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

Analysis of the Most Intense Periods During Elite Soccer Matches: Effect of Game Location and Playing Position

PURPOSE

This study aimed to quantify the game-speed demand of elite soccer players using time windows from 5 seconds to 10 minutes and to examine the effect of match location and playing position on game-speed outputs.

METHODS

Twenty-four Serie A (Italy) male professional soccer players (27.5 [4.1] y old) participated in this study across an entire season. The players' activity profiles during matches were analyzed using a semiautomatic video tracking system (Stats Perform), which provided 2-dimensional coordinates of the players, and from these data, total distance (TD) covered, high-speed running distance (HSRD), and sprint distance (SD) were calculated. The most intense periods of match play were calculated using a moving-average method within 15 time windows (ie, 5-10-15-30-60-90 s and from 2 to 10 min) and analyzed using a linear mixed model.

RESULTS

A slightly higher SD (estimate values = 3.98, P = .0192) was performed when playing a home match. Midfielders run the highest values for TD (P = .0001), center backs produced the lowest HSRD (P = .0011), and no significant differences between roles were found in terms of SD.

CONCLUSIONS

A univariate approach based on velocity can aid in designing training for the most intense periods of a match, considering positional differences for TD and HSRD. On the other hand, the consistency in SD across different roles suggests a team behavior during the most intense periods of the game such as attacking and defensive transition phases.

Less than 4% of participants in studies of carbohydrate-based fuelling strategies for soccer performance have been female: results from an audit of her representation

Women's soccer has increased markedly in popularity and professionalisation in recent years. Achieving adequate carbohydrate (CHO) availability before and during performance is often advised as a key priority for players. The aim of this study was to audit the literature that informs the current CHO-based guidelines for soccer performance and to assess the extent of evidence supporting their application to female players. Using an established protocol for auditing the published literature, seven databases were searched for research investigating the effects of acute CHO-based fuelling strategies before or during soccer performance. A total of 43 studies met the inclusion criteria. There were a total of 542 participants, of which 3.7% were female (n = 20 individuals) and 96.3% were male (n = 522 individuals). The majority of the studies were designed to examine the effects of CHO intake during soccer (n = 31; 72.1%), with the remaining studies employing pre-exercise CHO intake (n = 5; 11.6%) or CHO loading (n = 7; 16.3%) protocols. Most studies involved male-only cohorts (n = 41; 95.3%), while female-only (n = 1; 2.3%) and mixed-sex cohorts (n = 1; 2.3%) were less prevalent. Of the two studies that included females, neither provided any information around categorisation or control of menstrual cycle status. The current guidelines on acute CHO-based fuelling strategies for soccer are not informed by an adequate evidence base when applied to female players. Given the potential for between-sex differences in physiology and metabolism, the lack of female-specific research means that it is presently unknown whether the current guidelines on CHO-based fuelling strategies for soccer are optimal for female players.

Muscle Metabolism and Performance During Simulated Peak-Intensity Periods Occurring Early and Late in a Soccer-Specific Exercise Protocol in Well-Trained Male Players

We applied a novel model mimicking the most intense 5-min game periods to investigate muscle metabolic and fatigue responses to peak-intensity exercise occurring early and late in a simulated soccer game. Eleven well-trained male players completed a modified simulated soccer game (the Copenhagen Soccer Test) with 5-min peak-intensity period simulations inserted early (PP1; 10-15 min) and late (PP2; 85-90 min) in the game. Muscle biopsies and blood samples were obtained before and after each peak period. Muscle glycogen decreased during both peak periods (p < 0.001) by 62 ± 46 mmol kg-1 dw in PP1 and by 25 ± 37 mmol kg-1 dw in PP2, without a statistically significant difference in the glycogen breakdown in PP1 vs. PP2, despite a numerical trend (p = 0.115). Muscle lactate increased during both peak periods (p < 0.001) to 47 ± 25 mmol kg-1 dw and 32 ± 12 mmol kg-1 dw, with no clear difference in the increase (p = 0.108), despite blood lactate levels rising more in PP1 vs. PP2 (p = 0.031), reaching higher post PP1 levels (13.9 ± 3.6 mmol L-1 vs. 9.8 ± 2.4 mmol L-1, p = 0.003). Muscle ATP decreased by 4% (p = 0.004) and phosphocreatine by ~50% (p < 0.001) following both peak periods. RPE was higher during PP2 (10.0 ± 0.0 AU vs. 9.2 ± 0.8 AU, p = 0.023), while 10-m sprint performance declined by ~10% (p < 0.001), with no differences between PP1 and PP2 (p = 0.280). In conclusion, a 5-min peak period occurring early in a simulated game elicited a high anaerobic energy turnover, with marked muscle glycogen reductions, lactate accumulation, and PCr depletion. While high-energy phosphate metabolism remained similar during the late peak period, glycogenolytic rate appeared attenuated, accompanied by aggravated perceived exertion but similar sprint performance deteriorations.

