Motion characteristics of women's college soccer matches: Female Athletes in Motion (FAiM) study

Metabolomic profiling of elite female soccer players: urinary biomarkers over a championship season

INTRODUCTION

In soccer, most studies evaluate metabolic profile changes in male athletes, often using data from a single match. Given the current landscape of women's soccer and the effects of biological sex on the physiological response and adaptation to exercise, more studies targeting female athletes and analyzing pre- and post-game moments throughout the season are necessary.

OBJECTIVES

To describe the metabolomics profile of female soccer athletes from an elite team in Brazil. The study observed the separation of groups in three pre- and post-game moments and identified the discriminating metabolites.

METHODS

The study included 14 female soccer athletes. Urine samples were collected and analyzed using Nuclear Magnetic Resonance in pre-game and immediate post-game moments over three national championship games. The metabolomics data were then used to generate OPLS-DA and VIP plots.

RESULTS

Forty-three metabolites were identified in the samples. OPLS-DA analyses demonstrated a progressive separation between pre-post conditions, as supported by an increasing Q2 value (0.534, 0.625, and 0.899 for games 1, 2 and 3, respectively) and the first component value (20.2% and 19.1% in games 1 and 2 vs. 29.9% in game 3). Eight out of the fifteen most discriminating metabolites appeared consistently across the three games: glycine, formate, citrate, 3-hydroxyvalerate, glycolic acid, trimethylamine, urea, and dimethylglycine.

CONCLUSION

The main difference between the three games was the increasing separation between groups throughout the championship. Since the higher VIP-scores metabolites are linked to energy and protein metabolism, this separation may be attributed several factors, one being the accumulation of fatigue.

The Physical and Physiological Demands of Intercounty Camogie During Competitive Match-Play

ABSTRACT

Duggan, JD, Byrne, P, Malone, S, Cooper, S-M, and Moody, J. The physical and physiological demands of intercounty camogie during competitive match-play. J Strength Cond Res 38(9): e510-e520, 2024-The aim of this study was to determine the physical and physiological demands of intercounty camogie match-play between positions and halves of play. Data were collected from 28 players during 18 competitive games using global positioning systems (10-Hz) and heart rate monitors (2.4-GHz). The study demonstrated that intercounty camogie players covered a total distance (TD) (m ± SD) of 6,040 ± 628 m, relative distance (RD) of 83 ± 13 m·min-1, and maximum speed of 25 ± 1 km·h-1. Furthermore, the players covered a mean sprint distance of 214 ± 112 m and 14 ± 6 sprints. Players' mean heart rate (HRmean) and HRmax was 138 ± 23 b·min-1 and 164 ± 20 b·min-1, respectively. There were decrements between halves in TD (p < 0.01, ES = -0.45), RD (p < 0.01, ES = -0.45), maximum speed (p < 0.05, ES = -0.18), HRmax (p < 0.05, ES = -0.23), running (p < 0.01, ES = -0.34), high-speed running (p < 0.01, ES = 0.34), sprinting (p < 0.01, ES = -0.10), HRmax (p < 0.05, ES = -0.23), and HRmax % (p < 0.05, ES = -0.24). Midfielders covered a greater TD compared with full-forwards (p < 0.05, ES = -0.38) and half-forwards (p < 0.05, ES = -0.38). Full-backs covered a significantly lower RD than midfielders (p < 0.05, ES = -1.2), half-backs compared with full-forwards (p < 0.05, ES = 1.14), and half-forwards compared with full-forwards (p < 0.05, ES = 1.15). Full-forwards covered significantly less RD when compared with half-backs (p < 0.05, ES = -1.14), midfielders (p < 0.05, ES = -1.47), and half-forwards (p < 0.05, ES = -1.15). The findings provide physical and physiological values on the match demands of intercounty camogie match-play.

Effects of the menstrual cycle on the performance of female football players. A systematic review

Background

Women's football has been booming for a few years now, which has led to an increase in the expectation of the players' performance, leading to a more detailed study of women's physiology in the field of sports.

Objectives

To analyze the scientific evidence on the influence of menstruation on the performance of female footballers, as well as to analyze the methodological quality of the studies included in this review.

Materials and methods

The possible hormonal effects of the menstrual cycle phases on the performance of female footballers were analyzed. The databases used to conduct the searches were Pubmed, Scopus, Virtual Health Library, Web of Science, EBSCO and the Cochrane Library. All included studies met the inclusion criteria. The Cochrane risk of bias tool was used. This systematic review protocol was registered at the International Prospective Register of Systematic Reviews (PROSPERO: CRD42023390652).

Results

A total of nine clinical trials were included in this review. A low quality of evidence was observed in the studies. Not all the results support the idea that the menstrual cycle phases can alter the performance of female footballers.

Conclusion

This systematic review shows that there is a great deal of controversy about the influence of the menstrual cycle phases on the performance of female footballers. Studies are focused on solely biological factors and gender is normally no part of those studies. Further research with larger samples, and taking not only biological but also sociological factors, are necessary to determine the effects of menstruation on the performance of female footballers.

Prevalence of sports supplements consumption and its association with food choices among female elite football players

OBJECTIVES

The present study aimed to 1) investigate the consumption of Sports Supplements (SSs) among female elite football players, 2) evaluate the influence of age on SS consumption, and 3) determine the relationship between the consumption of SSs and dietary choices among elite football players.

METHODS

A total of 126 female football players of Primera Iberdrola and Reto Iberdrola who participated in this descriptive, observational, and cross-sectional study completed a self-administered questionnaire on SSs and the Athletes' Food Choices Questionnaire.

RESULTS

Overall, 84.1% of participants consumed supplements, mainly for improved sports performance (68.3%) and health (34.1%). The main sources of purchase were the Internet (34.9%) and specialized shops (23.8%), and players were commonly advised by a dietitian-nutritionist to use SSs (56.3%). The SSs most often consumed included whey protein (30.2%), sports drinks (28.6%), creatine monohydrate (28.6%), sports bars (27.8%), and caffeine (27.8%). Older players consumed more supplements at the time of data compilation. Players predominantly acquired these supplements by using the Internet and reported benefits from their use (all P ≤ 0.036). Additionally, players who consumed SSs conveyed more concern about their food choices.

CONCLUSIONS

A high prevalence of female football players consumed SSs, particularly SSs supported by robust scientific evidence. Older players had higher supplement consumption rates. The use of SSs was related to food choices through nutritional characteristics of foods, knowledge about health and nutrition, weight control with the help of food, and the performance benefits players could acquire.

Indicators of Fatigue during a Soccer Match Simulation Using GPS-Derived Workload Values: Which Metrics Are Most Useful?

Research into women's competitive soccer matches has shown distance and high-speed running (HSR) reductions over time, but the effects on some GPS-derived metrics have not been investigated. The purpose of this project was to examine the utility of common GPS metrics for indicating fatigue from the T-SAFT90 match simulation in collegiate soccer players. Unlike in competitive matches, changes to these metrics occurred as early as 15 min, with HSR, average and max speed, and speed intensity (SI) exhibiting significant declines. HSR and SI were even further decreased in later periods, with HSR lower in minutes 30-40 (T30-35 and T35-40) than T15-20 and lower in T70-85 than T45-60. SI showed a similar pattern of continued decline, reaching its lowest value in the last three time segments. Accelerations and decelerations were also decreased beginning at T15-20 and T20-25, respectively, but the fatigue index (FI), dynamic stress load (DSL), and step balance (SB) were unchanged. It can be concluded that in contrast to competitive matches where players can dictate their own intensity, a match simulation may result in a quicker onset of fatigue, but not all GPS-derived values change as expected in fatiguing environments. Coaches and sports scientists may use these findings to properly monitor fatigue in real time.

