Influence of match status and possession status on the physical and technical characteristics of elite youth female soccer match-play.

This study compared the influence of match status (drawing, losing, or winning) and possession status (in-possession, out-of-possession, or ball-out-of-play) on the physical and technical characteristics of U14 and U16 elite youth female soccer match-play. Data were collected from 189 female academy players during 45 competitive matches, resulting in 387 match observations. Linear mixed models estimated relative; total distance, high-speed running (≥3.00 m·s-1), very high-speed running (≥4.83 m·s-1), and sprinting (≥5.76 m·s-1) distance according to match status and possession status, and 21 technical variables according to match status. Differences in physical and technical characteristics were observed between and within age-groups, dependent upon match status and possession status. Regardless of match status, both age-groups covered greater distances when the ball was in-play compared to ball-out-of-play (107-130 vs 58-68 m·min-1). U16s covered greater distances when out-of-possession than in-possession, regardless of match status. Whilst U14s covered greater distances out-of-possession when drawing or losing only. Differences in physical and technical characteristics when drawing, losing, or winning, suggest a change in playing style according to match status, likely in an attempt to influence or maintain the score-line. These findings have practical implications for coaching, talent identification and development practices within youth female soccer.

The effects of simulated vision impairment on performance in football.

Footballers with vision impairment (VI) are eligible to compete in the Para sport if they meet a minimum impairment criteria (MIC) based on measures of their visual acuity (VA) and/or visual field. Despite the requirements of the International Paralympic Committee Athlete Classification Code that each sport uses an evidence-based classification system, VI football continues to use a medical-based system that lacks evidence to demonstrate the relationship between impairment and performance in the sport. The aim of this study was to systematically simulate vision loss to establish the minimum level of impairment that would affect performance in futsal. Nineteen skilled sighted players completed tests of individual technical skill and anticipation performance under six levels of simulated blur that decreased both VA and contrast sensitivity (CS). VA needed to be reduced to a level of acuity that represents worse vision than that currently used for inclusion in VI football before meaningful decreases in performance were observed. CS did not have a clear effect on football performance. These findings produce the first evidence for the minimum impairment criteria in VI football and suggest a more severe degree of impairment may be required for the MIC.

Rationale and Practical Recommendations for Testing Protocols in Female Soccer: A Narrative Review.

ABSTRACT: Beato, M, Datson, N, Anderson, L, Brownlee, T, Coates, A, and Hulton, A. Rationale and practical recommendations for testing protocols in female soccer: A narrative review. J Strength Cond Res 37(9): 1912-1922, 2023-The aim of this narrative review is to evaluate the presented literature on tests (aerobic, speed, changes of direction [COD], strength, power, jump, and anthropometry) of the varied components of female soccer and to draw attention to the most suitable protocols to allow practitioners to accurately track players' fitness status. The 2 most common field tests used to assess aerobic fitness are the Yo-Yo intermittent test (level 1 and level 2) and the 30-15 intermittent fitness test because of an ability to measure multiple players at once with a soccer-specific intermittent profile. The sprinting performance can be assessed on distances of <30 m; however, longer distances (e.g., 40 m) allow for achieving peak speed (flying sprint test), which can be assessed using global navigation satellite system. Changes-of-direction capacity has been found to be an important component of players testing and training programs, although there is no "gold standard" to assess COD or repeated sprint ability performance in female players. Lower-limb power can be assessed using jump tests that can use force platforms, jump mats, and optoelectronic devices, while maintaining a good reliability. Several in-direct tests are currently available for assessing anthropometry parameters, such as skinfold thickness, hydrodensitometry, and ultrasound. However, dual-energy x-ray absorptiometry is the most valid and reliable method for assessing body composition in team sport athletes, with the addition of bone health that is a key measure in female athletes. In conclusion, the evidence reported in this review will be able to aid practitioners, coaches, and researchers to decide which tests meet the requirements of their environment.

Determining age-specific velocity thresholds for elite youth female soccer players.

