Performance aspects of an injury prevention program: a ten-week intervention in adolescent female football players

Injury Prevention Programmes Fail to Change Most Lower Limb Kinematics and Kinetics in Female Team Field and Court Sports: A Systematic Review and Meta-Analysis of Randomised Controlled Trials

BACKGROUND

One mechanism by which exercise interventions may be effective in reducing anterior cruciate ligament (ACL) injury risk is through changes in lower limb biomechanics. Understanding how training programmes affect lower-limb kinematics and kinetics may help refine injury prevention programmes.

OBJECTIVE

The aim of this systematic review and meta-analysis was to assess the effect of injury prevention programmes on kinematics and kinetics during tasks related to ACL injury in female team field and court sports.

DATA SOURCES

Five databases were searched in October 2022.

ELIGIBILITY CRITERIA

Randomised controlled trials assessing the effect of injury prevention programmes compared with usual training/no training on lower limb kinematics and kinetics in female team field and court sports were eligible for review.

RESULTS

Sixteen studies were included. A total of 976 female athletes were included. Most of the studies included interventions with multiple components (12/16). Commonly used components were plyometrics (12/16), strength (8/16), and balance/stability (7/16). Thirteen studies had routine training or sham interventions as the control group and three studies had no training. Very low certainty evidence suggests that injury prevention programmes increase knee flexion angles (mean difference = 3.1° [95% confidence interval 0.8-5.5]); however, very low to low certainty evidence suggests no effect on hip flexion angles/moments, knee flexion moments, hip adduction angles/moments, knee adduction angles/moments, hip internal rotation angles/moments, ankle dorsiflexion angles, and ground reaction forces, compared with usual training/no training.

CONCLUSION

Injury prevention programmes may be effective in increasing knee flexion angles during dynamic landing and cutting tasks but may have no effect on other lower limb biomechanical variables. As such, the benefits of injury prevention programmes may be mediated by factors other than altered biomechanics and/or may happen through other biomechanical measures not included in this review.

Effectiveness of a specific strength program of the gluteus maximus muscle to improve dynamic postural control in female basketball players. A randomized controlled trial

BACKGROUND

Basketball is a team sport in which players perform multidirectional movements, jumps and landings, experiencing abrupt accelerations and decelerations and numerous changes of rhythm. In this sport, speed and intensity are two key factors that are associated with an increased risk of injury. The aim of this randomized controlled trial was to determine the effectiveness of a specific gluteus maximus strength programme as preventive work for young female basketball players, to improve dynamic postural stability and to observe its impact in the rate of lower limb injuries, vertical jump, dynamic knee valgus and pain.

RESEARCH QUESTION

Is effective a strength programme to improve dynamic postural stability, vertical jump and dynamic valgus in female basketball players?

METHODS

A hundred and thirteen female basketball players that play in professional clubs were recruited, reaching the final stage 92 (46 per group). One group (CG) received conventional injury prevention training while the experimental group (EG) added to the conventional team prevention program, a gluteus maximus strength programme of 5 months composed of 4 exercises/2 days per week/2 sets of 10 repetitions per leg.

RESULTS

The total injury incidence decreased from 0.33 to 0.16 cases (control group pre=0.43 to post=0.14 cases, EG pre=022 to post=0.19). The EG improved overall (p = 0.000), posterior (p = 0.001), posteromedial (p = 0.001) and posterolateral (p = 0.000) dynamic stability of the right leg; anterior (p = 0.024), medial (p = 0.07) and posteromedial (p = 0.01) of the left leg. Both groups improved vertical jump (GC: p = 0.045 and GE: p = 0.000). There was no significant improvement in pain or valgus.

SIGNIFICANCE

This strength programme is effective in improving dynamic stability especially of the dominant leg and jump height.

The efficacy of neuromuscular training, with minimal or no equipment, on performance of youth athletes: A systematic review with meta-analysis

OBJECTIVES

To investigate the effects of neuromuscular training, with minimal or no equipment, on physical performance of youth athletes.

DESIGN

Systematic review with meta-analysis.

METHODS

MEDLINE, EMBASE, CENTRAL, CINAHL, PEDro and SportDiscuss from inception to March/2022.

SELECTION CRITERIA

youth athletes (15-24years), from Olympic team sports; used neuromuscular training 2-3 times/week for, at least, 6 weeks; had a control group/usual training group; physical performance as outcomes; randomized controlled trial.

DATA SYNTHESIS

Pooled estimate of standardized mean difference (SMD), and 95% confidence interval (95%CI).

RESULTS

Thirty-four studies (1111 participants) were included. Results showed that neuromuscular training improved power (SMD: 0.84 [95%CI: 0.58, 1.10]; n = 805; I2 = 64%), speed (SMD: -1.12 [95%CI: -1.68, -0.57]; n = 688; I2 = 90%) and agility (SMD: -1.21 [95%CI: -1.60, -0.83]; n = 571; I2 = 76%) compared to control group, but showed no difference between groups for muscle strength (Quadriceps SMD: 0.34 [95%CI: -0.02, 0.69]; n = 132; I2 = 0%, Hamstrings: SMD: 0.64 [95%CI: -0.04, 1.33]; n = 132; I2 = 71%), balance and flexibility.

CONCLUSION

Clinically, neuromuscular training with minimal equipment may be useful for teams with limited resources to improve mainly athletes' power and agility, including those interventions that were designed to injury prevention. Future high-quality studies are likely to change these estimates.

Knee flexor muscle fatigue during repeated Nordic hamstring exercise

BACKGROUND

Nordic hamstring exercise is an effective method for preventing hamstring strain injury. In this study, we investigated the response of knee flexors regarding increased muscle force and fatigue when the Nordic hamstring exercise was performed repeatedly to further understand how it can prevent hamstring strain injury.

METHODS

The Nordic hamstring exercise was performed 10 times by 53 athletes; knee flexor peak tensile force and the respective flexion angle were compared at different phases during this sequence: phase 1, 1st Nordic hamstring exercise force; phase 2, mean value during the 2-4th repetitions; phase 3, mean value during the 5-7th repetitions; and phase 4, mean value during the 8-10th repetitions. We also divided the knee flexor peak force into deep and slight flexion zones and evaluated changes during different phases.

RESULTS

Knee flexor peak force was most significant in phase 2 and decreased during subsequent phases. The knee angle at which peak force was exerted was greatest in phase 1 and decreased thereafter. When we compared the knee flexor peak force in different flexion angle zones, increased muscle force in the slight flexion zone was greater than increased muscle force in the deep flexion zone in phases 2 and 3.

CONCLUSIONS

Enhancement of the knee flexor force, especially in the slight flexion zone occurs after only a few repetitions of the Nordic hamstring exercise.

Effects of Multicomponent Injury Prevention Programs on Children and Adolescents' Fundamental Movement Skills: A Systematic Review With Meta-Analyses

OBJECTIVE

Fundamental movement skills (FMS) are essential to participate in physical activity. Understanding the effects of multicomponent injury prevention programs (MIPP) on FMS may help promote safe physical activity. Our objective was to synthesize the evidence on the effects of MIPP on biomechanical outcomes and neuromuscular performance measured on children and adolescents while performing FMS.

