Fixture congestion modulates post-match recovery kinetics in professional soccer players

The Evolution of Match Running Performance in the Top Two Spanish Soccer Leagues: A Comparative Four-Season Study

Objectives: This study uniquely examines the evolution of match running performance in official matches over four consecutive seasons (2019/2020-2022/23) within Spain's top two professional soccer leagues (LaLiga). By analyzing differences between competitive league standards (First Division vs. Second Division), this research provides critical insights into how competition levels influence physical performance trends over time. Methods: A total of 6784 match observations were recorded from 95 teams competing in the First and Second Divisions (LaLiga). Performance metrics included total distance (TD), high-speed running (HSR, >21 km·h-1), very high-speed running (VHSR, 21.1-24 km·h-1), sprint distance (Sprint, >24 km·h-1), the number of HSR efforts (Nº. Sprints > 21 km·h-1), and sprint efforts (Nº. Sprints > 24 km·h-1), all analyzed using a computerized tracking system (TRACAB, ChyronHego, New York, NY, USA). Results: The primary findings indicated significantly higher match running performance in First Division matches compared to Second Division matches across all variables (p < 0.001). Furthermore, match running performance significantly increased over the four seasons in both leagues, with notably higher values during the 2021/22 and 2022/23 seasons for all physical performance metrics (p < 0.001). Conclusions: This study contributes to understanding the temporal evolution of soccer match performance across competition levels. The findings emphasize the importance of periodic performance monitoring and adapting training loads increasing high-intensity distances to align with escalating physical demands in modern soccer, offering valuable guidance for coaches and performance analysts.

Sleep Patterns Fluctuate Following Training and Games across the Season in a Semi-Professional, Female Basketball Team

Quantifying athlete sleep patterns may inform development of optimal training schedules and sleep strategies, considering the competitive challenges faced across the season. Therefore, this study comprehensively quantified the sleep patterns of a female basketball team and examined variations in sleep between nights. Seven semi-professional, female basketball players had their sleep monitored using wrist-worn activity monitors and perceptual ratings during a 13-week in-season. Sleep variables were compared between different nights (control nights, training nights, training nights before games, nights before games, non-congested game nights, and congested game nights), using generalized linear mixed models, as well as Cohen's d and odds ratios as effect sizes. Players experienced less sleep on training nights before games compared to control nights, training nights, nights before games, and congested game nights (p < 0.05, d = 0.43-0.69). Players also exhibited later sleep onset times on non-congested game nights compared to control nights (p = 0.01, d = 0.68), and earlier sleep offset times following training nights before games compared to all other nights (p < 0.01, d = 0.74-0.79). Moreover, the odds of players attaining better perceived sleep quality was 88% lower on congested game nights than on nights before games (p < 0.001). While players in this study attained an adequate sleep duration (7.3 ± 0.3 h) and efficiency (85 ± 2%) on average across the in-season, they were susceptible to poor sleep on training nights before games and following games. Although limited to a team-based case series design, these findings suggest basketball coaches may need to reconsider scheduling team-based, on-court training sessions on nights prior to games and consider implementing suitable psychological and recovery strategies around games to optimize player sleep.

Effects of congested fixture and matches' participation on internal and external workload indices in professional soccer players

This study aimed to verify the effects of congested fixture and matches’ participation on internal and external workload indexes in professional Brazilian soccer players. Rate of perceived exertion-based training load (sRPE), distance- and accelerometry-based measures were daily monitored over 119 training sessions and 33 matches performed by 29 male outfield players. Weeks were classified as congested (n = 11, two or more matches within a 7-day period) and regular (n = 10, one match or less within a 7-day period). The players were divided based on the matches’ participation: (1) players who played ≥ 60 min (G1); (2) players who played < 60 min (G2); (3) players who did not participate of the match (G3). The findings showed that independent of the levels of participation during the matches, regular weeks presented greater acute, monotony, and strain indices for internal and external workload measures than congested weeks. The G1 presented the highest values for most of the workload indices in both regular and congested weeks, except for monotony indices (internal and external load) that G2 showed greater values than G1 and G3. Coaches and practitioners should plan the training “doses” to reduce disparities of these different match’s participation and congested schedule weeks.

Selected Immunoendocrine Measures for Monitoring Responses to Training and Match Load in Professional Association Football: A Review of the Evidence

Biomarkers relating to player “stress balance,” immunological (ie, immunoglobulin-A), and hormonal (ie, testosterone and cortisol [T:C]) status are now commonly used in football. This article is our critical review of the scientific literature relating to the response of these measures to player load and their relationships with player health. The commonly reported relationship between immunoglobulin-A and training or match load highlights its sensitivity to changes in psychophysiological stress and the increased risk of compromised mucosal immunity. This is supported by its close relationship with symptoms of upper respiratory tract infection and its association with perceived fatigue in football players. Testosterone and cortisol concentrations and the testosterone–cortisol ratio are sensitive to changes in player load, but the direction of their response is often inconsistent and is likely influenced by player training status and non-sport-related stressors. Some evidence indicates that sustained periods of high training volume can increase resting testosterone and that sustained periods of low and high training intensity can increase resting cortisol, compromising the testosterone–cortisol ratio. These findings are noteworthy, as recent findings indicate interrelationships between testosterone, cortisol, and testosterone:cortisol and perceived measures of fatigue, sleep quality, and muscle soreness in football players. Variability in individual responses suggests the need for a multivariate and individualized approach to player monitoring. Overall, we consider that there is sufficient evidence to support the use of salivary immunoglobulin-A, testosterone, cortisol, and testosterone:cortisol measures as part of a multivariate, individualized player monitoring system in professional football.