Purpose: This study aimed to establish age-specific velocity thresholds for Under (U)14 and U16 elite youth female soccer players. Methods: Data was collected using 10 Hz GPS units during 50 matches from 187 players (U14 n = 89; U16 n = 98). Spectral clustering identified velocity thresholds for high-speed running (HSR), very high-speed running (VHSR), and sprinting (SPR), for 699 half-match observations (U14 n = 369; U16 n = 330). Linear mixed modelling determined youth (U14 and U16) and age-group (U14 or U16) velocity thresholds, and compared distances covered between these and existing senior thresholds. The effect of playing position and playing half on velocity thresholds was also quantified. Results: Youth velocity thresholds of HSR (≥3.00 m·s-1), VHSR (≥4.83 m·s-1), and SPR (≥5.76 m·s-1) were estimated from the model. Age-group and playing position influenced velocity thresholds but playing half did not. Adoption of youth and age-group velocity thresholds resulted in greater distance covered at HSR, VHSR, and SPR (p < 0.001; moderate-large effect size [ES] = 0.86-1.97) compared to senior thresholds. Both age-groups covered similar distances (trivial-small ESs = 0.002-0.23) when adopting youth and age-group velocity thresholds. Conclusion: These youth thresholds provide an alternative to arbitrary velocity thresholds within the literature, and thresholds derived from senior players or other populations, to inform appropriate quantification and interpretation of physical data within this population.

Men Are from Quartile One, Women Are from? Relative Age Effect in European Soccer and the Influence of Age, Success, and Playing Status.

The relative age effect (RAE) is characterised by an overrepresentation of athletes born earlier in the selection year. Whilst an RAE is consistently evident in male soccer, examinations in female players remain limited. The aim of the present study was to examine the influence of sex, as well as age, success, and playing status in European soccer players. The sample consisted of a total of 6546 soccer players from 55 soccer nations that competed in recent European Championship qualification campaigns. Results indicated an evident RAE in male [p = 0.017] but not female [p = 0.765] players. Male players were over-represented by players born in the first quartile for the U17 [p < 0.001] and U19 [p = 0.001] levels, however, this over-representation did not transfer to senior levels. No RAE was observed at any level for female players. Inside each age group, a slight selection bias towards those born in the first quartile for successful squads was observed but did not significantly differentiate between qualification status for either male or female players. Results from this study highlight the disparity in RAE prevalence between male and female players and raise further questions regarding the value of selecting relatively older players to metrics of success, transition, and selection for senior international soccer.

A systematic review of match-play characteristics in women's soccer.

This review aimed to (1) systematically review the scientific literature evaluating the match-play characteristics of women's soccer, (2) determine the methods adopted to quantify match-play characteristics of women's soccer, and (3) present the physical, technical and tactical characteristics of women's soccer match-play across age-groups, playing standards and playing positions. A systematic search of electronic databases was conducted in May 2021; keywords relating to the population, soccer and match-play characteristics were used. Studies which quantified physical, technical or tactical performance of women's soccer players during match-play were included. Excluded studies included adapted match-play formats and training studies. Sixty-nine studies met the eligibility criteria. Studies predominantly quantified match-play characteristics of senior international (n = 27) and domestic (n = 30) women's soccer match-play, with only seven studies reporting youth match-play characteristics. Physical (n = 47), technical (n = 26) and tactical characteristics (n = 2) were reported as whole-match (n = 65), half-match (n = 21), segmental (n = 17) or peak (n = 8) characteristics. Beyond age-groups, playing standard, and playing position, fourteen studies quantified the impact of contextual factors, such as environment or match outcome, on match-play characteristics. Distance was the most commonly reported variable (n = 43), as outfield women's soccer players covered a total distance of 5480-11160 m during match-play. This systematic review highlights that physical match-performance increases between age-groups and playing standards, and differs between playing positions. However, further research is warranted to understand potential differences in technical and tactical match-performance. Coaches and practitioners can use the evidence presented within this review to inform population-specific practices, however, they should be mindful of important methodological limitations within the literature (e.g. inconsistent velocity and acceleration/deceleration thresholds). Future research should attempt to integrate physical, technical and tactical characteristics as opposed to quantifying characteristics in isolation, to gain a deeper and more holistic insight into match-performance.

Inter-methodological quantification of the target change for performance test outcomes relevant to elite female soccer players.