DATA SOURCE

We searched PubMed, SPORTDiscus, Web of Science, and SCOPUS.

STUDY INCLUSION AND EXCLUSION CRITERIA

We included peer-reviewed randomized controlled trials, published in English, that analyzed the effects of MIPP on biomechanics and neuromuscular performance of FMS in participants under 18 years of age.

DATA EXTRACTION

Two reviewers screened the articles, assessed the quality of the evidence using the Physiotherapy Evidence Database (PEDro) scale, and synthesized the data.

DATA SYNTHESIS

We conducted meta-analyses and reported the characteristics, outcomes, and risk of bias of studies.

RESULTS

We included 27 articles that reported data from 1,427 participants. Positive effects on FMS were reported in 23 of the 27 included articles. Vertical Jump, running speed, acceleration, and dynamic balance presented positive-significant pooled effect sizes. Dribbling and horizontal jump presented non-significant pooled effect sizes.

CONCLUSION

MIPP can positively affect FMS in children and adolescents in sports-related settings. Lack of participant compliance and implementation fidelity may affect MIPP effectiveness. Including MIPP in physical literacy interventions, physical education classes, and organized physical activity may lead to functional adaptations that help promote safe physical activity.

A Controlled Trial of the Effects of Neuromuscular Training on Physical Performance in Male and Female High School Athletes

BACKGROUND

Neuromuscular training (NMT) has demonstrated efficacy as an intervention to decrease the risk of anterior cruciate ligament injuries and improve sports performance. The effect of this training on the mechanisms that contribute to improved physical performance has not been well defined.

HYPOTHESIS

Athletes in the NMT group will have better mechanisms of fundamental movements and agility tests that may contribute to improved sports performance.

STUDY DESIGN

Prospective cohort study.

LEVEL OF EVIDENCE

Level 2.

METHODS

Eight high school teams (111 athletes, 53% male, mean age 16 years) participated, with half performing NMT. Physical performance was measured using the dorsaVi ViPerform system, a US Food and Drug Administration-cleared wireless sensor system. Agility was assessed using a timed 3-cone test. Independent sample t tests were used to compare differences between the intervention and control groups.

RESULTS

Matched pre- and postseason data were collected from 74 athletes after excluding athletes with injury and those lost to follow-up. Significant improvements were observed in the NMT group for loading/landing speed ratios during a single-leg hop test (right lower extremity = -0.19 [-0.37, 0.03], P = 0.03 and left lower extremity = -0.27 [-0.50, -0.03], P = 0.03). The control group had lower ground reaction forces compared with the NMT group (P < 0.02), while significant improvements were found in the NMT group for initial peak acceleration (P < 0.02) and cadence (P = 0.01) during a straight-line acceleration/deceleration test. For the 3-cone agility test, the postseason time decreased compared with preseason in the NMT group, whereas the time for the control group increased (-0.37 s vs 0.14 s, P < 0.00).

CONCLUSION

The results demonstrate that NMT administered by sports medicine clinicians can significantly improve some physical performance of fundamental movements in high school athletes.

CLINICAL RELEVANCE

Coaches should be trained to effectively deliver NMT in order to improve sports performance.

Effects of FIFA 11 + warm-up program on kinematics and proprioception in adolescent soccer players: a parallel‑group randomized control trial

This study aimed to compare the effects of 8 weeks 11 + warm-up injury prevention program on kinematics and proprioception in adolescent male and female soccer players. Forty adolescent soccer players (20 males, 20 females) aged between 14-16 years old were randomly assigned into four groups. The experimental group performed the 11 + program for 8 weeks and the control group did their warm-up program. The kinematic variable in a cutting maneuver was measured using VICON motion analysis and ankle and knees' proprioception by joint position sense (JPS) was measured using a digital inclinometer. For kinematic variables only significant differences in knee valgus among females 11 + compared with female and male control groups were found (P < 0.05). Moreover, there were significant improvements in joint position sense variables in 11 + groups compared to control groups (P < 0.05). In conclusion, the 11 + program was proven to be a useful warm-up protocol in improving knee valgus and JPS among female and male adolescent soccer players. We suggest adding more training elements to the 11 + program that aimed to enhance the proper alignment of lower extremities which may consequently improve joint kinematics.

A Systematic Review of Flywheel Training Effectiveness and Application on Sport Specific Performances

The objective of this systematic review was to examine the effectiveness of flywheel training, which allows for the replication of specific sports movements, overloading both the concentric and eccentric phases. Inclusion criteria were injury prevention outcomes; ability in terms of strength, power, sprinting, jumping and change of direction; competitive athletes; and RCTs. Exclusion criteria were a lack of a control group and lack of baseline and/or follow-up data. The databases used were Web of Science, Scopus, PubMed, Cochrane Library, and Sage. The revised Cochrane risk-of-bias tool was used to assess the quality of the selected RCTs. The Oxford Centre for Evidence-Based Medicine 2011 Levels of Evidence was used. A PICOS (participants, intervention, comparators, study outcomes, and study design) approach was used to evaluate eligibility. A total of 21 RCTs with 8 to 54 participants in each study analyzed flywheel technology and its application in nine sports. The results showed that flywheel training is a good strategy to improve sports performance, providing variation in training methodologies and athletes’ adherence. Further studies are needed to define guidelines on training modality, weekly frequency, volume, and inertia load. Only a few studies have applied the flywheel device directly to overload specific multidirectional movements at different joint angles. This method is not exempt from criticalities, such as the cost and the ability to carry out only individual training.

[Importance and application of injury prevention in Austrian football - a survey among 687 coaches]

BACKGROUND

Soccer is one of the most popular sports in the world but associated with a high risk of injury. For this reason, the study of the etiology of injuries is of great interest and numerous prevention programs have been developed in recent years. Since these prevention programs must be embedded into training routine, trainers are primarily responsible for their implementation. The present study aimed to survey Austrian soccer coaches engaged in professional, amateur or youth teams with respect to their opinions on injuries as well as the application of respective prevention programs.

METHODS

An online questionnaire was developed and sent to all coaches registered in the Austrian Football Association.In addition to personal data, the trainers' attitudes to the subject of injury prevention were also asked. It was also asked which preventive measures the trainers consider important and which they also use in their training and to what extent.

RESULTS

A total of 687 trainers took part in the survey. 2,3%, 37,5% and 43,6% of trainers were engaged in professional, amateur and youth clubs, respectively. The rest gave no information. The majority of respondents (56%) considered injuries a major concern in soccer. Inadequate fitness (75,7%) as well as insufficient preparation (60,7%) and poor regeneration (59,2%) were seen as the greatest risk factors for injuries. Appropriate warm-up (66,8%), regeneration (59,4%) and core stabilization training (58,2%) were considered the most effective preventative measures. More than 50% of the participants were not familiar with any of the most widely applied injury prevention programs, and only 15.4% actually implemented those programs in their training.The substantial interest in injury prevention notwithstanding, the respective standard of knowledge amongst Austrian coaches is poor. In light of the high prevalence of injuries, it is most important to inform trainers about injury prevention programs and possibilities to implement them in training practice.

