The acceleration and deceleration profiles of elite female soccer players during competitive matches

Influence of Menstrual Phase and Symptoms on Match Running in Professional Footballers

This study examined the effects of menstrual cycle phases and symptoms on match running performance in football (soccer) players. Twenty-one nonhormonal contraceptive using football players from four professional teams were monitored for up to four menstrual cycles during a domestic league season. Menstrual phases, classified as early-follicular phase (EFP), mid-late follicular phase (MFP), and luteal phase (LP), were determined by self-reporting of menstruation and urinary hormone tests (luteinizing hormone and pregnanediol-3-glucuronide). On match day, players completed a menstrual symptom severity questionnaire. In repeated matches, players wore 10 Hz Global Positioning Satellite (GPS) devices to measure relative (/min) total distance, high-speed running distance, very high-speed distance, peak speed, acceleration count, and deceleration count. Linear mixed models were performed for each GPS measure to determine the relationship with phase or symptoms. Data for 7 and 10 players were included for menstrual phase and menstrual symptoms analyses, respectively. A significantly higher total distance was reported during MFP compared to EFP (Δ 5.1 m min-1; p = 0.04) and LP (Δ 5.8 m min-1; p = 0.007). Significantly greater high-speed running was reported during MFP compared to EFP (Δ 1.2 m min-1; p = 0.012) and LP (Δ 1.1 m min-1; p = 0.007). No significant effect of menstrual phase was found for any other GPS measures (p > 0.05). Accelerations declined with increasing symptom severity (p = 0.021, estimate = -0.01count.min-1). Menstrual symptom severity did not affect any other GPS measures (p > 0.05). In conclusion, greater total distance and high-speed running occurred during the MFP. Additionally, accelerations minimally decreased with increasing menstrual symptom severity. Large intra- and inter-variability existed, suggesting individualized monitoring and management of menstrual effects on performance would be beneficial.

How Match-Related Variables Influence the Physical Demands of Professional Female Soccer Players during the Regular Season

To investigate how contextual or environmental factors may influence the athletic performance of female soccer players during competitions, this study aimed to assess the impact of match-related variables (playing surface; opponent levels; opponent result trends; match status, and match outcomes) on the athletic performance of professional female soccer athletes. Seventeen athletes (25.5 ± 4.3 years of age) from the same team competing in the Italian second division were divided into two groups according to their roles and athletic characteristics: Group A (central defenders and forwards) and Group B (right/left full-backs and midfielders). Total distance (TD) and sprint distance (SD); high-speed running (HSR), acceleration (ACC), and deceleration numbers (DEC); average and maximal heart rate (HR_avg; HR_max); and match-related factors were collected during the 22 regular season matches. A T-test and ANOVA were used to calculate the differences between groups in GPS and HR variables and the effects of match-related factors, respectively. Results showed higher running performance in the B group compared to the A group during matches. Increased ACC number was seen in matches played on artificial turf; winning was associated with decreased HR_max and increased DEC number. Athletes covered higher TD reaching lower HR_max when playing against lower-ranking opponents while matches lost/drawn resulted in higher HSR. High HRs (max and avg) were found when playing against a team with a positive performance trend. In summary, match-related factors and opponents' characteristics can affect athletic performance in female soccer athletes. These factors should be considered during in-seasonal training to personalize match preparation and optimize athlete performance.

Most common movements preceding goal scoring situations in female professional soccer

This study aimed to assess movements occurring during goal scoring situations in a female professional league.Data from all the goals on the Women's Super League 2018/2019 were collected through time-motion analysis using a modified version of the Bloomfield Movement Classification with differences analysed through chi-square. Analysis was performed on players (assistant, scorer [attackers], defender of assistant and defender of scorer [defenders]), movements, intensities and directions.Linear advancing motion (walking, jogging, running or sprint) (total percentage [95% CI] 37% attackers and 32.7% defenders) was the most common action preceding a goal, followed by deceleration (21.5% attackers; 18.4% defenders) and turn (19.2% attackers; 17.6% defenders). Other movements involved but with lower percentages were change in angle run (cut and arc run), ball blocking, lateral advancing motion (crossover and shuffle) and jumps. Players displayed similar tendencies but presented variations based on the role, with attackers performing more linear actions, subtle turns and cuts and defenders more ball blocking actions, lateral movements and high intensity linear actions and decelerations. Assistant performed the less percentage of involvements with at least 1 high intensity action (67.4%), scorer and defender of assistant showed similar values (86.3% and 87.1%), while defender of scorer had the highest percentage (97.3%).This study shows the importance of linear actions with other movements also being of high significance but with differentiated characteristics based on the role. This study could help practitioners design drills for the enhancement of physical capabilities related to movements occurring in goal scoring situations.

Effect of the role, playing position and the body characteristics on physical performance in female soccer players

The aims of this study were to know the physical demands according to the playing position and team role, and to assess the effect of the body characteristics on the physical performance of semi-professional female soccer players. Forty-five female semi-professional soccer players during 9 home-matches of the 2021-2022 season were analyzed and GPS devices (GPEXE ®) were used. ANCOVA tests were performed with playing time as covariate. The results showed greater physical demands in forwards and wide-midfielders and offensive role players. Total distance, metabolic power, accelerations, deaccelerations, and distance covered to medium and high speed obtained a strong effect size in these analyses according to the playing position. Furthermore, relationships between body weight and physical performance were found (p < 0.05). In conclusion, the main finding of this study showed that semi-professional female soccer players compete differently, caused by differentiated functions, evidenced in the playing positions and role in the team. Offensive role, forwards and wide-midfielder female players performed the highest physical demands in the competition. This study has shown relevant information for coaches, S&C coaches, and training staff of the semi-professional female soccer teams in order to propose new keys and ways of planning training sessions.

