Technical match actions and plasma stress markers in elite female football players during an official FIFA Tournament

Adequate Interval between Matches in Elite Female Soccer Players

The present study compared four different intervals between three simulated soccer matches for changes in muscle damage and performance parameters. Thirteen well-trained female university soccer players performed three bouts of 90-min Loughborough Intermittent Shuttle Test (LIST) with four different intervals between bouts; one (1d), two (2d), three (3d) and four days (4d), with >12-weeks between conditions in a counterbalanced order. Heart rate, blood lactate, rating of perceived exertion and distance covered in each LIST were measured. Changes in several muscle damage markers (e.g., maximal voluntary isometric torque of the knee extensors: MVC-KE, muscle soreness), performance parameters (e.g., Yo-Yo intermittent recovery test level 1: Yo-Yo IR1), and blood measures (e.g., osmolality, high sensitivity cardiac troponin T) before the first LIST, 1 h after each LIST, and one to five days after the third LIST were compared among the conditions. The total distance covered during the first two LISTs was not different among the conditions, but that during the third LIST was shorter (P < 0.05) for the 1d (9,416 ± 885 m) and 2d conditions (9,737 ± 246 m) than the 3d (10,052 ± 490 m) and 4d conditions (10,432 ± 538 m). Changes in all measures were smaller (P < 0.05) in the 3d and 4d conditions (e.g., the decrease in MVC-KE at one day after the third LIST was -13 ± 4% and -10 ± 3%, respectively) when compared with the 1d and 2d conditions (-20 ± 7%, -18 ± 5%). Performance parameters showed smaller (P < 0.05) changes in the 4d (e.g., the decrease in Yo-Yo IR1 at one day after the third LIST was -9 ± 3%) and 3d (-13 ± 6%) conditions when compared with the 1d (-19 ± 4%) and 2d (-20 ± 8%) conditions. These results suggest that muscle damage and fatigue accumulate when soccer matches are performed three consecutive days or every other day, but if more than three days are inserted between matches, this could be minimized.

Comparison of the effects of pea protein and whey protein on the metabolic profile of soccer athletes: a randomized, double-blind, crossover trial

Introduction

Pea protein (PP) concentrate is a plant-based alternative to animal protein sources, such as whey protein (WP). In addition to its valuable amino acid composition, PP has a low environmental impact, making it a sustainable, nutritious, and viable alternative for enhanced sports performance, such as in soccer. PP Therefore, this study aimed to evaluate the effects of PP and WP supplementation on biochemical and metabolic parameters in soccer players.

Methods

Twelve male under-20 soccer players were included in this double-blind, randomized crossover intervention study. For 10 consecutive days, each participant received either 0.5 g/kg of the PP or WP supplementation after training, starting 7 days before the test game, and continuing until 2 days after. After a 4-day washout period, the athletes switched groups and the intervention was restarted. Blood samples were collected before and after the game, as well as 24 h, 48 h, and 72 h intervals thereafter. Creatine kinase (CK), aspartate transaminase, alanine transaminase (ALT), lactate (LA), urea, creatinine, and uric acid were analyzed using commercial kits. Exploratory metabolic profiling of the serum samples was performed using nuclear magnetic resonance spectroscopy.

Results

A comparison of biochemical markers showed that the PP group had lower CK in the post-game moment, 24 h, and 48 h. Lower LA in the post-game moment, and lower ALT in the post-game moment and at 24 h. Of the 48 metabolites analyzed, 22 showed significant differences between the time points, such as amino acids, ketone bodies, and glucose metabolism. Glutamate and lactate levels significantly increased between the pre- and post-game moments in the WP group. After the game, the WP group exhibited reduced levels of metabolites such as arginine and taurine, whereas no such change was observed in the PP group. There was no difference in metabolites 72 h after the game.

Conclusions

Despite the slight advantage of the PP group in specific biochemical markers, these differences are not sufficient to justify the choice of a particular type of protein. However, the results highlight the viability of plant protein as a potential alternative to animal protein without compromising athletic performance or recovery.

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

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

Biomarkers of post-match recovery in semi-professional and professional football (soccer)

High-level football (soccer) players face intense physical demands that result in acute and residual fatigue, impairing their physical performance in subsequent matches. Further, top-class players are frequently exposed to match-congested periods where sufficient recovery times are not achievable. To evaluate training and recovery strategies, the monitoring of players' recovery profiles is crucial. Along with performance and neuro-mechanical impairments, match-induced fatigue causes metabolic disturbances denoted by changes in chemical analytes that can be quantified in different body fluids such as blood, saliva, and urine, thus acting as biomarkers. The monitoring of these molecules might supplement performance, neuromuscular and cognitive measurements to guide coaches and trainers during the recovery period. The present narrative review aims to comprehensively review the scientific literature on biomarkers of post-match recovery in semi-professional and professional football players as well as provide an outlook on the role that metabolomic studies might play in this field of research. Overall, no single gold-standard biomarker of match-induced fatigue exists, and a range of metabolites are available to assess different aspects of post-match recovery. The use of biomarker panels might be suitable to simultaneously monitoring these broad physiological processes, yet further research on fluctuations of different analytes throughout post-match recovery is warranted. Although important efforts have been made to address the high interindividual heterogeneity of available markers, limitations inherent to these markers might compromise the information they provide to guide recovery protocols. Further research on metabolomics might benefit from evaluating the long-term recovery period from a high-level football match to shed light upon new biomarkers of post-match recovery.

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

Background

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

Methods

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

Results

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

Conclusions

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

Registration

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

Supplementary Information

The online version contains supplementary material available at 10.1186/s40798-022-00466-3.

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.

Gut microbiota of elite female football players is not altered during an official international tournament

The current study aimed to investigate if the gut microbiota composition of elite female football players changes during an official international tournament. The study was conducted throughout ten consecutive days, encompassing seven training sessions, and three official matches. The matches were separated by 48-72 h. Seventeen elite female football players from the Portuguese women's national football team participated in the study. Fecal samples were collected at two time points: at the beginning and end of the tournament. Fecal microbiota was analyzed by sequencing the 16S rRNA gene. Throughout the study, the duration and rating of perceived exertion (RPE) were recorded after training sessions and matches. The internal load was determined by the session RPE. The gut microbiota of players was predominantly composed of bacteria from the phyla Firmicutes (50% of relative abundance) and Bacteroidetes (20%); the genera Faecalibacterium (29%) and Collinsella (16%); the species Faecalibacterium prausnitzii (30%) and Collinsella aerofaciens (17%). Overall, no significant changes were observed between time points (p ≥ 0.05). Also, no relationship was found between any exercise parameter and the gut microbiota composition (p ≥ 0.05). These findings demonstrate that the physical and physiological demands of training and matches of an official international tournament did not change the gut microbiota composition of elite female football players. Furthermore, it supports that the gut microbiota of athletes appears resilient to the physical and physiological demands of training and match play.