INTRODUCTION: Valid and informed interpretations of changes in physical performance test data are important within athletic development programmes. At present, there is a lack of consensus regarding a suitable method for deeming whether a change in physical performance is practically relevant or not. METHODS: We compared true population variance in mean test scores between those derived from evidence synthesis of observational studies to those derived from practioner opinion (n = 30), and to those derived from a measurement error (minimal detectable change) quantification (n = 140). All these methods can help to obtain 'target' change score values for performance variables. RESULTS: We found that the conventional 'blanket' target change of 0.2 (between-subjects SD) systematically underestimated practically relevant and more informed changes derived for 5-m sprinting, 30-m sprinting, CMJ, and Yo-Yo Intermittent Recovery Level 1 (IR1) tests in elite female soccer players. CONCLUSIONS: For the first time in the field of sport and exercise sciences, we have illustrated the use of a principled approach for comparing different methods for the definition of changes in physical performance test variables that are practically relevant. Our between-method comparison approach provides preliminary guidance for arriving at target change values that may be useful for research purposes and tracking of individual female soccer player's physical performance.

A valid and reliable test of technical skill for vision impaired football.

OBJECTIVES: The International Paralympic Committee requires international federations to develop and implement sport-specific classification guidelines based on scientific evidence. Performance tests are key to developing new evidence-based criteria in football for athletes with vision impairment (VI). Therefore, the aim of this study was to develop a valid and reliable test of technical performance for VI football. METHODS: To assure content and face validity, the Vision Impaired Football Skills (VIFS) test was based on recommendations from experienced players and coaches. To test construct validity, we compared 24 sighted football players split into two groups based on highest-level of performance but matched on experience. To test reliability participants completed the VIFS three times on two separate days. RESULTS: Results supported construct validity through detecting differences in performance times between the two groups (p = .004, g = 1.28 95% CI = 0.41 - 2.15). Bias between visits (.54s ± 2.93s; 95% LoA = -5.21- 6.29) and intraclass correlations (.81, 95% CI = .56 - .92) showed between-day agreement and reliability. Within-day reliability was good after a familiarisation trial. CONCLUSIONS: Results support the suitability for the VIFS test for classification research. Future work should establish feasibility for players with a VI.

Reference values for performance test outcomes relevant to English female soccer players.

The purpose of this study was to present reference standards for physical performance test outcomes relevant to elite female soccer players. We analysed mixed-longitudinal data (n = 1715 observations) from a sample of 479 elite youth and senior players as part of the English Football Association's national development programme (age range: 12.7 to 36.0 years). Semi-parametric generalized additive models for location, scale and shape (GAMLSS) estimated age-related reference centiles for 5-m sprinting, 30-m sprinting, countermovement jump (CMJ) height, and Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IR1) performance. The estimated reference centiles indicated that the median of the distribution of physical performance test scores varied non-linearly with advancing chronological age, improving until around 25 years for each performance variable. These are the first reference ranges for performance test outcomes in elite English female soccer players. These data can assist practitioners when interpreting physical test performance outcomes to track an individual's progress over time and support decision-making regarding player recruitment and development.

Understanding the Presence of Mental Fatigue in Elite Female Football.

Purpose: Previous research investigating the impact of induced mental fatigue in football (soccer) has demonstrated associated performance decrements in physical, technical, tactical and decision-making performance. A common limitation amongst this research is the protocols used to induce mental fatigue which provides low ecological validity, and the inclusion of recreational or sub-elite players. Therefore, understanding the presence of mental fatigue in elite football can provide insight into protocols with greater ecological validity. Methods: The current study used focus groups with 10 elite female football players, focusing on five topics (travel, fixture congestion, receiving tactical information, pre-match routine and pressure to win) related to the perceived causes of mental fatigue in elite football (directed by anecdotal quotes in elite football and research-based theories). Results: Several themes emerged from the data; travel fatigue, inability to switch off from football, fatigue experienced following team meetings, use of pre-match music and internal pressure to succeed. Conclusion: These findings present practical recommendations to reduce mental fatigue in elite football settings, such as considering the timing, content and duration of team meetings, providing players with free time/rest where possible, and considering the modality of coaching instructions during matches.

Physiological Characteristics of Female Soccer Players and Health and Performance Considerations: A Narrative Review.