Variability of whole and peak match physical performance in highly trained female academy soccer players: A multi-club analysis

OBJECTIVE

Quantify between-match, -player and -team variability and compare whole- and peak-match locomotor characteristics between positions in elite female academy soccer.

METHOD

Foot-mounted inertial measurement unit data were collected from 11 Women's Super League Academy teams (n = 257 players; 171 matches). Differences between positions and variability were analysed using partial least squares correlation analysis (PLSCA) and linear mixed effects. Two latent variables were computed as composite scores of either whole match or peak intensity variables from the PLSCA.

RESULTS

Between-match variability of whole- and peak-match locomotor characteristics were similar (2 to 24% vs 0.2 to 22%). Between-team and -player variability was higher for whole- than peak-match locomotor characteristics (1 to 20% vs 0.1 to 3%, 8 to 112% vs 0.3 to 77%). From 30 pairwise comparisons, there were two large effect size (ES) differences (p < 0.001), WM had greater whole and peak match composite intensity than CDM. There were 10 moderate ES differences (p < 0.05), with WM greater than CD and CAM, F greater than CD and CDM and WD greater than CDM. All other comparisons were non-significant, trivial or small.

CONCLUSION

Whole- and peak- match locomotor characteristics are similar across all outfield positions in elite female academy soccer. Between-match variability was greater for sprint distance than all other locomotor characteristics. Low variability between teams for peak locomotor characteristics means practitioners can be confident using peak reference values from this study and use them to evaluate training drill intensities of tactical-technical drills.

Ventilatory thresholds in professional female soccer players

This study investigated the ventilatory thresholds (VT1 and VT2) along with the corresponding heart rates, velocities and % of V̇O2 max at which these thresholds are reached in professional female soccer players. It also examined positional differences in the aforementioned parameters. Thirty-three professional players from two teams (age range 18-31 years) were recruited. The players underwent maximal exercise testing on the treadmill for the detection of VT1 (V̇E versus V̇O2 plot) and VT2 (V̇E versus V̇CO2 plot). The test began at a speed of 6km/h and was increased by 2 km/h every 3.15 minutes, with the inclination constant at 1%. Results indicated that the players had an average V̇O2 max of 50.24 ml·kg- 1.min- 1. VT1 (% max) and VT2 (% max) were shown at 72.87% and 91.26% of V̇O2 max, respectively. The respective velocities at VT1 and VT2 were indicated at 10.85 km/h and 12.91 km/h, respectively, while the average VV̇O2 max was 14.61 km/h. The average heart rates at VT1, VT2 and V̇O2 max were 159.33, 185.15 and 192.85 beats per minute, respectively. Furthermore, analysis of variance ANOVA indicated significant differences in velocity at V̇O2max. This study provides important normative data regarding the ventilatory thresholds of female soccer players.

Influence of Training Load on Muscle Contractile Properties in Semi-Professional Female Soccer Players Across a Competitive Microcycle: A Pilot Study

This study aimed to evaluate changes in muscle contractile properties during a training microcycle in semi-professional female football players and explore their relationship with training load variables. Nineteen players (age: 23.9 ± 3.9 years; body mass: 60.6 ± 6.9 kg; height: 164.5 ± 6.7 cm) underwent myotonometric assessments of the biceps femoris (BF) and rectus femoris (RF) before and after the following training sessions: MD1 (i.e., 1 day after the match), MD3, MD4, and MD5. Training loads were quantified for each session, revealing significant variations, with MD4 exhibiting the highest values for high-speed running distance, number of sprints, and accelerations. Notably, MD3 showed the highest perceived exertion (RPE), while MD5 recorded the lowest total distance run. Myotonometric assessments indicated significant differences in stiffness of the RF in MD3 and BF in MD5, as well as RF tone in MD5. The findings underscore a notable relationship between training load and myotometric variables, particularly in muscle stiffness and tone. These results emphasize the need for further research to clarify how training loads affect muscle properties in female athletes.