Match-Play External Load and Internal Load in NCAA Division II Women's Soccer

ABSTRACT

Choice, EE, Tufano, JJ, Jagger, KL, and Cochrane-Snyman, KC. Match-play external load and internal load in NCAA Division II women's soccer. J Strength Cond Res 37(12): e633-e639, 2023-The purpose of this study was to describe average match-play demands for NCAA DII women's soccer, including positional and time-specific differences, and relationships between variables. External load was assessed using total distance, relative distance, sprint distance, number of power plays, peak speed, and Player Load. Internal load was assessed using session rating of perceived exertion (sRPE). Mixed factor analysis of variance was used to assess time by position (midfielder, forward, or defender) for dependent measures. Correlations were assessed between separate pair groups. Average match-play demands included 9,463 ± 2,591 m total distance, 172 ± 48 m·min -1 relative distance, 531 ± 301 m sprint distance, peak speeds of 26 ± 1.6 kph, 46.71 ± 21.75 power plays, and 457.84 ± 121.78 AU Player Load. Significant ( p < 0.05) positional differences were found for total distance, Player Load, match load, and peak speed. Significant, moderate correlations were found between relative distance and match load, and sRPE and total distance, Player Load, and power plays (all p < 0.001). Results indicate there are positional differences within a women's DII soccer team, with midfielders accumulating the longest distances (10,509 ± 2,913 m) and greatest Player Load (527.79 ± 130.5 AU) and match load (576 ± 343 AU), forwards running the fastest peak speeds (26.8 ± 1.5 kph), and defenders maintaining most consistent performance. Match-play external and internal load data should be monitored by player position and half for DII women's soccer.

Effect of Different Nonstarter Compensatory Strategies on Training Load in Female Soccer Players: A Pilot Study

BACKGROUND

In soccer, the day of the week with the highest external load is match day (MD), with starters (>60 minutes per match) showing higher levels of physical fitness and seasonal high-intensity loading. It is necessary, therefore, to determine training strategies to reduce the differences between starters and nonstarters. The aim of this study was to analyze and compare the external load of different training compensatory strategies with match external load in female nonstarters.

HYPOTHESIS

A strategy combining small-sided games (SSG) and running-based drills (RBD) would reproduce match demands, with RBD leading to greater high-intensity running and SSG leading to a greater number of accelerations and decelerations.

STUDY DESIGN

Descriptive and comparative study.

LEVEL OF EVIDENCE

Level 4.

METHODS

The training and match external load of 14 female players belonging to the same reserve squad of a Spanish First Division Club (Liga Reto Iberdrola) was registered. In the first session after the match (MD+1), nonstarters (<60 minutes in the match) performed 1 of 3 different compensatory strategies: RBD, SSG, or a mixed intervention combining the previous strategies (RBD+SSG). Starters carried out a recovery session.

RESULTS

A marked difference in load was observed between the compensatory training strategies and MD. In comparison with MD, RBD showed greater high-intensity and sprint distances and lower acceleration, SSG showed less high-intensity running and sprint distances, lower peak velocity, and greater acceleration, and RBD+SSG registered lower accelerations. In addition, nonstarters covered greater high-intensity running and sprint distances in RBD and achieved higher accelerations in SSG.

CONCLUSION

RBD and SSG compensatory strategies could be recommended to nonstarter female soccer players in MD+1 to compensate for match external load deficits.

CLINICAL RELEVANCE

This study provides comprehensive information on the compensatory exercises of female soccer players, which can be useful for strength and conditioning coaches when developing recovery strategies during a microcycle.

Accumulated Workload Differences in Collegiate Women's Soccer: Starters versus Substitutes

The purpose of this study was to estimate the workloads accumulated by collegiate female soccer players during a competitive season and to compare the workloads of starters and substitutes. Data from 19 college soccer players (height: 1.58 ± 0.06 m; body mass: 61.57 ± 6.88 kg) were extracted from global positioning system (GPS)/heart rate (HR) monitoring sensors to quantify workload throughout the 2019 competitive season. Total distance, distance covered in four speed zones, accelerations, and time spent in five HR zones were examined as accumulated values for training sessions, matches, and the entire season. Repeated-measures ANOVA and Student's t tests were used to determine the level of differences between starter and substitute workloads. Seasonal accumulated total distance (p < 0.001), sprints (≥19.00 km/h; p < 0.001), and high-speed distance (≥15.00 km/h; p = 0.005) were significantly greater for starters than substitutes. Accumulated training load (p = 0.08) and training load per minute played in matches (p = 0.08) did not differ between starters and substitutes. Substitutes had similar accumulated workload profiles during training sessions but differed in matches from starters. Coaches and practitioners should pursue strategies to monitor the differences in workload between starters and substitutes.

Motion characteristics of Under-15, Under-17 and Under-19 Italian youth women soccer matches

BACKGROUND

Despite the constant development of women's football, few studies to date addressed the physical requirements of youth female soccer players in regional (specific) contexts. This research characterized the activity profiles of élite Italian U15, U17 and U19 female games.

METHODS

Sixty players (U15, N.=18; U17, N.=20; U19, N.=22) from a high-level club in North-East Italy were involved. Players were equipped with a 10-Hz GPS device. Forty-six games were monitored (9 vs. 9 for U15, 11 vs. 11 for U17-U19) and the following dependent variables were extracted: total distance, equivalent distance, normalized distance (m/min) in six speed and metabolic power ranges. Total high-speed (>14.1 km/h) and total high-power (>18 W) distances were computed based on thresholds parametrized to the young female athlete. A multivariate general linear model was fit to analyze the effect of age category, match periods and their interaction.

RESULTS

Some game parameters increased with age, especially from U15 to U17. Among them: total distance (5.5 km, 7.8 km, and 8.8 km for U15, U17, U19), distance at very-high (18-22 km/h) and maximum (>22 km/h) speed, distance at high power (18-31.5 W). Normalized distance was ~90 m/min and comparable among age groups. A reduction of very-high (31.5-49.5 W) and maximum power (>49.5 W) distance was observed in U15 matches, and of high-power distance in U17 and U19.

CONCLUSIONS

These findings quantify the physical demands of Italian youth female match-play. These data support evidence-based training planning, set a reference for players approaching higher playing standards, and could suggest informed redesign of playing formats.

The variability of physical match demands in elite women's football

Peak locomotor demands are considered as key metrics for conditioning drills prescription and training monitoring. However, research in female football has focused on absolute values when reporting match demands, leading to sparse information being provided regarding the degrees of variability of such metrics. Thus, the aims of this study were to investigate the sources of variability of match physical performance parameters in female football players and to provide a framework for the interpretation of meaningful changes between matches.54 female players from four top-level clubs were monitored during one season. GPS APEX (STATSports, Northern Ireland), with a sampling frequency of 10 Hz, were used in 60 official matches (n = 393) to determine the full-match and 1-min peak locomotor demands of total distance (TD), high-speed running distance (HSRD), sprint distance (SpD), accelerations and decelerations (Acc/Dec) and peak speed (Pspeed). For each variable, the between-team, between-match, between-position, between-player, and within-player variability was estimated using linear mixed-effect modelling.With exception to SpD (29.4 vs. 31.9%), all other metrics presented a higher observed match-to-match variability in the 1-min peaks than in the full-match (6.5 vs. 4.6%; 18.7% vs. 15.9%; 12.9 vs. 11.7%; for TD, HSRD and Acc/Dec, respectively). With the exception of SpD, higher changes in 1-min peaks than in full-match values are required to identify meaningful changes in each variable.Different sources of variability seem to impact differently the match physical performance of female football players. Furthermore, to identify meaningful changes, higher changes in 1-min peaks than in full-match values are required.

