Core stability is associated with dynamic postural balance in soccer players experiencing groin pain without time-loss

Objectives

The study sought to evaluate possible relationships between dynamic postural balance and pain, core stability, and hip range of motion in soccer players who were experiencing groin pain (GP). Furthermore, the study aimed to compare these measurements in symptomatic and asymptomatic players.

Methods

The study included 42 male soccer players experiencing GP and an equal number of asymptomatic players. Dynamic postural balance, pain, hip range of motion and trunk endurance were measured.

Results

The GP group revealed reduced dynamic balance performance (p < 0.01-0.001) in injured and non-injured limbs compared to control group. Further, players experiencing GP demonstrated lower hip range of motion in internal (p < 0.05) and total rotations (p < 0.01) in the injured limb, and lower trunk endurance (p < 0.001) compared to their asymptomatic peers. In general, core stability was associated (r = 0.13-0.61, p < 0.05-0.001) with the poor dynamic balance performance in the GP group while standing on injured and non-injured limbs. No significant correlations between dynamic postural balance, pain and hip range of motion were observed.

Conclusion

Poor core endurance was found to be associated with dynamic balance disorders in soccer players experiencing GP. This information can aid in the development of targeted strategies to enhance dynamic postural balance in these players.

Sport-related concussion attitudes and knowledge in elite English female footballers

BACKGROUND

Sport-related concussions (SRC) are more common and more severe in women's football than men's yet the knowledge and attitudes of SRC in the women's game are not well understood. The objective of this study was to assess the SRC knowledge and attitude in elite female footballers.

METHODS

An online questionnaire was sent to all registered players in the English Football Association Women's Super League (WSL) and Championship. Respondents completed an amended version of the Rosenbaum Concussion Knowledge and Attitudes Survey (RoCKAS). Concussion Knowledge Index (CKI) and Concussion Attitudes Index (CAI) scores were derived for all respondents.

RESULTS

One hundred and twenty-three players completed the survey with 111 fitting the inclusion criteria. The mean CKI score was 20.5 ± 2.3 and the mean CAI score was 63.3 ± 6.3. A weak positive correlation was shown between the CKI and CAI (r = 0.20; p = 0.03). Previous concussion education had a significant impact on increased knowledge (U = 1198; p = 0.04). There was no significant difference in concussion attitudes and knowledge between the WSL and Championship or in those with a previous concussion history and no previous concussion (p > 0.05).

CONCLUSION

Previous SRC education demonstrated an increased knowledge around concussion but a limited impact towards concussion attitudes. It is suggested that concussion education should be mandated across the professional game to enhance player welfare.

Passing path predicts shooting outcome in football

What determines the outcome of a shot (scored or unscored) in football (soccer)? Numerous studies have investigated various aspects of this question, including the skills and physical/mental state of the shooter or goalkeeper, the positional information of shots, as well as the attacking styles and defensive formations of the opposing team. However, a critical question has received limited attention: How does the passing path affect the outcome of a shot? In other words, does the path of the ball before shooting significantly influence the result when the same player takes two shots from the same location? This study aims to fill the gap in the literature by conducting qualitative studies using a dataset comprising 34,938 shots, along with corresponding passing paths from top-tier football leagues and international competitions such as the World Cup. Eighteen path features were extracted and applied to three different machine-learning models. The results indicate that the passing path, whether with or without the positional information of shots, can indeed predict shooting outcomes and reveal influential path features. Moreover, it suggests that taking quick actions to move the ball across areas with a high probability of scoring a goal can significantly increases the chance of a successful shot. Interestingly, certain path features that are commonly considered important for team performance, such as the distribution of passes among players and the overall path length, were found to be less significant for shooting outcomes. These findings enhance our understanding of the effective ball-passing and provide valuable insights into the critical factors for achieving successful shots in football games.

A Systematic review of the factors that affect soccer players' short-passing ability-based on the Loughborough Soccer Passing Test

OBJECTIVE

This study synthesizes evidence from the Loughborough Passing Test to evaluate the short-passing ability of soccer players and summarizes the reported variables that affect this ability to provide support for the development and improvement of short-passing abilities in soccer players.

METHODS

In this systematic review using the PRISMA guidelines, a comprehensive search was conducted in Web of Science, PubMed, and EBSCOhost from inception to July 2023 to identify relevant articles from the accessible literature. Only studies that used the Loughborough test to assess athletes' short-passing ability were included. The quality of the included studies was independently assessed by two reviewers using the PEDro scale, and two authors independently completed the data extraction.

RESULTS

Based on the type of intervention or influencing factor, ten studies investigated training, nine studies investigated fatigue, nine studies investigated supplement intake, and five studies investigated other factors.

CONCLUSION

Evidence indicates that fitness training, small-sided games training, and warm-up training have positive effects on athletes' short-passing ability, high-intensity special-position training and water intake have no discernible impact, mental and muscular exhaustion have a significantly negative effect, and the effect of nutritional ergogenic aid intake is not yet clear. Future research should examine more elements that can affect soccer players' short-passing ability.

TRIAL REGISTRATION

https://inplasy.com/ ., identifier: INPLASY20237.

[Injury prevention in football : A challenge for team doctors and coaching team]

High injury rates and long injury-related downtimes demonstrate the need for effective and differentiated injury prevention strategies in football. Preventive measures should take place in various fields and should not be reduced to training programmes or medical approaches. The so-called "Big 6 of injury prevention" provide an overview of the key areas that should be addressed. In modern sports medicine, it should be a matter of course that the team doctor already participates in the primary prevention strategies and does not only get involved in the post-traumatic treatment. Similarly, a decision on a player's return to play after an injury should not be based solely on the medical assessment of the team doctor. Good communication and interdisciplinary cooperation, therefore, form the basis for successful prevention.

The alterations of functional brain networks and its relationship with sport decision-making and training duration in soccer players across different skill levels

Studies have indicated that skilled soccer players possess superior decision-making abilities compared to their less-skilled counterparts. However, the underlying neural mechanism for this phenomenon remains incompletely understood. In our investigation, we explored distinctions in the topology of functional brain networks between skilled and less-skilled soccer players. Employing mediating analysis, we scrutinized the relationships among functional brain network parameters, training duration, and decision-making accuracy. Our findings revealed that skilled soccer players demonstrated significantly higher decision-making accuracy compared to their less-skilled counterparts. Skilled players also exhibited increased values in the cluster coefficient, characteristic path length and local efficiency but lower global efficiency. Moreover, we observed enhanced functional brain connectivity within the occipital and cingulo-opercular networks, as well as between the fronto-parietal and cingulo-opercular networks in skilled soccer players. Cluster coefficient and functional connectivity between fronto-parietal and cingulo-opercular networks had positive mediating effects on the association between training duration and sport decision-making accuracy. In conclusion, our study provides initial evidence for distinctions in functional brain network parameters between soccer players with varying skill levels and their relationship with sport decision-making accuracy.

Repeated-sprint sets test: a new method for evaluating and forecasting fitness in elite young male soccer players

The objective of the current study was to explore the correlation between repeated sprint sets (RSS) ability and several physical attributes, including maximum sprint speed, maximal aerobic speed, maximal anaerobic speed, aerobic capacity, and explosive strength. Moreover, the aim was to assess the suitability of RSS as a comprehensive evaluation tool for physical qualities and to determine which physical field tests most accurately predict RSS in elite young male soccer players. A total of thirty-two young elite male soccer players (mean age 14.6 ± 0.3 years; predicted years from peak height velocity (PHV): - 0.4 ± 0.3; years in training: 3.7 ± 0.5) voluntarily participated in the study. The players participated in eight consecutive specific physical tests, with a minimum 72-h recovery between each session to minimize the impact of fatigue during the second trial. The participants completed the tests in the following order: RSS test, Vam-Eval test, a constant velocity test performed until exhaustion at 100% of vVO2max (tlim100), 20-m Multi-Stage Shuttle Run test (VMSRT), Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1), Maximal Anaerobic Shuttle Running Test (VMASRT), Maximal Sprinting Speed Test (20-m flying sprint), Countermovement Jump (CMJ), and Standing Long Jump test (SLJ). The results of the study showed that there were very large negative correlations between tlim100 and SST (sum of sprint times), and large negative correlations between Yo-Yo IR1, Vam-Eval, and SST during RSS in young elite male soccer players (p < 0.05). Additionally, VMASRT and SLJ demonstrated a moderate negative correlation with SST (p < 0.05). In contrast, significant positive correlations were found between 20-m flying sprint and the SST (p < 0.05). According to the stepwise multiple linear regression analysis, the primary predictors of SST, ranked by importance, were tlim100 and Yo-Yo IR1. These two predictors collectively accounted for 72% of the variance in players' SST (p < 0.0001). Due to the importance of aerobic capacity and short repeated accelerations/sprint sets for overall competitive performance in soccer, in conclusion, our results suggest that elite young male soccer players should perform both high intensity interval training and aeorobic capactity exercises as part of soccer training if the primary outcome is to improve repeated sprint ability performance.