Quo Vadis Nordic Hamstring Exercise-Related Research?-A Scoping Review Revealing the Need for Improved Methodology and Reporting

The objective of this scoping review is to assess Nordic Hamstring Exercise quality (ANHEQ) of assessments and interventions according to the ANHEQ rating scales and to present practical recommendations for the expedient design and reporting of future studies. A total of 71 Nordic Hamstring Exercise (NHE) assessments and 83 NHE interventions were selected from the data sources PubMed, Scopus, and SPORTDiscus. Research studies which were presented in peer-reviewed academic journals and implemented the NHE during laboratory-based assessments or multi-week interventions met the eligibility criteria. NHE assessments analyzed force (51%), muscle activation (41%), knee angle kinematics (38%), and bilateral symmetry (37%). NHE interventions lasted 4-8 weeks (56%) and implied an exercise volume of two sessions per week (66%) with two sets per session (41%) and ≥8 repetitions per set (39%). The total ANHEQ scores of the included NHE assessments and interventions were 5.0 ± 2.0 and 2.0 ± 2.0 (median ± interquartile range), respectively. The largest deficits became apparent for consequences of impaired technique (87% 0-point-scores for assessments) and kneeling height (94% 0-point-scores for interventions). The 0-point-scores were generally higher for interventions compared to assessments for rigid fixation (87% vs. 34%), knee position (83% vs. 48%), kneeling height (94% vs. 63%), and separate familiarization (75% vs. 61%). The single ANHEQ criteria, which received the highest score most frequently, were rigid fixation (66% of assessments) and compliance (33% of interventions). The quality of NHE assessments and interventions was generally 'below average' or rather 'poor'. Both NHE assessments and interventions suffered from imprecise reporting or lacking information regarding NHE execution modalities and subsequent analyses. Based on the findings, this scoping review aggregates practical guidelines how to improve the design and reporting of future NHE-related research.

Exercise-Based Training Strategies to Reduce the Incidence or Mitigate the Risk Factors of Anterior Cruciate Ligament Injury in Adult Football (Soccer) Players: A Systematic Review

Anterior cruciate ligament (ACL) is one of the most concerning injuries for football players. The aim of this review is to investigate the effects of exercise-based interventions targeting at reducing ACL injury rate or mitigating risk factors of ACL injury in adult football players. Following PRISMA guidelines, a systematic search was conducted in CINAHL, Cochrane Library, PubMed, Scopus, SPORTDiscus and Web of Science. Studies assessing the effect of exercise-based interventions in ACL injury incidence or modifiable risk factors in adult football players were included. 29 studies evaluating 4502 male and 1589 female players were included (15 RCT, 8 NRCT, 6 single-arm): 14 included warm-up, 7 resistance training, 4 mixed training, 3 balance, 1 core stability and 1 technique modification interventions. 6 out of 29 studies investigated the effect of interventions on ACL injury incidence, while the remaining 23 investigated their effect on risk factors. Only 21% and 13% studies evaluating risk of injury variables reported reliability measures and/or smallest worthwhile change data. Warm-up, core stability, balance and technique modification appear effective and feasible interventions to be included in football teams. However, the use of more ecologically valid tests and individually tailored interventions targeting specific ACL injury mechanisms are required.

Influence of 2D:4D ratio on fitness parameters and accumulated training load in elite youth soccer players

BACKGROUND

Digit ratio (2D:4D) characterized by the length of the second digit (2D) divided by the length of the fourth digit (4D), is a powerful marker of athletic performance. Some studies showed a negative correlation between 2D:4D ratio and sports performances.

OBJECTIVES

The purpose of the present study was three-fold: (1) to analyze the influence of anthropometric and 2D:4D ratio on variations of accumulated training load (ATL) and fitness parameters: maximal oxygen uptake (V̇O_2max), countermovement jump (CMJ), isometric muscular strength of the knee extensor for hamstring (ISH) and flexor for quadriceps (ISQ) muscles; along three stages of evaluation of soccer players based on playing positions; (2) to analyze the correlations between 2D:4D ratio and aforementioned parameters; and (3) to investigate if variance in fitness levels and ATL can explain the 2D:4D ratio.

METHODS

Twenty-four elite players under 17 years were daily monitored for their rating perceived exertion and ATL across 24 weeks over the season. Soccer players have also measured in three stages for anthropometric traits and fitness parameters.

RESULTS

Significant differences were observed between playing positions for body mass, goalkeepers had higher body mass compared to centre-midfielder and winger players. Moreover, there were significant differences in ATL between early-season to mid-season in goalkeepers (P = 0.032). The 2D:4D ratio (left and right) shown largely and negatively association with muscular strength (ISQ: r =  - 0.80; r =  - 0.78, P ≤ 0.001, ISH: r =  - 0.63; r =  - 0.62, P = 0.001, respectively) and VO_2max changes (r =  - 0.55, P = 0.005; r =  - 0.50, P = 0.013, respectively); lastly, both 2D:4D ratio significantly predicted changes in muscular strength and VO_2max in young soccer players.

CONCLUSIONS

Goalkeepers tended to have higher body mass compared to centre-midfielder and winger players; and 2D:4D ratio revealed a mighty predictor of physical fitness changes in soccer players. Evidence should be helpful to professionals to highlight the usefulness of the 2D:4D into the identification of talent, but also to optimize young players' performance.

Association Between Endocrine Markers, Accumulated Workload, and Fitness Parameters During a Season in Elite Young Soccer Players

The purpose of this study was to analyze differences between endocrine markers in soccer players, based on playing positions, and correlations between endocrine markers (testosterone, cortisol, growth hormone, and insulin-like growth factor-1), with accumulated workload training and fitness parameters [maximal oxygen uptake (VO2max), countermovement jump (CMJ), and isometric maximal strength (1-RM) of the knee for hamstring (ISH) and quadriceps (ISQ) muscles] during early-, mid-, and end-seasons. Twenty-four elite soccer players under 17 participated in this study. The results showed that there was no difference between levels of the endocrine markers among the different positions of the players. Significant correlations were observed between endocrines parameters and fitness performance (ISQ, ISH, VO2max, and CMJ). Regression analysis showed that 1-RM and VO2max were the best predictors of endocrine markers. These findings demonstrated that the activity profiles of youth soccer players were not influenced by endocrine markers. Also, it may be assumed that endocrines levels can be used to better explain the physical capacities of this population. Finally, endocrines markers may help to predict changes in 1-RM and VO2max.

The Protective Effect of Neuromuscular Training on the Medial Tibial Stress Syndrome in Youth Female Track-and-Field Athletes: A Clinical Trial and Cohort Study

CONTEXT

Few reports have analyzed the effects of neuromuscular (NM) training programs on the injury incidence among youth female track-and-field athletes.

