The independent effects of match location, match result and the quality of opposition on subjective wellbeing in under 23 soccer players: a case study

Influence of Prematch Perceived Wellness on High-Intensity Locomotor Activities of Professional Soccer Players During in-Season Matches

PURPOSE

The aim of this study was to determine the influence of prematch perceived wellness on high-intensity locomotor activities of professional soccer players during in-season matches.

METHODS

Twenty male soccer players (26.74 [3.27] y; 179.77 [6.06] cm; 76.72 [9.33] kg), members of a professional soccer team, participated in this longitudinal study. Data collection was conducted during the competitive period of 1 season and involved the 34 league official matches. Perceived wellness was assessed individually 3 hours before each match using a 5-point Likert questionnaire, and external loads during matches were monitored using global navigation satellite system devices. Each wellness item (ie, fatigue, delayed-onset muscle soreness [DOMS], sleep, and stress) was considered as an individual wellness component and analyzed as raw score, team z score, and individualized z score. Different random forest regression models and linear mixed models were carried out for statistical analysis.

RESULTS

Individualized z scores should be considered the most important variables to estimate the proportion of external-load variation during match play, but the proportion of the variance that may be explained from the prematch perceived wellness suggests a limited capacity in relation to external-load measures. Only individualized z scores of DOMS showed significant effects on sprint running distance (>24.0 km·h-1) and number of sprints (>24.0 km·h-1) during matches (P < .05).

CONCLUSIONS

Sprint performance of professional soccer players during in-season matches may be slightly influenced by the players' day-to-day variation of prematch perceived DOMS.

Future Directions in Understanding Acute and Chronic Effects of Mental Fatigue in Sports: A Commentary on Bridging Laboratory Findings and Real-World Applications

BACKGROUND

Mental fatigue (MF) is a psychobiological state that could negatively impact physical and cognitive performance, although the extent of this impact remains controversial. While laboratory studies have provided valuable insights into the acute effects of MF, their ecological validity in real-world sport settings remains limited. Recent research indicates that MF can naturally arise during sport activities, leading to chronic effects on endurance and perceptual-cognitive skills. These effects may persist beyond individual sessions, potentially increasing the risk of injury due to their cumulative nature.

PURPOSE

This commentary aims to guide future research by emphasizing the need to investigate the natural occurrence and chronic effects of MF in applied sport settings.

CONCLUSIONS

Understanding how MF develops and manifests in real-world settings, particularly individual differences in perception and response, is crucial for creating more effective management strategies. Addressing these factors will enable better support for athletes who may experience prolonged periods of MF that could affect their training and competitive performance. Future research should prioritize studying MF in natural sport settings to enhance the ecological validity of findings. By focusing on the chronic and cumulative nature of MF, as well as individual variability, researchers can develop more tailored and effective strategies for managing MF. This research will not only bridge the gap between laboratory studies and real-world applications but also contribute to more precise monitoring and intervention techniques. Ultimately, these advancements will improve athletes' ability to maintain peak performance and reduce the risk of injury, thereby enhancing overall athletic well-being.

'Supporting the Support Staff': A Narrative Review of Nutritional Opportunities to Enhance Recovery and Wellbeing in Multi-Disciplinary Soccer Performance Staff

BACKGROUND

With ever-increasing training, match-play and travel demands in professional soccer, recovery is vital for athletic performance, a statement amplified in tournament and in-season scenarios. However, alongside supporting the tasks associated with these increased demands, the recovery and wellbeing strategies recommended for playing staff are often unavailable to their support staff counterparts, who routinely experience extended working hours over and above scheduled player attendance.

METHODS

Focusing on the contributions of nutrition to this undoubtedly multifactorial issue, this narrative review aimed to (1) identify potential strategies to enhance recovery and wellbeing in multi-disciplinary soccer support staff and (2) highlight future research opportunities exploring the benefits of nutrition for those staff in soccer performance-related support roles.

RESULTS

The potential health and wellbeing consequences of chronic sub-optimal practices suggest that chrononutrition strategies may be an area of future interest. Notably, nutritional strategies that enhance sleep hygiene and immune function warrant consideration. Individualizing such strategies to maximize recovery and wellbeing in multi-disciplinary soccer support staff should offer an adjunct and complementary strategy to the holistic performance-focused support provided to professional soccer players.

CONCLUSIONS

Policymakers responsible for organizational and club structures aligned with soccer performance could consider 'Supporting the Support Staff' when seeking to improve overall performance.