The 11+ injury prevention programme decreases rate of hamstring strain injuries in male collegiate soccer players

OBJECTIVES

To investigate if the 11+ injury prevention programme decreases the risk of hamstring injury and improves recovery time and determine whether compliance with the 11+ affects hamstring injury risk.

METHODS

This study is a secondary analysis from a prospective cluster randomised controlled trial that included 65 National Collegiate Athletic Association (NCAA) division I and II men's soccer teams over the fall 2012 season. Thirty-one teams were randomised to the intervention group that were using the 11+ as their warm-up and 35 teams to the control group that continued to use their traditional warm-up. Each certified athletic trainer (ATC) collected data on demographics, hamstring injury (HSI), mechanism of injury, position, playing surface, time lost due to injury and compliance to the 11+ programme.

RESULTS

The 11+ decreased the risk of HSI by 63% compared with the control group (RR=0.37, 95% CI 0.21 to 0.63). Difference in return to play after HSI between the control (9.4±11.2 days) and intervention groups (10.2±11.3 days) was not significant (p=0.8). High compliance (>2 or more doses on average per week) reduced the risk of HSI by 78% (RR=0.22, 95% CI 0.06 to 0.87) compared with low compliance (<1 dose on average per week), and moderate compliance (1 to <2 doses on average per week) decreased the risk of HSI by 67% (RR=0.33, 95% CI 0.11 to 0.97) compared with low compliance. There was no significant difference between high and moderate compliance.

CONCLUSION

The 11+ decreased the risk of HSI by 63% but did not improve recovery time. High to moderate compliance is essential and makes the programme more effective at reducing HSI.

Injury prevention in Brazilian women's football: Perceptions of physiotherapists and practices within elite clubs

OBJECTIVES

To describe the perceptions of physiotherapists and the injury prevention practices implemented within elite women's football clubs in Brazil.

DESIGN

Cross-sectional study.

SETTING

Online survey.

PARTICIPANTS

Head physiotherapists from 32 Brazilian elite clubs.

MAIN OUTCOME MEASURES

Structured questionnaire.

RESULTS

Physiotherapists identified ACL rupture as the primary target for prevention. The top-five perceived injury risk factors included 'early return to sport after injury', 'workload too high', 'previous injury', 'poor sleep/rest', and 'muscle strength/power deficit'. 'Adoption of return to sport criteria' was almost unanimously recognized as a very important preventive strategy. 'Poor infrastructure' was elected as the main barrier to implementing prevention programs. From a practical standpoint, at least two-third of clubs implemented multi-component exercise interventions for injury prevention. These interventions typically encompassed flexibility/mobility, balance/proprioception, lumbo-pelvic stability, and agility exercises, alongside exposure to sprinting. Strength training routines typically included traditional, functional, and eccentric exercises. Most teams also employed other prevention strategies, including adoption of return to sport criteria, internal workload monitoring, post-exercise recovery modalities, preseason risk factor screening, and application of rigid strapping tapes.

CONCLUSIONS

This study provided unprecedented insights into the physiotherapists' perceptions and injury prevention practices implemented within elite women's football clubs.

Male elite soccer players have a higher incidence of accessory ossicles in the foot and ankle

PURPOSE

Accessory ossicles are caused by the failure of the fusion of secondary ossification centres and are more likely to occur due to heavy loading during the growth period or improper treatment after injury. This study aimed to investigate the incidence of foot and ankle accessory ossicles in male professional soccer players.

METHODS

This study included male professional soccer players who underwent medical checkups at our hospital between 2017 and 2023 as the soccer group. Medical checkups included radiographs of bilateral anteroposterior and oblique foot, as well as bilateral anteroposterior and lateral ankle. Male patients age-matched with the soccer group who visited our hospital undergoing anteroposterior and oblique foot or anteroposterior and lateral ankle radiography were included in the control group. The incidence of accessory ossicles was investigated and compared between the soccer and control groups.

RESULTS

In this study, 276 ankles and 276 feet, as well as 121 ankles and 79 feet, were included in the soccer and control groups, respectively. The incidence of accessory ossicles in the soccer and control groups was as follows: accessory navicular 35.9%, 24% (P = .049), os peroneum 8.0%, 2.5% (P = .09); os supranaviculare 7.6%, 1.3% (P = .039); os infranaviculare 1.4%, 1.3% (P = .090); os calcaneus secundarius 4.3%, 0% (P = .059); os vesalianum 0%, 0%; os subfiblare 12.7%, 2.5% (P < .001); os subtibiale 18.1%, 2.5% (P = .001); and os trigonum 89%, 24% (P < .001).

CONCLUSIONS

Male professional soccer players had a higher incidence of accessory navicular, os supranaviculare, os subfiblare, os subtibiale, and os trigonum.

Uncovering injuries in Brazilian elite women's football: A prospective cohort study

OBJECTIVES

To elucidate the injury profile in Brazilian elite women's football.

DESIGN

Prospective cohort study.

METHODS

Time-loss injuries, along with match and training exposure, were monitored throughout a full season in four Brazilian elite clubs.

RESULTS

Sixty-three out of 133 players (47 %) sustained 112 time-loss injuries along the season, leading to 0.8 injuries per player on average. The overall injury incidence rate was 5.0 injuries per 1000 h of exposure. Sudden onset injuries occurred at a rate of 4.2/1000 h of overall exposure, with rates of 15.9/1000 h during matches and 2.9/1000 h during training sessions. Forty-eight percent of the time-loss injuries were attributed to non-contact events. Gradual onset injuries accounted for 16 % of the injuries, resulting in a rate of 0.8/1000 h of overall exposure. The most affected locations were knee and thigh (29 % of all injuries for each), followed by ankle (17 %) and hip/groin (13 %). Muscle/tendon was the most affected tissue (47 % of all injuries), followed by ligament/joint capsule (33 %), bone (10 %), and cartilage/synovium/bursa (7 %). Ankle sprains, hamstring strains, and anterior cruciate ligament injuries accounted for over one-third of the injuries. Mild, moderate, and severe injuries account for 40 %, 43 %, and 17 % of cases, respectively. Overall, 18 % of cases were categorized as re-injuries, and 40 % of those occurred within 2 months of the index injury.

CONCLUSIONS

This study provides the initial understanding into the injury profile of Brazilian elite women's football. This information should serve as a guiding resource for injury prevention programs.

The effect of complex contrast training with different training frequency on the physical performance of youth soccer players: a randomized study

Background

Complex contrast training (CCT) is potentially an efficient method to improve physical abilities such as muscle strength, power output, speed, agility, are extremely important in developing soccer players of different age categories.

Aim

This study aimed to analyze the effects of 6 weeks of CCT program applied in different training frequency (sessions per week) on youth soccer players performance.

Methods

Twenty-one youth soccer players (age: 15.3 ± 1.1 years; body mass 64.9 ± 0.7 kg; height 175.4 ± 0.7 cm) were randomized into three groups: a regular pre-season training control group (G0, n = 8), a group with regular pre-season training plus twice-a-week CCT (G2, n = 6), and a group with regular pre-season training plus thrice-a-week CCT (G3, n = 7). The CCT consisted of soccer skills-based exercises distributed across five stations, to be performed before common regular practice during a 6-week pre-season period. The agility (505 Agility test), sprint (S5 and S15), jump (SJ and CMJ), and free kick speed (11 m from the goal) of the groups were analyzed pre- and post-CCT intervention. During a 6-week pre-season period, the players integrated CCT into their regular training sessions. Furthermore, performance variables were compared between the groups.

Results

A statistical difference was identified for the timepoint for the players' CMJ (p = 0.023; η2 = 0.343) and the free kick speed (p = 0.013; η2 = 0.383) using ANOVA. The G3 showed a significant improvement in the CMJ (p = 0.001) and the free kick speed (p = 0.003) between pre- to post-CCT test. No other significant changes in performance were observed (p > 0.05).

Conclusion

The CCT training program with a weekly frequency of 3 days per week is effective in improving free kick speed and CMJ performance in young male soccer players (U-15 and U-17 categories). CCT training programs have the potential to refine an athlete's preparation for competition. However, certain performance tests did not demonstrate substantial enhancements. Consequently, additional investigations are required to ascertain the effectiveness of CCT.

Is digit ratio (2D:4D) a biomarker for lactate? Evidence from a cardiopulmonary test on professional male footballers

BACKGROUND

Lactate accumulation is associated with vigorous exercise, cardiovascular disease and a number of cancers. Digit ratio (2D:4D) has also been linked to oxygen metabolism, myocardial infarction and various cancers. Such similarities suggest the possibility that 2D:4D is a biomarker of lactate. Here, we consider the relationship between 2D:4D and lactate during an incremental cardiopulmonary exercise test.

METHOD

The participants were male professional football players. The treadmill test began at a speed of 8 km/h when the first lactate measurement was taken. The speed was increased by 2 km/h every 3.15 min, with measurements at 10, 12, 14 and 16 km/h.