OBJECTIVE

To determine the effects of NM training on reducing lower limb injury incidence and to establish its effects on countermovement jump performance, balance, 30-m sprint, and joint position sense in youth female track-and-field athletes.

DESIGN

Single-blind, randomized controlled clinical trial.

SETTING

Sports research laboratory.

PARTICIPANTS

Twenty-two female athletes were allocated into 2 groups: Conventional (CONV) training (n = 11; age = 15.3 [2.1] y) and NM training (n = 11; age = 15.0 [2.7] y).

INTERVENTIONS

Interventions were performed during the preseason of 6 weeks. The CONV training included anaerobic, strength, and aerobic training. The NM training consisted of a multicomponent program that integrated jumps, landings, and running with strength, endurance, agility, balance, and CORE training.

MAIN OUTCOME MEASURES

A follow-up of the cohorts was carried out through the evaluation of lower limb injuries (main outcome) during a regular season (weeks 7-18). Secondary outcomes were measured before and after the intervention: Y-balance test, active joint repositioning, ground reaction force, and countermovement jump height.

RESULTS

The injury incidence rate was 17.89 injuries per 1000 hours athlete-exposure in CONV training, and 6.58 in NM training (relative risk = 0.38; 95% confidence interval,  0.18 to 0.82; P = .044). Particularly, the medial tibial stress syndrome incidence rate was 5.96 injuries per 1000 hours athlete-exposure in CONV training and 0.82 in NM training (relative risk = 0.17; 95% confidence interval, 0.02 to 1.12; P = .012). In addition, a significant training × time interaction was noted, favoring improvements in 30-m sprint and countermovement jump height after NM.

CONCLUSION

The NM training may improve youth female athlete's physical fitness and reduce their injury relative risk of medial tibial stress syndrome injury.

The FIFA 11+ does not alter performance in amateur female basketball players-a randomized control trial

OBJECTIVES

The FIFA-Medical and Assessment Research Centre (F-MARC) introduced the warm-up FIFA 11+ program to reduce injuries and promote fair play. Although the FIFA11+ program is a well-established warm-up protocol for injury prevention, studies on the program's performance enhancement aspects have had controversial results. Therefore, the objective of the study is to investigate the efficacy of FIFA11+ program on sports performance parameters such as running speed, agility, and vertical jump performance in amateur female basketball players.

METHODS

In this study, 59 amateur female basketball players were recruited and randomized into an experimental group (n=30) and a control group (n=29). The experimental group completed the FIFA 11+ program for 12 weeks (three times/week), while the control group members completed their regular training programs. The study adopted a pretest-posttest design. 20-yard sprint run, t test and vertical jump test were the outcome measures.

RESULTS

No statistically significant difference in the sports performance parameters (sprint test p=0.21, t test p=0.16, vertical jump test p=0.09) was found between groups' post-test measurements. The paired sample t test revealed that the 12-week FIFA 11+ program did not demonstrate any significant improvement in the participants' sprint, agility, and vertical jump performance (p>0.05).

CONCLUSIONS

The present study showed no enhancement in sports performance parameters such as sprint speed, agility, and vertical jump performance in amateur female basketball players. This lack of improvement in performance measures suggests that the program cannot be used as a training strategy for the targeted sports performance parameters.

Injury prevention programmes with plyometric and strengthening exercises improve on-field performance: a systematic review

Importance

Injury prevention programmes (IPPs) have been demonstrated to be highly efficacious in protecting young athletes from anterior cruciate ligament and other lower-extremity injuries. However, the effectiveness of these programme in practice has been limited due to poor adherence among coaches of organised sports teams.

Objective

A change in messaging from injury reduction to performance enhancement may be an effective strategy for improving adherence. We conducted a systematic review to address whether implementing IPP can also provide benefits on sports performance as measured by on-field tests.

Evidence review

Data Sources: PubMed, EMBASE and Cochrane Library databases were searched from January 2000 to August 2018.

Study Selection: English-language studies were selected if they evaluated on-field performance testing before and after participation in the IPP or compared with another programme/control. No limitations were placed on study design or study population. Studies were excluded if they evaluated programme without an explicit focus on injury prevention or reported on injury risk factors that were not related to athletic performance.

Study design

Systematic review

Data extraction

Study design, population, sport and level, comparison group and duration/frequency of the IPP were extracted from full-text articles. The results of performance testing were summarised into the following categories: balance, sprinting, agility, jumping, physical fitness and sport-specific skills.

Findings

The evidence shows that IPP can have beneficial effects on measures of sports performance and physical fitness. Factors that resulted in significant improvement included longer frequency and duration of the programme, as well as inclusion of plyometric and muscle strengthening exercises.

Conclusions

There is a wide variety of measures used for athletic performance. IPPs that are done more frequently for longer durations and that include strengthening and plyometric exercises have been shown to improve athletic performance. Enhanced performance with tests that can be conducted on the field with existing equipment may help convince coaches and athletes to improve adherence with the IPP exercises.

Level of evidence

Level II

Integrative Neuromuscular Training in Young Athletes, Injury Prevention, and Performance Optimization: A Systematic Review

The aim of this systematic review was to evaluate the current evidence by assessing the effectiveness of integrative neuromuscular training programs in injury prevention and sports performance in young athletes. Different data sources were analyzed up to January 2018. Eligible studies contained information on population (young athletes), intervention (neuromuscular training), comparator (control group or another exercise intervention), outcomes (injury prevention or sport performance), and study design (randomized trials or prospective studies). The trials were restricted based on the language (English) and for publication date (after January 1st, 2007). Fourteen randomized controlled trials were included: Seven included dynamic stability-related outcomes. Three assessed the coordination performing fundamental movements and sport-specific skills, while other five studies analyzed muscle strength and two assessed plyometric tests. Agility was evaluated in three studies and speed tests were also considered by four studies. Finally, fatigue resistance in three studies and injury risk in four were assessed. This review provides evidence that integrative neuromuscular training programs can enhance performance and injury prevention in young athletes, taken into account that adherence to the training program is adequate. Collectively, well-designed, randomized studies are necessary to collaborate with the present findings.

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.

Proprioception is not associated with lower extremity injuries in U21 high-level football players

Football is a contact sport with a significant risk of injury. Although proprioception is well studied in rehabilitation, little is known about the association between proprioception and the occurrence of sport injuries. The purpose of this study was to look into the association between ankle and knee proprioception and lower extremity injuries in young football players. Seventy-three football players from the highest U-21 league in Iran volunteered to participate in this study. Before the start of the 2017-2018 competitive season, joint position sense was measured at 30°, 60° and 90° knee flexion and at 10° and 15° ankle dorsiflexion, and inversion using the Biodex Isokinetic pro 4 system. The teams' medical staff recorded football-related lower extremity injuries. We used mixed effects Cox regression models to calculate hazard ratios (HRs) with 95% CIs, acknowledging the clustered data structure. Twenty-two players (30.1%) suffered one or more lower extremity injuries during the season. None of the proprioception measures examined was significantly associated with the risk of lower extremity injuries. Based on these results of our sample, joint position sense does not seem to be associated with lower extremity injuries in young male football 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.