Changing the criteria applied to acceleration and deceleration efforts changes the types of player actions detected

This study identified and profiled the types of player actions of Australian football players executed during high acceleration and/or deceleration efforts and identified how the duration exceeding the acceleration or deceleration threshold influenced the identified executed player actions. The commencing speed of the acceleration and deceleration efforts were also assessed. Acceleration and deceleration efforts of 22 Australian football players monitored with a 10-Hz GNSS device across two matches were analysed. Synchronised video footage of the matches was used to identify the player actions executed during acceleration and deceleration efforts. Linear mixed models were conducted to examine the relationship between commencing speed, player action, and duration exceeding the effort threshold. 'Linear movement' and 'jump' were the most frequently executed player actions for high accelerations and 'stop' and 'being tackled' for high decelerations. Significant differences were observed in commencing speed between player actions for the high deceleration efforts. Furthermore, it was found that a higher commencing speed was associated with an increased duration exceeding the deceleration threshold. These findings will help practitioners and researchers with selecting minimum-duration criteria for acceleration and deceleration efforts and provide an understanding of the types of player actions executed during these efforts.

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.

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.

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

ABSTRACT

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

Effects of different training schedules based on distance and accelerometry measures: A full-season case study in professional soccer players

This study aimed to evaluate external load based on distance and accelerometry measures in six different microcycle schedules with congested (CW2, CW3, and CW4) and regular weeks (RW4, RW5, and RW6) in professional soccer players. Twelve Iranian First League players (age: 28.2 ± 3.8 years; body mass: 77.92 ± 4.72 kg, and height: 183.2 ± 0.06 cm) participated in this study. A GPSPORTS system was used to collect training/match durations, total distance, distance covered at different speeds, number of accelerations, delecelerations and body load over 29 weeks, 40 matches, and 121 training sessions. Data were analysed by weekly mean and accumulated weekly values. The results showed a tendency for higher values in CWs than RWs. Regarding mean total distance, RW4 and RW5 presented lower values with very large effect size than CW2 (all, p < 0.05). The mean distance covered between 16 and 23 km/h showed that all RWs presented significantly lower values than all CWs (p < 0.05 with considerable effect size). In addition, mean acceleration values at < 2 m/s2 showed significantly lower values than all CWs (p < 0.05 with a very large effect size). Therefore, it is recommended to coaches pay special attention to players who participate in matches to reduce fatigue and improve the performance of professional soccer players. Ensuring recovery mechanisms are in place to minimize the external load is recommended. Coaches arrange practice sessions for non-starters who do not experience similar external loads compared to starters to prepare them for potential competition.

Effects of Biological Age on Athletic Adaptations to Combined Plyometric and Sprint with Change of Direction with Ball Training in Youth Soccer Players

There is evidence for the effectiveness of youth combined plyometric and sprint with change of direction (COD) training. However, the evidence is not well-known regarding the in-season effects of biological age (peak height velocity—PHV) on the motor adaptive processes following combined plyometric and COD with ball training (P-CODBT) in youth soccer players. This study aimed to examine the in-season effects of P-CODBT (8 weeks and twice a week) on the athletic performances of male youth soccer players, circa- and post-PHV. In a randomized controlled training study with pre-to-post measurements, forty-eight male players were assigned into two experimental (performing P-CODBT; n = 12 × circa-PHV and n = 12 × post-PHV) and two control groups (CONG; n = 12 × circa-PHV and n = 12 × post-PHV). The pre- and post-training participants were assessed for their anthropometric, linear sprinting with and without a ball, COD speed with and without a ball, vertical jump, dynamic balance, and endurance-intensive performances. After the intervention, the experimental condition induced significant (all p < 0.0001) and small to large effect size (ES = 0.263−3.471) additional gains only on explosive measures compared to CONG. Both the experimental (all p < 0.0001; ES = 0.338−1.908) and control (p = 0.011−0.0001; ES = 0.2−1.8) groups improved their athletic performances over the training period. The improvements generated by p-CODBT were not affected by biological age. In-season short-term P-CODBT (twice a week) could be safe way to generate benefits in explosive performances in youth soccer players, which are relevant components of match-winning actions in soccer.

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.

Techniques to derive and clean acceleration and deceleration data of athlete tracking technologies in team sports: A scoping review

The application of acceleration and deceleration data as a measure of an athlete's physical performance is common practice in team sports. Acceleration and deceleration are monitored with athlete tracking technologies during training and games to quantify training load, prevent injury and enhance performance. However, inconsistencies exist throughout the literature in the reported methodological procedures used to quantify acceleration and deceleration. The object of this review was to systematically map and provide a summary of the methodological procedures being used on acceleration and deceleration data obtained from athlete tracking technologies in team sports and describe the applications of the data. Systematic searches of multiple databases were undertaken. To be included, studies must have investigated full body acceleration and/or deceleration data of athlete tracking technologies. The search identified 276 eligible studies. Most studies (60%) did not provide information on how the data was derived and what sequence of steps were taken to clean the data. Acceleration and deceleration data were commonly applied to quantify and describe movement demands using effort metrics. This scoping review identified research gaps in the methodological procedures and deriving and cleaning techniques that warrant future research focussing on their effect on acceleration and deceleration data.