Menstrual Cycle and Situational Match Variables: Effects on Well-Being in Professional Female Soccer Players

Purpose: We examined whether the situational match factors (location, result, and opposition quality), as well as playing position and menstrual cycle phase, influenced self-reported well-being in female soccer players. Methods: Twenty-two professional players (25 ± 5 years) from a squad in the Women's Super League in England self-reported their menstrual cycle phase via an online survey, and their soreness, sleep, stress, mood, and fatigue on a 1 (positive) to 5 (negative) scale on the morning of match day (MD) and for the next 3 days (referred to as MD + 1, MD + 2, MD + 3, respectively). Data was collected for 26 matches across the 2021-2022 season. Session rate of perceived exertion (sRPE) and total distance covered (measured with GPS) were measured on match and training days. Results: Menstrual cycle phase and the situational match factors had no influence on distance covered during matches and sRPE (p > .05). Sleep was worse on MD + 1 (p < .001; g = 1.59) and MD + 2 (p = .005; g = 0.98) after away matches. Stress and mood were > 28% worse after playing top vs. mid and bottom table opposition at MD + 1, and significantly worse when losing compared to winning and drawing (p > .05). Playing position and menstrual cycle phase has no influence on self-reported well-being (p > .05). Conclusion: Sleep quality was worse after away matches and losing matches negatively affects stress and mood for 2 days post-match, but menstrual cycle phase does not influence post-match well-being.

The influence of physical fitness qualities, individual characteristics and contextual factors on youth basketball players' perceived exertion and recovery responses to official games

BACKGROUND

This study examined the influence of physical fitness qualities, individual characteristics, and contextual factors on perceived exertion and recovery responses to official games in youth basketball players.

METHODS

Twenty-six males (age: 15.8±1.2 years; 12 guards, 9 forwards, and 5 centers) and 7 females (age: 16.1±0.9 years; 3 guards, 4 forwards) were monitored for an entire basketball season (N.=635 observations). Yo-Yo Intermittent Recovery (level 1) and countermovement jump (CMJ) tests were administered, with players categorized as high and low Yo-Yo and CMJ groups according to test results. Ratings of perceived exertion (RPE) were collected after each official game. Before the game and the day after, the Total Quality of Recovery (scores) were collected, and the difference between post- and pregame TQR was calculated (TQRΔ). Separate linear mixed models evaluated the effects of sex (M; F), fitness qualities (high Yo-Yo; low Yo-Yo) (high CMJ; low CMJ), playing position (guard; forward; center), game outcome (won; loss) and game location (home; away).

RESULTS

Male players reported higher RPE (7.0±0.3) than females (5.5±0.4) (P=0.003, effect size [ES]: moderate). Players with high Yo-Yo performance also reported higher RPE (6.7±0.4) than low Yo-Yo (5.8±0.3) (P=0.049, ES: small). TQRΔ was higher in guards (-1.3±0.2) than forwards (-0.8±0.2) (P=0.041, ES: trivial), and lower after lost games (-0.8±0.2) compared to won games (-1.2±0.2) (P=0.002, ES: small).

CONCLUSIONS

In youth basketball, postgame perceived exertion and recovery responses are influenced by players' sex, intermittent endurance capacity, and game outcome. Current findings can help youth basketball practitioners to better understand their players' performances and perceptual responses.

Heart Rate Variability in Professional and Semiprofessional Soccer: A Scoping Review

In modern soccer, fitness and fatigue monitoring tools tend to be focused on noninvasive, time-efficient and player-friendly measures. Heart rate variability (HRV) has been suggested as an effective method for monitoring training response and readiness to perform. However, there is still a lack of consensus on HRV monitoring when it comes to soccer. Thus, this scoping review aims to map existing evidence on HRV in professional and semiprofessional soccer settings, and to identify knowledge gaps to inform future research directions. A search of databases (PubMed, Scopus, Web of Science, Google Scholar) according to the PRISMA-ScR statement was employed. Studies were screened for eligibility on inclusion criteria: (1) HRV was among the topics discussed in the article; (2) adult professional or semiprofessional soccer players were involved in the study; (3) both male and female participants; (4) no geographical area exclusion; (5) articles published in English; and (6) article full text available. The search of the selected databases revealed 8456 records. The titles and abstracts of all articles were retrieved for screening of eligibility, leaving 30 articles for further consideration. Following screening against set criteria, a total of 25 studies were included in this review, the sample size of which ranged from 6 to 124 participants. The participants in the included studies were professional and semiprofessional soccer players, interviewed clubs staff, and practitioners. Along with other monitoring strategies, morning vagally mediated HRV analysis via (ultra)short-term orthostatic measurements may be an efficient way to assess training adaptations and readiness to perform in professional and semiprofessional soccer players. Further research is required to make definitive recommendations.

The impact of sprint, middle-distance, and long-distance orienteering races on perceived mental fatigue in national level orienteers

Experiencing mental fatigue (MF) before an orienteering race can lead to a slower completion time. This study aimed to explore the changes in perceived MF, mood and other psychological responses during an orienteering competition. Sixteen national level orienteering athletes (20.8 ± 4.9 years) provided informed consent and completed the online surveys, before and immediately after each race, and 24- and 48-hours post competition (48POST). This study measured MF, physical fatigue, stress, tiredness and motivation using 0-100 Visual Analogue Scale, and the mood was assessed using The Brunel Mood Scale (BRUMS). A moderate to large increase in MF (ES = 0.93 [0.54 to 1.31]), BRUMS fatigue (ES = 0.61 [0.3 to 0.92]), and PF (ES = 1.21 [0.81 to 1.61]) was reported following orienteering races. A small increase in tiredness and BRUMS confusion, and a small decrease in motivation, stress and BRUMS vigour was also reported. There was a delay in recovering from the MF elicited by competition, with a small increase in MF (ES = 0.54 [0.08 to 1.15]) at 48POST compared to the pre-competition value. This study found that orienteers experience MF during competition and have a delayed recovery that can last up to two days after the competition.