RESULTS

There were 72 Caucasian and 7 Black participants, results are reported for the most numerous group. Lactate levels increased with running speed and were not correlated with age, body size or body composition. Median splits of digit ratios (right, left and right-left 2D:4D [Dr-l]) were calculated. In comparison to the Low ratio group, the High ratio group showed higher lactate levels across speeds. Effect sizes varied from very large to huge (right 2D:4D), large (left 2D:4D) and medium (Dr-l). At the individual level, positive correlations between digit ratios and lactate at the five different speeds varied from large (right 2D:4D), medium (left 2D:4D) and small (Dr-l).

CONCLUSION

There were large positive associations between right 2D:4D and lactate at all running speeds. We discuss our findings in relation to oxygen metabolism and suggest that 2D:4D may be a biomarker for lactate in the wider context of the latter's importance in health and disease.

Progressive increase of brain gray matter volume in individuals with regular soccer training

The study aimed to investigate alterations in gray matter volume in individuals undergoing regular soccer training, using high-resolution structural data, while also examining the temporal precedence of such structural alterations. Both voxel-based morphometry and source-based morphometry (SBM) methods were employed to analyze volumetric changes in gray matter between the soccer and control groups. Additionally, a causal network of structural covariance (CaSCN) was built using granger causality analysis on brain structural data ordering by training duration. Significant increases in gray matter volume were observed in the cerebellum in the soccer group. Additionally, the results of the SBM analysis revealed significant increases in gray matter volume in the calcarine and thalamus of the soccer group. The analysis of CaSCN demonstrated that the thalamus had a prominent influence on other brain regions in the soccer group, while the calcarine served as a transitional node, and the cerebellum acted as a prominent node that could be easily influenced by other brain regions. In conclusion, our study identified widely affected regions with increased gray matter volume in individuals with regular soccer training. Furthermore, a temporal precedence relationship among these regions was observed.

A comprehensive two-dimensional scoring system to assess the single-leg squat task in football players

BACKGROUND

The single-leg squat (SLS) is a safe and widespread functional test commonly performed in the mid-stages of rehabilitation after severe knee injuries. The use of reliable objective measures has been advocated to improve the quality of SLS assessment. The aim of this study was to describe a qualitative whole-body scoring system based on two-dimensional (2D) video analysis during SLS test and validate it against three-dimensional (3D) kinetics and kinematics.

METHODS

Thirty-four competitive football (soccer) players performed a series of SLS tasks. 3D kinematics and kinetics were collected through infrared cameras, and 2D video analysis was performed through a scoring system with sub-scores ranging from 0/2 (non-adequate movement) to 2/2 (adequate movement) based on frontal and lateral planes objective measurements. 3D kinematics and kinetics were grouped according to the results of the 2D evaluation and compared through the analysis of variance (P < 0.05).

RESULTS

Higher hip adduction, hip internalrotation, and knee valgus collapse were found in trials rated 0/2 or 1/2 compared with theone rated 2/2 in the limb stability score. Hip flexion and hip/knee moment ratio were lower in those scoring 0/2 comparedwith those scoring 2/2 in the movement strategy criterion. A low total score was associated with higherknee valgus collapse and lower hip/knee extensor moment ratio. Compensatory strategieswere found in frontal plane scores.

CONCLUSIONS

The 2D scoring system described was strongly associated with kinematics and kinetics from gold-standard 3D motion capture and might represent a valid tool to describe the movement quality of an SLS task.

Monitoring of sprint and change of direction velocity, vertical jump height, and repeated sprint ability in sub-elite female football players throughout their menstrual cycle

AIMS

The aim of this study was to investigate the associations between the early follicular (EF, i.e., menstruation), late follicular (LF), and middle luteal (ML) phases of the menstrual cycle and different factors that may influence football performance.

METHODS

To this end, 11 eumenorrheic sub-elite female football players underwent field tests to assess sprint speed, lower extremity power, repeated sprint ability, velocity on change of direction, and technical skills at each cycle phase.

RESULTS

Performance during the 15-m change of direction ability test, 15-m ball dribbling test, squat jump height, total sprint time [sum of 7 sprints] and decrement score [(mean sprint time/best sprint time × 100) - 100], maximum and mean heart rate, and perceived exertion did not significantly differ among menstrual cycle phases. Conversely, the linear sprint velocity over 10, 20, 30-m distances was decreased in EF vs LF (10-, 20- and 30-m) and in ML vs LF (10- and 20-m) (p < 0.05). The 40-m sprint velocity did not change in the different menstrual cycle phases.

CONCLUSION

Overall, our study suggests that sex hormone fluctuations during the menstrual cycle are not associated with vertical jump, velocity on change of direction, and repeated sprint ability, but may influence linear sprint velocity over short distances (10, 20, and 30 m).

On-field rehabilitation in football: current practice and perceptions. A survey of the English Premier League and Football League

INTRODUCTION

Return to play related research is increasing rapidly, with two recent competency-based frameworks offering conceptualised support for on-field rehabilitation (OFR) decision-making. It is still unknown, however, who is responsible for OFR and how they typically select, monitor, and progress OFR processes.

AIMS

The purpose of this study was to investigate current OFR practice within English professional football to support practitioners with decision-making and highlight opportunities for future research related to the design, monitoring, and progression of OFR.

METHODS

Sixty-nine practitioners responsible for the design and implementation of OFR at 69 clubs (75% of the English Premier League and Football League) responded to a survey containing 30 questions (14 open and 16 closed).

RESULTS

The main findings were that therapists (physiotherapists/sports therapists) have the largest influence on OFR, followed by physical performance coaches (sports scientists/strength and conditioning coaches), technical coaches and medical doctors. There was more agreement for the ordering of specific OFR drills earlier in the process when activities are easier to control. The most frequently reported objective monitoring tool was global positioning systems (GPS), with functional/clinical experience/expertise remaining subjectively vital. GPS outputs (e.g., sprint metrics and accelerations/decelerations) were most used for between session decision-making, with verbal communication being key for within session decision-making.

CONCLUSION

Future research should use evidence of current practice, such as drill design and monitoring techniques, to explore drill-level analysis and give practitioners greater insights into which stage of current OFR frameworks specific drills fall, and how they might be more objectively progressed/regressed.

Association Between Total Genotype Score and Muscle Injuries in Top-Level Football Players: a Pilot Study

BACKGROUND

Recently, genetic predisposition to injury has become a popular area of research and the association between a few single nucleotide polymorphisms (SNPs) and the susceptibility to develop musculoskeletal injuries has been shown. This pilot study aimed to investigate the combined effect of common gene polymorphisms previously associated with muscle injuries in Italian soccer players.

RESULTS

A total of 64 Italian male top football players (age 23.1 ± 5.5 years; stature 180.2 ± 7.4 cm; weight 73.0 ± 7.9 kg) were genotyped for four gene polymorphisms [ACE I/D (rs4341), ACTN3 c.1729C > T (rs1815739), COL5A1 C > T (rs2722) and MCT1 c.1470A > T (rs1049434)]. Muscle injuries were gathered for 10 years (2009-2019). Buccal swabs were used to obtain genomic DNA, and the PCR method was used to genotype the samples. The combined influence of the four polymorphisms studied was calculated using a total genotype score (TGS: from 0 to 100 arbitrary units; a.u.). A genotype score (GS) of 2 was assigned to the "protective" genotype for injuries, a GS of 1 was assigned to the heterozygous genotype while a GS of 0 was assigned to the "worst" genotype. The distribution of genotype frequencies in the ACE I/D (rs4341), ACTN3 c.1729C > T (rs1815739) and MCT1 c.1470A > T (rs1049434) polymorphisms was different between non-injured and injured football players (p = 0.001; p = 0.016 and p = 0.005, respectively). The incidence of muscle injuries was significantly different among the ACE I/D (rs4341), ACTN3 c.1729C > T (rs1815739) and COL5A1 C > T (rs2722) genotype groups, showing a lower incidence of injuries in the "protective" genotype than "worse" genotype (ACE, p < 0.001; ACTN3, p = 0.005) or intermediate genotype (COL5A1, p = 0.029). The mean TGS in non-injured football players (63.7 ± 13.0 a.u.) was different from that of injured football players (42.5 ± 12.5 a.u., p < 0.001). There was a TGS cut-off point (56.2 a.u.) to discriminate non-injured from injured football players. Players with a TGS beyond this cut-off had an odds ratio of 3.5 (95%CI 1.8-6.8; p < 0.001) to suffer an injury when compared with players with lower TGS.

CONCLUSIONS

These preliminary data suggest that carrying a high number of "protective" gene variants could influence an individual's susceptibility to developing muscle injuries in football. Adapting the training load parameters to the athletes' genetic profile represents today the new frontier of the methodology of training.

