Assessing the individual relationships between physical test improvements and external load match parameters in male professional football players-a brief report

Purpose

This study aimed to explore whether a meaningful improvement in physical performance following an in-season strength training intervention can be related to external load match parameters at an individual level in professional male football players.

Methods

Eight male professional football players (25.4 ± 3.1 years, 184.1 ± 3.4 cm, 79.3 ± 2.2 kg) completed a 10-week strength intervention period in addition to football-specific training and matches. Commonly used physical and external load measures were assessed before and after intervention. Physical performance improvements had to exceed the measurement's typical error and the smallest worthwhile difference (SWD) to be considered meaningful. External load match parameters were assessed before and after the intervention period using SWD and non-overlap of all pairs (NAP) analysis. A Bayesian pairwise correlation analysis was performed to evaluate relationships between changes in physical performance and external load match parameters.

Results

Three players displayed meaningful improvements in two to five physical performance measures. However, positive changes exceeding the SWD and positive effects in NAP results were observed for all players in external load match parameters. Kendall's tau correlation analysis showed evidence (base factor >3) for only one correlation (maximum speed - decelerations, τ = -0.62) between the changes in physical performance and external load measures, while the remaining comparisons exhibited no relation.

Conclusions

The findings suggest that improvements in physical performance may not necessarily translate to improvements in external load match parameters. Further research, with larger sample sizes, is needed to understand potential mechanisms between acute and chronic physical performance changes and football external load parameters during training and matches.

Professional soccer players perceptions of the English Football Association 4 corner model in supporting first team transitions

The English Football Association (FA from hereon in) 4 Corner Model is a multidisciplinary framework that aims to enhance player talent identification and development, and is characterised by physical, social, technical/tactical and psychological components. Despite the framework being prominent within English football development pathways, player insights into the effectiveness of the framework in supporting academy to first team transitions are lacking. Therefore, the aim of this study was to explore established first team professional footballer's perceptions of the FA 4 Corner Model, in relation to the attributes that they perceived to facilitate the successful transition to a professional first team environment. Twelve current (n = 8) and ex (n = 4) professional players who had successfully transitioned from a youth academy, and subsequently became an established first team player, were interviewed for the study. Interpretations across the qualitative data set highlighted the importance of players adapting to physical and tactical demands, while also dealing with different psychosocial factors when entering a first team setting. The study highlights that disparities can exist between players, coaches, practitioners, and sport scientists perceived development needs, a situation that could hinder players progression through the player pathway.

Weekly Training Load Differences between Starting and Non-Starting Soccer Players

The aim of this study was to examine the differences in the weekly training load between starters and non-starters classified based on the match starting line-up, with respect to the playing position and a training day. Notably, 31 young adult soccer players (age: 18.79 ± 1.04 years) competing in the 3rd Czech division were monitored across the season. The weekly training load was measured using a GPS system as follows: total distance covered (TD), high-speed running distance (HSR), sprint running distance (SR), and acceleration and deceleration distance (ACDC). We found higher values in three out of four observed variables (HSR, SR, and ACDC, excluding TD) for starters compared to non-starters (p < 0.05), with small to moderate effect sizes (d = 0.40-0.49). Differences were observed especially in players who were fullbacks, offensive midfielders, and forwards. Moreover, the largest differences were found in training prior to a match day for HSR, SR, and ACDC (p < 0.05). Non-starters experienced lower weekly external loads in offensive player positions, predominantly in high-intensity variables, which are essential for their physical performance. It seems that non-starters may experience potential under-loading in the training process. Coaches and practitioners should be aware of this potential risk and find an appropriate method to compensate for load discrepancies, particularly in terms of high-intensity activities.

Surveying the youth-to-senior transition landscape in Major League Soccer: a new frontier

PURPOSE

The aim of this study was to survey Major League Soccer stakeholders' attitudes and perspectives on the youth-to-senior transition with a particular interest in the league's evolving club structures, specifically the reserve team and youth academy entities. The survey assessed various stakeholders' views on clubs' organisational aims and structure, the capabilities of club entities to prepare players for the first team, and the transition process to the first team within MLS.

METHODS

A total of 80 participants working in various 'player operation' roles for MLS clubs in the United States and Canada voluntarily completed the online survey.

