registration number

PROSPERO CRD42018106150.

Current trends in sport injury prevention

Participation in sport and recreation has important positive implications for public health across the lifespan; however, the burden of sport-related musculoskeletal injury is significant, with the greatest risk being in youth and young adults. Moving upstream to primary prevention of injury is a public health priority that will have significant implications for reducing the long-term consequences of musculoskeletal injury including early post-traumatic osteoarthritis. The primary targets for the prevention of musculoskeletal injury in sport include neuromuscular training (NMT), rule modification, and equipment recommendations. Currently, there is significant high-quality evidence to support the widespread use of NMT warm up programs in team and youth sport, with an expected significant impact of reducing the risk of musculoskeletal injury by over 35%. Policy disallowing body checking in youth ice hockey has led to a >50% reduction in injuries, and rules limiting contact practice in youth American football has significant potential for injury prevention. There is evidence to support the use of bracing and taping in elite sport to reduce the risk of recurrent ankle sprain injury but not for use to prevent the primary injury, and wrist guards are protective of sprain injuries in snowboarding. Future research examining the maintenance of NMT programs across real-world sport and school settings, optimization of adherence, additional benefit of workload modification, and evaluation of rule changes in other sports is needed.

Effects of a multifactorial injuries prevention program in young Spanish football players

BACKGROUND

The high injury rate in football has highlighted the need to research strategies that allow the modification of the dynamic risk factors. Most of the preventive proposals have focused on standardized protocols. However, the aim of this study was to evaluate the effect of a multifactorial injuries prevention program (MC-7) in Spanish football players.

METHODS

A total of 219 Spanish football male players aged 16-23 were enrolled. The study was conducted over two consecutive seasons (2012-2013, 2013-2014). The first season was the control season (SC) and the second one was the experimental season (ES). Injuries were recorded prospectively during the two seasons in accordance with the criteria established by the consensus statement. During CS the injuries were just observed, while during ES, the players participated in the MC-7: training methodology, specific warm-up protocol (FIFA 11+), basic injury recovery strategies, continuous training of coaches, conferences for parents/family and education sessions for players.

RESULTS

The frequency of injuries was significantly reduced by 63.8% in the ES. Muscle-tendon and joint injuries were reduced by 65% and 56.7% respectively, with a significant decrease in the lower-limbs injuries. The incidence of injuries was reduced by 71.4%, with significant differences in the typology, location and severity of injuries.

CONCLUSIONS

The rate of injury in football is reduced when multifactorial strategies are applied. Reducing the frequency and severity of injuries allowed players to greatly increase their available for sports practice.

Limb Differences in Unipedal Balance Performance in Young Male Soccer Players with Different Ages

In soccer, the dominant leg is frequently used for passing and kicking while standing on the non-dominant leg. Consequently, postural control in the standing leg might be superior compared to the kicking leg and is further enhanced with increasing age (i.e., level of playing experience). Unfortunately, leg differences in postural control are associated with an increased risk of injuries. Thus, we examined differences between limbs in unipedal balance performance in young soccer players at different ages. Performance in the Lower Quarter Y Balance Test (YBT-LQ) of the dominant and non-dominant leg and anthropometry was assessed in 76 young male soccer players (under-13 years [U13]: n = 19, U15: n = 14, U17: n = 21, U19: n = 22). Maximal reach distances (% leg length) and the composite scores were used for further analyses. Statistical analyses yielded no statistically significant main effects of leg or significant Leg × Age interactions, irrespective of the measure investigated. However, limb differences in the anterior reach direction were above the proposed cut-off value of >4 cm, which is indicative of increased injury risk. Further, statistically significant main effects of age were found for all investigated parameters, indicating larger reach distances in older (U19) compared to younger (U13) players (except for U15 players). Although reach differences between legs were non-significant, the value in the anterior reach direction was higher than the cut-off value of >4 cm in all age groups. This is indicative of an increased injury risk, and thus injury prevention programs should be part of the training of young soccer players.

Efficacy of FIFA 11+ training program on functional performance in amateur male soccer players

BACKGROUND

The FIFA-Medical and Assessment Research Centre developed FIFA 11+ program as a warm-up program for soccer players. Although the FIFA 11+ program is a well-established warm-up protocol for injury prevention among soccer players, the program's performance enhancement aspect is not frequently discussed in the literature.

OBJECTIVE

To investigate the effects of the FIFA 11+ training program on functional performance in amateur male soccer players.

METHODS

The study included 57 amateur male soccer players from Jamia Hamdard University, who were randomly placed in an experimental group (n= 29) or a control group (n= 28). The experimental group underwent the FIFA 11+ training program for 12 weeks (five times per week) and the control group continued their regular training. The study adopted a pretest-posttest design. The outcome measurements included the following tests: vertical jump, 20-yard sprint run, Illinois agility run test, and t-tests.