Effect of Injury Prevention Programs on Lower Extremity Performance in Youth Athletes: A Systematic Review

BACKGROUND

Understanding how existing youth injury prevention programs affect specific modifiable injury risk factors will inform future program development for youth athletes.

OBJECTIVE

To comprehensively evaluate the effects of injury prevention programs on the modifiable intrinsic risk factors associated with lower extremity performance in youth athletes.

DATA SOURCES

This systematic review followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A systematic search of the literature was performed using multiple databases (PubMed, EBSCOhost [including CINAHL, Medline, and SPORTDiscus], and PEDro). Secondary references were appraised for relevant articles. Article types included randomized or cluster randomized controlled trials and randomized cohort designs with youth athletes engaged in organized sports, along with outcomes that included at least 1 physical performance outcome measure.

STUDY SELECTION

Eight studies met inclusion and exclusion criteria and were reviewed by 2 independent reviewers, with a third consulted in the case of disagreement, which was not needed.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Level 3.

DATA EXTRACTION

Included studies underwent review of methodological quality using the Physiotherapy Evidence Database scale.

RESULTS

Studies included mixed-sex samples of youth athletes who predominantly participated in soccer at different skill levels. The FIFA 11+ series was the most commonly used injury prevention program. Among studies, the mean percentage of improvement identified was 11.3% for force generation, 5.7% for coordination, 5.2% for posture, and 5.2% for balance. The lowest mean percentage improvement was in speed (2.2%). Endurance was not significantly affected by any of the programs.

CONCLUSION

This systematic review shows that injury prevention programs improve several modifiable intrinsic risk factors of lower extremity performance among youth athletes, particularly force generation. However, several intrinsic risk factors were either not significantly affected or specifically addressed by existing programs.

Evaluating the Effects of a Novel Neuromuscular Neck Training Device on Multiplanar Static and Dynamic Neck Strength: A Pilot Study

Versteegh, TH, Dickey, JP, Emery, CA, Fischer, LK, MacDermid, JC, and Walton, DM. Evaluating the effects of a novel neuromuscular neck training device on multiplanar static and dynamic neck strength: A pilot study. J Strength Cond Res 34(3): 708-716, 2020-The neck serves an important function in damping the transference of acceleration forces between the head and the trunk, such as that occurring during contact sports or motor vehicle collisions. An inability to adequately dissipate forces has been proposed as a potential mechanism for clinical conditions such as whiplash or concussion, but current approaches to neck training may not be targeting the correct mechanisms. The purpose of this study was to explore the training effect of a novel neuromuscular strengthening protocol on dynamic and static neck strength. This was a quasiexperimental pilot study design with intervention (n = 8) and control (n = 10) groups. The intervention group was trained (twice/week, ∼10 minutes, for 7 weeks) on a training device that uses self-generated centripetal force to create a dynamic rotational resistance. This protocol is intended to target the ability of the neck muscles to perform coordinated multiplanar plyometric contractions. Both groups also continued with traditional neck strengthening that included training on a straight-plane, isotonic, 4-way neck machine. Performance on the training device showed improvement after routine practice within 1 week, as evidenced by a trend toward increased peak speed in revolutions per minute (RPM). After 7 weeks, peak RPM increased from 122.8 (95% confidence interval [CI], 91.3-154.4) to 252.3 (95% CI, 241.5-263.1). There was also a large positive effect size (Hedge's d, 0.68) in isometric composite (multiplane) neck strength favoring the intervention group over the control group (difference, 20 N; 95% CI, -8 to 48). The largest magnitude strength improvement in a single plane was in axial rotation and also favored the intervention group over the control group (Hedge's d, 1.24; difference, 46 N; 95% CI, 9-83). Future studies should explore whether the dynamic training presented here could help reduce the risk of sports concussion, whiplash, or other head-neck trauma.

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.

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.

Landing Styles Influences Reactive Strength Index without Increasing Risk for Injury

The aim was to determine which three landing styles - stiff (ST), self-selected (SS), or soft (SF) - exhibit safer landing mechanics and greater jumping performance. Thirty participants (age: 26.5±5.1 years; height: 171.0±8.8 cm; weight: 69.7±10.1 kg) performed five trials of three randomized drop jump (40 cm) landing styles including SF (~60° knee flexion), ST (knees as straight as possible), and SS. Knee flexion and valgus angles and kinetics were measured. An electromyography system measured muscle activity of the gluteus maximus, quadriceps, hamstrings, tibialis anterior, and gastrocnemius. Reactive strength index (RSI) was used to measure jumping performance. ANOVAs were used to compare the three landings. All landings differed in knee flexion (p<0.001; effect size (η 2 ): 0.9) but not valgus (p=.13; η 2 :.15). RSI (mm·ms -1 ) showed differences for all jumps (p<0.001; η 2 : 0.7) with SS (0.96) showing the highest value, then ST (0.93), and SF (0.64). Ground reaction forces were different between jumps (p<0.001; η 2 : 0.4) with SF (1.34/bodyweight (bw)) showing lower forces, then SS (1.50/bw), and ST (1.81/bw). No between-jump differences were observed for EMG (p>0.66; η 2 : 0.3). No landing demonstrated valgus landing mechanics. The SS landing exhibited the highest RSI. However, the 1.8/bw exhibited by the ST landing might contribute to overload of musculotendinous structures at the knee.

Neuromuscular training reduces lower limb injuries in elite female basketball players. A cluster randomized controlled trial

The study was a two-armed, parallel group, cluster randomized controlled trial in which 15 teams (160 players) were assigned to either an experimental group (EG, 8 teams n = 86), which warmed-up with bodyweight neuromuscular exercises, or a control group (CG, 7 teams, n = 74) that performed standard tactical-technical exercises before training. All injuries during the 2015-2016 regular season were counted. Epidemiologic incidence proportion and incidence rate were also calculated. Countermovement jump (CMJ) and composite Y-Excursion Balance test (YBT) were used to assess lower limb strength and postural control. A total of 111 injuries were recorded. Chi-square test detected statistically significant differences between EG and CG (32 vs 79, P = .006). Significant differences in the injuries sustained in the EG (21 vs 11, P = .024) and CG (52 vs 27, P = .0001) during training and matches, respectively, were observed. Significant differences in post-intervention injuries were observed between in EG and CG during training (21 vs 52, P < .0001) and matches (11 vs 27, P = .006). Significant differences in epidemiologic incidence (0.37 vs 1.07, P = .023) and incidence rate (1.66 vs 4.69, P = .012) between the EG and the CG were found. Significant improvement in CMJ (+9.4%, P < .0001; d = 1.2) and composite YBT (right: +4.4%, P = .001, d = 1.0; left: +3.0%, P = .003; d = 0.8) for the EG was noted. Significant differences in post-intervention CMJ (+5.9%, P = .004) and composite YBT scores (right, +3.7%, P = .012; left, +2.3%, P = .007) between the EG and the CG were observed. Including bodyweight neuromuscular training into warm-up routines reduced the incidence of serious lower limb injuries in elite female basketball players.