Differences across Playing Levels for Match-Play Physical Demands in Women’s Professional and Collegiate Soccer: A Narrative Review

Advancements in sport technology have made quantifying match-play external load (e.g., total distance, sprint distance, number of sprints) a popular option for athletics personnel. These variables of volume and intensity are useful for both objectively monitoring training in field-based sports and for designing training programs. As physical abilities differ across playing levels, match-play demands likely also differ. This narrative review compiles and compares the match-play external load data for women’s soccer at the professional and collegiate levels. Databases were searched through July 2022, yielding 13 primary articles that assessed the match-play demands of women’s soccer (3 professional, 8 Division I, 1 Division II, and 1 Division III). The results indicate that the average total distance covered were similar between the professional, Division I and Division III levels, but the variability was greater among Division III compared to professional and Division I players. Data for Division II are scarce, but the total distance covered appears to be less than for professional, Division I and Division III. There was also large variability for sprint distance and number of sprints across data at all playing levels. Considering the lack of studies of Division II and Division III players, more research is necessary to determine how playing level may affect external load profiles, as isolated studies likely only reflect data from isolated teams.

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- and intra-microcycle external load analysis in female professional soccer players: A playing position approach

This study analyzes the inter- and intra-differences in external load across the microcycle in professional female soccer players. External load during four consecutive microcycles (i.e., M1, M2, M3, and M4) and training sessions (i.e., MD-4, MD-3, MD-2, and MD-1) and a match day (i.e., MD) were registered in seventeen female professional soccer players (age: 26.3 ± 4.6 years; height: 166.3 ± 6.1 cm; body mass: 59.8 ± 6.8 kg; and body mass index: 21.6 ± 1.7 kg·m^-2) who belonged to the same team in Spanish first division. A 10-Hz GPS that integrated a 100-Hz triaxial accelerometer was used to register external load. The results showed lower decelerations in M2 compared to M1 and M3 (p < 0.05), lower high-intensity distance (>16.0 km·h^-1) in M3 vs. M2, and greater relative sprint distance (>21.0 km·min^-1) in M4 vs. M1 and M3 (p < 0.05). MD-3 registered the highest load for all variables (p < 0.05). Forwards (FWs) performed (p < 0.05) significantly more sprints (meters and number > 21.0 km·h^-1) than central midfielders (CMs) and central defenders (CDs) in MD-2 and MD. Both, fitness and conditioning staff should pay special attention to the external loads for each playing position in training sessions to optimize the training process.

A Comparison of Sprint Mechanical Parameters Measured With Timing Gates and a Laser Gun

The aim of the study was to compare sprint mechanical parameters measured with timing gates and a laser gun. Thirty-four female team handball players (age: 17.0 ± 2.3 years, height: 1.70 ± 0.07 m, body mass: 66.7 ± 9.7 kg) performed three 30 m sprints in which the times were measured at 5, 10, 20 and 30 m with timing gates (accuracy 0.01 s) together with the distance over time by a laser gun. The main findings were that with a correction of +0.21 s (timing gates) the times and sprint mechanical properties calculated with the spreadsheet of Morin between timing gates and laser gun were not different. But when peak velocity was derived directly from the laser gun (MusclelabTM system) this was significantly higher than maximal velocity (vmax), and lower than the theoretical maximal velocity (v0) calculated with the spreadsheet. It was concluded that a correction of +0.21 s should be used to get correct mechanical properties when measuring with timing gates compared with laser gun measurements on an indoor court.

Impact of the Menstrual Cycle Phases on the Movement Patterns of Sub-Elite Women Soccer Players during Competitive Matches

The purpose of this study was to evaluate the influence of the menstrual cycle phases on the movement patterns of sub-elite women soccer players during competitive matches over three consecutive seasons. Individual movement data were analyzed and compared in eight players from the second French League at the early follicular (EF), late follicular (LF) and mid-luteal (ML) phases of their menstrual cycle, determined by the calendar method. The movement patterns, expressed as meters per minute, were recorded during competitive matches using devices placed on the player’s ankle. Our results showed significantly lower distances covered at moderate and high velocity in the EF phase than in the LF and ML phases (Cohen’s d effect size = 1.03 and 0.79, respectively). The total distance covered during matches and the number of sprints also were reduced during EF compared with LF (d = 0.78 and 0.7, respectively). Overall, the total distance and distance covered at low velocity were significantly lower during the second half-time of the matches (d = 1.51), but no menstrual cycle phase × game period interaction was noted. In conclusion, our study suggests that EF may impact the movement pattern of sub-elite women soccer players during competitive matches, without any modulation of this effect by the playing time. Despite the low sample size, these results can be useful for coaches and support staff to modulate training loads and player rotation during soccer games.

The positional and temporal running demands of elite inter-county camogie match play across 5-min intervals

Purpose

Camogie is a native Irish female field sport game. This investigation aimed to establish elite camogie players’ positional and temporal running demands across 5-min intervals during competitive match play.

Methods

Thirty-one (n = 31) inter-county camogie players (age: 24 ± 4 years; height: 167.2 ± 6.3 cm; body mass: 67.0 ± 7.5 kg) from two squads wore commercially available 10-Hz Playertek GPS units (Playertek by Catapult, Australia) during Senior All-Ireland Championship games (n = 8). Players were categorised according to match positions (defenders, mid-fielders, forwards). Games were split into quarters, and subsequently into 5-min intervals for analysis (5-min intervals are more closely associated with small-sided games and training than half-by-half comparisons).

Results

Analysis revealed significant positional and temporal differences to exist (p < 0.05). Mid-fielders covered greater total (r = 0.16–0.19) and relative distance (r = 0.15–0.17), with forwards covering greater high-speed distances (r = 0.09–0.19). Mid-fielders had greater temporal performance decrements for sprint distance between all first quarter intervals and 55–60 interval (Kendall’s W (W = 0.86–1.00), as well as the 0–5 and all final quarter intervals for total distance (W = 0.86–1.00). Defenders had significant performance decreases during the 25–30 (W = 0.29–0.60) and 40–45 interval (W = 0.14–0.57) for both total and relative distance. Forwards exhibited the lowest performance decrement, with no significant differences for peak speed, high-speed running, or sprint distance (W = 0.00–0.53).

Conclusion

Positional and temporal differences are evident in elite camogie match play. Mid-fielders have the greatest total and sprint distance decrements, with defenders also exhibiting total and relative distance decreases. Coaches should focus on temporal differences with respect to position, to minimise performance decrements.

Contextual Variation in External and Internal Workloads across the Competitive Season of a Collegiate Women's Soccer Team

As sports technology has continued to develop, monitoring athlete workloads, performance, and recovery has demonstrated boundless benefits for athlete and team success. Specifically, technologies such as global positioning systems (GPS) and heart rate (HR) monitors have granted the opportunity to delve deeper into performance contributors, and how variations may exist based upon context. A team of NCAA Division I women’s soccer athletes were monitored during games throughout one competitive season. Individual athlete, positional groups, and team external and internal workloads were explored for differences based upon game location, opponent ranking, game result, and the final score differential. Game location and opponent ranking were found to have no effect on team-wide absolute or relative external workloads, whereas game result and score differential did. Internal workloads across the team tended to only vary by game half, independent of game context; however, the HR of defenders was determined to be higher during losses as compared to wins (p = 0.0256). Notably, the games that resulted in losses also represented the games with the fewest number of substitutions. These findings suggest high value in monitoring performance and workloads that are characteristic of varying, often multifaceted, contexts. It is hoped that this information can lead to more informed approaches to vital game-time and coaching decisions.