RESULTS

Vertical jump and sprint speed were significantly improved in the FIFA 11+ program group compared to the control group (p< 0.05). No statistically significant difference in agility parameters (p> 0.05) was found between the groups.

CONCLUSION

The results show that the FIFA 11+ program may improve the performance of young amateur soccer players. This study may serve as the foundation for further studies with larger participant numbers.

Specific interventions for prevention of muscle injury in lower limbs: systematic review and meta-analysis

Abstract Introduction: Muscle injuries show an incidence associated with extreme stretching, or even a high-intensity eccentric contraction. Such injuries cause severe damage to athletes, including lower performance, withdrawal, and psychological distress. In this scenario, the study of effective preventive methods is an indispensable factor in the routine of professional athletes, to reduce the incidence of injuries. Objective: To verify the effectiveness of three different interventions (warm-up, neuromuscular training, and eccentric exercise) to prevent muscle injuries in the lower limbs. Method: We searched the Cochrane Library, EMBASE, SPORTDiscus, PEDro, and PubMed databases from the earliest records until January 20, 2018. The search was performed from word combinations such as clinical trial, muscle strain, injury prevention. The data related to the outcome of prevention were grouped in meta-analysis and described in Risk Ratio (RR) with 95% confidence interval. Results: Sixteen studies were included: five assessed eccentric exercise, three investigated neuromuscular training, and eight observed warm-up. The eccentric exercise (RR = 3.49, 95% CI 2.36, 5.16, p < 0.00001) and the neuromuscular training (RR = 2.73, 95% CI 2.03, 2.68, p < 0.00001) showed significant effects on the prevention of muscle injuries in lower limbs. On the other hand, warm-up (RR = 1.57, 95% CI 0.92, 2.7, p = 0.10) was irrelevant in reducing the incidence of injuries in the body segment investigated. Conclusion: The outcomes presented provide clinical relevance inherent in the field practices, with intrinsic potential for practical application in the management of specific preventive techniques.

Physical Fitness and Body Composition in 10-12-Year-Old Danish Children in Relation to Leisure-Time Club-Based Sporting Activities

This study investigated whether the physical fitness and body composition of 10–12-year-old Danish children are related to participation in leisure-time club-based sporting activities. The study involved 544 Danish 10–12-year-old 5th-grade municipal schoolchildren (269 boys and 275 girls, 11.1 ± 0.4 years). After answering a questionnaire about leisure-time sporting activities, the children were divided into four groups: football club participation (FC; n=141), other ball games (OBG; n=42), other sports (OS; n=194), and no sports-club participation (NSC; n=167). The children completed a battery of health and fitness tests, including a 20 m sprint test, a standing long-jump test, the Yo-Yo IR1 children's test (YYIR1C), and body composition, blood pressure, resting heart rate (HR_rest), and the flamingo balance test. The children engaged in club-based ball games (FC and OBG) had higher (p<0.05) lean body mass than NSC (FC: 17.5 ± 2.9; OBG: 18.4 ± 2.6; OS: 16.7 ± 2.9; NSC: 16.4 ± 2.8 kg), performed better (p<0.05) in the YYIR1C test (FC: 1083 ± 527; OBG: 968 ± 448; OS: 776 ± 398; NSC: 687 ± 378 m), and had lower (p<0.05) %HR_max after 1, 2, and 3 min of YYIR1C. Moreover, HR_rest was lower (p<0.05) for FC than for OS and NSC (FC: 68 ± 9 vs OS: 72 ± 10 and NSC: 75 ± 10 bpm), and lower (p<0.05) for OBG than for NSC (OBG: 70 ± 10 vs NSC: 75 ± 10 bpm). This study found that 10–12-year-old Danish children engaged in club-based football and other ball games had better exercise capacity, lower resting heart rate, and higher muscle mass than children not engaged in leisure-time sports. Thus, participation in club-based leisure-time ball-game activities seems to be of importance for the fitness and health profile of prepubertal children.

Female athletes: managing risk and maximizing benefit

PURPOSE OF REVIEW

The purpose of this review is to provide an updated summary on the unique aspects of caring for female youth and adolescent athletes.

RECENT FINDINGS

Recent research on female athletes has led to a better understanding of injuries and conditions that are more likely to occur in female youth and adolescent athletes, including the frequency and severity of concussions, musculoskeletal injury such as involving the anterior cruciate ligament, and the female athlete triad. Social factors, such as the growing pressure to specialize in a sport particularly at an early age, also put young female athletes at risk for issues such as overuse injuries. Researchers continue to explore the benefits of athletic participation that extend beyond physical fitness.