Neuromuscular Adaptations to Multimodal Injury Prevention Programs in Youth Sports: A Systematic Review with Meta-Analysis of Randomized Controlled Trials

Objective: Neuromuscular injury prevention programs (IPP) can reduce injury rate by about 40% in youth sport. Multimodal IPP include, for instance, balance, strength, power, and agility exercises. Our systematic review and meta-analysis aimed to evaluate the effects of multimodal IPP on neuromuscular performance in youth sports.

Methods: We conducted a systematic literature search including selected search terms related to youth sports, injury prevention, and neuromuscular performance. Inclusion criteria were: (i) the study was a (cluster-)randomized controlled trial (RCT), and (ii) investigated healthy participants, up to 20 years of age and involved in organized sport, (iii) an intervention arm performing a multimodal IPP was compared to a control arm following a common training regime, and (iv) neuromuscular performance parameters (e.g., balance, power, strength, sprint) were assessed. Furthermore, we evaluated IPP effects on sport-specific skills.

Results: Fourteen RCTs (comprising 704 participants) were analyzed. Eight studies included only males, and five only females. Seventy-one percent of all studies investigated soccer players with basketball, field hockey, futsal, Gaelic football, and hurling being the remaining sports. The average age of the participants ranged from 10 years up to 19 years and the level of play from recreational to professional. Intervention durations ranged from 4 weeks to 4.5 months with a total of 12 to 57 training sessions. We observed a small overall effect in favor of IPP for balance/stability (Hedges' g = 0.37; 95%CI 0.17, 0.58), leg power (g = 0.22; 95%CI 0.07, 0.38), and isokinetic hamstring and quadriceps strength as well as hamstrings-to-quadriceps ratio (g = 0.38; 95%CI 0.21, 0.55). We found a large overall effect for sprint abilities (g = 0.80; 95%CI 0.50, 1.09) and sport-specific skills (g = 0.83; 95%CI 0.34, 1.32). Subgroup analyses revealed larger effects in high-level (g = 0.34–1.18) compared to low-level athletes (g = 0.22–0.75), in boys (g = 0.27–1.02) compared to girls (g = 0.09–0.38), in older (g = 0.32–1.16) compared to younger athletes (g = 0.18–0.51), and in studies with high (g = 0.35–1.16) compared to low (g = 0.12–0.38) overall number of training sessions.

Conclusion: Multimodal IPP beneficially affect neuromuscular performance. These improvements may substantiate the preventative efficacy of IPP and may support the wide-spread implementation and dissemination of IPP. The study has been a priori registered in PROSPERO (CRD42016053407).

Compliance with Sport Injury Prevention Interventions in Randomised Controlled Trials: A Systematic Review

INTRODUCTION

Sport injury prevention studies vary in the way compliance with an intervention is defined, measured and adjusted for.

OBJECTIVE

The objective of this systematic review was to assess the extent to which sport injury prevention randomised controlled trials (RCTs) have defined, measured and adjusted results for compliance with an injury prevention intervention.

METHODS

An electronic search was performed in MEDLINE, PubMed, the Cochrane Center of Controlled Trials, CINAHL (Cumulative Index to Nursing and Allied Health Literature), PEDro (Physiotherapy Evidence Database) and SPORTDiscus. English RCTs, quasi-RCTs and cluster-RCTs were considered eligible. Trials that involved physically active individuals or examined the effects of an intervention aimed at the prevention of sport- or physical activity-related injuries were included.

RESULTS

Of the total of 100 studies included, 71.6 % mentioned compliance or a related term, 68.8 % provided details on compliance measurement and 51.4 % provided compliance data. Only 19.3 % analysed the effect of compliance rates on study outcomes. While studies used heterogeneous methods, pooled effects could not be presented.

CONCLUSIONS

Studies that account for compliance demonstrated that compliance significant affects study outcomes. The way compliance is dealt with in preventions studies is subject to a large degree of heterogeneity. Valid and reliable tools to measure and report compliance are needed and should be matched to a uniform definition of compliance.

Effect of a specialized injury prevention program on static balance, dynamic balance and kicking accuracy of young soccer players

AIM

To study the effect of balance intervention program using the “FIFA 11+” program on static and dynamic balance and kicking accuracy of young soccer players.

METHODS

Twenty young soccer players were allocated to experimental (n = 10) or control (n = 10) groups. The experimental group performed the “FIFA 11+” program three times a week for six weeks. The control group performed their normal warm-up routine. The primary outcomes were measured pre and post intervention, and assessed kicking accuracy, static balance and dynamic balance.

RESULTS

No differences were found in kicking accuracy following intervention, for both groups, however, static balance improved significantly among the experimental group with significant interaction with the control group, and with high effect size. In addition, the dynamic balance of the left leg of the experimental group, with medium effect size for interaction between groups.

CONCLUSION

The large effect size of balance improvement that was observed following six weeks of intervention sessions, implies that soccer trainers and coaches should consider the inclusion of “FIFA 11+” as components of programs aimed at improving balance ability/control in young soccer players, as improvement in balance abilities may prevent injuries.

Effects of Two Warm-up Programs on Balance and Isokinetic Strength in Male High School Soccer Players

Ghareeb, DM, McLaine, AJ, Wojcik, JR, and Boyd, JM. Effects of two warm-up programs on balance and isokinetic strength in male high school soccer players. J Strength Cond Res 31(2): 372-379, 2017-One of the most common warm-up programs used to prevent injury in soccer, FIFA11+, integrates aerobic, strength, and balance. The purpose of this study was to compare FIFA11+ to a new warm-up program (NWP) on balance and isokinetic strength of the quadriceps and hamstrings at 60, 180, and 300°·s in male high school soccer players. Participants at one school (n = 17) performed the NWP before practice for 6 weeks during one soccer season, whereas participants at another school (n = 17) performed FIFA11+. There were no differences at baseline. At posttest, players in NWP significantly improved (p < 0.01) in Overall Stability Index Balance, Anterior/Posterior Index Balance, and Medial Lateral Index with large effect sizes (ES) > 1.3. No changes were seen in FIFA11+. Isokinetic strength peak torque increased at 60°·s in the quadriceps and hamstrings in dominant and nondominant legs in NWP (p < 0.01, ES, 0.59-1.02) and in hamstrings in FIFA11+ (p ≤ 0.05, ES, 0.32-0.40). At 180°·s, NWP improved peak torque (p < 0.01, ES, 0.74-0.90) except hamstrings in the nondominant leg, whereas FIFA11+ showed improvements across all muscle groups (p < 0.01), but with smaller ES, 0.25-0.84. Both programs improved isokinetic peak torque at 300°·s except hamstrings in the nondominant leg in NWP, although ES were higher in NWP (ES, 0.60-1.03) than FIFA11+ (ES, 0.31-0.42). The NWP seems to be effective for soccer conditioning by improving balance and isokinetic strength.