In-Season Internal Load and Wellness Variations in Professional Women Soccer Players: Comparisons between Playing Positions and Status

The internal intensity monitoring in soccer has been used more in recent years in men's football; however, in women's soccer, the existing literature is still scarce. The aims of this study were threefold: (a) to describe the weekly variations of training monotony, training strain and acute: chronic workload ratio through session Rated Perceived Exertion (s-RPE); (b) to describe weekly variations of Hooper Index [stress, fatigue, Delayed Onset Muscle Soreness (DOMS) and sleep]; and (c) to compare those variations between playing positions and player status. Nineteen players (24.1 ± 2.7 years) from a Portuguese BPI League professional team participated in this study. All variables were collected in a 10-week in-season period with three training sessions and one match per week during the 2019/20 season. Considering the overall team, the results showed that there were some associations between Hooper Index categories and s-RPE like stress or fatigue (0.693, p < 0.01), stress or DOMS (0.593, p < 0.01), stress or s-RPE (-0.516, p < 0.05) and fatigue or DOMS (0.688, p < 0.01). There were no differences between all parameters in playing positions or player status. In conclusion, the study revealed that higher levels of fatigue and DOMS occur concurrently with better nights of sleep. Moreover, any in-season variations concerning internal load and perceived wellness seems independent of position or status in outfield players. The data also showed that the higher the players' reported stress, the lower the observed s-RPE, thus possibly indicating a mutual interference of experienced stress levels on the assimilation of training intensity by elite women soccer players.

Nutritional optimization for female elite football players-topical review

Women's football is an intermittent sport characterized by frequent intense actions throughout the match. The high number of matches with limited recovery time played across a long competitive season underlines the importance of nutritional strategies to meet these large physical demands. In order to maximize sport performance and maintain good health, energy intake must be optimal. However, a considerable proportion of female elite football players does not have sufficient energy intake to match the energy expenditure, resulting in low energy availability that might have detrimental physiologic consequences and impair performance. Carbohydrates appear to be the primary fuel covering the total energy supply during match-play, and female elite football players should aim to consume sufficient carbohydrates to meet the requirements of their training program and to optimize the replenishment of muscle glycogen stores between training bouts and matches. However, several macro- and micronutrients are important for ensuring sufficient energy and nutrients for performance optimization and for overall health status in female elite football players. The inadequacy of macro-and micronutrients in the diet of these athletes may impair performance and training adaptations, and increase the risk of health disorders, compromising the player's professional career. In this topical review, we present knowledge and relevant nutritional recommendations for elite female football players for the benefit of sports nutritionists, dietitians, sports scientists, healthcare specialists, and applied researchers. We focus on dietary intake and cover the most pertinent topics in sports nutrition for the relevant physical demands in female elite football players as follows: energy intake, macronutrient and micronutrient requirements and optimal composition of the everyday diet, nutritional and hydration strategies to optimize performance and recovery, potential ergogenic effects of authorized relevant supplements, and future research considerations.

Position specific physical performance and running intensity fluctuations in elite women's football

The purpose of the present study was to investigate the physical performance of elite female football players during match play along with transient alterations in running performance following 1- and 5-min univariate peak periods. 54 elite female players from four top-level Norwegian teams were monitored for one season (n = 393 match observations), and physical performance data collected using STATSport GPS APEX. Results revealed significant differences in physical performance between the positions during full match play, particularly between wide and central players. Both full backs (FBs) and wide midfielders (WMs) covered more total distance (TD), high-speed running distance (HSRD), and sprint distance (SpD) than center backs (CBs) (p < 0.05-0.001), while WMs also covered more HSRD than both central midfielders (CMs) (p < 0.01) and forwards (FWs) (p < 0.05), and more acceleration -and deceleration distance (Acc_dist and Dec_dist ) than both CBs and CMs (p < 0.01-0.001). A similar pattern was observed for the peak period analysis, with FBs and WMs covering more SpD in peak 1 min than CBs and CM (p < 0.001) and more SpD in peak 5-min than CBs, CMs, and FWs (p < 0.001). Irrespective of the variable analyzed, greater distances were covered during the peak 5-min period than in the next-5 and mean 5-min periods (p < 0.001). Significant (p < 0.001), but small to trivial (Cohen's D_z : 0.07-0.20), decreases in distance covered were also observed for each variable following each univariate peak 5-min period. In conclusion, practitioners should account for differences in physical performance when developing training programs for female football players and be aware of transient reductions in physical performance following univariate peak 1- and 5-min periods. Specifically, the very high intensity in 1-min peak periods adds support to the principal of executing speed endurance activities during training to mirror and be prepared for the physical demands of match play.

Running Performance of High-Level Soccer Player Positions Induces Significant Muscle Damage and Fatigue Up to 24 h Postgame

This study aimed to determine the impact of a soccer game on the creatine kinase (Ck) response and recovery and the specific Global Positioning System (GPS)-accelerometry-derived performance analysis during matches and comparing playing positions. A sample composed of 118 observations of 24 professional soccer teams of the Brazil League Serie A was recruited and classified according to playing positions, i.e., Left/Right Defenders (D = 30, age: 25.2 ± 5.8 years, height: 187 ± 5.5 cm, weight: 80 ± 5.8 kg), Offensive Midfielders (OM = 44, age: 25.1 ± 0.2 years, height: 177 ± 0.3 cm, weight: 73 ± 1.2 kg), Forwards (F = 9, age: 25.1 ± 0.2 years, height: 176.9 ± 4.3 cm, weight: 74.5 ± 2.1 kg), Left/Right Wingers (M = 23, age: 24.5 ± 0.5 years, height: 175 ± 1.1 cm, weight: 74 ± 4.4 kg), and Strikers (S = 12, age: 28 ± 0.2 years, height: 184 ± 1.0 cm, weight: 80 ± 1.4 kg). Blood Ck concentration was measured pre-, immediately post-, and 24 h postgame, and the GPS-accelerometry parameters were assessed during games. Findings demonstrated that Ck concentrations were higher at all postgame moments when compared with pregame, with incomplete recovery markers being identified up to 24 h after the game (range: 402–835 U/L). Moreover, Midfielders (108.6 ± 5.6 m/min) and Forwards (109.1 ± 8.3 m/min) had a higher relative distance vs. other positions (100.9 ± 10.1 m/min). Strikers [8.2 (8.1, 9.05) load/min] and Defenders [8.45 (8, 8.8) load/min] demonstrated lower load/min than Wingers [9.5 (9.2, 9.8) load/min], Midfielders [10.6 (9.9, 11.67) load/min], and Forwards [11 (10.65, 11, 15) load/min]. These results could be used to adopt specific training programs and recovery strategies after match according to the playing positions.