Correlation between strength and skin temperature asymmetries in the lower limbs of Brazilian elite soccer players before and after a competitive season

This study aimed to investigate the correlation between strength and skin temperature (T_sk) asymmetries in the lower limbs of elite soccer players before and after a competitive season. The sample (n = 20) was composed of elite male soccer players. Strength asymmetry and T_sk asymmetry was measured through the countermovement jump (CMJ) test and infrared thermography, respectively. Asymmetries were quantified using the symmetry angle (SA) equation. A strong correlation was found between the SA of rate of force development (RFD) and the SA of T_sk before (baseline) (r = 0.7; r² = 0.43; p = 0.03) and after (r = 0.6; r² = 0.42; p = 0.04) the competitive season. Moreover, after the competitive season there were significant decreases in Peak force (p < 0.018), Impulse (p < 0.04), RFD (p = 0.0001) and CMJ height (p = 0.05), and significant increases in T_sk (p < 0.03), C-reactive protein (p = 0.03), Creatine kinase (p = 0.0001) and Cortisol (p = 0.04), even after a 3-day rest interval (no training). These results suggest that the CMJ test can be combined with infrared thermography for monitoring strength asymmetry and contribute to the prevention of muscle injuries.

Effects of Variations in Resistance Training Frequency on Strength Development in Well-Trained Populations and Implications for In-Season Athlete Training: A Systematic Review and Meta-analysis

BACKGROUND

In-season competition and tournaments for team sports can be both long and congested, with some sports competing up to three times per week. During these periods of time, athletes need to prepare technically, tactically and physically for the next fixture and the short duration between fixtures means that, in some cases, physical preparation ceases, or training focus moves to recovery as opposed to progressing adaptations.

OBJECTIVE

The aim of this review was to investigate the effect of training frequency on muscular strength to determine if a potential method to accommodate in-season resistance training, during busy training schedules, could be achieved by utilizing shorter more frequent training sessions across a training week.

METHODS

A literature search was conducted using the SPORTDiscus, Ovid, PubMed and Scopus databases. 2134 studies were identified prior to application of the following inclusion criteria: (1) maximal strength was assessed, (2) a minimum of two different training frequency groups were included, (3) participants were well trained, and finally (4) compound exercises were included within the training programmes. A Cochrane risk of bias assessment was applied to studies that performed randomized controlled trials and consistency of studies was analysed using I² as a test of heterogeneity. Secondary analysis of studies included Hedges' g effect sizes (g) and between-study differences were estimated using a random-effects model.

RESULTS

Inconsistency of effects between pre- and post-intervention was low within-group (I² = 0%), and moderate between-group (I² ≤ 73.95%). Risk of bias was also low based upon the Cochrane risk of bias assessment. Significant increases were observed overall for both upper (p ≤ 0.022) and lower (p ≤ 0.008) body strength, pre- to post-intervention, when all frequencies were assessed. A small effect was observed between training frequencies for upper (g ≤ 0.58) and lower body (g ≤ 0.45).

CONCLUSION

Over a 6-12-week period, there are no clear differences in maximal strength development between training frequencies, in well-trained populations. Such observations may permit the potential for training to be manipulated around competition schedules and volume to be distributed across shorter, but more frequent training sessions within a micro-cycle rather than being condensed into 1-2 sessions per week, in effect, allowing for a micro-dosing of the strength stimuli.

Accelerometry-Workload Indices Concerning Different Levels of Participation during Congested Fixture Periods in Professional Soccer: A Pilot Study Conducted over a Full Season

The aim of this study was to analyze the variations of acute load (AL), acute: chronic workload ratio (ACWR), training monotony (TM), and training strain (TS) of accelerometry-based GPS measures in players who started in three matches (S3M), two matches (S2M), and one match (S1M) during congested weeks. Nineteen elite professional male players from a Portuguese team (age: 26.5 ± 4.3 years) were monitored daily using global positioning systems (GPSs) over a full season (45 weeks). Accelerometry-derived measures of high metabolic load distance (HMLD), high accelerations (HA), and high decelerations (HD) were collected during each training session and match. Seven congested weeks were classified throughout the season, and the participation of each player in matches played during these weeks was codified. The workload indices of AL (classified as ACWR, TM, and TS) were calculated weekly for each player. The AL of HMLD was significantly greater for S2M than S1M (difference = 42%; p = 0.002; d = 0.977) and for S3M than S1M (difference = 44%; p = 0.001; d = 1.231). Similarly, the AL of HA was significantly greater for S2M than S1M (difference = 25%; p = 0.023; d = 0.735). The TM of HD was significantly greater for S2M than S3M (difference = 25%; p = 0.002; d = 0.774). Accelerometry-based measures were dependent on congested fixtures. S2M had the greatest TS values, while S3M had the greatest TM.