Effect of specific exercise-based football injury prevention programmes on the overall injury rate in football: a systematic review and meta-analysis of the FIFA 11 and 11+ programmes

OBJECTIVE

To investigate the effect of FIFA injury prevention programmes in football (FIFA 11 and FIFA 11+).

DESIGN

Systematic review and meta-analysis.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised controlled trials comparing the FIFA injury prevention programmes with a control (no or sham intervention) among football players.

DATA SOURCES

MEDLINE via PubMed, EMBASE via OVID, CINAHL via Ebsco, Web of Science, SportDiscus and Cochrane Central Register of Controlled Trials, from 2004 to 14 March 2016.

RESULTS

6 cluster-randomised controlled trials had assessed the effect of FIFA injury prevention programmes compared with controls on the overall football injury incidence in recreational/subelite football. These studies included 2 specific exercise-based injury prevention programmes: FIFA 11 (2 studies) and FIFA 11+ (4 studies). The primary analysis showed a reduction in the overall injury risk ratio of 0.75 (95% CI 0.57 to 0.98), p=0.04, in favour of the FIFA injury prevention programmes. Secondary analyses revealed that when pooling the 4 studies applying the FIFA 11+ prevention programme, a reduction in the overall injury risk ratio (incidence rate ratio (IRR) 0.61; 95% CI 0.48 to 0.77, p<0.001) was present in favour of the FIFA 11+ prevention programme. No reduction was present when pooling the 2 studies including the FIFA 11 prevention programme (IRR 0.99; 95% CI 0.80 to 1.23, p=0.940).

CONCLUSIONS

An injury-preventing effect of the FIFA injury prevention programmes compared with controls was shown in football. This effect was induced by the FIFA 11+ prevention programme which has a substantial injury-preventing effect by reducing football injuries by 39%, whereas a preventive effect of the FIFA 11 prevention programme could not be documented.

TRIAL REGISTRATION NUMBER

PROSPERO CRD42015024120.

Motor learning strategies in basketball players and its implications for ACL injury prevention: a randomized controlled trial

PURPOSE

Adding external focus of attention (EF, focus on the movement effect) may optimize current anterior cruciate ligament (ACL) injury prevention programmes. The purpose of the current study was to investigate the effects of an EF, by a visual stimulus and an internal focus, by a verbal stimulus during unexpected sidestep cutting in female and male athletes and how these effects remained over time.

METHODS

Ninety experienced basketball athletes performed sidestep cutting manoeuvres in three sessions (S1, S2 and S3). In this randomized controlled trial, athletes were allocated to three groups: visual (VIS), verbal (VER) and control (CTRL). Kinematics and kinetics were collected at the time of peak knee frontal plane moment.

RESULTS

Males in the VIS group showed a larger vertical ground reaction force (S1: 25.4 ± 3.1 N/kg, S2: 25.8 ± 2.9 N/kg, S3: 25.2 ± 3.2 N/kg) and knee flexion moments (S1: -3.8 ± 0.9 Nm/kg, S2: -4.0 ± 1.2 Nm/kg, S3: -3.9 ± 1.3 Nm/kg) compared to the males in the VER and CTRL groups and to the females in the VIS group (p < 0.05). Additionally, the males in the VIS group reduced knee valgus moment and the females in the VER group reduced knee varus moment over time (n.s.).

CONCLUSION

Male subjects clearly benefit from visual feedback. Females may need different feedback modes to learn a correct movement pattern. Sex-specific learning preferences may have to be acknowledged in day by day practice. Adding video instruction or feedback to regular training regimens when teaching athletes safe movement patterns and providing individual feedback might target suboptimal long-term results and optimize ACL injury prevention programmes.

LEVEL OF EVIDENCE

I.

Effects of the FIFA 11 training program on injury prevention and performance in football players: a systematic review and meta-analysis

Objective:

To investigate the effects of FIFA 11 training on injury prevention and performance in football players.

Design and methods:

Systematic review and meta-analysis. We conducted a systematic search using four databases (CINAHL, Cochrane Library, EMBASE, and PubMed) to find controlled trials evaluating the effects of FIFA 11 on injury prevention and performance among football players. Weighted mean differences, standard mean differences, risk ratios, and 95% confidence intervals were calculated, and heterogeneity was assessed using the I2 test.

Results:

We analyzed 11 trials, including 4700 participants. FIFA 11 resulted in a significant reduction in injury risk (risk ratio = 0.69; 95% confidence interval, 0.49–0.98; P = 0.02) and improvements in dynamic balance (weighted mean difference = 2.68; 95% confidence interval, 0.44–4.92; P = 0.02) and agility (standard mean difference = −0.36; 95% confidence interval, 0.70–0.02; P = 0.04). The meta-analysis indicated a non-significant improvement in jump height (standard mean difference = 0.25; 95% confidence interval, 0.08–0.59; P = 0.14) and running sprint (standard mean difference = −0.24; 95% confidence interval, 0.58–0.10; P = 0.17) in the FIFA 11 group.

Conclusions:

FIFA 11 can be considered as a tool to reduce the risk of injury. It may improve dynamic balance and agility and can be considered for inclusion in the training of football players.

Critical components of neuromuscular training to reduce ACL injury risk in female athletes: meta-regression analysis

OBJECTIVE

The aim of this study was to determine key components in neuromuscular training that optimise ACL injury reduction in female athletes using meta-regression analyses.

DESIGN

Systematic review and meta-regression.

DATA SOURCES

The literature search was performed in PubMed and EBSCO.

ELIGIBILITY CRITERIA

Inclusion criteria for the current analysis were: (1) documented the number of ACL injuries, (2) employed a neuromuscular training intervention that aimed to reduce ACL injuries, (3) had a comparison group, (4) used a prospective control study design and (5) recruited female athletes as participants. Two independent reviewers extracted studies which met the inclusion criteria. Methodological quality of included study and strength of recommendation were evaluated. Number of ACL injuries and participants in control and intervention groups, age of participants, dosage of neuromuscular training, exercise variations within neuromuscular training and status of verbal feedback were extracted.

RESULTS

The meta-regression analyses identified age of participants, dosage of neuromuscular training, exercise variations within neuromuscular training and utilisation of verbal feedback as significant predictors of ACL injury reduction (p=0.01 in fixed-effects model, p=0.03 in random-effects model). Inclusion of 1 of the 4 components in neuromuscular training could reduce ACL injury risk by 17.2-17.7% in female athletes. No significant heterogeneity and publication bias effects were detected. Strength of recommendation was rated as A (recommendation based on consistent and good-quality patient-oriented study evidence).

CONCLUSIONS

Age of participants, dosage of neuromuscular training, exercise variations within neuromuscular training and utilisation of verbal feedback are predictors that influence the optimisation of prophylactic effects of neuromuscular training and the resultant ACL injury reduction in female athletes.