Comparison of Physical Fitness and Anthropometrical Profiles Among Brazilian Female Soccer National Teams From U15 to Senior Categories

ABSTRACT

Ramos, GP, Nakamura, FY, Penna, EM, Mendes, TT, Mahseredjian, F, Lima, AM, Garcia, ES, Prado, LS, and Coimbra, CC. Comparison of physical fitness and anthropometrical profiles among Brazilian female soccer national teams from U15 to senior categories. J Strength Cond Res 35(8): 2302-2308, 2021-This study aimed to compare anthropometric and physical fitness of Brazilian female national team soccer players from the U15 to senior categories, and to compare the physical performance between selected and nonselected players. Subjects included 231 athletes (U15, n = 46, U17, n = 49, U20, n = 98, and Senior, n = 38). Body mass, height, sum of skinfolds, squat jump (SJ), countermovement jump (CMJ), 20-m linear sprint, and Yo-Yo IR1 were assessed. The U15 players were shorter than all other groups (p < 0.01) and lighter than U20 players (p < 0.01). Regarding physical tests, Senior athletes presented higher SJ compared with U20, and both showed higher CMJ and SJ compared with the U15 and U17 (p < 0.05). Senior athletes were also faster than players of all other categories in 20-m sprint (p < 0.01) and covered the greatest distance in the Yo-Yo IR1 (p < 0.05). U20 were better in the Yo-Yo IR1 than the younger groups (p < 0.05). When comparing selected and nonselected players, no differences were identified in anthropometric measures (p > 0.05). However, selected players from U17, U20, and Senior teams showed better performance in Yo-Yo IR1 than nonselected ones (p < 0.05). Finally, selected senior athletes also presented higher CMJ and SJ than nonselected players (p < 0.05). These results suggest that, although there is a tendency for maintenance in anthropometric measures from the age of 15 years, there are substantial improvements in speed, lower-body power, and aerobic capacity from U20 age group. In addition, it seems that intermittent aerobic fitness contributes to the selection of players to international tournaments in national teams.

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.

Physical Demands of Women's Soccer Matches: A Perspective Across the Developmental Spectrum

Female soccer players are exposed to specific physical demands during matches, which vary according to the standard of play. Existing studies have largely focused on quantifying the distances covered for professional and international level players. This approach is limited in scope regarding the broader aspects around physical demands and is detached from development pathway models. An understanding of the demands across all standards will provide valuable insights about appropriate player development and help ensure physical readiness for the demands of the sport. The aim of this perspective paper is to describe the physical demands experienced during women's soccer matches across the developmental spectrum. A combination of evidence from the literature and data from the author's research (JDV) is presented. Specifically highlighted are the trends for locomotor distances, acceleration and deceleration frequency, and metabolic power metrics for youth (≤U17), college (NCAA/U20), professional (domestic) and international standards of women's soccer. In addition, the changes in match demands between levels of play are used to help illustrate gaps that must be overcome in order to successfully achieve physical readiness to compete at higher levels. The evidence demonstrates the importance of training appropriate attributes to prepare female soccer players who are striving to play at progressively higher standards.

Physical performance and loading for six playing positions in elite female football: full-game, end-game, and peak periods

The present study investigated the position-specific match demands and heart rate response of female elite footballers, with special focus on the full-game, end-game, and peak-intensity periods. In total, 217 match observations were performed in 94 players from all eight teams of the best Danish Women's League, that is, goalkeepers (GK, n = 10), central defenders (CD, n = 23), full-backs (FB, n = 18), central midfielders (CM, n = 28), external midfielders (EM, n = 18), and forwards (FW, n = 11). Positional data (GPS; 10 Hz Polar Team Pro) and HR responses were collected. HR_mean and HR_peak were 87%-89% and 98%-99% of HR_max , for outfield players, with no positional differences. CM, EM, and FB covered 8%-14% greater (P < .001) match distances than CD. EM, FW, FB, and CM performed 40%-64% more (P < .05) high-speed running and 41%-95% more (P < .01) very-high-speed running (VHSR) than CD. From the first to the last 15-minute period, total distance, except for FW, number of VHSR, except FB, peak speed and sum of accelerations and sum of decelerations decreased (P < .05) for all outfield positions. In the most intense 5-minute period, EM, FB, and CM performed 25%-34% more (P < .01) HSR than CD, whereas EM, FW, and FB performed 36%-49% more (P < .01) VHSR than CD. In conclusion, competitive elite female matches impose high physical demands on all outfield playing positions, with high aerobic loading throughout matches and marked declines in high-speed running and intense accelerations and decelerations toward the end of games. Overall physical match demands are much lower for central defenders than for the other outfield playing positions, albeit this difference is minimized in peak-intensity periods.

External and internal loads during the competitive season in professional female soccer players according to their playing position: differences between training and competition

The aim of this study was to compare external (EL) and internal loads (IL) during training sessions compared to official matches between elite female soccer players according to their playing position.Training and match data were obtained during the 2017/18 season from eighteen players (age: 26.5±5.7 years; height: 164.4±5.3 cm; body mass: 58.56±5.58 kg) from a first Division Spanish team. The EL (total distance covered; high-speed running distance; number of accelerations and decelerations) was assessed with a Global Positioning System (GPS) and triaxial accelerometer. The IL was assessed with ratings of perceived exertion (RPE; and session-RPE).The EL and the IL from official matches were higher compared to training sessions (p<0.05; effect size [ES]:0.6-5.4). In matches, the EL was greater in Attackers (AT) and Central Midfielders (CM) versus Central Backs (p<0.05; ES:0.21-1.74). During training sessions, the EL was similar between playing positions (p>0.05; ES:0.03-0.87). The EL and the IL are greater in matches compared to training sessions, with greater match-related EL in AT and CM players. Current results may help practitioners to better understand and modulate training session's loads according to playing position, potentially contributing to their performance readiness and injury risk reduction.

Effects of high-carbohydrate versus mixed-macronutrient meals on female soccer physiology and performance

PURPOSE

Athletes are often told to minimize intakes of fiber, fat, and protein in pre-competition meals to avoid gut distress, but this guidance is based on scant direct evidence. This study evaluated the physiological and perceptual effects of pre-competition mixed-macronutrient (MM) and high-carbohydrate (HCHO) meals in collegiate female soccer players.

METHODS

Fifteen players participated in this randomized, investigator-blinded, crossover study involving two ~ 1000-kcal meals (HCHO and MM) consumed 4 h prior to 70-min scrimmages. Assessments included global positioning system (GPS) tracking, heart rate (HR), perceived exertion (RPE), ratings of fatigue (ROF), gut symptoms, and perceptions of satiety, hunger, and fullness. Differences between conditions for HR, RPE, ROF, and gut symptoms were evaluated with Wilcoxon signed-rank tests. GPS data and hunger, satiety, and fullness scores were compared using within-subjects repeated measures ANOVAs.

RESULTS

No statistically significant differences were found between the conditions at any time point for HR, RPE, ROF, or gut symptoms. Significant time effects were found for two GPS variables (total distance covered and high-speed running), indicating that participants covered less distance during the second half of the scrimmages in comparison to the first half. However, there were no significant condition or condition × time interactions for GPS data. Finally, there were no condition or condition × time interactions for hunger, fullness, and satiety, though significant time effects were observed.

CONCLUSION

A MM meal consumed 4 h prior to 70 min of soccer competition does not increase gut symptoms and can be similarly ergogenic as a HCHO meal.