Young para-athletes display more hedonic well-being than people with disabilities not taking part in competitive sports: insights from a multi-country survey

Hedonic well-being relates to how individuals experience and rate their lives. People with disabilities due to their pathology may more frequently suffer from anxiety and depressive disorders than their able-bodied counterparts. Sports participation is an essential way to cope with disability. On the other hand, compared with their able-bodied peers, para-athletes undergo a unique series of stressors. Little is known in terms of hedonic well-being in this specific population. We present the results of a multi-country survey of self-perceived hedonic well-being by para-athletes of different sports disciplines and a control group (disabled individuals not playing competitive sports), using the "Psychological General Well-Being Index" (PGWBI). We included 1,208 participants, aged 17.39 years, 58.4% male, 41.6% female, and 70.3% para-athletes. Para-athletes exhibited higher well-being than disabled people, for all domains of the PGWBI scale. The nature of disability/impairment was significant, with those with acquired disability reporting lower well-being. Those taking part in wheelchair basketball, para-athletics, and para-swimming competitions had a higher likelihood of reporting well-being, whereas those engaged in wheelchair rugby exhibited lower well-being compared with controls. This large-scale investigation can enable a better understanding of the self-perceived hedonic well-being of disabled people.

The Effects of Fixture Congestion on Injury in Professional Male Soccer: A Systematic Review

BACKGROUND

Professional soccer teams are often required to compete with ≤ 4 days recovery between matches. Since congested schedules reduce recovery time between matches, players are possibly at an increased injury risk. To date, there are no published systematic reviews on the impact of match congestion on injuries during professional male soccer.

OBJECTIVE

The aim of this systematic review was to assess the effects of fixture congestion on injuries during professional soccer.

METHODS

Following pre-registration on the Open Science Framework ( https://osf.io/86m25/ ) and conforming with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, systematic searches of four electronic databases (PubMed, Scopus, SPORTDiscus, and Web of Science) were conducted by independent researchers from inception until February 2022. Articles were included if they were original articles written in English and contained relevant time-loss injury data (injury that results in unavailability for training and/or match-play) for male professional soccer players regarding periods of fixture congestion (a minimum of two matches with ≤ 4 days recovery).

RESULTS

A total of eight articles were included in the review. Five studies identified that congested fixture schedules expose players to increased match injury incidence, although layoff duration was typically lower during congested periods. Two studies identified that training and overall injury incidence were higher during congested periods, with another study identifying a lower training injury incidence during congested periods.

CONCLUSION

Injury risk is, overall, increased during fixture-congested periods; however, the layoff duration is typically shorter. The current findings have implications for practitioners regarding the management, periodisation, monitoring, and design of training and competition schedules.

The Relationship Between Subjective Wellness and External Training Load in Elite English Premier League Goalkeepers and a Comparison With Outfield Soccer Players

PURPOSE

To investigate the relationship between training load and subjective wellness in English Premier League goalkeepers (GKs) and examine potential positional differences in subjective wellness.

METHODS

A total of 34 players (GK = 7, outfield = 27) completed a daily subjective wellness questionnaire assessing sleep quality, sleep hours, fatigue, mood, soreness, and total wellness over two and a half seasons. Ten-Hertz GPS devices were worn during training to calculate previous-day and 7-day total distance, player load, total dives, total dive load, average time to feet, and high, medium, and low jumps.

RESULTS

All previous 7-day training loads were associated with all wellness markers (r = .073 to .278, P < .05). However, associations between previous 7-day dive load and mood, average time to feet, and both sleep quality and quantity, and between low jumps and sleep quality, were not significant. For previous-day metrics, total distance was associated with all wellness markers (r = .097 to .165, P < .05). In addition, player load and high jump were associated with fatigue, soreness, and wellness (r = .096 to .189, P < .05). Total dives and soreness were also related (r = .098, P < .05), and relationships were evident between average time to feet, medium jumps, and all wellness markers excluding sleep quality (r = .114 to .185, P < .05). No positional differences in subjective wellness occurred (P > .05).

CONCLUSION

Some GK GPS variables are associated with subjective wellness, which could inform training-load prescription to maximize recovery and performance. In addition, GKs are no more vulnerable to poorer subjective wellness when compared with outfield players.

