Explaining the difference between men's and women's football

Predicting goal probabilities with improved xG models using event sequences in association football

In association football, predicting the likelihood and outcome of a shot at a goal is useful but challenging. Expected goal (xG) models can be used in a variety of ways including evaluating performance and designing offensive strategies. This study proposed a novel framework that uses the events preceding a shot, to improve the accuracy of the expected goals (xG) metric. A combination of previously explored and unexplored temporal features is utilized in the proposed framework. The new features include; "advancement factor", and "player position column". A random forest model was used, which performed better than published single-event-based models in the literature. Results further demonstrated a significant improvement in model performance with the inclusion of preceding event information. The proposed framework and model enable the discovery of event sequences that improve xG, which include; opportunities built up from the sides of the 18-yard box, shots attempted from in front of the goal within the opposition's 18-yard box, and shots from successful passes to the far post.

A mechanical comparison of the translational traction of female-specific and male soccer boots

The studded outsole of a soccer boot provides additional traction to players to minimise the risk of slipping while performing high-speed manoeuvres. As excessive traction can lead to foot fixation and injury risk, there has been significant research surrounding the influence of stud configuration on the level of traction generated. This previous research, however, has predominately focused on the stud patterns, foot morphology and lower limb loading patterns of male players. As the popularity of women's soccer increases, the aim of this investigation was to examine the differences in translational traction of female-specific soccer boots and male soccer boots currently available. A custom-built apparatus was used to determine the translational traction on both natural and artificial grass for four different movement directions. It was hypothesised that the female-specific boot in each pair would produce lower levels of translational traction as they are designed to be safer for female players who are more at risk of lower limb fixation injuries compared to males. An independent samples T-test showed that while there were some loading conditions where female boots produced lower translational traction compared to male boots, across all loading scenarios there was no significant difference between male and female boots (p = 0.818), thus the null hypothesis was rejected.

Analysing substitutions in recent World Cups and European Championships in male and female elite football - influence of new substitution rules

Substitutions play a key role in modern football and can substantially affect the physical and overall performance of a team, and the recent substitution rule changes are worth investigating. This study explored the characteristics of substitutions, including different substitution rules, game results, sex, competition stages, tournaments and penalty shoot-outs success rates. We analysed data from a total of 3,738 substitutions from the last 10 years (2013-2023) of European Championships and World Cups, both men's and women's games. Non-parametric tests and chi-square tests were used for statistical analysis with the significance level set at p < 0.05. With the 5-substitution rule, 48% more substitutions occurred compared to the 3-substitution rule (4.26 ± 1.07 vs. 2.87 ± 0.43, p < 0.05) with a slight increase in the average substitution time (70.6 ± 14.3 vs. 69.2 ± 14.6 min, p < 0.05), and 10% more substitutions in the men's game compared to the women's game (p < 0.05). The timing of the first substitution was slightly different in the knock-out stage compared to group stage (59.8 ± 14.7 vs. 57.2 ± 13.3 min, p < 0.05), and the timing for the winning team and drawing team was later than for the losing team (p < 0.05). A total of 13.2% goals were scored by substitutes, with no significant difference between the 5-substitution rule (15.9%) vs the 3-substition rule (12.5%) (p > 0.05). Interestingly, substitute players had a lower success rate in penalty shoot-out compared to starters (61 vs. 74%, p < 0.05). Additionally, substitute player goal scorers entered the pitch later (p < 0.05) in male games compared to female games and in knock-out stage games compared to group games. This study highlights the importance of substitution rules and timing in modern elite football matches. The timing of the first substitution, introduction of substitutes in knock-out stages, and a lower success rate of substitute players in penalty shoot-outs are crucial factors to consider. Coaches can use this information to make strategic substitution decisions to improve team performance.

'Considering the reality, I am very lucky': how professional players and staff perceive injury prevention and performance protection in women's football

OBJECTIVE

To explore the beliefs and perceptions of professional female footballers and staff regarding injury prevention and performance protection in professional women's football.