RESULTS

The predominant aim for both reserve teams and academies in MLS is to develop players for the first team. The organisational structure and governance of reserve teams are varied across the league, but an overarching feature is their function as a development team. When players are transitioning, communication between staff may or may not be clear and effective. Finally, for players within an MLS club's talent pathway, a variety of support strategies are made available during the transition into the first team, but psychological support in particular may be limited or unavailable.

CONCLUSION

Similar to European soccer, the aim of MLS reserve teams and youth academies is to develop first team players for the club. However, while players are transitioning into the first team, communication may or may not be clear and effective, and psychological support may be absent, which may impair player development initiatives.

A global perspective on collision and non-collision match characteristics in male rugby union: Comparisons by age and playing standard

This study quantified and compared the collision and non-collision match characteristics across age categories (i.e. U12, U14, U16, U18, Senior) for both amateur and elite playing standards from Tier 1 rugby union nations (i.e. England, South Africa, New Zealand). Two-hundred and one male matches (5911 min ball-in-play) were coded using computerised notational analysis, including 193,708 match characteristics (e.g. 83,688 collisions, 33,052 tackles, 13,299 rucks, 1006 mauls, 2681 scrums, 2923 lineouts, 44,879 passes, 5568 kicks). Generalised linear mixed models with post-hoc comparisons and cluster analysis compared the match characteristics by age category and playing standard. Overall significant differences (p < 0.001) between age category and playing standard were found for the frequency of match characteristics, and tackle and ruck activity. The frequency of characteristics increased with age category and playing standard except for scrums and tries that were the lowest at the senior level. For the tackle, the percentage of successful tackles, frequency of active shoulder, sequential and simultaneous tackles increased with age and playing standard. For ruck activity, the number of attackers and defenders were lower in U18 and senior than younger age categories. Cluster analysis demonstrated clear differences in all and collision match characteristics and activity by age category and playing standard. These findings provide the most comprehensive quantification and comparison of collision and non-collision activity in rugby union demonstrating increased frequency and type of collision activity with increasing age and playing standard. These findings have implications for policy to ensure the safe development of rugby union players throughout the world.

"I hardly have a problem […] I have my period quite rarely too": Female football players' and their coaches' perceptions of barriers to communication on menstrual cycle

Introduction

Symptoms related to the menstrual cycle (MC) affect the performance level and health of female athletes in various ways. Previous research has reported MC symptoms such as pain, mood disturbance, reduced coordination and competition distraction as well as diminished performance levels and an increased injury risk among female elite athletes. Despite this, the coach-athlete communication related to the female hormonal cycle is limited. The aim of the present study was to explore the perceptions of MC communication in a group of junior elite football players and their male coaches in a case study of one youth football team in a specific club in Norway.

Methods

The study used a qualitative approach with semi-structured interviews. In total, 8 female junior elite players (aged 16-20) from a Norwegian football team and 2 of their male coaches participated in the study.

Results

The data analysis revealed two main communication barriers: 1. interpersonal barriers (e.g., false assumptions about the coach/athletes and social discomfort) and 2. knowledge barriers (e.g., unaware/perceptions of insufficient knowledge levels).

Discussion

As the players seemed to be unaware of their insufficient MC knowledge (e.g., failed to see a connection between the MC and their health and performance level), the coaches perceived their knowledge as insufficient and coped mainly by outsourcing MC communication to female staff and apps. Hence, the MC communication was hindered by both the athletes and the coaches (e.g., mutual avoidance). In line with previous research, this study supports that there is a need for developing effective strategies to overcome the interpersonal barriers and knowledge gaps.

A survey of organizational structure and operational practices of elite youth football academies and national federations from around the world: A performance and medical perspective

Aim

Medical and performance units are integral components of player development programmes in elite football academies. Nevertheless, the nature of the operational processes implemented by practitioners within clubs and national federations remains unexplored. The aim of the present study, therefore, was to survey elite youth professional football academies from around the world regarding the operational processes adopted by their medical and performance units.

Methods

Of the 50 organizations invited, 10 national federations and 25 clubs took part in the survey resulting in a response rate of 70% (95% confidence interval, 56%-81%). The respondents represented three groups: senior club and academy management, performance, and medical staff.