Well-being and quality of life in people with disabilities practicing sports, athletes with disabilities, and para-athletes: Insights from a critical review of the literature

Global well-being (GWB) is a complex, multi-dimensional, and multi-faceted construct that can be explored from two different, but often overlapping, complementary perspectives: the subjective and the objective ones. The subjective perspective, in turn, is comprised of two dimensions: namely, the hedonic and the eudaimonic standpoints. Within the former dimension, researchers have developed the concept of subjective hedonic well-being (SHWB), whereas, within the latter, they have built the framework of psychological and social well-being (PSWB). Disabled people have poorer well-being due to their pathology and may more frequently suffer from anxiety and depressive disorders than their able-bodied counterparts. Sports participation is an essential way to cope with disability. On the other hand, compared with their able-bodied peers, athletes with disabilities and para-athletes undergo a unique series of stressors. Little is known in terms of hedonic and eudaimonic well-being and quality of life in this specific population. Here, we review the literature, with an emphasis on the current state-of-art and gaps in knowledge that need to be addressed by future research. High-quality, large-scale investigations are needed to have a better understanding of the self-perceived (hedonic) and objective (eudaimonic) well-being and quality of life of disabled people practicing sports, athletes with disabilities, and para-athletes.

Effect of a Four-Week Soccer Training Program Using Stressful Constraints on Team Resilience and Precompetitive Anxiety

The present study examined the effects of stressful constraints during soccer trainings on psychological skill development and internal load when compared with control (nonstressful) trainings. A total of 51 elite male youth soccer players (27 in the experimental group, M = 16.54 years; 24 in the control group, M = 15.44 years) participated in the study. In a 12-week longitudinal survey, team resilience, using the Spanish version of the Characteristics of Resilience in Sports Teams Inventory, and anxiety, using the Sport Anxiety Scale, were measured at baseline (after 4 weeks of regular trainings), postprotocol (after 4 weeks of control or experimental trainings), and follow-up (after 4 weeks of regular trainings). Results show that, when compared with the control group, a program with stressful constraints helped young soccer players to develop better psychological skills: specifically, increased ability to cope with impairments in resilience (both resilience characteristics and team vulnerability under pressure; p < 0.001). Increases in anxiety (p = 0.06) and decreases in preoccupation (p < 0.001) and lack of concentration (p < 0.001) were also observed. The adaptation of human behavior to specific trainings may explain these results. In conclusion, the regular exposure of young soccer players to stressful situations during trainings shows benefits for their psychological skill development in soccer. Then, benefits on internal load were also observed.

Curcumin Attenuates Delayed-Onset Muscle Soreness and Muscle Function Deficits Following a Soccer Match in Male Professional Soccer Players

PURPOSE

To examine the effects of acute curcumin (CURC) supplementation on recovery from a soccer match in male professional players.

METHODS

In a randomized, placebo-controlled, crossover design, 11 players from the under-23 team of an English Premier League club (age 19 [1] y, body mass 79.4 [7.9] kg, height 180.8 [5.7] cm) consumed 500 mg of CURC or a control (medium-chain triglycerides) immediately and 12 and 36 hours after a 90-minute match. Countermovement jump height (CMJ), reactive strength index (RSI), delayed-onset muscle soreness (DOMS, 0-200 mm), and subjective well-being were measured before and 12, 36, and 60 hours postmatch. Global positioning systems measured external load during matches, and dietary intake was recorded across the testing period.

RESULTS

External load and dietary intake did not differ between conditions (P ≥ .246). CURC attenuated deficits in CMJ (P ≤ .004) and RSI (P ≤ .001) and reduced DOMS (P ≤ .004) at all postmatch time points (except 60 h post for RSI). The greatest difference between control and CURC was 12 hours post for CMJ (P < .001, 1.91 [4.40] cm, 95% CI, 1.25 to 2.57, g = 0.36) and RSI (P = .003, 0.40 [0.41] AU, 95% CI, 0.17 to 0.63, g = 0.90) and 36 hours post for DOMS (P < .001, 47 [23] mm, 95% CI, -67 to -27, g = 2.12).

CONCLUSIONS

CURC intake <36 hours after a soccer match attenuated DOMS and muscle function deficits, suggesting that CURC may aid recovery in professional male soccer players.

Effects of an Offshore Sailing Competition on Anthropometry, Muscular Performance, Subjective Wellness, and Salivary Cortisol in Professional Sailors

INTRODUCTION

Evidence regarding the impact of offshore sailing on fatigue and readiness variables is conspicuous by its absence. This study investigated the acute effects of an offshore sailing regatta on anthropometry, muscular performance, subjective recovery, and salivary biomarker cortisol.

METHODS

Ten professional offshore sailors from a mixed-sex crew partook in the study (N = 10; mean [SD] age = 32.2 [3.96] y; stature = 179.1 [7.30] cm; body mass = 84.2 [12.1] kg). The race involved 3 offshore legs over a 3-week period. Baseline measures of anthropometry, lower- and upper-body muscular function, perceptions of subjective wellness, and salivary cortisol were assessed 3 hours prior to competition (ie, before the first leg). These measures were repeated within 30 minutes after the cessation of each leg. During each leg, boat movements were recorded via global positioning system units.

RESULTS

There were significant reductions in lower (effect size [ES] = 0.49) and upper muscular (ES = 0.21) functions, as well as in subjective wellness (ES = 1.65). Salivary cortisol levels increased (ES = 0.84).