METHODS

This qualitative study applied semistructured interviews with 18 participants from 3 top-tier teams from 2 countries (Portugal and England) and 4 nationalities, including 2 physiotherapists, 5 players, 3 team doctors, 2 head coaches, 3 strength and conditioning coaches, 2 managers, and 1 head of performance. Data analysis applied constant comparison analysis, using principles of grounded theory. There were no major differences in the perspectives of players and staff, and the findings are presented together.

RESULTS

Identifying and reporting injuries and recognising potential injury risk factors were mentioned to influence the prevention of injury. Participants stated that the growth and evolution of women's football could influence injury risk. Before reaching the professional level, exposure to potential risk factors, such as lack of recovery, limited awareness and opportunities for prevention (eg, preventive exercises and load management strategies), was believed to impact players' injury risk. Players further described their experiences and the 'bumpy road' to becoming a professional player, their current context and potential future improvements for women's football regarding injury prevention and performance protection.

CONCLUSION

Professional female football players face different injury risks during different moments of their careers. According to elite players and staff, amateur and semiprofessionals have limited resources and lack injury prevention strategies. Professional players and staff perceived the current preventive measures as good and relied on the value of individualised care and a multidisciplinary approach. In the future, more resources and structured injury prevention strategies are needed in youth and non-professional levels of women's football to reduce injury risk and allow more players to reach their maximal performance.

The Evolution of Physical Performance throughout an Entire Season in Female Football Players

Research on the evolution of performance throughout a season in team sports is scarce and mainly focused on men's teams. Our aim in this study was to examine the seasonal variations in relevant indices of physical performance in female football players. Twenty-seven female football players were assessed at week 2 of the season (preseason, PS), week 7 (end of preseason, EP), week 24 (half-season, HS), and week 38 (end of season, ES). Similar to the most common used conditioning tests in football, testing sessions consisted of (1) vertical countermovement jump (CMJ); (2) 20 m running sprint (T20); (3) 25 m side-step cutting maneuver test (V-CUT); and (4) progressive loading test in the full-squat exercise (V1-LOAD). Participants followed their normal football training procedure, which consisted of three weekly training sessions and an official match, without any type of intervention. No significant time effects were observed for CMJ height (p = 0.29) and T20 (p = 0.11) throughout the season. However, significant time effects were found for V-CUT (p = 0.004) and V1-LOAD (p = 0.001). V-CUT performance significantly improved from HS to ES (p = 0.001). Significant increases were observed for V1-LOAD throughout the season: PS-HS (p = 0.009); PS-ES (p < 0.001); EP-ES (p < 0.001); and HS-ES (p = 0.009). These findings suggest that, over the course of the season, female football players experience an enhancement in muscle strength and change of direction ability. However, no discernible improvements were noted in sprinting and jumping capabilities during the same period.

Future horizons in the analysis of technical-tactical performance in women's football: a mixed methods approach to the analysis of in-depth interviews with professional coaches and players

Introduction

Scientific knowledge about the criteria that determine success in women's football is beginning to develop.

Methods

This study was carried out with the aim of detecting regularities in the offensive success in elite women's football, as well as carrying out an interrelational analysis of linked behaviors, based on in-depth interviews with professional coaches and players. Eight in-depth interviews were conducted with professional Spanish coaches and players. The interviews were analyzed by indirect observation from a process of "quantitizing," through the construction of an indirect observation ad hoc instrument. The segmentation of the transcription of the interviews was carried out in textual units, and the creation of a matrix of codes. Two types of analysis were performed: first, a lag sequential analysis (LSA) was performed and, then, a polar coordinates analysis (PCA), which allowed to find, respectively, a wide number of established communicative patterns with offensive performance in women's football, as well as an interrelational map between the established codes.