Fitness, Fatness, and Academic Attainment in Male Schoolchildren from a Soccer Academy

This investigation explored the association between anthropometric measures, fitness, and academic attainment (mathematics and science grade point average [GPA]) in male schoolchildren from a soccer academy. Thirty-one males (age: 10.3 ± 1.19 years; body mass: 41.7 ± 6.5 kg; height: 1.43 ± 0.07 m; body mass index (BMI): 20.2 ± 2.8 kg/m2) participated. Body mass, body fat percentage (%BF), and BMI were used as measures of anthropometry. The Yo-Yo Intermittent Recovery Test (level 1), squat and counter-movement jumps (SJ and CMJ), static balance, 10 and 15 m sprint, and a T-half test for change-of-direction (CoD) performance were used to measure fitness parameters. The GPA of mathematics and science determined academic attainment. All physical performance tests showed excellent relative reliability. ICC was between 0.87 (10 m sprint) and 1.00 (15 m sprint, CMJ). Regarding correlations between fatness and academic attainment, we found three correlations of practical value (r > 0.5), but only for mathematics (BMI: r = 0.540, subscapular skinfold: r = 0.589, body fat: r = 0.560). Mathematics was relevantly correlated with 15 m sprint (r = 0.574) and Yo-Yo IR1 test (r = 0.770). Only static balance (r = 0.428) did not reach the relevance criteria (r > 0.5). Science only showed large correlations with static balance (r = 0.620) and Yo-Yo IR1 test (r = 0.730). In conclusion, fatness and fitness are related to academic attainment in schoolchildren. In addition, except for static balance, all physical performance parameters were relevantly (r > 0.5) correlated with mathematics.

Sprint Performance and Mechanical Force-Velocity Profile among Different Maturational Stages in Young Soccer Players

The aim of the present study was to determine the influence of maturation status on the components of the sprint force-velocity (F-V) profile in young soccer players. Sixty-two young male soccer players from the same professional soccer academy took part in the present study. A cross-sectional design was implemented to compare the main components of the sprint F-V profile (i.e., maximal theoretical force (F₀), velocity (V₀), power (P_max), and ratio of horizontal-to-resultant force (RF_peak), and decrease in the ratio of horizontal-to-resultant force (DRF)) and sprint performance (5, 20, and 30 m sprint time) among participants’ maturation stages (i.e., pre-, mid- and post-peak height velocity (PHV) groups). The results show that the ES of differences in 5 min sprint performance, F₀, and RF_peak (i.e., strength- and acceleration-related components of the sprint F-V profile) were greater between pre- and mid-PHV groups than those between mid- and post-PHV groups (i.e., large and very large effects (1.24 ≤ ES ≤ 2.42) vs. moderate, small, and zero effects (0 ≤ ES ≤ 0.69), respectively). However, the ES of differences in V₀ and DRF (i.e., peak speed-related components of the sprint F-V profile) were greater between mid- and post-PHV groups than those between pre- and mid-PHV groups (i.e., large effects (1.54 ≤ ES ≤ 1.92) vs. moderate effects (−0.59 ≤ ES ≤ 1), respectively). Once the strength development is achieved to a great extent from the pre- to mid-PHV groups, specific strength training methods may be used for young soccer players to improve their sprint performance.

Assessment of Peak Physical Demands in Elite Women Soccer Players: Can Contextual Variables Play a Role?

Aim: To describe and compare the peak physical demands through the worst-case scenario method (WCS), according to different rolling average (RA) time epochs (i.e. 1 min, 3 min, and 5 min) and contextual variables in women soccer players. Methods: Using an observational-comparative study design, an elite women soccer team from the Spanish 1^st league division was monitored during 27 matches. Nine WCS-dependent variables were assessed, including total distance (TD), high-speed running distance (HSR), sprint distance (SP), acceleration, and deceleration distance at different intensities by players position (i.e., central defenders [CD], wide defenders [WD], central midfielders [CM], wide midfielders [WM], forwards [F]), match half, location, and match outcome. Results: The 1-min RA showed the lowest variability (CV = 9.8-65.8%) for all nine dependent variables. The WD presented the highest TD (168 ± 15.71 m/min). Differences between positions were observed for: CM<F (-10.19 m/min), CM<WM (-11.20 m/min), and CM<WD (-12.70 m/min). For SP: CM<F (-10.03 m/min), CM<WM (-11.91 m/min), CM<WD (-10.03 m/min), and CM<CD (-5.31 m/min). The WCS-dependent variables were also affected by match half and match outcome. Conclusions: 1-min RA time epochs allow greater accuracy and reliability to identify nine key WCS outcomes in elite women soccer players. Different contextual variables, particularly player's position, influenced the peak periods.

Effects of Post-Activation Performance Enhancement (PAPE) Induced by a Plyometric Protocol on Deceleration Performance

Post-Activation Potentiation (PAP) is a phenomenon which can improve power performance executed after a previous conditioning activity. PAP is usually evoked through heavy resistance or plyometric exercise. It has been suggested to refer to as Postactivation Performance Enhancement (PAPE) when research is field-based on explosive activities. To our best knowledge, no studies have investigated the effects of PAPE on deceleration performance, which is a key factor in sports involving change of directions. Therefore, the aim of this study was to investigate the influence of a plyometric exercise protocol on a subsequent deceleration running performance. University soccer players (n = 18) performed seven deceleration trials and were assessed at baseline and after ~15 s, 2, 4, 8, 12 and 16 min either following a walking control condition (C) or three sets of ten repetitions of alternate-leg bounding (plyometric, P). Results showed no significant differences at any of the trials under the control condition (C) in comparison to the relative baseline. Under the plyometric condition (P), deceleration performance executed two minutes after the plyometric activity resulted in significantly faster results compared to the baseline values (p = 0.042; ES = 0.86, large effect; % of improvement = 4.13 %). The main findings are that plyometric exercise improves a subsequent running deceleration performance, 2 min after its execution. Future investigations should focus on more complex actions such as changes of direction and agility.