No evidence that visual exploratory activity distinguishes the super elite from elite football players

Visual exploratory activities (VEA) refer to head and body movements that football players make prior to receiving the ball to search possibilities for action. VEA is considered a key performance indicator that differentiates the skill level of players. This study revisited whether VEA also distinguishes super elite, award winning players from their elite teammates without awards. To this end, video footage from the men's UEFA Champions League season 2018-2019 featuring the super elite players (n = 18) and the elite players (n = 18) was analyzed. To reduce the potential differences in match dynamics as much as possible, the selected players in the two groups were of the same team, playing the same match, in the same positioning line. VEA (i.e. frequency per unit time) during the penultimate and final pass prior to ball reception and performance (i.e. percentages of adequate ball contacts and subsequent actions) were compared between the two groups of players using ANOVA and Mann-Whitney tests, respectively. In addition, hierarchical stepwise regression analyses were conducted to explore the degree to which VEA was predicted by group and subsequent performance. The results showed that the players had higher VEA during the final pass (M = 0.45) than the penultimate pass (M = 0.41). There were no significant differences in VEA or performance between the two groups. Also, the regression analyses did not deliver significant models. We conclude that with partial control for match dynamics, no evidence emerged to support that VEA distinguishes super elite players from elite football players.

Metabolic, cognitive and neuromuscular responses to different multidirectional agility-like sprint protocols in elite female soccer players - a randomised crossover study

PURPOSE

Resistance to fatigue is a key factor in injury prevention that needs to be considered in return-to-sport (RTS) scenarios, especially after severe knee ligament injuries. Fatigue should be induced under game-like conditions. The SpeedCourt (SC) is a movement platform for assessing multidirectional sprint performance, typical of game-sports, due to change-of-direction movements in response to a visual stimulus. Designing adequate fatigue protocols requires the suitable arrangement of several loading variables such as number of intervals, sprint distance or work/relief ratio (W:R). Therefore, this study analysed the acute fatigue effects of different SC protocols on metabolic load, cognitive function and neuromuscular performance.

METHODS

Eighteen female soccer players (mean ± SD; age: 23.1 ± 4.6 years) of the 1st German Division participated in this randomised, crossover study. Using a random allocation sequence, players completed four volume-equated protocols differing in W:R and sprint distance per interval (P1:12 × 30 m, W:R = 1:2 s; P2:12 × 30 m, W:R = 1:3 s; P3:18 × 20 m, W:R = 1:2 s; P4:18 × 20 m, W:R = 1:3 s). Pre- and post-exercise, metabolic load was measured per blood lactate concentration (BLaC), cognitive function per reaction time (RT), and neuromuscular performance including multiple rebound jumps (MRJ height, primary outcome variable; Reactive Strength Index, RSI) and 5 m sprint times (SP5).

RESULTS

Repeated-measures ANOVA revealed significant main time effects (p < .05) with improved performance post-exercise in RT (504 vs. 482 ms, d = 1.95), MRJ height (24.0 vs. 24.8 cm, d = 0.77), RSI (1.39 vs. 1.43, d = 0.52), and SP5 (1.19 vs. 1.17 s, d = 0.56). There was significant main time (p < .001) and time x protocol interaction effects in BLaC (p < .001). P1 induced higher BLaC values (4.52 ± 1.83 mmol/L) compared to P2 (3.79 ± 1.83 mmol/L; d = 0.74) and P4 (3.12 ± 1.83 mmol/L; d = 1.06), whereas P3 (4.23 ± 1.69 mmol/L) elicited higher BLaC values compared to P4 (d = 0.74).

CONCLUSION

All protocols caused an improved cognitive function and neuromuscular performance. The former may be related to enhanced noradrenergic activation or exercise specificity which induced an improved stimulus processing. The latter may be explained by a possible post-activation performance enhancement effect on jump and sprint performance. A shorter relief duration in W:R as opposed to sprint distance per interval produced higher BLaC values. The protocols may serve as reference data for improved RTS decision-making in elite female soccer players.

TRIAL REGISTRATION

Deutsches Register Klinischer Studien (DRKS), No.: DRKS00033496 , Registered 19. Februar 2024, Retrospectively Registered.

Effect of maturation level on normative specific-agility performance metrics and their fitness predictors in soccer players aged 11-18 years

BACKGROUND

In sports sciences, normative data serve as standards for specific physical performance attributes, enhancing talent identification within a specific population. The aim of this study was to provide standard data for Agility-15 m, Ball-15 m tests, and skill index, considering maturation level, specifically age at peak height velocity (PHV). The study also investigated the relationship between relative performances in these tests and anthropometrics, jumping (squat jump [SJ], countermovement jump [CMJ]), and sprinting abilities (S-5 m, S-10 m, S-20 m, S-30 m) in young soccer players.

METHODS

The study involved 647 soccer players aged 11-18 years, categorized into three groups: pre-PHV, circum-PHV, and post-PHV. Statistical analysis was conducted using analysis of variance and Bonferroni post hoc testing to detect variations among maturation groups, and Pearson's correlation test to examine the relationship between factors.

RESULTS

Agility-15 m and ball-15 m performances among maturity groups showed significant differences (p < 0.01). Significant correlations were identified in pre-PHV group, between lower limb length and Agility-15 m (r=-0.23, p < 0.05) and between height and Ball-15 m (r=-0.23, p < 0.05). In post-PHV group, there was a correlation between body fat percentage (BF %) and Agility-15 m (r = 0.17, p < 0.05) and Ball-15 m (r = 0.21, p < 0.05). In all maturity groups, there were significant correlations between agility and sprint tests (S-5 m, S-10 m, S-20 m, and S-30 m) and muscle power (SJ and CMJ).

CONCLUSION

The study revealed that both speed and lower limb power significantly influence agility in young soccer players, providing valuable insights for coaches and practitioners to create tailored training plans and interventions for different age groups and maturity levels.

An analysis of transition-resulted goal scoring patterns in football leagues: a comparison of the first 5 rounds and the last 5 rounds prior midway of the season

OBJECTIVE

This study investigated the concept of 'game style' in football, focusing on a team's distinctive approach characterized by tactics, formations, and strategies. The objective is to compare goal-scoring patterns related to "non-offensive transition," "set pieces," "offensive transition," and "positive outcomes" across different league groups.

METHODOLOGY

The sample comprises 702 football games, categorized into three league groups: Top Leagues, Marginal Leagues, and Emerging Leagues. A total of 2140 goals were analyzed, classifying them into four types: "No Transitions", "Set Pieces", "Offensive Transitions (direct), and "Positive Outcomes" of offensive transitions. The study aims to identify relevant differences between two distinct competitive periods, namely "Rounds 1 to 5" and "Rounds Last 5."

RESULTS

The analysis reveals no significant differences in scoring methods between "Rounds 1 to 5" and "Rounds Last 5" across all variables in the analyzed league groups, except for goals conceded by "No Transition" in the Emerging Leagues. Additionally, results indicate that goals resulting from direct offensive transitions and positive outcomes substantially impact the Top Leagues, constituting 54% of the total scoring.

CONCLUSION

The study emphasizes the importance of establishing and maintaining consolidated game patterns, as demonstrated by the consistent scoring patterns across different league groups. While most leagues show no variations in scoring methods between early and late rounds, attention to goals conceded by "No Transition" in Emerging Leagues is warranted. The prominence of direct offensive transitions and positive outcomes in Top Leagues highlights the relevance of these strategies in the scoring process, emphasizing the need for teams to focus on developing and implementing effective game patterns.

Evaluation of Strength and Functional Ability of Soccer Players Two Years After Anterior Cruciate Ligament Reconstruction: A Cross-sectional Study

OBJECTIVES

This study examines the strength and functional capacity of active soccer players two years post anterior cruciate ligament reconstruction (ACLR).

METHODS

Sixteen players, two years post ACLR, participated. Isokinetic tests assessed Peak Torque (PT) for concentric and eccentric contractions, along with conventional (H/Qconv) and functional (H/Qfunc) H/Q ratios at various angular velocities. Functional ability was gauged through hop tests. Paired-Samples T Test compared PT and hop test values, as well as H/Qconv and H/Qfunc ratios between involved and non-involved limbs. Limb symmetry was evaluated using the Limb Symmetry Index (LSI).

RESULTS

After two years, participants exhibited significant differences in concentric PT between limbs. The non-involved limb demonstrated superior performance at isokinetic speeds. Eccentrically, PT for knee extensors and flexors showed no significant disparities between the operated and non-operated limbs across all velocities tested. Most participants did not achieve LSI 90-110% for knee extensors and flexors. No noteworthy distinctions were observed in H/Qconv, H/Qfunc, and hop tests between limbs. The majority met LSI 90-110% in hop tests, except in the 30-second side hop (37%).

CONCLUSIONS

Two years post ACLR, soccer players still manifest strength and functional deficits, heightening the risk of injury.

Technical and tactical evolution of the offensive team sequences in LaLiga between 2008 and 2021. Is Spanish football now a more associative game?