Female soccer has seen a substantial rise in participation, as well as increased financial support from governing bodies over the last decade. Thus, there is an onus on researchers and medical departments to develop a better understanding of the physical characteristics and demands, and the health and performance needs of female soccer players. In this review, we discuss the current research, as well as the knowledge gaps, of six major topics: physical demands, talent identification, body composition, injury risk and prevention, health and nutrition. Data on female talent identification are scarce, and future studies need to elucidate the influence of relative age and maturation selection across age groups. Regarding the physical demands, more research is needed on the pattern of high-intensity sprinting during matches and the contribution of soccer-specific movements. Injuries are not uncommon in female soccer players, but targeting intrinsically modifiable factors with injury prevention programmes can reduce injury rates. The anthropometric and physical characteristics of female players are heterogeneous and setting specific targets should be discouraged in youth and sub-elite players. Menstrual cycle phase may influence performance and injury risk; however, there are few studies in soccer players. Nutrition plays a critical role in health and performance and ensuring adequate energy intake remains a priority. Despite recent progress, there is considerably less research in female than male soccer players. Many gaps in our understanding of how best to develop and manage the health and performance of female soccer players remain.

Whole and peak physical characteristics of elite youth female soccer match-play.

This study quantified whole and peak physical characteristics of Under (U)14 and U16 elite youth female soccer, and compared by position and age-group. Data was collected using 10 Hz GPS units from 431 match observations, during 50 matches involving 201 players (U14 n = 93; U16 n = 108) representing Regional Talent Centres in The Football Association's Girl's England Talent Pathway League. Whole match data were reported as absolute and relative; total (TD), high-speed running (HSR; ≥3.46 m·s-1), very high-speed running (VHSR; ≥5.29 m·s-1), and sprinting (SPR; ≥6.26 m·s-1) distance, and maximum velocity. Moving average analysis determined peak data (1-10 minute durations). Linear mixed models established position-specific differences. U16s covered greater; absolute distance at all speeds (small-moderate ESs; p < 0.001); relative VHSR and SPR m·min-1 (small-moderate ESs; p < 0.001); peak TD and HSR m·min-1 (small ESs) across several peak-durations, and VHSR m·min-1 (small ESs; p < 0.001) across all peak-durations compared to U14s. Position-specific differences were observed across all positions between and within both age-groups, identifying whole and peak physical characteristics are age- and position-dependent within elite youth female soccer match-play. Findings may facilitate informed coaching practices and training programme design, talent identification and development processes.

The developmental and professional activities of female international soccer players from five high-performing nations.

We study the developmental and professional activities engaged in by 86 female adult soccer players from the senior national teams of Australia, Canada, England, Sweden, and the United States of America. Players completed the Participation History Questionnaire (PHQ) to elicit the amount and type of activities engaged in across their developmental and professional years, including milestones, soccer-specific activity and engagement in other sport activity. Greater specialisation than diversification characterised their childhood developmental activities, including all players starting in soccer in childhood and accumulating more hours in soccer activity than other sports during this period. However, interindividual variation further characterised these childhood activities, with a proportion of players diversifying into other sports and/or soccer play to a greater or lesser degree during childhood when compared to the other players. The amount of coach-led soccer practice increased for all players across their development culminating in an average of 15-16 h/wk across a 40-week season in early adulthood. In contrast, the amount of engagement in other sports and soccer peer-led play varied between players but generally decreased across adolescence to negligible amounts in late adolescence. Findings are commensurate with the deliberate practice framework and early engagement.

High-intensity endurance capacity assessment as a tool for talent identification in elite youth female soccer.

Talent identification and development programmes have received broad attention in the last decades, yet evidence regarding the predictive utility of physical performance in female soccer players is limited. Using a retrospective design, we appraised the predictive value of performance-related measures in a sample of 228 youth female soccer players previously involved in residential Elite Performance Camps (age range: 12.7-15.3 years). With 10-m sprinting, 30-m sprinting, counter-movement jump height, and Yo-Yo Intermittent Recovery Test Level 1 (IR1) distance as primary predictor variables, the Akaike Information Criterion (AIC) assessed the relative quality of four penalised logistic regression models for determining future competitive international squads U17-U20 level selection. The model including Yo-Yo IR1 was the best for predicting career outcome. Predicted probabilities of future selection to the international squad increased with higher Yo-Yo IR1 distances, from 4.5% (95% confidence interval, 0.8 to 8.2%) for a distance lower than 440 m to 64.7% (95% confidence interval, 47.3 to 82.1%) for a score of 2040 m. The present study highlights the predictive utility of high-intensity endurance capacity for informing career progression in elite youth female soccer and provides reference values for staff involved in the talent development of elite youth female soccer players.