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.

An 8-Week Program of Plyometrics and Sprints with Changes of Direction Improved Anaerobic Fitness in Young Male Soccer Players

This study examined the effects of 8 weeks of twice-weekly combined plyometric and sprint with change-of-direction (CPSCoD) training into habitual training regimes of young male soccer players. Participants were randomly allocated to an experimental group (n = 17, age: 14.6 ± 0.44 years, body mass: 61.2 ± 7.34 kg, height: 1.67 ± 0.09 m, body fat: 11.2 ± 1.56%) and a control group (n = 16, age: 14.6 ± 0.39 years, body mass: 61.1 ± 3.96 kg, height: 1.67 ± 0.05 m, body fat: 11.8 ± 1.47%). Measures obtained pre- and post intervention included vertical and horizontal jump performance (i.e., squat jump (SJ), countermovement jump (CMJ), and standing long jump (SLJ)), and sprint performance (i.e., 5 m and 20 m sprint). In addition, Measures obtained pre- and post-intervention included change-of-direction ability (4 × 5 m sprint test (S 4 × 5 m) and sprint 9-3-6-3-9 m with backward and forward running (SBF)), repeated change of direction (RCoD), and static balance performance (stork balance test). The training group experienced superior jump (all p < 0.05; d ≥ 0.61), sprint (all p < 0.05; d ≥ 0.58), change-of-direction (CoD) ability (all p < 0.05; d ≥ 0.58), RCoD (all parameters except the fatigue index p < 0.01; effect size (d) ≥ 0.71), and static balance (all p < 0.05; d ≥ 0.66) improvement. Adding twice-weekly CPSCoD training to standard training improves the anaerobic performance of U15 male soccer players.

Relationship between Physical Fitness and Match Performance Parameters of Chile Women's National Football Team

The aim of this study was to analyze the relationships between the level of physical fitness and the physical performance parameters recorded by GPS in official FIFA matches of the Chilean women’s senior national football team in the period 2018–2020. Twenty-six female field players (age (mean ± SD) 26.8 ± 3.3 years, height 157.8 ± 21.5 cm, weight 58.9 ± 4.9 kg) participated in the study. Physical fitness variables were assessed: muscular strength, countermovement jump (CMJ), speed, agility and aerobic fitness. Physical performance variables were recorded by GPS in 26 official FIFA matches. The most notable associations with significant statistical significance (p < 0.001) were those observed between neuromuscular variables such as time to run 10 m (T10; r = −0.629) and jump (CMJ; r = 0.502) and the number of accelerations; aerobic fitness showed a highly significant relationship with meters run per minute (M/M; r = 0.589). The findings of this study provide evidence of how the level of physical fitness (neuromuscular and aerobic) relates to physical performance parameters recorded in official competitions.

A systematic review of intervention programs that produced changes in speed and explosive strength in youth footballers

A soccer player should possess a reasonable level of different skills and abilities, so the playing position, level of training, style of play, physical and physiological demands can influence his performance. The objective was to identify the intervention programs that have been applied in search of generating positive effects on explosive strength and speed in young soccer players, as well as to identify the percentage of improvement among soccer players. A bibliographic study of systematic review was carried out. Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement, bibliographic searches were performed in the PubMed database. The following descriptors were used: Explosive Strength, soccer players, jump performance, CMJ, SJ, VJ, Plyometrics, power, speed, sprint, kicking speed, change of direction speed, soccer player, football and training, intervention. Articles were included only if they were original articles, studied populations of young soccer players and showed an intervention program related to explosive strength and speed. Six studies were identified that applied intervention programs to look for changes in speed and explosive strength in young soccer players. In the 5m speed tests, significant changes were observed, improving from (0.26 to 0.53m/s), 10m speed (0.07 to 0.27m/s), 20m speed (0.08 to 1.92m/s) and 40m speed (0.25 to 0.62m/s). In explosive strength, performance in the test squat jump SJ (4.1 to 8.6cm), countermovement jump CMJ (1.0 to 8.8cm), horizontal jump HJ (12.17 to 24.4cm) and vertical jump VJ (5.0 to 11.0cm). Speed and explosive strength are relevant components of athletic performance and can be improved through training programs that include 20 to 40min sessions, training two to five times per week over a period of approximately 6 to 9 weeks.