Results

The results obtained allowed us to suggest a statistically significant association between success in women's football and criteria such as the physical characteristics of a particular player, the individual action space, the duration of the attack, the type of dynamic start, individual and collective technical and tactical aspects, decision making and the type of attack used.

Discussion

Based on these results, the influence of these criteria on performance in women's soccer can be studied in future studies. In addition, with the aim of increasing the validity of these conclusions, new studies on this subject may be carried out following strategies such as the Delphi Method.

A data-driven framing of player and team performance in U.S. Women's soccer

Introduction

In establishing historical benchmarks for success on the pitch and striving to achieve parity off it, the United States Women's National Team (USWNT) and the National Women's Soccer League (NWSL) have long served as standard bearers for professional women's soccer around the globe. However, off-field dilemmas and incessant juxtapositions to men's soccer frequently overshadow the elements that make U.S. women's soccer unique; that is, in the quest to expose and rid the women's game of blatant misconduct, discriminatory practices, and negative stereotypes, relatively little attention has been devoted to performance features that separate the U.S. women's soccer product from its competition. Because many of the issues hindering the progress of women's soccer are rooted in media and managerial practices that marginalize or ignore its positive traits, a need exists for analyses that will properly identify its innate characteristics and competitive advantages so that media members, managers, and fans can accurately frame their perceptions of women competing in the sport.

Methods

To this end, we collected reliable samples of public event data from 560 professional soccer matches and used ANOVAs and t-tests to identify the characteristics that distinguish U.S. women's soccer from other professional leagues and teams.

Results and Discussion

In doing so, we showed that the USWNT tends to shoot from more opportune areas and press opponents at a higher rate, and that the NWSL has recently been matched in quality across certain performance metrics by England's FA Women's Super League.

Fatigue and Recovery Time Course After Female Soccer Matches: A Systematic Review And Meta-analysis

BACKGROUND

This study aimed to analyze the extent of fatigue responses after female soccer matches and the ensuing recovery time course of performance, physiological, and perceptual responses.

METHODS

Three databases (PubMed, Web of Science, and SPORTDiscus) were searched in October 2020 and updated in November 2021. Studies were included when participants were female soccer players, regardless of their ability level. Further, the intervention was an official soccer match with performance, physiological, or perceptual parameters collected pre- and post-match (immediately, 12 h, 24 h, 48 h, or 72 h-post).

RESULTS

A total of 26 studies (n = 465 players) were included for meta-analysis. Most performance parameters showed some immediate post-match reduction (effect size [ES] = - 0.72 to - 1.80), apart from countermovement jump (CMJ; ES = - 0.04). Reduced CMJ performance occurred at 12 h (ES = - 0.38) and 24 h (ES = - 0.42) and sprint at 48 h post-match (ES = - 0.75). Inflammatory and immunological parameters responded acutely with moderate-to-large increases (ES = 0.58-2.75) immediately post-match. Creatine kinase and lactate dehydrogenase alterations persisted at 72 h post-match (ES = 3.79 and 7.46, respectively). Small-to-moderate effects were observed for increased cortisol (ES = 0.75) and reduced testosterone/cortisol ratio (ES = -0.47) immediately post-match, while negligible to small effects existed for testosterone (ES = 0.14) and estradiol (ES = 0.34). Large effects were observed for perceptual variables, with increased fatigue (ES = 1.79) and reduced vigor (ES = - 0.97) at 12 h post-match, while muscle soreness was increased immediately post (ES = 1.63) and at 24 h post-match (ES = 1.00).

CONCLUSIONS

Acute fatigue exists following female soccer matches, and the performance, physiological, and perceptual parameters showed distinctive recovery timelines. Importantly, physical performance was recovered at 72 h post-match, whereas muscle damage markers were still increased at this time point. These timelines should be considered when planning training and match schedules. However, some caution should be advised given the small number of studies available on this population.

REGISTRATION

The protocol for this systematic review was pre-registered on the International Prospective Register of Systematic Reviews (PROSPERO, Registration Number: CRD42021237857).