The aim of this investigation was to study the technical and tactical evolution of the offensive team sequences in the Spanish football teams from 2008/09 to 2020/21. A comparative analysis including twelve variables related to the development of offensive sequences in 4940 matches was performed from 2008/09 to 2020/21 seasons of the Spanish professional football league (LaLiga). All match observations were recorded using a validated video tracking system. Multilevel linear mixed models were used to examine the differences across seasons, considering the effects of contextual variables. The number of passes per sequence (2.4 [CI: 2.2-2.5] vs 3.2 [CI: 3.0-3.4]; +33.3%), the passing accuracy (72.1 [CI: 70.6-73.5] vs 76.9 [CI: 75.4-78.3]%; +6.8%) and the average duration of the team sequences (6.4 [CI: 5.9-6.8] vs 8.3 [CI: 7.8-8.7] seconds; +25.76%) showed a small increasing trend over the seasons (P < 0.05). In contrast, variables such as the direct speed of progression (2.2 [CI: 2.1-2.3] vs 1.6 [CI: 1.5-1.7] metres/second; -24.5%), key passes (8.1 [CI: 7.6-8.5] vs 6.8 [CI: 6.3-7.2]; -15.8%), and the sequences that ended in the attacking third (64.8 [CI: 62,7-66.8] vs 57.1 [CI: 55.1-59.2]; -11.7%) or in a shot (13.0 [CI: 12.4-13.6] vs 10.2 [CI: 9.6-10.8]; -21.6%) showed a small decreasing trend from 2008/09 to 2020/21 (P < 0.05). Spanish professional football teams slightly evolved technically and tactically towards a more associative style of play that includes longer passing sequences. This evolution also involved a decreasing speed of progression and fewer technical actions such as through balls, key passes and shots.

Lost in transition: Exploring injury risk in academy footballers shifting between the second and first teams

OBJECTIVES

To compare the injury profiles of football players shifting between second and first teams with those of second- and first-team players, and to examine the opinions of shifting players.

DESIGN

Prospective cohort study.

METHODS

170 male players from Athletic Club (second team = 90, shifting = 20, first team = 60) were followed over eight seasons. Injuries and exposure time were recorded following the FIFA consensus, and 18 shifting players answered a seven-item questionnaire on their experience.

RESULTS

35 % shifting players became full-time first-team players, in contrast to only 8 % of second-team players (odds ratio = 6.4, p < 0.01). There were no differences in the overall injury incidence, but the overall burden of injuries was higher in second-team (172 days lost/1000 h) and shifting players (194 days lost/1000 h) compared with first-team players (114 days lost/1000 h, p < 0.01). Shifting players had a higher burden of knee joint/ligament injuries compared with first-team players (137 vs. 18 days lost/1000 h, p < 0.01) and anterior cruciate ligament (ACL) ruptures (122 vs. 10 days lost/1000 h, p < 0.01). There was a trend towards a higher burden of ACL ruptures in shifting players than in second-team players (122 vs. 41 days lost/1000 h, p = 0.07). Shifting players reported constant pressure and better communication with the second-team coaching staff than with the first-team staff.

CONCLUSIONS

The high burden of injuries in shifting players, particularly from ACL ruptures, highlights the need for action. Ensuring high-quality communication between second- and first-team staff remains a key challenge.

Health and performance effects of 12 weeks of small-sided street football training compared to grass football training in habitually active young men

PURPOSE

The purpose of the present study was to investigate the health and exercise performance effects of street football training on very small pitches surrounded by boards in young habitually active men in comparison to small-sided football training on grass.

METHODS

Thirty-nine habitually active men (30.7 ± 6.7 years, 90.9 ± 16.6 kg, 183.8 ± 4.5 cm, 39.6 ± 6.0 mL/min/kg) were randomly assigned to a street football training group (ST) or grass football group (GR) playing small-sided games for 70 min, 1.5 and 1.7 times per week for 12 weeks, respectively, or an inactive control group (CO). Intensity during training was measured using heart rate (HR) and GPS units. Pre- and post-intervention, a test battery was completed.

RESULTS

Mean HR (87.1 ± 5.0 vs. 84.0 ± 5.3%HRmax; P > 0.05) and percentage of training time above 90%HRmax (44 ± 28 vs. 34 ± 24%; P > 0.05) were not different between ST and GR. VO2max increased (P < 0.001) by 3.6[95% CI 1.8;5.4]mL/min/kg in GR with no significant change in ST or CO. HR during running at 8 km/h decreased (P < 0.001) by 14[10;17]bpm in ST and by 12[6;19]bpm in GR, with no change in CO. No changes were observed in blood pressure, resting HR, total body mass, lean body mass, whole-body bone mineral density, fasting blood glucose, HbA1c, plasma insulin, total cholesterol(C), LDL-C or HDL-C. Moreover, no changes were observed in Yo-Yo IE2 performance, 30-m sprint time, jump length or postural balance.

CONCLUSION

Small-sided street football training for 12 weeks with 1-2 weekly sessions led to improvements in submaximal exercise capacity only, whereas recreational grass football training confirmed previous positive effects on submaximal exercise capacity as well as cardiorespiratory fitness.

Physical match demands across different playing positions during transitional play and high-pressure activities in elite soccer

This study explored physical match demands across different playing positions during transitional play, to inform the need for position-specific training interventions. Data was collected using 10 Hz GPS units from 10 competitive matches including 23 elite soccer players of the 1st Polish Division (Ekstraklasa) in season 2020-21. A total of 4249 positional observations were made; center backs (n = 884), full backs (n = 972), central defensive midfielders (n = 236), central attacking midfielders (n = 270), central midfielders (n = 578), wingers (n = 778), and attackers (n = 531). Match data reflected distances covered per minute (m · min-1): total distance (TD), high-speed running distance (HSRD, > 19.8 km · h-1), sprint distance (SD, > 25.2 km · h-1), and the frequency of high-intensity accelerations and decelerations (A+D, > 3 m · s-2; n · min-1). Total absolute sprint distance (SD, > 25.2 km · h-1) and total relative sprint distance (Rel B5) were also quantified. A univariate analysis of variance revealed position-specific differences. Significant effects of position were found for all analysed metrics during transitional play (large ESs; p <.001). Central attacking midfielders displayed higher TD (m · min-1), fullbacks covered highest SD (m · min-1) and wingers achieved the highest A+D (n · min-1) (p ≤ 0.05). Centre backs displayed the lowest physical outputs when compared to all other positions, except in A+D (n · min-1) during defensive transitions (p ≤ 0.05). Attackers displayed the highest physical metrics during high pressure activities (p ≤ 0.05). Coaches should carefully consider positional transitional demands to better inform training design. With specific attention paid to drills that replicate game play.

Does playing football really increase the risk of knee osteoarthritis? A Systematic Review and Meta-analysis

OBJECTIVE: To evaluate the relationship between football (soccer) participation and tibiofemoral knee osteoarthritis (OA), considering the influence of competitive level and previous knee injuries. DESIGN: Aetiology systematic review with meta-analysis. LITERATURE SEARCH: PubMed, Embase, AMED and Cochrane were searched for relevant publications. STUDY SELECTION CRITERIA: Studies of football players that included a control group consisting of mainly sedentary non-football players, and the relationship of knee OA, were considered. The studies had to report radiographically-verified knee OA and specify football activity. DATA SYNTHESIS: Eleven studies, involving 1,805 football players and 4,022 control individuals were included. Subgroups consisting of data regarding level of play and previous injuries were also synthesized. RESULTS: The overall prevalence of knee OA among football players was increased among professional and recreational players, compared with controls. When knee injuries were excluded, there was no difference in knee OA between football players and controls (OR 1.25; [95% CI 0.61-2.54]). Football players with a previous knee injury had a greater risk of knee OA when compared with football players with no history of previous knee injury (OR 4.16; [95% CI 1.97-8.77]). CONCLUSION: Football players were at increased risk of knee OA. However, after excluding participants with a history of previous knee injury, there were no differences in knee OA between football players and controls. Previous knee injury was important for developing knee OA. Playing football, in the absence of major knee injuries, did not increase the risk of knee OA.

In which rounds were the most rotations of key players made, and how did this affect physical activity? Analysis of the eight best teams of the 2018 FIFA world cup Russia

BACKGROUND

Team management, especially player selection, rotation, and availability, are critical issues when dealing with the high demands of modern training and gameplay. As such, research continuously seeks ways to improve these actions or implement new ideas to gain a competitive advantage through the rotation of players in the starting line-up. The current study aimed to examine the rounds of the 2018 FIFA World Cup Russia in which the most rotations of key players were made and how this affected physical activity.

METHODS

The sample consisted of 110 players from the top eight teams in the 2018 World Cup Russia who played entire matches for up to 90 min in seven consecutive games. All players were divided into key players (KPs, n = 58) and non-key players (NKPs, n = 52). The analysis used data collected by an advanced motion analysis system known as STATS®, with physical activity variables analyzed, including total distance covered (TDC), distance covered with high intensity over 20 km/h (HIR), and the number of sprints undertaken. In statistical analysis, differences between categories and consecutive matches were calculated using the Kruskal-Wallis H test, and if a significant effect size was found, a multiple comparisons p values test was performed.