Quantifying Accelerations and Decelerations in Elite Women Soccer Players during Regular In-Season Training as an Index of Training Load

Accelerations (ACC) and decelerations (DEC) are important and frequent actions in soccer. We aimed to investigate whether ACC and DEC were good indicators of the variation of training loads in elite women soccer players. Changes in the training load were monitored during two different selected weeks (considered a “low week” and a “heavy week”) during the in-season. Twelve elite soccer women playing in the French first division wore a 10-Hz Global Positioning System unit recording total distance, distance within speed ranges, sprint number, ACC, DEC, and a heart rate monitor during six soccer training sessions and rated their perceived exertion (RPE). They answered the Hooper questionnaire (sleep, stress, fatigue, DOMS) to get an insight of their subjective fitness level at the start (Hooper S) and at the end of each week (Hooper E). A countermovement jump (CMJ) was also performed once a week. During the heavy week, the training load was significantly greater than the low week when considering number of ACC >2 m·s⁻² (28.2 ± 11.9 vs. 56.1 ± 10.1, p < 0.001) and number of DEC < −2 m·s⁻² (31.5 ± 13.4 vs. 60.9 ± 14.4, p < 0.001). The mean heart rate percentage (HR%) (p < 0.05), RPE (p < 0.001), and Hooper E (p < 0.001) were significantly greater during the heavy week. ACC and DEC showed significant correlations with most outcomes: HR%, total distance, distance per min, sprint number, Hooper index of Hooper E, DOMS E, Fatigue E, RPE, and session RPE. We concluded that, for elite women soccer players, quantifying ACC and DEC alongside other indicators seemed to be essential for a more complete training load monitoring. Indeed, it could lead to a better understanding of the reasons why athletes get fatigued and give insight into neuromuscular, rather than only energetic, fatigue.

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.

Relationships between Fitness Status and Match Running Performance in Adult Women Soccer Players: A Cohort Study

Background and Objectives: The aim of this study was twofold: (i) to analyze the relationships between fitness status (repeated-sprint ability (RSA), aerobic performance, vertical height jump, and hip adductor and abductor strength) and match running performance in adult women soccer players and (ii) to explain variations in standardized total distance, HSR, and sprinting distances based on players' fitness status. Materials and Methods: The study followed a cohort design. Twenty-two Portuguese women soccer players competing at the first-league level were monitored for 22 weeks. These players were tested three times during the cohort period. The measured parameters included isometric strength (hip adductor and abductor), vertical jump (squat and countermovement jump), linear sprint (10 and 30 m), change-of-direction (COD), repeated sprints (6 × 35 m), and intermittent endurance (Yo-Yo intermittent recovery test level 1). Data were also collected for several match running performance indicators (total distance covered and distance at different speed zones, accelerations/decelerations, maximum sprinting speed, and number of sprints) in 10 matches during the cohort. Results: Maximal linear sprint bouts presented large to very large correlations with explosive match-play actions (accelerations, decelerations, and sprint occurrences; r = -0.80 to -0.61). In addition, jump modalities and COD ability significantly predicted, respectively, in-game high-intensity accelerations (r = 0.69 to 0.75; R2 = 25%) and decelerations (r = -0.78 to -0.50; R2 = 23-24%). Furthermore, COD had significant explanatory power related to match running performance variance regardless of whether the testing and match performance outcomes were computed a few or several days apart. Conclusion: The present investigation can help conditioning professionals working with senior women soccer players to prescribe effective fitness tests to improve their forecasts of locomotor performance.

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.

Influence of Pitch Size on Short-Term High Intensity Actions and Body Impacts in Soccer Sided Games

The aim of this study was to compare external training loads between small-sided games (SSGs) and largesided games (LSGs) in soccer players. Twenty outfield soccer players (14.8 ± 0.6 years old) who competed in the Spanish U16 Provincial Division and belonged to the same team participated in the study. The soccer sided games were played at different individual interaction space (IIS) per player (i.e., SSG = 100 m² and LSG = 200 m²) and were disputed in the same format (five-a-side plus goalkeepers) on two different pitch sizes (i.e., 38 x 26 vs. 53 x 37 m) defending an official soccer-goal. The sided games' duration was 4 bouts of 6 min with 2 min rest intervals between bouts. The results of this study showed no meaningful differences in the total distance and intensity of accelerations and decelerations between SSGs and LSGs except for the lower distance covered at medium intensity (2.5 - 4 m·s^-2) observed during LSGs (-10.2%; ES (effect size): -0.51). Players registered greater sprints, maximum velocity (Vel_max) and body impacts at different intensities (i.e., I5-6g, I6-6.5g, I6.5-7g, I7-8g, I8-10g,) in LSGs in comparison to SSGs. These findings suggest that an increase in the pitch size (i.e., IIS per player) can induce higher external loads for soccer players.

Acceleration and High-Speed Running Profiles of Women's International and Domestic Football Matches

Acceleration and deceleration are important given football is an intermittent sport with constant changes in velocity and direction. It is unclear, however, if the accelerations and decelerations performed by players differ between competition levels. The aim of the present study was to compare the acceleration, deceleration, and high-speed running profiles of players during international and domestic matches and to determine if differences were apparent across playing positions (defenders, midfielders, and attackers). GPS data from 21 Australian women's domestic football league matches over 2 seasons (2016-2018) and 15 Australian women's international matches (2017-2018) were collected and analyzed. Movement pattern data was collected using VX Sport and GPSports 10 Hz GPS receivers. Variables analyzed included: total distance, distance covered high-speed running (16-20 km·h-1) distance covered sprinting (> 20 km·h-1) and time spent accelerating and decelerating in four predetermined bands (1-2 m·s-2, 2-3 m·s-2, 3-4 m·s-2, and > 4 m·s-2). Results revealed that players competing in international matches covered significantly greater total distances, greater high-speed running distances and greater sprinting distances as well as spending a greater duration accelerating in band 4 compared to players in domestic competitions (p < 0.05). Players competing in international matches spent significantly less duration decelerating in bands 2 and 3, compared to players in domestic competitions. International defenders and midfielders recorded significantly higher total distances and high-speed running distance compared to players in domestic matches. Our findings suggest that preparing players for international-level competition should include progressive exposure to high-speed running and sprinting distances, as well as high magnitude accelerations. Furthermore, the higher running speeds experienced by players during international matches appears to be a result of less time spent decelerating. The optimal deceleration necessary for specific situations appears important and emphasizes the need for specific deceleration training. The increased effort of high-intensity activity that is required for players competing in international matches affects defenders and midfielders to the greatest degree. Gradual exposure to the increased running demands for midfielders and defenders competing in international matches is needed to improve performance and reduce the potential risk of injury.