Strength and Conditioning Practices of University and High School Level Cricket Coaches: A South African Context

Pote, L and Christie, CJ. Strength and conditioning practices of University and high school level cricket coaches: a South African context. J Strength Cond Res 30(12): 3464-3470, 2016-Although the sport of cricket is well established, the strength and conditioning practices of cricket players are not well known. Therefore, the purpose of this study was to examine the current strength and conditioning practices that coaches implement for South African schoolboy and University level cricket players. An online survey, adapted from previous strength and conditioning questionnaires, was sent to 38 schoolboy and 12 University teams that participated in the top competitions in the country (n = 50). Of these, 24 replied indicating a response rate of 48%. Results indicated that although some forms of conditioning, workload monitoring and injury prevention were being implemented, the correct practices were not being administered. Furthermore, it was identified that most coaches had insufficient qualifications and experience to administer the correct training techniques. It was concluded that coaches require further education so that scientifically based training programs can be implemented. This was deemed particularly necessary for adolescent bowlers who are at an increased risk of injury, specifically in the lower back region.

Injury characteristics in the German professional male soccer leagues after a shortened winter break

CONTEXT

The winter break in the top 2 German professional soccer leagues was shortened from 6.5 to 3.5 weeks in the 2009-2010 season.

OBJECTIVE

To investigate whether this change affected injury characteristics by comparing the second half of the 2008-2009 (long winter break) with the equivalent period in the 2009-2010 season (short winter break).

DESIGN

Prospective cohort study.

SETTING

German male professional soccer leagues.

PATIENTS OR OTHER PARTICIPANTS

Seven professional German male soccer teams (184 players in the 2008-2009 season, 188 players in the 2009-2010 season).

MAIN OUTCOME MEASURE(S)

Injury incidences and injury characteristics (cause of injury, location, severity, type, diagnosis), including their monthly distribution, were recorded.

RESULTS

A total of 300 time-loss injuries (2008-2009 n = 151, 2009-2010 n = 149) occurred. The overall injury incidence per 1000 soccer hours was 5.90 (95% confidence interval = 5.03, 6.82) in 2008-2009 and 6.55 (5.58, 7.69) in 2009-2010. Match injuries per 1000 hours were 31.5 (25.0, 38.0) in the first season and 26.5 (20.2, 32.7) in the second season; the corresponding training values were 2.67 (2.08-3.44) and 3.98 (3.19-4.95), respectively. The training injury incidence (incidence rate ratio = 1.49 [95% confidence interval = 1.07, 2.08], P = .02) and the risk of sustaining a knee injury (incidence rate ratio = 1.66 [1.00, 2.76], P = .049) were higher in 2009-2010 after the short winter break; the incidence of moderate and severe injuries (time loss >7 days) trended higher (incidence rate ratio = 1.34 [0.96, 1.86], P = .09).

CONCLUSIONS

Shortening the winter break from 6.5 to 3.5 weeks did not change the overall injury incidence; however, a higher number of training, knee, and possibly more severe injuries (time loss >7 days) occurred.

The “FIFA 11+” warm-up programme for preventing injuries in soccer players: a systematic review

Introduction Soccer is among the sports with the highest injury rate. A group of international experts from the Fédération Internationale de Football Association — FIFA’s Medical Assessment and Research Centre — have developed the “FIFA 11+”, a warm-up programme whose main goal is to reduce the risk of common injuries in both male and female soccer players. Objective To conduct a literature review in order to check the efficiency of the “FIFA 11 +” warm-up programme in preventing injuries in soccer players. Methods We conducted a systematic review of studies in the databases MEDLINE/PubMed, SciELO, ScienceDirect and SPORTDiscus, using the following keywords in combination with one another: “injury”, “prevention” and “warm-up”. Results Five studies met the inclusion criteria. In four studies, the authors conclude that the “FIFA 11 +” warm-up programme is effective for preventing injuries in soccer players. In one study, this protective effect was not observed. Conclusion The analyzed studies indicate that the FIFA 11+ warm-up programme for the prevention of sports injuries show positive signs that the use of the programme may help reduce the incidence of injuries in girls aged 13–17 years. In a male children population the results are inconclusive and further research is needed.

Effects of spine flexion and erector spinae maximal force on vertical squat jump height: a computational simulation study

The purpose of this study was to evaluate the single and combined effects of initial spine flexion and maximal isometric force of the erector spinae on maximal vertical jump height during maximal squat jumping. Seven initial flexions of the 'thorax-head-arm' segment (between 20.1° and 71.6°) and five maximal isometric forces of the erector spinae (between 5600 and 8600 N) were tested. Thus, 35 squat jumps were simulated using a 2D simulation model of the musculoskeletal system. Vertical jump height varied at most about 0.094 and 0.021 m when the initial flexion of the 'thorax-head-arm' segment and the maximal force of the erector spinae were, respectively, maximal. These results were explained for the most part by the variation of total muscle work. The latter was mainly influenced by the work produced by the erector spinae which increased at most about 57 and 110 J when the initial flexion of the 'thorax-head-arm' segment and the maximal force of the erector spinae were, respectively, maximal. It was concluded that the increase in the initial flexion of the 'thorax-head-arm' segment and in the maximal isometric force of the erector spinae enables an increase in maximal vertical jump height during maximal squat jumping.

Specific exercise effects of preventive neuromuscular training intervention on anterior cruciate ligament injury risk reduction in young females: meta-analysis and subgroup analysis

CONTEXT

Clinical trials have demonstrated that preventive neuromuscular training (PNMT) can be effective to reduce ACL injuries in young females. However, the magnitude of the overall effect of PNMT for ACL injury reduction has not reached consensus. In addition, the effects of individual exercises in PNMT that optimise ACL injury reduction are unknown.

OBJECTIVE

The purpose of this project was to systematically review previously published clinical trials and evaluate types of exercises that best support ACL injury reduction in young females.

DATA SOURCES

The key words 'knee', 'anterior cruciate ligament', 'ACL', 'prospective', 'neuromuscular', 'training', 'female', and 'prevention' were used for studies published from 1995 to May 2012 in PubMed and EBSCO host.

STUDY SELECTION

Inclusion criteria for the current analysis were: (1) documented number of ACL injuries, (2) employed a PNMT intervention that aimed to reduce ACL injuries, (3) had a comparison group, (4) used a prospective controlled study design, (5) recruited female athletes and (6) recorded exercises implemented in the PNMT.

DATA EXTRACTION

The number of ACL injuries and female athletes in each group (control and intervention) were extracted. In addition, exercises were categorised into four types and analysed for each investigation.

DATA SYNTHESIS

A total of 14 clinical trials met the inclusion criteria. The subgroup analyses identified fewer ACL injuries in PNMT that focused on strengthening (OR 0.32, 95% CI 0.23 to 0.46, p=0.001), proximal control exercises (OR 0.33, 95% CI 0.23 to 0.47, p=0.001) and multiple exercise interventions (OR 0.32, CI 0.22 to 0.46, p=0.001).

CONCLUSIONS

The current subgroup analyses indicate strengthening, proximal control exercises and multi exercise genres increased efficacy in PNMT intervention designed to reduce ACL injury in young female athletes.