Very high-speed running (VHSR) profile in elite female football: An update

The aim of the present study it's a providing an update of the profile of very high-speed running (VHSR) of professional female football players. In this study 23 official matches of the Spanish First Division of Women´s Football were analysed. A total of 15 players participated, who were classified according to their location on the matches played: central-corridor (CCP, n = 7), and lateral-corridor (LCP, n = 8). The variables recorded were: 1) Very High-Speed Running (VHSR), considering the accumulated distance, duration, and frequency, and the individual characteristics of the efforts (distance and duration); 2) Recovery between efforts (VHSRe) and; 3) VMAX. The results show that LCP described higher values in accumulative VHSR and VHSR by distance bands, with greater distances, durations and VMAX of VHSRe, with less recovery between efforts. There seems to be an evolutionary trend in the distribution of the efforts, with a higher % of efforts in the 10-20 m band. The results provide useful information that coaching staff of professional women's football teams could use to design specific very high-speed running training to optimize performance in competition.

Analysis of peak locomotor demands in women's football-the influence of different epoch lengths

The quantification of peak locomotor demands has been gathering researchers' attention in the past years. Regardless of the different methodological approaches used, the most selected epochs are between 1-, 3-, 5- and 15-minutes time windows. However, the selection of these time frames is frequently arbitrary. The aim of this study was to analyse the peak locomotor demands of short time epochs (15, 30, 45, and 60 seconds) in women's football, with special emphasis over the high-speed metrics. During two seasons, the match physical performance of 100 female football players was collected with Global Positioning System units (STATSports Apex). Peak locomotor demands for the selected variables were calculated by using a 1-second moving average approach. For statistical procedures, linear mixed modelling was used, with total distance, high-speed running distance (>16 km∙h-1), sprint distance (>20 km∙h-1), and acceleration and deceleration distance (±2.26 m∙s-2) considered as the dependent variables and the epoch lengths (15, 30, 45, and 60 seconds) considered as the independent variables. A novel finding was the high ratio observed in the 15 seconds epochs of high-speed running distance and sprint distance (77.6% and 91.3%, respectively). The results show that most peak high-speed demands within 60 seconds are completed within just 15 seconds. Thus, intensity-related variables, such as high-speed metrics, would be better contextualised and adapted into training practices if analysed in shorter epoch lengths (15-30 seconds), while longer periods might be used for volume-related metrics (i.e., total distance), depending on the purpose of the analysis.

Monitoring Readiness to Train and Perform in Female Football: Current Evidence and Recommendations for Practitioners

PURPOSE

Monitoring player readiness to train and perform is an important practical concept in football. Despite an abundance of research in this area in the male game, to date, research is limited in female football. The aims of this study were, first, to summarize the current literature on the monitoring of readiness in female football; second, to summarize the current evidence regarding the monitoring of the menstrual cycle and its potential impact on physical preparation and performance in female footballers; and third, to offer practical recommendations based on the current evidence for practitioners working with female football players.

CONCLUSIONS

Practitioners should include both objective (eg, heart rate and countermovement jump) and subjective measures (eg, athlete-reported outcome measures) in their monitoring practices. This would allow them to have a better picture of female players' readiness. Practitioners should assess the reliability of their monitoring (objective and subjective) tools before adopting them with their players. The use of athlete-reported outcome measures could play a key role in contexts where technology is not available (eg, in semiprofessional and amateur clubs); however, practitioners need to be aware that many single-item athlete-reported outcome measures instruments have not been properly validated. Finally, tracking the menstrual cycle can identify menstrual dysfunction (eg, infrequent or irregular menstruation) that can indicate a state of low energy availability or an underlying gynecological issue, both of which warrant further investigation by medical practitioners.

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.

Differences in Situational Patterns During Change of Direction Movements Greater than 90° in Youth Male and Female Soccer Players

Change of direction (COD) maneuvers in soccer create tactical advantages, but also expose the player to an increased risk of injury. COD ability is commonly tested with pre-planned drills including cuts greater than 90°. These tests do not take into consideration positional differences players encounter during games. This case-series study used principal component analysis (PCA) to examine situational differences during COD movements between playing positions in youth soccer games. For each of the four teams included (26 females, 27 males), one game was analyzed using video-analysis. Two independent reviewers identified situational patterns and a PCA was used to examine differences between playing positions. Three principal components explained 89% of the variation in the data and were categorized as the total quantity of CODs, attacking/goal-scoring and defensive reacting types of CODs. One-way ANOVA on the individual principal component (PC) scores showed significant differences (p < 0.05) between centre midfielders, goalkeepers, and centrebacks in the quantity of CODs (PC1), and between wingers and fullbacks and centre backs in attacking/goal-scoring CODs (PC2), whereas PC3 was not different between playing positions. Differences between playing positions suggest that training and testing protocols in soccer could be enhanced to better match the individual and playing position-based needs.