Effects of an eccentric overload and small-side games training in match accelerations and decelerations performance in female under-23 soccer players

BACKGROUND

The aims of this study were: 1) to investigate the impacts that an eccentric overload training (EOT) and a small-side game training (SSGT) have on the characteristics of the accelerations (ACC) and decelerations (DCC) of the players in a soccer match; and 2) to determine if EOT and SSGT could affect the ACC and DCC reduction over time in a soccer match.

METHODS

Twenty-three female soccer players from a Spanish professional club were split into three groups: a small-sided game training group (SGG), an eccentric overload training group (EOG) and a control group (CG).

RESULTS

The SSG improved the high intensity distance performed (ES [CI]=0.72 [0.22; 1.22]), the number of high intensity actions (ES [CI]=0.65 [0.01; 1.29]), the percentage of repeated high intensity actions (ES [CI]=0.54 [-0.17; 1.25]), the initial velocity of the ACC (ES [CI]=0.55 [-0.08; 1.17]) and the percentage of repeated accelerations (ES [CI]=0.87 [-0.18; 1.91]) with respect to the control group. The EOG obtained better results in distance travelling accelerating (ES [CI]=0.84 [0.09; 1.60]) and decelerating (ES [CI]=0.87 [0.23; 1.51]) above 3 m/s2, maximum ACC (ES [CI]=1.92 [0.90; 2.94]) and DCC (ES [CI]=1.29 [0.44; 2.14]) and the average of maximum ACC (ES [CI]=0.89 [0.23; 1.54]) and DCC (ES [CI]=1.08 [0.62; 1.55]) with respect to the CG. A decrement in the ACC and DCC performance was observed between the first and last 15 minutes of the competition, except for the EOG.

CONCLUSIONS

The SSG obtained mainly improvements in variables related with efforts repetitions and the capacity of maintaining the ACC and the DCC over time, while improvements in the EOG were related to intensity in the ACC and DCC.

Contextual factors influencing the characteristics of female football players

Women's football participation rates are projected to increase to 60 million worldwide by 2026, doubling the current participation. Growing investment and the increase in research in women's football has had a positive effect on the level of performance over the last 10 years. The present review aimed to examine the literature on the physical and physiological characteristics of female football players from 2010 to 2019 to reflect the recent changes in professionalism. Characteristics investigated include anthropometry, strength, speed, endurance, power, change of direction and repeated sprint ability. These characteristics are presented in relation to playing position, age and competition-level. Results revealed that goalkeepers (171 cm, 66 kg) and defenders (168 cm, 61 kg) were the tallest and had the greatest body mass, while attackers were the fastest players over 20 m (3.05 s) and 30 m (4.38 s) and midfielders had the highest endurance (55.4 mL∙kg^-1∙min^-1) (P<0.05). Characteristics tended to improve with age until full biological maturity around 17 to 18 years of age. Competition comparisons demonstrated international players have significantly greater speed, repeated sprint ability, power and endurance characteristics (P<0.05). By identifying influential factors, coaches may be able to optimize their training and physical assessment practices, to better expose players to the required stimulus to develop these characteristics considered crucial to improved performance.

Effect of testing procedures on gait speed measurement: A systematic review

BACKGROUND

Although gait speed is a widely used measure in older people, testing methods are highly variable. We conducted a systematic review to investigate the influence of testing procedures on resulting gait speed.

METHODS

We followed the PRISMA checklist for this systematic review. Two independent reviewers screened Pubmed and Embase for publications on pairwise comparisons of testing procedures of usual gait speed. Descriptives were abstracted from the included publications using a predefined extraction tool by two independent reviewers. We defined the cut-off for the minimal clinically imporant diffence in gait speed as 0.1 m/sec.

RESULTS

Of a total of 2109 records identified for screening, 29 reports on 53 pairwise comparisons were analyzed. The median (range) difference in gait speed for dynamic versus static start was 0.06 (-0.02 to 0.35) m/sec (14 reports); for longer versus shorter test distance 0.04 (-0.05 to 0.23) m/sec (14 reports); for automatic versus manual timing 0.00 (-0.05 to 0.07) m/sec (12 reports), for hard versus soft surfaces -0.11 (-0.18 to 0.08) m/sec (six reports), and electronic walkways versus usual walk test 0.04 (-0.08 to 0.14) m/sec (seven reports), respectively. No report compared the effect of finishing procedures.

CONCLUSIONS

The type of starting procedure, the length of the test distance, and the surface of the walkway may have a clinically relevant impact on measured gait speed. Manual timing resulted in statistically significant differences of measured gait speed as compared to automatic timing, but was below the level of clinical importance. These results emphasize that it is key to use a strictly standardized method for obtaining a reliable and valid measurement of gait speed.