RESULTS

The best teams at the 2018 FIFA World Cup Russia used the most KP rotations with NKPs in the third match of the group stage. In addition, this was even more visible among more successful teams than less successful teams. The rotation strategy among the best eight teams allowed them to maintain the physical activity of KPs and NKPs in all rounds of the tournament.

CONCLUSIONS

Coaches and coaching staff should incorporate squad rotation that includes a large group of players in their team management to improve their success. Team management expertise in player rotation during matches played over congested schedules at top tournaments maintains high levels of physical activity indicators (TDC, HIR, and sprints).

Coaches of youth field sports as delivery agents of injury prevention programmes: how are we training the trainers? A scoping review

OBJECTIVE

To systematically map the coach education (CE) component of injury prevention programmes (IPPs) for youth field sports by identifying and synthesising the design, content and facilitation strategies used to address competency drivers and behaviour change.

DESIGN

Scoping review.

DATA SOURCES

PubMed, PsycInfo, EMBASE, CINAHL, SportDiscus and Google Scholar electronic databases were searched using keywords related to IPPs and youth field sports.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies of IPPs in youth field sports, that provided 'train-the-trainer' education to coaches as designated delivery agents.

RESULTS

20 studies from two field sports (soccer/football; n=17, Rugby Union; n=3) fulfilled the eligibility criteria. Eleven CE interventions occurred in the preseason and 18 occurred at one time-point (single day). Five studies cited use of a behavioural change theory or model in the design of their CE, most frequently the Health Action Process Approach model (n=5); and use of behavioural change techniques varied. Twelve of twenty studies (60%) reported some form of ongoing support to coaches following the CE primary intervention concurrent with IPP implementation.

CONCLUSION

CE that occurs on 1 day (one time-point) is most popular for preparing coaches as delivery agents of IPPs in youth field sports. While recognising pragmatic barriers, more expansive in-service training, support and feedback may enhance the effective implementation of IPPs.

TRIAL REGISTRATION NUMBER

https://doi.org/10.17605/OSF.IO/FMHGD.

UEFA Women's Elite Club Injury Study: a prospective study on 1527 injuries over four consecutive seasons 2018/2019 to 2021/2022 reveals thigh muscle injuries to be most common and ACL injuries most burdensome

OBJECTIVE

Injuries in women's football (soccer) have scarcely been investigated, and no study has been conducted in the highest competitive level involving club teams from different countries. Our aim was to investigate the time-loss injury epidemiology and characteristics among women's elite football players over four seasons.

METHODS

596 players from 15 elite women's teams in Europe were studied prospectively during the 2018/2019 to 2021/2022 seasons (44 team seasons). Medical staff recorded individual player exposure and time-loss injuries. Injury incidence was calculated as the number of injuries per 1000 playing hours and injury burden as the number of days lost per 1000 hours.

RESULTS

1527 injuries were recorded in 463 players with an injury incidence of 6.7 (95% CI 6.4 to 7.0) injuries per 1000 hours and a nearly fourfold higher incidence during match play compared with training (18.4, 95% CI 16.9 to 19.9 vs 4.8, 95% CI 4.5 to 5.1; rate ratio 3.8, 95% CI 3.5 to 4.2). Thigh muscle injuries (hamstrings 12%, 188/1527, and quadriceps 11%, 171/1527) were the most frequent injury, while anterior cruciate ligament (ACL) injury had the highest burden (38.0 days lost per 1000 hours, IQR 29.2-52.1) with median days lost of 292 (IQR 246-334) days. Concussions constituted 3% (47/1527) of all injuries, with more than half of them (55%, 26/47) due to ball-related impact.

CONCLUSION

An elite women's football team can expect approximately 35 time-loss injuries per season. Thigh muscle injury was the most common injury and ACL injury had the highest injury burden.

Designing a study on footballers' injuries in the 2024 African cup of nations competition (Ivory Coast)

INTRODUCTION

To enhance players' performance and implement effective injury prevention protocols and surveillance programs in football, it is essential to conduct epidemiological studies. Since significant disparities in injury rates across various football competitions were reported, it is important to characterize injuries in the context of the African cup of nation (AFCON) competition.

AIM

To determine the incidence and factors associated with injuries among African footballers during the 2024 AFCON competition, which will be held in Ivory Coast from January 13 to February 11, 2024.

METHODS

Two expert physician in sports medicine will perform an analytical study (i.e.; a video-based analysis) of the 52 matches that will be played during the 2024 AFCON. The following parameters will be noted: i) Injury incidence, ii) Characteristics of injured players such as age, on-field position, and player league continent, iii) Characteristics ofinjuries such as mechanism, body location, moment of injury in terms of the minute of play and the round of the match, place of the injury in term of stadium zone, replacement consequent to the injury, absence next match, re-injury, recurrence of the injury with the same location during the competition, referee decision, and stoppage time for on-field injury, and iv) Characteristics of matches such as the match' schedule, ambient temperature, humidity, and wind speed.

CONCLUSION

This study will allow enriching the existing literature with additional data regarding the injuries and the players' characteristics in the African context.

The effects of proprioceptive exercise training on physical fitness and performance of soccer skills in young soccer players

The purpose of this study is to analyze the effect of proprioceptive exercise training on soccer skills and physical fitness in young soccer players. Nineteen young soccer players participated in the study. Participants were divided into proprioceptive exercises training (PT) and control (Cont) groups. The physical fitness and soccer skill performance test assessed at pre- and posttraining. Balance ability and power significantly improved in both groups after 8 weeks of training (P<0.05). Dribble in the PT group was similar between pre- and posttraining, with a statistically significant difference in the Cont group (P<0.05). There were no significant differences within and between groups according to training in the left and right feet for juggling. The PT and Cont groups did not differ significantly regarding short passes posttraining. However, a significant improvement in long passes was observed in the PT group after training period (P<0.05). Shooting was no different between and within the groups. In conclusion, these inconsistent findings are thought to be due to the applied exercise method, training duration, and the specificity of the physical growth period of the young players. Therefore, it is necessary to increase the frequency and time of proprioceptive exercise training and apply factors for cognitive ability improvement to training programs for young soccer players in future studies. These studies could suggest appropriate training methods necessary to improve the performance of young soccer players.

Sport-related concussion in soccer -a scoping review of available guidelines and a call for action to FIFA & soccer governing bodies

Introduction

Sport-related concussions (SRC) have been a concern in all sports, including soccer. The long-term effects of soccer-related head injuries are a public health concern. The Concussion in Sport Group (CISG) released a consensus statement in 2017 and several soccer governing associations have published their own SRC guidelines while referring to it but it is unclear whether this has been universally adopted.

Research question

We aimed to investigate whether guidelines published by soccer associations have any discrepancies; and the extent to which they follow the CISG recommendations.

Materials and methods

A scoping review of available soccer-specific SRC guidelines was performed via databases PubMed, Google Scholar, and official soccer association websites via web browser Google. The inclusion criteria were soccer-specific SRC guidelines. Comparisons between guidelines were made concerning the following index items: initial (on-site) assessment, removal from play, re-evaluation with neuroimaging, return-to-sport protocol, special populations, and education.

Results

Nine soccer associations with available guidelines were included in this review. Guidelines obtained were from official associations in the United Kingdom, United States of America, Canada, Australia, and New Zealand. When compared to each other and the CISG recommendations, discrepancies were found within guidelines regarding the index items. Additionally, major soccer associations in some countries famous for soccer were found to have not published any publicly available guidelines.

Discussion and conclusion

SRC guidelines from different soccer associations contain discrepancies which may be detrimental to athletes, both short and long-term. We recommend that all major soccer governing associations publish guidelines that are standardised and accessible to all athletes.

Mechanical and metabolic power in accelerated running-Part II: team sports

PURPOSE

This manuscript is devoted to discuss the interplay between velocity and acceleration in setting metabolic and mechanical power in team sports.

METHODS

To this aim, an essential step is to assess the individual Acceleration-Speed Profile (ASP) by appropriately analysing training sessions or matches. This allows one to estimate maximal mechanical and metabolic power, including that for running at constant speed, and hence to determine individual thresholds thereof.

RESULTS

Several approaches are described and the results, as obtained from 38 official matches of one team (Italian Serie B, season 2020-2021), are reported and discussed. The number of events in which the external mechanical power exceeded 80% of that estimated from the subject's ASP ([Formula: see text]) was 1.61 times larger than the number of accelerations above 2.5 m s-2 ([Formula: see text]). The difference was largest for midfielders and smallest for attackers (2.30 and 1.36 times, respectively) due to (i) a higher starting velocity for midfielders and (ii) a higher external peak power for attackers in performing [Formula: see text]. From the energetic perspective, the duration and the corresponding metabolic power of high-demanding phases ([Formula: see text]) were essentially constant (6 s and 22 W  kg-1, respectively) from the beginning to the end of the match, even if their number decreased from 28 in the first to 21 in the last 15-min period, as a consequence of the increased recovery time between [Formula: see text] from 26 s in the first to 37 s in the last 15-min period.