SUMMARY

Female participation in youth sports has increased dramatically during the past 50 years. This has led to greater research on how to manage risks and maximize benefits for young female athletes, although there is still much to be learned. Providers should educate patients, parents, and coaches on both the increased risks for female athletes and ways to provide better support and accessibility of youth sports to all children.

A New Direction to Athletic Performance: Understanding the Acute and Longitudinal Responses to Backward Running

Backward running (BR) is a form of locomotion that occurs in short bursts during many overground field and court sports. It has also traditionally been used in clinical settings as a method to rehabilitate lower body injuries. Comparisons between BR and forward running (FR) have led to the discovery that both may be generated by the same neural circuitry. Comparisons of the acute responses to FR reveal that BR is characterised by a smaller ratio of braking to propulsive forces, increased step frequency, decreased step length, increased muscle activity and reliance on isometric and concentric muscle actions. These biomechanical differences have been critical in informing recent scientific explorations which have discovered that BR can be used as a method for reducing injury and improving a variety of physical attributes deemed advantageous to sports performance. This includes improved lower body strength and power, decreased injury prevalence and improvements in change of direction performance following BR training. The current findings from research help improve our understanding of BR biomechanics and provide evidence which supports BR as a useful method to improve athlete performance. However, further acute and longitudinal research is needed to better understand the utility of BR in athletic performance programs.

A Multinational Cluster Randomised Controlled Trial to Assess the Efficacy of '11+ Kids': A Warm-Up Programme to Prevent Injuries in Children's Football

Objective

The objective of this study was to assess the efficacy of a newly developed warm-up programme (‘11+ Kids’) regarding its potential to reduce injuries in children’s football.

Methods

Children’s football teams (under 9 years, under 11 years, and under 13 years age groups) from Switzerland, Germany, the Czech Republic and the Netherlands were invited. Clubs were randomised to an intervention group and a control group, and followed for one season. The intervention group replaced their usual warm-up by ‘11+ Kids’, while the control group warmed up as usual. The primary outcome was the overall risk of football-related injuries. Secondary outcomes were the risks of severe and lower extremity injuries. We calculated hazard ratios using extended Cox models, and performed a compliance analysis.

Results

In total, 292,749 h of football exposure of 3895 players were recorded. The mean age of players was 10.8 (standard deviation 1.4) years. During the study period, 374 (intervention group = 139; control group = 235) injuries occurred. The overall injury rate in the intervention group was reduced by 48% compared with the control group (hazard ratio 0.52; 95% confidence interval 0.32–0.86). Severe (74% reduction, hazard ratio 0.26; 95% confidence interval 0.10–0.64) and lower extremity injuries (55% reduction, hazard ratio 0.45; 95% confidence interval 0.24–0.84) were also reduced. Injury incidence decreased with increasing compliance.

Conclusion

‘11+ Kids’ is efficacious in reducing injuries in children’s football. We observed considerable effects for overall, severe and lower extremity injuries. The programme should be performed at least once per week to profit from an injury preventive effect. However, two sessions per week can be recommended to further increase the protective benefit.

Trial Registration

ClinicalTrials.gov identifier: NCT02222025.

Electronic supplementary material

The online version of this article (10.1007/s40279-017-0834-8) contains supplementary material, which is available to authorized users.

The "FIFA 11+" injury prevention program improves body stability in child (10 year old) soccer players

The suitability of the FIFA 11+ prevention programme to improve selected performance outcomes in children aged < 14 years has not been established yet. This study aimed to investigate the effects of the FIFA 11+ programme on jump ability and stability in 10-year-old child soccer players. Sixteen young soccer players (aged 10 years) were randomly assigned to a conventional or a FIFA 11+ warm-up group. During a 5-week training period with 2 sessions per week the FIFA 11+ group warmed up with the 11+ programme, whereas the control group subjects performed their usual warm-up programme (e.g. running exercises with dribbling and/or passing techniques included). After the warm-up, both groups performed the same training exercises during each session. Before and after the training period, standing long jump performance and body stability (S3 Check, unstable uniaxial platform) were assessed. Significant improvements in the stability index were found in both groups (5.6±1.1 to 3.5±1.0 and 5.5±0.8 to 4.0±1.5 for the FIFA 11+ and the control group, respectively, p<0.001, partial η²=0.886 for the training effect of the analysis of variance) with likely (qualitative inference analysis) greater improvements in the FIFA 11+ group compared to the control group (p=0.078, partial η²=0.205 for the training x group interaction effect of the analysis of variance). Training had no effect on standing long jump performance (p>0.05). Data indicate that in 10-year-old soccer players the FIFA 11+ programme may have the potential to improve stability. Thus, the FIFA 11+ programme might contribute to injury prevention and possibly to better soccer performance as well. This might especially apply if the programme is performed over a longer period and/or with more weekly training sessions. Based on the present results the inclusion of such a programme within the training practice of the child soccer player can be recommended.