Efficacy of Injury Prevention Training Is Greater for High-Risk vs Low-Risk Elite Female Youth Soccer Players.

BACKGROUND: The efficacy of robustness training for high- versus low-risk individuals within high-risk groups is currently unknown. PURPOSE: To explore the efficacy of robustness training on injury risk factors among female youth soccer players and to examine if high-risk athletes are greater responders to such training. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 125 elite youth female soccer players on the English FA talent pathway were randomly selected into a training group (n = 71) or a control group (n = 54). Relative leg stiffness, 2-dimensional knee valgus and knee flexion range of motion from a single-legged countermovement jump, and probability of high knee abduction moment (pKAM) risk were all determined before and after a 16-week robustness training program. For further analysis, participants in the training group were split into groups based on risk: high risk (pKAM >0.80, n = 33) and low risk (pKAM <0.55, n = 33). Magnitude-based inferences were used to explore differences between the control and intervention groups and the high- and low-risk groups. RESULTS: Magnitude-based inferences demonstrated significant beneficial effects in the training group for knee valgus, pKAM, and leg stiffness as compared with the control group. The control group demonstrated possible worthwhile differences in knee flexion range of motion as compared with the intervention group. The high-risk group demonstrated likely/very likely worthwhile differences versus the low-risk group for all parameters. CONCLUSION/CLINICAL RELEVANCE: Robustness training induces significant beneficial improvements in injury risk factors among female youth soccer players. The beneficial effects of this multidimensional program are greater for those classified as high risk.

Match Physical Performance of Elite Female Soccer Players During International Competition.

Datson, N, Drust, B, Weston, M, Jarman, IH, Lisboa, P, and Gregson, W. Match physical performance of elite female soccer players during international competition. J Strength Cond Res 31(9): 2379-2387, 2017-The purpose of this study was to provide a detailed analysis of the physical demands of competitive international female soccer match play. A total of 148 individual match observations were undertaken on 107 outfield players competing in competitive international matches during the 2011-2012 and 2012-2013 seasons, using a computerized tracking system (Prozone Sports Ltd., Leeds, England). Total distance and total high-speed running distances were influenced by playing position, with central midfielders completing the highest (10,985 ± 706 m and 2,882 ± 500 m) and central defenders the lowest (9,489 ± 562 m and 1,901 ± 268 m) distances, respectively. Greater total very high-speed running distances were completed when a team was without (399 ± 143 m) compared to with (313 ± 210 m) possession of the ball. Most sprints were over short distances with 76% and 95% being less than 5 and 10 m, respectively. Between half reductions in physical performance were present for all variables, independent of playing position. This study provides novel findings regarding the physical demands of different playing positions in competitive international female match play and provides important insights for physical coaches preparing elite female players for competition.

Applied physiology of female soccer: an update.

The popularity and professionalism of female soccer has increased markedly in recent years, with elite players now employed on either a professional or semi-professional basis. The previous review of the physiological demands of female soccer was undertaken two decades ago when the sport was in its relative infancy. Increased research coupled with greater training and competition demands warrants an updated review to consider the effect on physical performance and injury patterns. The physical demands of match-play along with the influence of factors such as the standard of competition, playing position and fatigue have been explored. Total distance covered for elite female players is approximately 10 km, with 1.7 km completed at high speed (>15 kmh(-1)) [corrected].Elite players complete 28% more high-speed running and 24 % more sprinting than moderate-level players. Decrements in high-speed running distance have been reported between and within halves, which may indicate an inability to maintain high-intensity activity. Although the physical capacity of female players is the most thoroughly researched area, comparisons are difficult due to differing protocols. Elite players exhibit maximal oxygen uptake (VO2max) values of 49.4-57.6 mL·kg(-1)·min(-1), Yo Yo Intermittent Endurance test level 2 (YYIE2) scores of 1,774 ± 532 m [mean ± standard deviation (SD)] and 20 m sprint times of 3.17 ± 0.03 s (mean ± SD). Reasons for the increased prevalence of anterior cruciate ligament injuries in females (2-6 times greater than males) are discussed, with anatomical, biomechanical loading and neuromuscular activation differences being cited in the literature. This review presents an in-depth contemporary examination of the applied physiology of the female soccer player.