Results

The majority (60%-90%) of clubs and national federations reported strategic alignment between senior and academy medical and performance units as well as between academy medical and performance units. Survey responses indicated substantial heterogeneity in the composition and number of medical and performance professionals employed in academies. The majority of respondents agreed their medical and performance departments were effective in utilizing staff knowledge and external sources of knowledge to inform their practice (56%-80%). Performance staff (40%-50%) and physiotherapists (30%-32%) were deemed most influential in injury prevention programmes. During the return-to-play process, the influence of specific practitioners in the medical and performance units was dependent upon the phase of return-to-play. Shared decision-making was common practice amongst performance and medical staff in injury prevention and return-to-play processes. Medical and performance data were generally centralized across the first team and academy in majority (50%-72%) of clubs and national federations. Data were integrated within the same data management system to a higher degree in clubs (68%) vs. national federations (40%). Research and development activity were reported for most academies (50%-72%), and generally led by the head of performance (37%) or team doctor (21%). Research activities were largely undertaken via internal staff (~100%), academic collaborations (50%-88%) and/or external consultants and industry partnerships (77%-83%) in the national federation and clubs.

Conclusion

Collectively, these findings provide a detailed overview regarding key operational processes delivered by medical and performance practitioners working in elite football academies.

External load differences between elite youth and professional football players: ready for take-off?

This study examines differences in weekly load between the first (FT) and the under 19 team (U19) within a professional football setting. Data were collected in 11 FT and 9 U19 players (2016-2017 season). FT data was divided into weeks with (FT-M1) or without (FT-M0) a mid-week match. Indicators were total distance (TD) and TD at 12-15, 15-20, 20-25 and >25 km‧h^-1 and were analysed as external load (m), intensity (m‧min^-1) and load monotony (a.u.). TD-based load was higher for U19 compared to FT-M0 (very likely moderate) and FT-M1 (likely large). Differences at higher velocities were substantially less (trivial to possibly small), with TD >25 km‧h^-1 being lower than FT-M0 (very likely moderate) and FT-M1 (likely small). All intensity indicators were lower for U19 (likely small to almost certainly large). Load monotony was higher compared to FT-M1 (possibly small to almost certainly very large). Compared to FT-M0, monotony was higher for TD (possibly very large) and TD >25 km‧h^‑1 (possibly moderate) but lower for TD 12-15 (possibly small) and 15-20 km‧h^‑1 (likely moderate). So, despite higher weekly external loads at low velocity for elite youth players, external intensity and load variation increases when these players may transition to professional football.

Premature Professionalisation or Early Engagement? Examining Practise in Football Player Pathways

There is a growing debate, both in the academic and sporting worlds, about the most appropriate pathway for high potential young players in sport. In this regard, there has been a considerable focus on the age of selection into structured talent development pathways and the nature of the experience once players have been recruited. Given the economic and reputational currency associated with developing professional footballers in particular, it is unsurprising that professional football clubs continue to invest significant financial resources into their academy structures. Understandably, this recruitment policy has attracted substantial attention within the media and research community, with ethical concerns arising surrounding the impact early selection may have on the welfare and the experiences of the young players within the pathway. The aim of this perspective article was to critically consider the research underpinning the early engagement practises of football clubs and the extent to which, and how, the pathway can provide players with the most appropriate starting point for their development. This evidence points to the need to look beyond the prevalent 'early specialisation vs. diversification' debate in youth sport towards a consideration of an early engagement perspective that reflects the biopsychosocial influences on talent development and the socio-political environment that influences decisions. We provide practical recommendations focused on the quality of the early engagement experience.

Increasing tactical complexity to enhance the synchronisation of collective behaviours: An action-research study throughout a competitive volleyball season

An Action-Research (AR) design was implemented throughout a competitive season in which Constraint-led and Step-Game approaches were combined. This intervention study investigated the impact of increased performance complexity on emergence of counterattacking synchronisation tendencies in team players (laterally and longitudinally on court) at different set moments. Fifteen youth volleyball team players were studied across three action-research cycles, with performance in one competitive match analysed per cycle. Team synchronisation tendencies were assessed using the cluster phase method, with a 3 (matches) x 2 (set moments) x 2 (court direction) repeated-measures ANOVA statistical procedure to calculate differences in cluster amplitude mean values. Results revealed a reduction in team synchrony levels when tactical complexity of counterattacking play increased (second AR-cycle). Nevertheless, similar levels of team synchrony emerged between the first and third AR-cycles. Results also revealed the final moments of a set as a significant environmental constraint that shaped synchronisation tendencies. Evidence suggested that the (re)achievement of functional synchrony was realised through integration of Constraint-led and Step-Game approaches during practices designed to enhance tactical awareness in players. Finally, an insider action-research design provided relevant contextualised insights on the development of a team's synchronisation tendencies.