CONCLUSION

These data underline the flaws of acceleration counting above fixed thresholds.

Optimised return to play: high treatment success rate in core muscle injury with surgical release of the anterior tendon of the rectus abdominis muscle and proximal tenotomy of the adductor longus muscle

OBJECTIVES

Core muscle injury is a debilitating condition that causes chronic groin pain in athletes, particularly common in soccer players. The condition is characterised by pain in the inguinal region and can lead to a significant number of absences from high-intensity physical activity. It is caused by repetitive overload without proper counterbalance from the abdominal muscles, hip flexors, and adductors in susceptible athletes. Surgical indications for core muscle injury consider cases where non-surgical treatments have not provided sufficient relief. The aim of this study was to assess the results of surgical intervention for core muscle injury using the technique employed by the Sports Medicine Group of (Institute of Orthopedics and Traumatology of Hospital das Clínicas - Universidade de São Paulo). The procedure involves releasing the anterior portion of the tendon of the rectus abdominis muscle near the pubic symphysis, along with proximal tenotomy of the adductor longus muscle tendon.

METHODS

This study utilised a consecutive historical cohort analysis of the medical records of 45 male athletes, of which, 75.6% were professional soccer players, who underwent surgical treatment between January 1, 2002, and December 31, 2021. The participants included active athletes aged between 18 and 40 years, with a mean age of 23.9 years, and were diagnosed with myotendinous core muscle injury. These athletes experienced pain in the pubic symphysis and adductor tendon region and had previously undergone medical treatment and physical therapy for a duration of three to six months without significant improvement.

RESULTS

The average time for athletes to return to sport after surgery was 135 days, with a majority of participants being soccer and futsal players. The surgical intervention yielded promising results, with a positive correlation between unilateral injuries and the time taken to return to sport. The complication rate was low, at 6.7%. Notably, the rate of symptom resolution was high, at 93.3%. Furthermore, the analysis indicated that the player's position on the field significantly influenced the discharge period, suggesting that the game position plays a role in the recovery process.

CONCLUSION

The combined surgical procedure involving the release of the rectus abdominis tendon and adductor longus muscle tenotomy demonstrates favourable outcomes for athletes with core muscle injury. This study provides strong support for the effectiveness of this surgical approach in managing the condition and offers a potential path to recovery and return to sports activities.

LEVEL OF EVIDENCE: 4

STUDY DESIGN

Cross-sectional study.

Decrease in aerial challenges after revision of goal kick rules in Japan Professional Soccer League: explorative study of the possibility of a risk reduction for head injury, concussion, and brain damage by a rule revision

In 2019, FIFA revised the goal kick (GLK) rule such that a GLK could be performed even if the kicker had teammates in the penalty area. This study aimed to examine whether the rule revision reduced the frequency of aerial challenge (AC) and long GLKs (LGLKs), which are risk factors for head injury and concussion in soccer. We analyzed all official league matches (306 matches/season) of the Japan Professional Soccer League 1st Division before (2018 season) and after the rule revision (2020 season). The analysis categorized GLKs into short GLKs (SGLKs) and LGLKs, depending on the GLK distance, and included the frequency and causes of AC, in each match following a GLK, which were compared between the 2018 and 2020 seasons. The average number of LGLKs per match in the 2020 season (8.85) decreased compared to that in the 2018 season (14.20). Additionally, for ACs following a GLK, the frequency of ACs decreased from 6.08 to 3.92 per match. Meanwhile, the frequency of LGLKs tended to increase toward the end of the first and second halves in matches. The results of this study revealed that the 2019 GLK rule revision reduced the number of LGLKs and ACs.

Shoulder injuries in Brazilian professional football players: epidemiological analysis of 3828 games

OBJECTIVES

Football is a globally played sport that poses potential risks for musculoskeletal injuries. Upper-limb injuries have a lower incidence rate than lower-limb injuries but can still cause absenteeism and performance impairment in football players. This descriptive epidemiological study aimed to evaluate and compare the epidemiological data on shoulder injuries among professional football players in two major Brazilian football championships.

METHODS

Data were collected throughout the championships, and club physicians medically evaluated each player during official games using two online forms. The collected information included the player's age and position, injury diagnosis, laterality, location on the field where the injury occurred, playing time, imaging examinations performed, need for surgical treatment, time to return to play (TRP), and recurrence of the injury. The incidence of injuries was evaluated using the Federation Internationale de Football Association (FIFA) incidence formula.

RESULTS

A total of 107 shoulder injuries were recorded (4.3% of all injuries), with a FIFA incidence of 0.847. Glenohumeral dislocations (GHDs) and acromioclavicular dislocations (ACDs) accounted for 37.38% and 35.51% of all shoulder injuries, respectively. Goalkeepers and defenders presented, respectively, a 2.15 and 1.57 times increased risk of suffering shoulder injuries, while attackers presented a 0.63 times decreased risk. Injury recurrence was observed in 14.95% of cases, with GHDs and ACDs showing recurrence rates of 35.00% and 5.26%, respectively. Surgery was performed in 9.35% of cases, with GHDs representing 50% of all surgeries. The average TRP was 22.37 days, with severe and major injuries accounting for 11.21% and 10.28% of all injuries, respectively. Goalkeepers had the highest average TRP of 36.15 days. Recurring injuries had a higher average TRP of 33.44 days compared to nonrecurring injuries, which had an average TRP of 20.43 days. Surgically treated injuries had the highest average TRP of 112.5 days.

CONCLUSION

Shoulder injuries in the professional football scenario are of great concern due to the high recurrence rate and need for surgical treatment, which will lead to a long TRP. These findings emphasize the need to implement prevention protocols and effective treatments to reduce the consequences of such injuries, which are usually underestimated in this sport.

LEVEL OF EVIDENCE

III.

Youth soccer players: patterns of injury involving the primary growth plates of epiphyses

Youth soccer (football) is immensely popular internationally. Earlier participation, sport sub-specialization, and year-around practice have led to an increased incidence of injury from both acute trauma and repetitive overuse. The growth plates (physes) of the immature skeleton are particularly vulnerable to injury and delayed diagnosis can lead to future growth disturbance and long-term morbidity. Familiarity with the various components of the growth plate complex necessary for ensuring normal endochondral ossification is fundamental in understanding the various patterns of imaging findings following injury. This review discusses the zonal columnar arrangement of the growth plate proper and the contrasting function of the vasculature within the subjacent epiphysis and metaphysis. This is followed by an evidence-based discussion of the common patterns of injury involving the epiphyseal primary growth plate observed among youth soccer players: subcategorized into physeal fractures (direct injury) and physeal stress injuries (indirect insult to subjacent metaphysis). In this section, the role of imaging and characteristic imaging features will be discussed. While the normal physiologic and pathophysiologic mechanisms can be applied to other growth plates, such as primary growth plates underlying the apophyses and secondary growth plates surrounding the secondary ossificiation centers, which also undergo endochondral ossification, the current review is focused on injuries involving the primary growth plates underlying epiphyses.

'More than likely the men come first. That's just very frustrating'. A qualitative exploration of contextual factors affecting the implementation of injury prevention initiatives and the provision of effective injury management in elite-level women's club football in Ireland

OBJECTIVES

The aim of our study was to explore the contextual factors that affect the implementation of football injury prevention initiatives and the provision of effective injury management in the Irish Women's National League (WNL).

METHODS

We used a criterion-based purposive sampling approach to recruit coaches (n=7), players (n=17) and medical personnel (n=8) representing eight of the nine clubs in the WNL to participate in one-to-one semistructured interviews. Our study was located within an interpretivist, constructivist research paradigm. The interview data were analysed using reflexive thematic analysis.

RESULTS

The participants identified academic and work pressures, financial challenges, conflict with college football, inadequate facilities and gender inequity as being barriers to the implementation of injury prevention initiatives and the provision of effective injury management. Financial constraints within clubs were perceived to limit the provision of medical care and strength and conditioning (S&C) support and this was deemed to be associated with a heightened risk of injuries.

CONCLUSION

Specific contextual factors were identified which curtail the implementation of injury prevention initiatives and the provision of effective injury management in elite-level women's club football in Ireland. Gender inequity was identified as one of the factors impacting the availability of high-quality medical care, S&C support, as well as access to training and match facilities. Our results provide new insights that could be used to inform the design and implementation of injury prevention and management initiatives for women football players in Ireland.