CONCLUSION

These results demonstrate that, during an intensified period of sailing competition, fatigue will progressively increase. This may impede sailing performance by reducing physical and cognitive efficiency. Furthermore, countermovement jump, handgrip strength, perception of subjective wellness, and cortisol concentration appear to be sensitive measures for monitoring fatigue and readiness in professional sailors.

Elite Junior Australian Football Players With Impaired Wellness Are at Increased Injury Risk at High Loads

BACKGROUND

Elite junior Australian football players experience high training loads across levels of competition and training. This, in conjunction with impaired wellness, can predispose athletes to injury.

HYPOTHESIS

Elite junior Australian football players exposed to high loads with poor wellness are more likely to be at risk of injury than those with improved wellness.

STUDY DESIGN

Longitudinal prospective cohort study.

LEVEL OF EVIDENCE

Level 3.

METHODS

Data were collected and analyzed from 280 players across the 2014 season. Internal load was measured via session rating of perceived exertion. Player wellness was reported according to ratings of sleep quality, fatigue, soreness, stress, and mood. Week- and month-based training load measures were calculated, representing a combination of absolute and relative load variables. Principal component analysis factor loadings, based on 17 load and wellness variables, were used to calculate summed variable covariates. Injury was defined as "any injury leading to a missed training session or competitive match." Associations between covariates and injury risk (yes/no) were determined via logistic generalized estimating equations.

RESULTS

A significant interaction term between load and wellness on injury was found [odds ratio (OR) 0.76; 95% CI 0.62-0.92; P < 0.01), indicating that wellness acts as a "dimmer switch" of load on injury. Further, there was evidence of moderated mediation (OR 0.71; 95% CI 0.57-0.87; P < 0.01). When wellness was low, injury risk started to increase substantially at a 1-week load of 3250 au.

CONCLUSIONS

Subjective measures of training load are associated with injury risk through a nonlinear relationship. This relationship is further influenced by player wellness, which can amplify the risk of injury. There is evidence that higher stress is linked with injury and that soreness and sleep mediate any stress-injury relationship.

CLINICAL RELEVANCE

Coaching efforts to manage training load and player adaptive responses, including wellness, may reduce the risk of injury, with stress, soreness, and sleep particularly relevant at this level.

Monitoring Postmatch Fatigue During a Competitive Season in Elite Youth Soccer Players

CONTEXT

Countermovement jump (CMJ) and perceived wellness measures are useful for monitoring fatigue. Fatigue indicators should simultaneously show sensitivity to previous load and demonstrate influence on subsequent physical output; however, these factors have not been examined.

OBJECTIVE

To explore the efficacy of CMJ and wellness measures to both detect postmatch fatigue and predict subsequent physical match output in elite youth soccer players.

DESIGN

Cross-sectional study.

PATIENTS OR OTHER PARTICIPANTS

Sixteen soccer players (18 ± 1 years) from 36 English Football League Youth Alliance League fixtures.

MAIN OUTCOME MEASURE(S)

Physical match outputs (total distance, high-speed running, very high-speed running, and accelerations and decelerations [AD]) were recorded using a 10-Hz global positioning system and 200-Hz accelerometer device during competitive match play. The CMJ height and perceived wellness were assessed weekly and daily, respectively, as indirect indicators of fatigue. Four subunits of wellness (perceived soreness, energy, general stress, and sleep) were measured using customized psychometric questionnaires.

RESULTS

Simple linear regression showed that match AD predicted energy (R2 = 0.08, P = .001), stress (R2 = 0.09, P < .001), and total wellness (R2 = 0.06, P = .002) at 2 days postmatch. The CMJ (R2 = 0.05, P = .002), stress (R2 = 0.08, P < .001), sleep (R2 = 0.03, P = .034), and total wellness (R2 = 0.05, P = .006) measures at 5 days prematch predicted AD during the subsequent match.

CONCLUSIONS

The CMJ and wellness measures may be useful for detecting postmatch fatigue. Wellness scores, but not CMJ, at 5 days prematch influenced subsequent match output and therefore may be used to plan and periodize training for the upcoming microcycle.

Impact of the Result of Soccer Matches on the Heart Rate Variability of Women Soccer Players

The present study aimed to evaluate the effects of a match lost and a match won on post-competitive heart rate variability (HRV) in semi-professional female soccer athletes. A total of 13 players, with a mean age of 23.75 (5.32), from the Cáceres Women Football Club of the Spanish Second National Division participated in our study. They were evaluated in two microcycles which correspond to a match lost and a match won. For each microcycle, baseline and post-competitive measures were collected. Results indicate that HRV was significantly reduced before a match lost and won. Significant differences in HRV variables were observed when compared the lost match, and the match won. Results highlight the importance and usefulness of analyzing the HRV as an indicator of post-competitive fatigue in semiprofessional soccer players. Therefore, a competition’s results could be considered a relevant variable to consider when programming training load.