Effect of the Modification of the Number of Players, the Size of the Goal, and the Size of the Field in Competition on the Play Actions in U-12 Male Football

A player’s sports development involves a long process. The modification of rules for youth players seeks to adapt the sport to the child and his/her development. The manipulation of rules affects the technical and tactical skills demonstrated by players and, therefore, their development. The objective of this study was to analyse the effect of a reduction in the number of players (from 8 per team to 5 per team), the size of the goal (from 6 × 2 m to 3 × 2 m) and the playing space (from 58 × 38 m to 38 × 20 m), on the technical and tactical actions in youth football players. A quasi-experimental A-B-A design was implemented to assess the effect of the rule changes. The players (n = 40) played three tournaments using two competition formats (official rules, modified rules, and official rules). The results show that the use of the modified rules generated a greater number and variability in the technical–tactical actions, a greater number of actions with teammates in the pass line, a greater continuity in the game, a greater number of attack and defence actions in areas close to the goal, and favours team play. The experimental format fits the players’ individual progression better (U-12) as well as the players’ and teams’ collective development, and it will allow players to evolve from the individual development of previous stages.

The Physical Characteristics of Specific Phases of Play During Rugby Union Match Play

PURPOSE

To quantify the frequencies and timings of rugby union match-play phases (ie, attacking, defending, ball in play [BIP], and ball out of play [BOP]) and then compare the physical characteristics of attacking, defending, and BOP between forwards and backs.

METHODS

Data were analyzed from 59 male rugby union academy players (259 observations). Each player wore a microtechnology device (OptimEye S5; Catapult, Melbourne, Australia) with video footage analyzed for phase timings and frequencies. Dependent variables were analyzed using a linear mixed-effects model and assessed with magnitude-based inferences and Cohen d effect sizes (ES).

RESULTS

Attack, defense, BIP, and BOP times were 12.7 (3.1), 14.7 (2.5), 27.4 (2.9), and 47.4 (4.1) min, respectively. Mean attack (26 [17] s), defense (26 [18] s), and BIP (33 [24] s) phases were shorter than BOP phases (59 [33] s). The relative distance in attacking phases was similar (112.2 [48.4] vs 114.6 [52.3] m·min-1, ES = 0.00 ± 0.23) between forwards and backs but greater in forwards (114.5 [52.7] vs 109.0 [54.8] m·min-1, ES = 0.32 ± 0.23) during defense and greater in backs during BOP (ES = -0.66 ± 0.23).

CONCLUSIONS

Total time in attack, defense, and therefore BIP was less than BOP. Relative distance was greater in forwards during defense, whereas it was greater in backs during BOP and similar between positions during attack. Players should be exposed to training intensities from in-play phases (ie, attack and defense) rather than whole-match data and practice technical skills during these intensities.

Goal Format in Small-Sided Soccer Games: Technical Actions and Offensive Scenarios of Prepubescent Players

The aim of this study was to investigate the influence of the number of goal-posts and the positioning of goal-posts used within small-sided games on the frequency of technical actions and offensive scenarios performed by prepubescent players within soccer. The participants were eight male prepubescent soccer players (12.1 ± 0.5 years). The participants were video recorded for 20 min playing four different formats of 4v4 small-sided games: (1) standard two goal game; (2) four goal game, one goal in each corner; (3) two goal game with goal-posts positioned 9.14 m/10 yd infield, scoring only through the back of the goal; (4) four goal-game, one goal positioned 9.14 m/10 yd infield in each corner, scoring through either the front or back of each goal. Chi-squared tests of independence were utilized to statistically explore the impact of the different small-sided game formats. There were significant associations (p < 0.05) observed between the different small-sided game formats and the frequency of turns, dribbles, shots, goals and overlaps performed. For example, players performed more turns in small-sided game format two and more shots during small-sided game format four. It is suggested coaches should consider using a variation of the number and positioning of goal-posts in small-sided games as an effective training tool in the development of prepubescent soccer players. This will enable coaches to vary the focus of sessions, and develop specific technical and tactical actions within a situation similar to that of real match-play.