Role of Basal Hormones on Sweat Rate and Sweat Na+ Loss in Elite Women Soccer Players

We aimed to determine whether basal concentrations of testosterone, cortisol or the ratio testosterone/cortisol were related to sweat Na⁺ loss, sweat Na⁺ concentration ([Na⁺]) and sweat rate during exercise. Twenty-two female elite soccer players participated in the study. Testosterone and cortisol were measured in blood samples before exercise. Sweat samples were collected during a training session (~20°C, ~30% RH, and ~0.55 m/s of wind speed) to measure sweat [Na⁺]. Sweat rate was determined by considering the difference between post-and pre-body weight, along with the amount of liquid consumed. During exercise, sweat Na⁺ loss (0.33[0.19] g/h) and sweat rate (0.49[0.20] L/h) were related to basal testosterone concentration (1.4[0.4] pg/mL) (r=0.54; r=0.55, respectively; p<0.05), but not with basal cortisol concentration (119.2[24.2] ng/mL) nor testosterone/cortisol ratio (0.012[0.003]) (p>0.05). However, when Na⁺ loss was adjusted to sweat rate, no association was found between Na⁺ loss and testosterone (p>0.05). In addition, no differences were found between players with high vs. low Na⁺ loss adjusted to sweat loss in menstrual phase or intensity during exercise (p>0.05). In conclusion, these results suggest that in these specific environmental conditions, basal levels of testosterone might increase sweat rate and therefore, the amount of Na⁺ lost during exercise in elite women soccer players.

Acute effects of two different initial heart rates on testing the repeated sprint ability in elite women soccer players

BACKGROUND

Repeated sprint ability (RSA) in women's soccer is crucial to ensure high level of performance during the game. The aim of this study is to investigate the acute effects of two different initial heart rates intensities on fatigue when testing the RSA.

METHODS

Since there are many kinds of pre-match warming-ups, the heart rate reached at the end of two different warm-up protocols (~90 vs. ≈60% HRmax) as an indicator of internal load has been selected and the respective RSA performances were compared. RSA tests were performed by 19 elite women soccer players (age: 22.5±3.3 years, height 163.9±7.3 cm, body mass 54.3±6.4 kg, BMI 20.6±1.5 kg/m2) with two sets of ten shuttle-sprints (15+15 m) with a 1:3 exercise to rest ratio, in different days (randomized order) with different initial HR% (60% and 90% HRmax). In order to compare the different sprint performances a Fatigue Index (FI%) was computed; the blood lactate concentrations (BLa-) were measured before and after testing, to compare metabolic energy.

RESULTS

Significant differences among trials within each set (P<0.01) were found, as evidence of fatigue. Differences between sets were not found, (Factorial ANOVA 2x10; P>0.05). Although the BLa- after warm-up was higher between 90% vs. 60% HRmax (P<0.05), at the completion of RSA tests (after 3 minutes) the differences were considerably low and not significant (P>0.05).

CONCLUSIONS

This study shows that, contrary to male soccer, the initial heart rates, induced by different modes of warming-up, do not affect the overall performance while testing RSA in women's soccer players.

Sex affects gait adaptations after exercise in individuals with anterior cruciate ligament reconstruction

BACKGROUND

Osteoarthritis after anterior cruciate ligament reconstruction has been linked with changes in gait. Individuals with reconstruction demonstrate gait changes after exercise, however there is no information on altered gait after exercise based on sex. The purpose of this study was to examine the association of sex on changes in running gait after exercise in individuals with reconstruction compared to healthy.

METHODS

Forty females (22 reconstructed) and 22 men (11 reconstructed) ran before and after exercise. Triplanar lower extremity kinematics and kinetics were measured on the involved limb. Data were reduced to 0-100% of gait. Change scores were calculated for each 1% with 90% confidence intervals. Mean differences were calculated for all significant differences.

FINDINGS

After exercise, females with reconstruction increased knee valgus (1.81°), knee external rotation (2.02°), lateral trunk flexion (1.24°) and trunk rotation (2.15°) compared to healthy females. Females with reconstruction increased knee extension moment (0.07 Nm/kg), knee abduction moment (0.08 Nm/kg), hip extension moment (0.14 Nm/kg) and hip internal rotation moment (0.04 Nm/kg) compared to healthy females. After exercise, males with reconstruction decreased knee varus (-4.83°), hip adduction (-1.99°), and hip internal rotation (-4.44°), however increased lateral trunk flexion (1.94°) compared to healthy males. Males with reconstruction increased knee extension moment (0.07 Nm/kg), knee adduction moment (0.31 Nm/kg), knee internal rotation moment (0.13 Nm/kg), hip flexion moment (0.17 Nm/kg), and hip external rotation moment (0.05 Nm/kg) compared to healthy males.

INTERPRETATION

Males with reconstruction increased hip loading while women with reconstruction increased trunk motion post-exercise. Sex should be considered when evaluating response to exercise after reconstruction.

The Physical Demands of NCAA Division I Women's College Soccer

Extensive research into women's collegiate soccer is scarce, leaving gaps in the literature with little information available detailing the physical demands at different standards of play. Our purpose was to elucidate the physical demands of the Division I collegiate level and identify differences between playing positions. Twenty-three field players were observed during four competitive seasons using 10-Hz GPS units (Catapult Sports, Melbourne, Australia). Descriptive statistics and 95% confidence intervals were used to determine group and position-specific physical demands. Linear mixed modelling (LMM) was used to compare attacker, midfielder, and defender position groups. Total distance, high-speed distance, and sprint distance were 9486 ± 300 m, 1014 ± 118 m, and 428 ± 70 m, respectively. Furthermore, attackers were observed to cover the greatest distance at all speeds compared to midfielders and defenders. Our findings suggest that the physical demands of Division I women's soccer differ by position and appear lower compared to higher standards of play. Therefore, coaches and sports scientists responsible for the physical training of Division I collegiate players should consider the specific physical demands of the collegiate level and playing position when prescribing training, as well as in the development of their annual training programs.

Effectiveness of Short-Term Heat Acclimation on Intermittent Sprint Performance With Moderately Trained Females Controlling for Menstrual Cycle Phase

Introduction

Investigate the effectiveness of short-term heat acclimation (STHA), over 5-days (permissive dehydration), on an intermittent sprint exercise protocol (HST) with females. Controlling for menstrual cycle phase.

Materials and Methods

Ten, moderately trained, females (Mean [SD]; age 22.6 [2.7] y; stature 165.3 [6.2] cm; body mass 61.5 [8.7] kg; V.⁢O2⁢peak 43.9 [8.6] mL⋅kg^–1⋅min^–1) participated. The HST (31.0°C; 50%RH) was 9 × 5 min (45-min) of intermittent exercise, based on exercise intensities of female soccer players, using a motorized treadmill and Wattbike. Participants completed HST1 vs. HST2 as a control (C) trial. Followed by 90 min, STHA (no fluid intake), for five consecutive days in 39.5°C; 60%RH, using controlled-hyperthermia (∼rectal temperature [T_re] 38.5°C). The HST3 occurred within 1 week after STHA. The HST2 vs HST3 trials were in the luteal phase, using self-reported menstrual questionnaire and plasma 17β-estradiol.

Results

Pre (HST2) vs post (HST3) STHA there was a reduction at 45-min in T_re by 0.20°C (95%CI −0.30 to −0.10°C; d = 0.77); T¯s⁢k (−0.50; −0.90 to −0.10°C; d = 0.80); and T¯b (−0.25; −0.35 to −0.15°C; d = 0.92). Cardiac frequency reduced at 45-min (−8; −16 to −1 b⋅min^–1; d = 1.11) and %PV increased (7.0; −0.4 to 14.5%: d = 1.27). Mean power output increased across all nine maximal sprints by 56W (−26 to 139W; d = 0.69; n = 9). There was limited difference (P > 0.05) for these measures in HST1 vs HST2 C trial.

Discussion

Short-term heat acclimation (5-days) using controlled-hyperthermia, leads to physiological adaptation during intermittent exercise in the heat, in moderately trained females when controlling for menstrual cycle phase.