Effects of Fatigue and Grit on Club Sports Coaches

The objective of this research is to identify the level of general fatigue (FG), physical fatigue (FF) and concentration/motivation (C/M) in sports coaches. Two components of grit, consistency of interest (CI) and perseverance in effort (PE), are also assessed. The possible effects of sex, age, marital status, employment contract, work dedication and grit on FG, FF and C/M in sports coaches are examined. This cross-sectional study analyses 335 sports club coaches (21.2% women, 78.8% male) with a mean age of 29.88 (SD = 9.97) years, at a significance level of p < 0.05 for all analyses. Different aspects of fatigue were determined using the Spanish translation of the Multidimensional Fatigue Inventory-20 (IMF-20). The Grit-S scale was used to measure the ability to persevere, have passion and commit. The results indicated that men scored higher in FF, C/M and PE, while women obtained higher values in FG and CI. Non-contract coaches had higher FG, CI and PE, while coaches with contracts scored higher on C/M and FF. In conclusion, coaches with higher CI had higher FG, and high levels of PE were associated with low FG levels.

Will Next Match Location Influence External and Internal Training Load of a Top-Class Elite Professional European Soccer Team?

Background: The purpose of this study is to compare training load (TL) preceding a home versus away match in a top-class elite European team during the 2015–2016 season. Methods: Twenty elite outfield soccer players with a mean ± SD age, height and body mass of 25.9 ± 4.6 years, 183.1 ± 6.6 cm and 78.6 ± 6.6 kg, respectively, participated in this study. Total distance covered, high-speed running distance (HSRD), average speed (AvS), rating of perceived exertion (RPE) multiplied by training duration (s-RPE) and Hooper index (HI) were collected. Data from 24 weeks were analyzed through match-day minus/plus approach (MD-5, -4, -3, -2, -1, MD + 1). Results: All external TL variables indicated a decrease from MD-5 until MD-1 and then an increase to MD + 1 (p < 0.01). HI decreased from MD-5 to MD-1, but s-RPE increased until MD-3 and then decreased until MD + 1. When comparing TL data that preceded home matches versus away matches, for MD-5, HSRD and muscle soreness exhibited higher values when away match neared (p < 0.05). For MD-4 and MD-3, total distance, HSRD and AvS exhibited higher values closer to an away match than a home match (p < 0.05). For MD-1, total distances covered were higher closer to a home match than an away match (p < 0.01). For MD + 1, all HI items and AvS were higher when an away match was played (p < 0.05). Conclusions: This study confirms and provides evidence regarding the influence on internal and external TL data preceding home and away matches from a team that played in European competitions.

A Sleep Analysis of Elite Female Soccer Players During a Competition Week

PURPOSE

(1) To compare the sleep of female players from a professional soccer team to nonathlete controls across an in-season week and (2) to compare the sleep of core and fringe players from the same team on the night after a match to training nights.

METHODS

Using an observational design, 18 professional female soccer players and 18 female nonathlete controls were monitored for their sleep via wristwatch actigraphy across 1 week. Independent-sample t tests and Mann-Whitney U tests were performed to compare sleep between groups, while an analysis of variance compared sleep on training nights to the night after a match.

RESULTS

Soccer players had significantly greater sleep duration than nonathlete controls (+38 min; P = .009; d: 0.92), which may have resulted from an earlier bedtime (-00:31 h:min; P = .047; d: 0.70). The soccer players also had less intraindividual variation in bedtime than nonathletes (-00:08 h:min; P = .023; r: .38). Despite this, sleep-onset latency was significantly longer among soccer players (+8 min; P = .032; d: 0.78). On the night after a match, sleep duration of core players was significantly lower than on training nights (-49 min; P = .010; d: 0.77). In fringe players, there was no significant difference between nights for any sleep characteristic.

CONCLUSIONS

During the in-season period, sleep duration of professional female soccer players is greater than nonathlete controls. However, the night after a match challenges the sleep of players with more match involvement and warrants priority of sleep hygiene strategies.

The Effect of Fixture Congestion on Performance During Professional Male Soccer Match-Play: A Systematic Critical Review with Meta-Analysis

BACKGROUND

Fixture congestion (defined as a minimum of two successive bouts of match-play, with an inter-match recovery period of < 96 h) is a frequent and contemporary issue in professional soccer due to increased commercialisation of the sport and a rise in the number of domestic and international cup competitions. To date, there is no published systematic review or meta-analysis on the impact of fixture congestion on performance during soccer match play.

OBJECTIVE

We sought to conduct a systematic review and meta-analysis of the literature related to the effects of fixture congestion on physical, technical, and tactical performance in professional soccer match-play.

METHODS

Adhering to PRISMA guidelines and following pre-registration with the Open Science Framework ( https://osf.io/fqbuj ), a comprehensive and systematic search of three research databases was conducted to identify articles related to soccer fixture congestion. For inclusion in the systematic review and meta-analysis, studies had to include male professional soccer players, a congestion period that contained two matches ≤ 96 h, and have outcome measures related to physical, technical or tactical performance. Exclusion criteria comprised non-male and/or youth players, data that only assessed impact of congestion on injury, used simulated protocols, or were grey literature, such as theses or dissertations.