Position specific physical demands in different phases of competitive matches in national level women's football

The purpose of the present study was twofold: to investigate position-specific physical match demands of national level women's football; and to examine if demands change during a match (comparison between first and second half and in 15-minute intervals). Seven teams from the Finnish National League participated in the study. Eighty-five players met the inclusion criteria, and a total of 340 individual match observations from 68 individual matches were included for analysis. The Polar Team Pro -player tracking system (with 10 Hz GPS units, including 200 Hz tri-axial accelerometer, gyroscope, magnetometer and HR monitor) was used to assess positional data and HR response of the players. This study demonstrated that women's national level football matches place a range of physical demands on players, which in general were highest for wide midfielders, and lowest for central defenders. Wide midfielders and forwards performed significantly more 'very high-speed' running, sprinting, accelerations, and decelerations than other outfield positions (p < 0.05). HRmean varied from 84-87% of HRmax and was significantly lower for central defenders than central midfielders (p < 0.001). External load variables varied during a match and generally decreased especially after 60 minutes of play compared to first 15-min period of the match. Present study showed that national level women football players' positional differences in match demands are similar to those reported with elite players in previous studies. On national level, players' physical performance tended to decrease towards the end of the match, especially in terms of total distance (~10%), high-speed running (~20%), and decelerations (~20%).

Temporal patterns of fatigue in repeated sprint ability testing in soccer players and acute effects of different IHRs: a comparison between genders

BACKGROUND

Repeated sprint ability (RSA) in soccer is deemed fundamental to ensure high level of performance. The aim of this study was to investigate the acute effects of two different Initial Heart Rates (IHR) on fatigue when testing RSA in males and females' soccer players and to compare the respective patterns of fatigue.

METHODS

Nineteen female soccer players (age: 22.5±3.3 years, height 163.9±7.3 cm, body weight 54.3±6.4 kg, BMI 20.6±1.5 kg·m^-2) and 15 male soccer players (age: 17.9±1.5 years, height 175.9±5.8 cm, body weight 68.5±9.6 kg, BMI 22.3±1.5 kg·m^-2) participated in this study. HRs reached at the end of two different warm-up protocols (~90 vs. ~ 60% HR<inf>max</inf>), have been selected and the respective RSA performances were compared, within and between the groups of participants. Two sets of ten shuttle-sprints (15+15 m) with a 1:3 exercise to rest ratio with different IHR% were administered, in different days, in randomized order. To compare the different sprint performances, we employed the calculated Fatigue Index (FI%). Blood lactate concentration (BLa^-) was also measured before and after testing, to compare metabolic energy.

RESULTS

Significant differences among trials within each set (P<0.01) were found in both genders. Differences between sets were found in male players, (Factorial ANOVA 2x5; P<0.001), not in female. BLa^- after warm-up was higher in 90% vs. 60% HR<inf>max</inf> (P<0.05), in both genders but at the completion of RSA tests (after 3 minutes) the differences were not significant (P>0.05).

CONCLUSIONS

difference between genders were found, suggesting specific approach in testing and training RSA in soccer players.

Evaluating Physical and Tactical Performance and Their Connection during Female Soccer Matches Using Global Positioning Systems

The objective of the present study was to evaluate the tactical and physical performance during official matches of a women's soccer league and to correlate both dimensions in periods of 15 min. To do this, eight official matches of a semi-professional soccer team belonging to the Women's Second Division of Spain (Reto Iberdrola) were analysed during the 2020-2021 season. The variables recorded were classified into two dimensions: tactical variables (i.e., Width, Length, Height and Surface Area) and physical variables (i.e., Total Distance Covered (TD), Total Distance Covered in High-Speed Running (HSR) and Total Distance Covered in Sprint). The main results were: (1) there were no differences between the periods in any of the tactical dimension variables; (2) in the physical dimension, a significant decrease in TD and HSR was described at the end of the match (period 60-75); and (3) some positive correlations were found among some variables of the tactical and physical dimension at the beginning and at the end of the match (periods 0-15, 60-75 and 75-90). The findings of the study suggest that connecting the tactical and physical dimension in the interpretation of team performance would allow for a better understanding of player and team performance and during competition.

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.

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.

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.