Prior workload has moderate effects on high-intensity match performance in elite-level professional football players when controlling for situational and contextual variables

This investigation examined the effect of prior workload on high-intensity football match performance. Player load variables were recorded using a global positioning system and converted into composite variables: rolling season accumulated load (AL), exponentially weighted moving average acute, chronic and acute:chronic workload ratio (A:C). Match-play high-intensity performance-per-minute: accelerations (ACC), sprints, high-speed running (HSR) and high metabolic load (HMLd) distances; and situational and contextual variables were recorded for all games. Partial least squares modelling, and backward stepwise selection determined the most parsimonious model for each performance variable. Quadratic relationships of small to moderate effect sizes were identified for sprint AL and sprint performance, HSR AL and HSR performance, acute HMLd and HMLd performance, acute sprint load and ACC performance and A:C sprint load and ACC performance. Match performance was typically greatest between the mean and +1SD. High chronic HMLd, and combined acceleration and deceleration (ACC+DEC) load exerted small beneficial effects on HMLd and HSR performance, whereas high acute load exerted trivial to moderate negative effects. High sprint A:C exerted a small beneficial effect on sprint performance and playing position exerted small effects on HSR and HMLd performance. Prior workload has trivial to moderate effects on high-intensity match performance in professional players.

Monitoring of Post-match Fatigue in Professional Soccer: Welcome to the Real World

Participation in soccer match-play leads to acute and transient subjective, biochemical, metabolic and physical disturbances in players over subsequent hours and days. Inadequate time for rest and regeneration between matches can expose players to the risk of training and competing whilst not entirely recovered. In professional soccer, contemporary competitive schedules can require teams to compete in excess of 60 matches over the course of the season with periods of fixture congestion occurring, prompting much attention from researchers and practitioners to the monitoring of fatigue and readiness to play. A comprehensive body of research has investigated post-match acute and residual fatigue responses. Yet the relevance of the research for professional soccer contexts is debatable, notably in relation to the study populations and designs employed. Monitoring can indeed be invasive, expensive, time inefficient, and difficult to perform routinely and simultaneously in a large squad of regularly competing players. Uncertainty also exists regarding the meaningfulness and interpretation of changes in fatigue response values and their functional relevance, and practical applicability in the field. The real-world need and cost-benefit of monitoring must be carefully weighed up. In relation to professional soccer contexts, this opinion paper intends to (1) debate the need for post-match fatigue monitoring; (2) critique the real-world relevance of the current research literature; (3) discuss the practical burden relating to measurement tools and protocols, and the collection, interpretation and application of data in the field; and (4) propose future research perspectives.

Can compression stockings reduce the degree of soccer match-induced fatigue in females?

Soccer-induced fatigue and performance are different between the sexes. The effect of compression stockings (CS) use on fatigue during the soccer match in females is unknown. Thus, we evaluated the impact of CS use during a female soccer match on match-induced fatigue. Twenty soccer players were randomly allocated to two groups (n = 10 for each group): CS and Control (regular socks), and equally distributed within two teams. At rest (baseline 48-h before the match) and immediately post-match, we assessed agility T-test, standing heel-rise test and YoYo Intermittent Endurance Test level 2 (YoYoIE2) performance. Effort during the match (heart rate and rating of perceived exertion) was similar (p > 0.05) between groups. The YoYoIE2 performance was decreased post-match (p < 0.05) equally for both groups. Otherwise, the CS group exhibited a greater post-match performance (p < 0.05) for the agility T-test and heel-rise test (large effect sizes). Therefore, we conclude that the use of CS during an amateur female soccer match resulted in less match-induced fatigue.

Variations of perceived load and well-being between normal and congested weeks in elite case study handball team

The aim of this study was two-fold: (i) to analyze the variations in internal load and well-being in professional handball players between normal and congested weeks and (ii) to analyze the variations between training days within weeks. Twenty male players (26.5 ± 4.9 yo) were monitored during a full season. MD-1 (match day -1) revealed larger decreases in muscle soreness (-17.3%, [-26.6;-6.9]) and fatigue (-16.6%, [-24.8;-7.4]) in congested weeks. Regarding MD-2, larger decreases in DOMS (-19.9%, [-30.5;-7.6]), fatigue (-19.7%, [-30.0;-7.9] and the Hooper index (-16.7%, [-25.6;-6.7]) were found in congested weeks. The results of this study reveal that larger variations between normal and congested weeks occurred in MD-2 and MD-3, with greater values of load and lower levels of well-being occurring in normal weeks. Within-weeks changes revealed greater loads occurring on MD-3 and MD-2 in comparison to MD-1; in the opposite way, greater values of muscle soreness and fatigue occurred on MD-1.