RESULTS

Out of sixteen articles included in the systematic review, only five were eligible for the meta-analysis, and the only variable that was measured consistently across studies was total distance covered. Fixture congestion had no impact on total distance covered [p = 0.134; pooled standardized mean difference; Hedge's G = 0.12 (- 0.04, 0.28)]. Between-study variance, heterogeneity, and inconsistency across studies were moderate [Cochrane's Q = 6.7, p = 0.150, I2 = 40.7% (CI 0.00, 93.34)]. Data from articles included in the systematic review suggest fixture congestion has equivocal effects on physical performance, with variation between studies and low quality of research design in some instances. Tactical performance may be negatively impacted by fixture congestion; however, only one article was identified that measured this element. Technical performance is unchanged during fixture congestion; however, again, research design and the sensitivity and relevance of methods and variables require improvement.

CONCLUSION

Total distance covered is not impacted by fixture congestion. However, some studies observed a negative effect of fixture congestion on variables such as low- and moderate-intensity distance covered, perhaps suggesting that players employ pacing strategies to maintain high-intensity actions. There is a lack of data on changes in tactical performance during fixture congestion. With ever increasing numbers of competitive matches scheduled, more research needs to be conducted using consistent measures of performance (e.g., movement thresholds) with an integration of physical, technical and tactical aspects.

Analysing the predictive capacity and dose-response of wellness in load monitoring

This study aimed to identify the predictive capacity of wellness questionnaires on measures of training load using machine learning methods. The distributions of, and dose-response between, wellness and other load measures were also examined, offering insights into response patterns. Data (n= 14,109) were collated from an athlete management systems platform (Catapult Sports, Melbourne, Australia) and were split across three sports (cricket, rugby league and football) with data analysis conducted in R (Version 3.4.3). Wellness (sleep quality, readiness to train, general muscular soreness, fatigue, stress, mood, recovery rating and motivation) as the dependent variable, and sRPE, sRPE-TL and markers of external load (total distance and m.min^-1) as independent variables were included for analysis. Classification and regression tree models showed high cross-validated error rates across all sports (i.e., > 0.89) and low model accuracy (i.e., < 5% of variance explained by each model) with similar results demonstrated using random forest models. These results suggest wellness items have limited predictive capacity in relation to internal and external load measures. This result was consistent despite varying statistical approaches (regression, classification and random forest models) and transformation of wellness scores. These findings indicate practitioners should exercise caution when interpreting and applying wellness responses.

Biomechanical and Physiological Responses to 120 Min. of Soccer-Specific Exercise

Purpose: The purpose of the study is to investigate biomechanical and physiological responses to soccer-specific exercise incorporating an extra-time period (ET) and assess the test-retest reliability of these responses. Methods: Twelve soccer players performed 120 min of soccer-specific exercise. Tri-axial (PL_Total) and uni-axial PlayerLoad™ in the vertical (PL_V), anterior-posterior (PL_A-P), and medial-lateral (PL_M-L) planes were monitored using a portable accelerometer. Likewise, respiratory exchange ratio (RER) was recorded throughout exercise. At the end of each 15-min period, players provided differential ratings of perceived exertion for legs (RPE-L), breathlessness (RPE-B) and overall (RPE-O), and capillary samples were taken to measure blood lactate (BLa) concentrations. The soccer-specific exercise was completed twice within 7 days to assess reliability. Results: A main effect for time was identified for PL_Total (p = 0.045), PL_V (p = 0.002), PL_A-P (p = 0.011), RER (p = 0.001), RPE-L (p = 0.001), RPE-O (p = 0.003), and CMJ (p = 0.020). A significant increase in PL_Total (234 ± 34 au) and decrease in RER (0.87 ± 0.03) was evident during 105-120 versus 0-15 min (215 ± 25 au; p = 0.002 and 0.92 ± 0.02; p = 0.001). Coefficients of variations were <10% and Pearson's correlation coefficient demonstrated moderate-to-very strong (0.33-0.99) reliability for all PL variables, RPE-B, BLa, and RER. Conclusions: These results suggest that mechanical efficiency is compromised and an increased rate of lipolysis is observed as a function of exercise duration, particularly during ET. These data have implications for practitioners interested in fatigue-induced changes during ET.

Athlete-Reported Outcome Measures for Monitoring Training Responses: A Systematic Review of Risk of Bias and Measurement Property Quality According to the COSMIN Guidelines

BACKGROUND

Athlete-reported outcome measures (AROMs) are frequently used in research and practice but no studies have examined their psychometric properties.

OBJECTIVES

Part 1-identify the most commonly used AROMs in sport for monitoring training responses; part 2-assess risk of bias, measurement properties, and level of evidence, based on the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) guidelines.

STUDY APPRAISAL AND SYNTHESIS METHODS

Methodological quality of the studies, quality of measurement properties, and level of evidence were determined using the COSMIN checklist and criteria.