Women's Football: An Examination of Factors That Influence Movement Patterns

Griffin, J, Larsen, B, Horan, S, Keogh, J, Dodd, K, Andretta, M, and Minahan, C. Title: Women's football: An examination of factors that influence movement patterns. J Strength Cond Res 34(8): 2384-2393, 2020-The popularity and professionalism of women's football has increased in conjunction with participation rates over the last 10 years, with projected female participation rates to double worldwide by 2026. Scientific interest has also increased, in part due to Fédération Internationale de Football Association now allowing global positioning system (GPS) units to be worn during all competitive matches, resulting in investigations into the match demands of women's football. Therefore, the purpose of the present review is to provide a summary of the literature specific to the movement patterns of women's football matches. Contemporary scientific investigation using GPS match data has led to a greater understanding of the movement patterns of football. Greater emphasis has been placed on high-speed running and sprinting during matches because of the strong link to scoring opportunities and being a distinguishing factor between international and national along with elite and subelite competition levels. Further research, however, is warranted in regard to accelerations and decelerations, given the high metabolic and mechanical loads and contribution to high-speed running and sprinting. With an influx of research into the movement patterns of match-play, investigators have begun to examine factors affecting match performance such as positional demands, age, level of competition, opponent, scoreline, and phase of the game. An understanding of the factors that influence match demands is vital to ultimately be able to understand the effects on performance and how manipulating these factors may improve football performance and reduce the risk of injury.

The influence of offside rule and pitch sizes on the youth soccer players' small-sided games external loads

The aim was to analyse the influence of the offside rule and pitch sizes on the external loads encountered by young soccer players during small-sided games (SSGs). Twenty-four U12 soccer players belonged to the same Spanish Performance Soccer Academy participated in the study. Each player participated in six different SSGs attending to the offside rule (i.e., offside not applicable [NOS] and with offside [WOS]) and the pitch sizes (i.e., individual interaction space [IIS] of 25, 50 and 75 m² per player). The obtained data included measures of external loads by global positioning systems. Players covered higher total distance and greater distances at jogging (8-12.9 km·h^-1), cruising (13.0-16.0 km·h^-1) and sprinting (>16.0 km·h^-1) in NOS₇₅ and WOS₇₅ SSGs (p < 0.01; d = 0.65-6.60). Besides, in the NOS₇₅ SSG, the total distance and the distance at cruising were higher in respect to WOS₇₅ (p < 0.01; d = 0.63-0.82). In addition, players performed lower sprints (p < 0.01; d = 1.17-1.71) and achieved lower V_max (p > 0.05; d = 1.10-1.88) during NOS₂₅ and WOS₂₅ SSGs. These findings could provide relevant information for coaches in order to apply different pitch sizes and the inclusion/absence of the offside rule throughout the microcycle.

An Approach to the Fatigue in Young Soccer Players Resulting from Sided Games

It is crucial to understand the fatigue associated with sided games (SGs) of soccer in the training context, in order to establish the appropriate intervals between training sessions. Thus, the aim of this study was to investigate the effects of different SGs on internal load, measured by the session rating of perceived exertion (sRPE), and on sprint performance. Ten outfield players (age: 14.5 ± 0.5 years, height: 169 ± 6 cm, body mass: 59.7 ± 6.4 kg) belonging to U15 age category participated in this study. The participants played four SG formats with modifications in the pitch size and in the bout duration, but with the same total duration for the SGs (SG1, SG2, SG3, and SG4). All the players performed a 10 and a 30 m sprint test before and after the SGs. The internal load was measured by the sRPE. The results showed no significant differences (p > 0.05) in the sRPE registered by the soccer players for the different SGs, but worse sprint performances over the 10 m (p < 0.05; ES: 0.74–1.38, large) and 30 m (p < 0.05; ES: 0.70–2.10, moderate to large) distances after completion of the SGs, except the 10 m sprint after SG2 and SG3 (p > 0.05; ES: 0.43–0.55, moderate). In addition, no correlation (p > 0.05) was reported between the sprint performances for the 10 and 30 m distances and the sRPE registered during the SGs. These results could be useful for technical staff wishing to design the playing area and bout duration of their training tasks effectively.

The influence of youth soccer players' sprint performance on the different sided games' external load using GPS devices

The aims of this study are 1) to compare sided games' (SGs) external responses encountered by players according to pitch size and to 2) examine the relationships between sprint performance and SGs' external physical responses. Twenty soccer players under 15 years of age (U-15) participated in this study. Each player performed a sprinting test (10 m and 30 m sprints) and played a SG on two different pitch sizes (small at 100 [SSG] and large at 200 [LSG] m² per player). Higher external responses (p < 0.01, ES = -6.41-1.22) were found in LSG in comparison to SSG, except to distance accelerating and decelerating (p > 0.05, ES = -0.26-0.27). Players who were faster over 10 and 30 m covered higher distances cruising and sprinting (r = -0.47/-0.66; ± 0.23/± 0.30, respectively, p < 0.05), performed a greater number of sprints, achieved higher maximum velocity (Vel_max) during LSG and covered a greater distance at high-intensity accelerating (r = -0.50/-0.70; ±0.21/±0.29, respectively, p < 0.05) during both SG. LSG demanded a higher external load in comparison with SSG. In addition, the improved sprint capacity could allow players to perform greater running activities and short-term actions at high-intensities during SG.

Deceleration characteristics of elite Australian male field hockey players during an Olympic tournament

OBJECTIVES

This study described the deceleration efforts of the Australian men's field hockey team during the 2016 Olympics by categorising efforts into 'bands' of intensity; and comparing the deceleration intensity and frequency by player position, game period and opponent.