The Influence of Caffeine Expectancies on Simulated Soccer Performance in Recreational Individuals

Caffeine (CAF) has been reported to improve various facets associated with successful soccer play, including gross motor skill performance, endurance capacity and cognition. These benefits are primarily attributed to pharmacological mechanisms. However, evidence assessing CAF's overall effects on soccer performance are sparse with no studies accounting for CAF's potential psychological impact. Therefore, the aim of this study was to assess CAF's psychological vs. pharmacological influence on various facets of simulated soccer performance. Utilising a double-dissociation design, eight male recreational soccer players (age: 22 ± 5 years, body mass: 78 ± 16 kg, height: 178 ± 6 cm) consumed CAF (3 mg/kg/body mass) or placebo (PLA) capsules, 60 minutes prior to performing the Loughborough Intermittent Shuttle Test (LIST) interspersed with a collection of ratings of perceived exertion (RPE), blood glucose and lactate, heart rate and performing the Loughborough Soccer Passing Test (LSPT). Whole-body dynamic reaction time (DRT) was assessed pre- and post- LIST, and endurance capacity (T_LIM) post, time-matched LIST. Statistical analysis was performed using IBM SPSS (v24) whilst subjective perceptions were explored using template analysis. Mean T_LIM was greatest (p < 0.001) for synergism (given CAF/told CAF) (672 ± 132 s) vs. placebo (given PLA/told PLA) (533 ± 79 s). However, when isolated, T_LIM was greater (p = 0.012) for CAF psychology (given PLA/told CAF) (623 ± 117 s) vs. pharmacology (given CAF/told PLA) (578 ± 99 s), potentially, via reduced RPE. Although DRT performance was greater (p = 0.024) post-ingestion (+5 hits) and post-exercise (+7 hits) for pharmacology vs. placebo, psychology and synergism appeared to improve LSPT performance vs. pharmacology. Interestingly, positive perceptions during psychology inhibited LSPT and DRT performance via potential CAF over-reliance, with the opposite occurring following negative perceptions. The benefits associated with CAF expectancies may better suit tasks that entail lesser cognitive-/skill-specific attributes but greater gross motor function and this is likely due to reduced RPE. In isolation, these effects appear greater vs. CAF pharmacology. However, an additive benefit may be observed after combining expectancy with CAF pharmacology (i.e. synergism).

Pitch Size and Game Surface in Different Small-Sided Games. Global Indicators, Activity Profile, and Acceleration of Female Soccer Players

López-Fernández, J, Gallardo, L, Fernández-Luna, Á, Villacañas, V, García-Unanue, J, and Sánchez-Sánchez, J. Pitch size and game surface in different small-sided games. Global indicators, activity profile, and acceleration of female soccer players. J Strength Cond Res 33(3): 831-838, 2019-The aim of this research was to evaluate the influence of game surface and pitch size on the movement profile in female soccer players during small-sided games (SSGs) of 4 v 4. Sixteen women played 3 different 4-a-side (400, 600, and 800 m) on 3 surfaces (ground [GR], artificial turf [AT], and natural grass [NG]). Time-motion variables were assessed through GPS devices (Spi Pro X, GPSports, Australia). Ground had the worst outputs on most variables. NG achieved higher results than AT in terms of total distance (SSG 400 [+37.000 m; p = 0.006]; SSG 600 [+59.989 m; p < 0.001]; and SSG 800 [+42.284 m; p = 0.001]). However, the smaller SSG (400) had the lowest values on most variables. However, although the middle SSG (600) presented higher output than the bigger one (800) for body load (NG [+7.745 a.u.; p < 0.001]; AT [+8.207 a.u.; p < 0.001]; and GR [+5.879 a.u.; p < 0.001]), it had lower results for high-intensity distance (NG [-13.15 m; p = 0.025] and AT [-13.59 m; p = 0.026]). Despite women's performance being higher on AT than GR, the NG surface still showed the highest outcomes in the most intense SSG. Moreover, although the performance increases in bigger pitches, if the size is too large the outputs could be reduced.

Profiling the Responses of Soccer Substitutes: A Review of Current Literature

Depending upon competition regulations, the laws of soccer allow between three and an unlimited number of substitutions that can be made on either a permanent or rolling basis. Substitutes are typically introduced to minimise/offset the effects of fatigue, alter tactics, replace players deemed as underperforming or injured, and/or give playing time to youth players or to squad members returning from injury. While the match-day practices of substitutes include participation in the pre-match warm-up, and sporadic periods of rewarm-up activity, it is currently unclear as to whether these pre-entry preparations facilitate optimal match performance thereafter. Acknowledging the contextual factors that possibly influence substitutes' performance, this review summarises the presently available literature on soccer substitutes, and makes recommendations for future research. Literature searching and screening yielded 13 studies, which have typically focused on characterising: (1) the patterns, including timing, of substitutes' introduction; (2) indices of match-performance; and (3) the emotional experiences of soccer substitutes. The majority of substitutions occur after the first-half has ended (i.e. at half-time or during the second-half), with introduced players exceeding the second-half physical performances of those who started the match. Observations of progressive improvements in running performance as playing time increases, and findings that substitutes mostly experience negative emotions, highlight the potential inadequacies of pre-match preparations, and present future research opportunities. Additional work is therefore needed to confirm these findings and to determine the efficacy of current preparation strategies, thereby providing opportunities to assess then address substitutes' pre-pitch entry preparations, on-field performance and emotional responses.

Physiological responses, fatigue and perception of female soccer players in small-sided games with different pitch size and sport surfaces

The aim of this research was to evaluate the influence of game surface and pitch size on the physiological responses, jump performance and perceptions of sub-elite female soccer players playing four-a-side games. Sixteen sub-elite female soccer players were divided into four groups of four players each. Three small-sided games (SSGs; pitch size: 400 m², 600 m² and 800 m²) were played on three surfaces (dirt [DT], artificial turf [AT] and natural grass [NG]). Players' heart rate (HR) was monitored during each game. Before and after each SSG, participants performed two counter-movement jumps (CMJs) and answered a questionnaire based on visual analogue scales (VASs) to indicate their perception of the effort required on each surface. DT obtained lower outputs for most variables. In the SSG 600 mean HR was higher on NG than AT (+3.31 %HR_max; p = 0.029), but players' overall satisfaction with both surfaces was similar (p>0.05). The SSG 400 received the lowest ratings for most variables, whereas the SSG 600 resulted in higher mean HR than SSG 800 [NG (+9.14 b.p.m.; p = 0.001); AT (+7.32 b.p.m.; p = 0.014)]. No surface differences in CMJ performance were found. In conclusion, a higher internal load can be achieved on NG, whereas DT is not recommended for playing soccer. Moreover, the internal load on players in SSGs can be controlled by manipulating pitch size, but over-large pitches may entail a reduction in the physiological profile of female soccer players.

Contextual factors on physical demands in professional women's soccer: Female Athletes in Motion study

The aim of this study was to examine the impact of contextual factors on relative locomotor and metabolic power distances during professional female soccer matches. Twenty-eight players (forwards, n = 4; midfielders, n = 12; defenders, n = 12) that competed in a 90-min home and away match (regular season only). The generalised estimating equations (GEE) was used to evaluate relative locomotor and metabolic power distances for three contextual factors: location (home vs. away), type of turf (natural vs. artificial), and match outcome (win, loss and draw). No differences were observed for home vs. away matches. Moderate-intensity running (20.0 ± 1.0 m min^-1 and 16.4 ± 0.9 m min^-1), high-intensity running (8.6 ± 0.4 m min^-1 and 7.3 ± 0.4 m min^-1) and high-metabolic power (16.3 ± 0.5 m min^-1 and 14.4 ± 0.5 m min^-1) distances were elevated on artificial turf compared to natural grass, respectively. Relative sprint distance was greater during losses compared with draws (4.3 ± 0.4 m min^-1 and 3.4 ± 0.3 m min^-1). Overall physical demands of professional women's soccer were not impacted by match location. However, the elevation of moderate and high-intensity demands while playing on artificial turf may have implications on match preparations as well as recovery strategies.