Hamstring muscle injury is preceded by a short period of higher running demands in professional football players

The aim of this study was to examine match running patterns before a hamstring muscle injury occurs during a match in male professional football players. A total of 281 male professional football players belonging to 7 teams from LaLiga were prospectively monitored over three seasons. Among these, 36 players suffered a non-contact hamstring muscle injury during an official match. The injuries were recorded by the medical staff, including the minute when the injury occurred. Running distances at different speed thresholds for 5 min and 15 min before the injury were compared to mean values of the previous 5 matches for the same time points. There were a total of 44 non-contact hamstring muscle injuries, which represents a hamstring muscle injury incidence of 3.34 injuries/1000 h of match exposure. The average time loss for these injuries was 33 ± 28 days (range 7 to 117 days). In the 15 min prior to the injury, players ran a similar distance as in control matches (p from 0.22 to 0.08). However, players ran a greater distance in the 5-min period before the injury than in control matches at 21.0-23.9 km/h (p < 0.001) and at ≥ 24 km/h (p < 0.001). The odds ratio for a hamstring muscle injury was 7.147 for those players who ran > 30.0 m at ≥ 21 km/h in a 5-min period (p < 0.001). Hamstring muscle injuries during competition were preceded by 5 min of higher running demands at > 21 km/h, compared with control matches. This suggests that a short period of unusual running increases the risk of hamstring muscle injury in professional football players.

Developmental differences of kinematic and muscular activation patterns in instep soccer kick

Kinematic and neuromuscular activity differences amongst soccer players in different age groups were examined in this study. Thirty male soccer players evenly divided into three age groups (Group 1: age 12-13; Group 2: age 14-15; Group 3: age 16-17) were asked to perform instep kicks towards a target 11 m away. Their anthropometrics, instep kick kinematics, resultant ball velocities, both legs isokinetic strength, and electromyography (EMG) during kicking were compared amongst the three age groups. There were significant differences in height, body mass, body mass index, ball velocities, and isokinetic strength values amongst three age groups. Also, kicking kinematics including angular and linear velocities of hip, knee, ankle, and toe were significantly different (p < 0.05) amongst groups in several kicking phases. Furthermore, the activities of m. rectus femoris, m. vastus medialis, m. biceps femoris were significantly different amongst groups (p < 0.05). The ball velocities and leg strength parameters increased with age, neuromuscular activations, and kinematic parameters differed especially in leg-coking and forward swing phase of instep soccer kick. It should be concluded that an increase of resultant ball velocity of the instep kick is closely associated with chronical age, the development of leg muscle strength, and the neuromuscular activity of the kicking leg.

Multiplanar lumbar, pelvis and kick leg sequencing during soccer instep kicking from different approach angles

Multiplanar kinematic and kinetic sequencing from different approach angles can highlight how soccer players perform fast and accurate kicks. This study therefore aimed to a) determine multiplanar torso, pelvis and kick leg sequencing during instep kicks and b) highlight the effect of different approach angles on these sequencing patterns. Twenty male soccer players (mass 77.9 ± 6.5 kg, height 1.71 ± 0.09 m, age 23.2 ± 3.7 years) performed kicks from self-selected (∼30-45°), straight (0°) and wide (67.5°) approaches and multiplanar lumbo-pelvic, hip and knee angular velocities, moments and powers were derived from 3D motion analysis. The results suggest tension arc release between the upper and lower body functions as a two-stage mechanism. The first phase of arc release was characterised by increases in concentric hip flexion and transverse lumbo-pelvic velocities towards the ball. The second phase was characterised by increasing concentric lumbo-pelvic flexion and knee extension work to angularly accelerate the kicking knee towards foot-to-ball contact. Further, alterations in kinematic and kinetic sequencing helped maintain performance (ball and foot velocities at ball contact) and accuracy at approach angles other than self-selected. These findings can help coaches and practitioners design effective training practices.

A rare soccer-related injury: Traumatic posterior hip fracture-dislocation - Case series and overview of the literature

BACKGROUND

Soccer is one of the most popular sports with millions of active professional and non-professional players worldwide. Traumatic hip dislocations are rare in soccer but can lead to major sequelae both physically and psychologically. The aim of this review was to obtain insight into the outcomes after surgerically repaired hip fracture-dislocation in soccer players as well as rehabilitation and prevention.

METHODS

Two cases of a posterior hip fracture-dislocation that occurred during an amateur soccer match are presented and mechanism of injury, complications and rehabilitation were analysed. Follow-up of both patients was at least one year after surgery. Questionnaires and physical examinations were obtained to quantify and qualify outcome.

RESULTS

In both cases the hip-dislocations were reduced within 3 h after injury. Semi-elective open reduction and internal fixation was performed within seven days. In one case, there was a concomitant Pipkin fracture and sciatic nerve neuropathy. There were no postoperative complications. Follow-up showed full of range of motion and normal hip functionality in both cases. However, both patients indicated a reduced quality of life and anxiety related to the accident.

CONCLUSION

Traumatic hip fracture-dislocations during soccer practice are extremely rare. Despite uncomplicated fracture healing after surgery and return of hip function, both patients still suffer from psychological problems resulting in a decreased quality of life. Further research is required to enhance psychological outcomes, as well as to facilitate return to pre-injury levels of participation and engagement in sports following traumatic hip fracture-dislocations related to soccer.

'Setting the Benchmark' Part 2: Contextualising the Physical Demands of Teams in the FIFA World Cup Qatar 2022

This study aimed to contextualise and benchmark the physical demands of teams in the FIFA World Cup Qatar 2022. With FIFA's official approval, all sixty-four games were analysed during the competition (n = 32 teams) using a multi-camera computerised tracking system. On average, teams during Qatar 2022 covered around 108.1 ± 3.6 km in total, with 9.0 ± 0.9 and 2.3 ± 0.3 km covered at the higher intensities (≥20.0 and ≥25.0 km · h-1), respectively. Compared to the FIFA World Cup Russia 2018, national teams in Qatar 2022 covered only 3% more total distance but 16-19% more distance at the higher intensities (P < 0.01; Effect Size [ES]: 0.9-2.0). When the data was adjusted based on the number of minutes played, tournament differences at the higher intensities were less pronounced (9-12%; P < 0.01; ES: 0.7-1.3). The United States, Canada, Saudi Arabia, Germany and IR Iran covered 19-34% more high-intensity distance than Argentina, Ecuador, Qatar, Poland and Costa Rica during the 2022 tournament (P < 0.01; ES: 3.2-3.5). Match-to-match variation of each team in Qatar 2022 revealed Ecuador and Uruguay were particularly consistent for the distances covered at higher intensities (Coefficient of Variation [CV]: 2-3%), whilst Japan demonstrated considerable variation (CV: 23-29%). Teams generally covered more total distance on a per-minute basis in the first versus the second half (P < 0.01; ES: 1.2), but no differences existed at higher intensities (P > 0.05; ES: 0.0-0.1). Correlations between the number of high-intensity runs and various phase of play events across all teams were strongest for defensive transitions and recoveries, in addition to progressions up the pitch and into the final third (r = 0.63-0.75; P < 0.01). The present findings provide valuable context into the contemporary team demands of international football. This information could be useful for practitioners to benchmark team performances and to potentially understand the myriad of factors impacting physical performances.

'Setting the Benchmark' Part 1: The Contextualised Physical Demands of Positional Roles in the FIFA World Cup Qatar 2022

This study aimed to contextualise and benchmark the positional role demands during the FIFA World Cup Qatar 2022. With FIFA's official approval, all sixty-four games were analysed during the competition (n=722) using a multi-camera computerised tracking system. During a typical FIFA World Cup Qatar 2022 match, defensive and central midfielders covered 8-19% more total distance than other positional roles (P<0.01; Effect Size [ES]: 0.8-2.5). The distances covered at higher intensities (≥20 and ≥25 km · h-1) were 16-92% and 36-138% higher for wide midfielders and wide forwards compared to central defenders, defensive and central midfielders as well as centre forwards (P<0.01; ES: 0.7-2.2 and ES: 0.6-1.4). Defensive and central midfielders covered a greater proportion of their distance at higher intensities (≥20 and ≥25 km · h-1) out-of-possession (71-83%; P<0.01; ES: 1.4-3.0), whilst attacking midfielders, wide and centre forwards more in-possession (55-68%; P<0.01; ES: 1.6-3.3). Nine out of the top ten sprint speeds attained at the tournament were from wide positional roles (35.3-35.7 km · h-1). All positional roles demonstrated a second half reduction in total distance covered compared to the first half (P<0.01; ES: 0.8-1.3). A decline between halves for the distances covered at higher intensities (≥20 and ≥25 km · h-1) were more evident in attacking midfielders, wide defenders and midfielders than for other positional roles (P<0.01; ES: 0.3-0.7). Defensive midfielders and centre forwards were found to have the highest coefficient of variation (CV: 30.9-35.9% and 67.7-67.8%) for the distances covered at higher intensities (≥20 and ≥25 km · h-1) compared to other positional roles. The current findings provide valuable contextual information about the contemporary positional demands of international football. This could be useful in the development and prescription of specific training regimes for national teams.