DESIGN

Descriptive retrospective analysis.

METHODS

Global positioning system sensors (MinimaxX S4, Catapult Sports Pty. Ltd., Melbourne, Australia; 10Hz) were worn by 15 male field hockey players during six games of the 2016 Olympic tournament.

RESULTS

There were 8998 individual deceleration efforts (≤-3ms^-2) performed over the tournament with the most intense effort measured at -13.6ms^-2. Deceleration intensity 'bands' were calculated using Receiver Operator Characteristic (ROC) curves as low intensity=-3 to -5.99ms^-2; medium intensity=-6 to -8.99ms^-2; high intensity=-9 to -11.99ms^-2; and, very high intensity=<-12ms^-2. There were no significantly different decelerations between field positions but decelerations performed within game period one were more intense than game period two (-0.11±0.01ms^-2, p<0.001). Deceleration efforts were more frequent in game period one than two [X²(3, N=8997)=12.00, p=0.007].

CONCLUSIONS

Decelerations are common in elite field hockey and very high intensities are present. These findings, in conjunction with other metrics can be used as a tool to monitor the load associated with training and match play in field hockey.

Activity Demands During Multi-Directional Team Sports: A Systematic Review

BACKGROUND

Late-stage rehabilitation programs often incorporate 'sport-specific' demands, but may not optimally simulate the in-game volume or intensity of such activities as sprinting, cutting, jumping, and lateral movement.

OBJECTIVE

The aim of this review was to characterize, quantify, and compare straight-line running and multi-directional demands during sport competition.

DATA SOURCES

A systematic review of PubMed, CINAHL, SPORTDiscus, and Cochrane Central Register of Controlled Trials databases was conducted.

STUDY ELIGIBILITY CRITERIA

Studies that reported time-motion analysis data on straight-line running, accelerations/decelerations, activity changes, jumping, cutting, or lateral movement over the course of an entire competition in a multi-directional sport (soccer, basketball, lacrosse, handball, field hockey, futsal, volleyball) were included.

STUDY APPRAISAL AND SYNTHESIS METHODS

Data was organized based on sport, age level, and sex and descriptive statistics of the frequency, intensity, time, and volume of the characteristics of running and multi-directional demands were extracted from each study.

RESULTS

Eighty-one studies were included in the review (n = 47 soccer, n = 11 basketball, n = 9 handball, n = 7 field hockey, n = 3 futsal, n = 4 volleyball). Variability of sport demand data was found across sports, sexes, and age levels. Specifically, soccer and field hockey demanded the most volume of running, while basketball required the highest ratio of high-intensity running to sprinting. Athletes change activity between 500 and 3000 times over the course of a competition, or once every 2-4 s. Studies of soccer reported the most frequent cutting (up to 800 per game), while studies of basketball reported the highest frequency of lateral movement (up to 450 per game). Basketball (42-56 per game), handball (up to 90 per game), and volleyball (up to 35 per game) were found to require the most jumping.

LIMITATIONS

These data may provide an incomplete view of an athlete's straight-line running load, considering that only competition and not practice data was provided.

CONCLUSIONS

Considerable variability exists in the demands of straight-line running and multi-directional demands across sports, competition levels, and sexes, indicating the need for sports medicine clinicians to design future rehabilitation programs with improved specificity (including the type of activity and dosage) to these demands.

Player Monitoring in Indoor Team Sports: Concurrent Validity of Inertial Measurement Units to Quantify Average and Peak Acceleration Values

The increasing interest in assessing physical demands in team sports has led to the development of multiple sports related monitoring systems. Due to technical limitations, these systems primarily could be applied to outdoor sports, whereas an equivalent indoor locomotion analysis is not established yet. Technological development of inertial measurement units (IMU) broadens the possibilities for player monitoring and enables the quantification of locomotor movements in indoor environments. The aim of the current study was to validate an IMU measuring by determining average and peak human acceleration under indoor conditions in team sport specific movements. Data of a single wearable tracking device including an IMU (Optimeye S5, Catapult Sports, Melbourne, Australia) were compared to the results of a 3D motion analysis (MA) system (Vicon Motion Systems, Oxford, UK) during selected standardized movement simulations in an indoor laboratory (n = 56). A low-pass filtering method for gravity correction (LF) and two sensor fusion algorithms for orientation estimation [Complementary Filter (CF), Kalman-Filter (KF)] were implemented and compared with MA system data. Significant differences (p < 0.05) were found between LF and MA data but not between sensor fusion algorithms and MA. Higher precision and lower relative errors were found for CF (RMSE = 0.05; CV = 2.6%) and KF (RMSE = 0.15; CV = 3.8%) both compared to the LF method (RMSE = 1.14; CV = 47.6%) regarding the magnitude of the resulting vector and strongly emphasize the implementation of orientation estimation to accurately describe human acceleration. Comparing both sensor fusion algorithms, CF revealed slightly lower errors than KF and additionally provided valuable information about positive and negative acceleration values in all three movement planes with moderate to good validity (CV = 3.9 – 17.8%). Compared to x- and y-axis superior results were found for the z-axis. These findings demonstrate that IMU-based wearable tracking devices can successfully be applied for athlete monitoring in indoor team sports and provide potential to accurately quantify accelerations and decelerations in all three orthogonal axes with acceptable validity. An increase in accuracy taking magnetometers in account should be specifically pursued by future research.