Are Current Physical Match Performance Metrics in Elite Soccer Fit for Purpose or Is the Adoption of an Integrated Approach Needed?

Time-motion analysis is a valuable data-collection technique used to quantify the physical match performance of elite soccer players. For over 40 years, researchers have adopted a "traditional" approach when evaluating match demands by simply reporting the distance covered or time spent along a motion continuum of walking through to sprinting. This methodology quantifies physical metrics in isolation without integrating other factors, and this ultimately leads to a 1-dimensional insight into match performance. Thus, this commentary proposes a novel "integrated" approach that focuses on a sensitive physical metric such as high-intensity running but contextualizes this in relation to key tactical activities for each position and collectively for the team. In the example presented, the integrated model clearly unveils the unique high-intensity profile that exists due to distinct tactical roles, rather than 1-dimensional "blind" distances produced by traditional models. Intuitively, this innovative concept may aid coaches' understanding of the physical performance in relation to the tactical roles and instructions given to the players. In addition, it will enable practitioners to effectively translate match metrics into training and testing protocols. This innovative model may well aid advances in other team sports that incorporate similar intermittent movements with tactical purpose. Evidence of the merits and application of this new concept is needed before the scientific community accepts this model as it may well add complexity to an area that conceivably needs simplicity.

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.

The Demands of a Women's College Soccer Season

The purpose of this study was to use GPS, accelerometers, and session rating of perceived exertion (sRPE) to examine the demands of a Division II women’s soccer team. Data was collected on 25 collegiate Division II women’s soccer players over an entire regular season (17 matches and 24 practices). Zephyr^TM BioHarnesses (BHs) were used to collect tri-axial acceleration information and GPS derived variables for all matches and practices. Acceleration data was used to calculate Impulse Load, a measure of mechanical load that includes only locomotor related accelerations. GPS was used to quantify total distance and distance in six speed zones. Internal Training Loads were assessed via sRPE. Mean Impulse Load, total distance, and sRPE during match play was 20,120 ± 8609 N·s, 5.48 ± 2.35 km, and 892.50 ± 358.50, respectively. Mean Impulse Load, total distance, and sRPE during practice was 12,410 ± 4067 N·s, 2.95 ± 0.95 km, and 143.30 ± 123.50, respectively. Several very large to nearly perfect correlations were found between Impulse Load and total distance (r = 0.95; p < 0.001), Impulse Load and sRPE (r = 0.84; p < 0.001), and total distance and sRPE (r = 0.82; p < 0.001). This study details the mechanical demands of Division II women’s soccer match play. This study also demonstrates that Impulse Load is a good indicator of total distance.

Physical demands and technical performance in Australian Football League Women's (AFLW) competition match-play

OBJECTIVES

To compare positional differences in the physical and technical demands of Australian Football League Women's (AFLW) match-play. A secondary aim was to examine the time course changes in activity profiles during AFLW match-play.

DESIGN

Longitudinal observational study.

METHODS

Global positioning system data were collected from 26 players (6 positional groups) from the same club during seven AFLW matches. Absolute and relative physical performance data were categorised into total distance, high-speed running (>14.4kmh^-1, HSR), very high-speed running (>18.0kmh^-1, VHSR), and sprinting distance (>20.0kmh^-1, Sprint). Technical performance data was obtained from a commercial statistics provider. A mixed model analysis was used to examine differences between positional groups and playing quarters.

RESULTS

Absolute measures of running performance did not differ between position groups. Relative total distance was moderately greater (ES=∼0.80, p<0.05) for midfielders, small backs and small forwards (125-128mmin^-1) than tall backs and tall forwards (102-107mmin^-1). Relative HSR distance was greater (ES=∼0.73) for midfielders and small backs (∼28mmin^-1) than tall backs (17mmin^-1). Analysis of technical performance indicators showed: midfielders and small forwards had the most inside 50s; tall backs had the highest number of rebound 50s; tall forwards scored more goals; while midfielders made more tackles (p<0.05). All relative running performance measures were reduced in the fourth quarter when compared to the first and second quarters (ES=0.32-0.77).

CONCLUSIONS

These data can be used as benchmarks for temporal analysis of AFLW match demands and assist in developing specific training strategies.

Quantifying the High-Speed Running and Sprinting Profiles of Elite Female Soccer Players During Competitive Matches Using an Optical Player Tracking System

The aim of this study was to determine the high-speed running and sprinting profiles of elite female soccer players during competitive matches using a new Optical Player Tracking system. Eight stationary video cameras were positioned at vantage points surrounding the soccer field so that when each camera view was combined, the entire field could be viewed simultaneously. After each match, an optical player tracking system detected the coordinates (x, y) of each player for every video frame. Algorithms applied to the x and y coordinates were used to determine activity variables for 12 elite female players across 7 competitive matches. Players covered 9,220-10,581 m of total distance, 1,772-2,917 m of high-speed running (3.4-5.3 m·s) distance, and 417-850 m of sprinting (>5.4 m·s) distance, with variations between positional groups (p < 0.001; partial η = 0.444-0.488). Similarly, the number of high-speed runs differed between positional groups (p = 0.002; partial η = 0.342), and a large proportion of high-speed runs (81-84%) and sprints (71-78%) were performed over distances less than 10 m. Mean time between high-speed runs (13.9 ± 4.4 seconds) and sprints (86.5 ± 38.0 seconds) varied according to playing position (p < 0.001; partial η = 0.409) and time of the match (p < 0.001; partial η = 0.113-0.310). The results of this study can be used to design match-specific conditioning drills and shows that coaches should take an individualized approach to training load monitoring according to position.

Metabolic Power of Female Footballers in Various Small-Sided Games with Different Pitch Surfaces and Sizes

Small-sided-games (SSGs) seem to be a useful tool for replicating most types of scenarios found in sport competitions, but it is not that clear in female soccer. Game surface and pitch size seem to affect the intensity of SSGs, but no one has yet analysed the influence of these two variables together. The objective of this research was to analyse the metabolic power demands of various SSGs on possession play without goal-keepers, played on three different surfaces. Sixteen sub-elite female players performed three different four-a-side games (400 m², 600 m², and 800 m²) on three different surfaces (ground [GR]; natural grass [NG]; and artificial turf [AT]), recording a total of 96 events. Metabolic variables were recorded through a global positioning system (GPS). The GR condition obtained the lowest outputs for all variables in all of the SSGs. Furthermore, NG resulted in higher outcomes than AT for Average Metabolic Power (SSG 400 [+0.65; p = 0.019]; SSG 600 [+0.70; p = 0.04]); and equivalent distance (SSG 400 [+33.0; p = 0.02]; SSG 600 [+36.53; p = 0.04]). Moreover, SSG 400 obtained lower results than SSG 600 and SSG 800 for both AT and NG. In conclusion, playing on GR reduces the metabolic power of SSGs, While NG seems to be the most suitable surface for attaining highest metabolic responses for sub-elite female players. On the other hand, too big a pitch size may not increase the metabolic demands of the game.