RESULTS

Part 1-from 9446 articles screened for title and abstract, 310 out of 334 full texts were included; 53.9% of the AROMs contained multiple items, while 46.1% contained single items. Part 2-from 1895 articles screened for title and abstract, 71 were selected. Most measurement properties of multiple-item AROMs were adequate, but content validity and measurement error were inadequate. With the exclusion of 2 studies examining reliability and responsiveness, no validity studies were found for single items.

CONCLUSIONS

The measurement properties of multiple-item AROMs derived from psychometrics were acceptable (with the exclusion of content validity and measurement error). The single-item AROMs most frequently used in sport science have not been validated. Additionally, nonvalidated modified versions of the originally nonvalidated items are common. Until proper validation studies are completed, all conclusions based on these AROMs are questionable. Established reference methods, such as those of clinimetrics, should be used to develop and assess the validity of AROMs.

Does the distribution of the weekly training load account for the match results of elite professional soccer players?

PURPOSE

The aim of the study was to compare training load (TL) of the days preceding a win, draw or defeat in a sample of elite professional soccer players across the in-season 2015/16.

METHODS

Twenty elite soccer players participated in this study. Total distance covered, high-speed running distance (HSRD), average speed, session rate of perceived exertion (s-RPE) and Hooper index scores (HI) were collected. Data from 24 weeks with one match were analysed through the match-day (MD-5, 4, 3, 2, 1) and MD+1.

RESULTS

The main finding emerges in MD-1, where a longer training duration preceding draws (95.1 ± 1.5 min) > defeats (91.5 ± 1.6 min) > wins (84.7 ± 0.5 min) was found, while total distance and average speed were higher in wins (3628.6 ± 57.2 m) > draws (3391.3 ± 153.3 m) > defeats (3236.1 ± 113.7 m) and draws (130.7 ± 17.6 m/min) > wins (86.0 ± 6.9 m/min) > defeats (54.8 ± 7.1 m/min), respectively. HSRD was higher in draws (42.8 ± 0.6 m) > wins (36.1 ± 1.7 m) > defeats (35.8 ± 1.7 m). In MD+1, there were differences in HI between wins vs draws (p<0.01).

CONCLUSIONS

The results are drawn from one team that participated in UEFA Champions League. It was observed that different TL applied in training sessions can influence match result. Our findings can be considered in future soccer planning and periodization to win matches. This study emphasizes the use of HI especially in the day following the match.

Heart rate variability and pre-competitive anxiety according to the demanding level of the match in female soccer athletes

The present study aimed to evaluate the effects of a highly-demanding match and a lowly-demanding match on pre-competitive heart rate variability (HRV) and anxiety in semi-professional female soccer athletes. A total of 14 players, with a mean age of 23.78 (4.93), from the Cáceres Women Football Club of the Spanish Second National Division participated in our study. They were evaluated in two microcycles which correspond to a highly- and a lowly-demanding matches. For each microcycle a baseline and a pre-competitive measures were collected. Results indicated that HRV was significantly reduced before a highly demanding match whereas a lowly-demanding match did not lead to any change. Significant differences in HRV and cognitive anxiety were observed when compared the highly and the lowly demanding matches, which means an increase in the anxiety levels before the highly-demanding match. HRV could be an indicator of precompetitive anxiety in semi-professional female soccer players. This could be used by coaches or physical trainers as a tool to examine the precompetitive anxiety in athletes.

Does exercise intensity affect wellness scores in a dose-like fashion?

Wellness questionnaires are common in monitoring systems, yet the sensitivity to variations in acute training intensity is unclear. This study examined the controlled dosage effects of differing exercise intensities on wellness variables and subsequent associations with neuromuscular performance. Participants (n = 10) completed low-, moderate- and high-intensity conditions of a 90 min simulated football match shuttle running protocol scaled relative to beep test scores. The protocols were completed in a randomised and counterbalanced fashion matched for time of day. Wellness (sleep quality, readiness to train, soreness, fatigue, stress, mood, motivation) and neuromuscular performance (maximal voluntary contraction, countermovement jump, 6 s cycle-ergometer sprint) were assessed pre-, post- and 24 h post-exercise. Heart rate (HR) and rating of perceived exertion (RPE) were recorded during, and session RPE (sRPE) after exercise. Generalised linear mixed models demonstrated main effects between conditions with increased HR, RPE and sRPE (P < 0.03; d > 0.8) responses from the low-high condition. Total and z-score wellness showed no significant differences between trials at any time-point (P > 0.05; d = 0.03-0.91). Fatigue was lower 24 h post-exercise for the low, compared to moderate and high conditions (P = 0.006-0.047; d = 1.20-1.77). Ratings of fatigue and soreness increased from pre- to 24 h post-trial (P < 0.003; d = 0.96-2.48), while total wellness and readiness to train decreased over time (P < 0.04; d = 0.91-1.86). Wellness showed limited capacity to differentiate training intensities. Practitioners should be aware while wellness may be highly practical, it may be limited to solely determine athlete accommodation of load considering the strength of association observed with the applied load.

Predicting Future Perceived Wellness in Professional Soccer: The Role of Preceding Load and Wellness

PURPOSE

The influence of preceding load and future perceived wellness of professional soccer players is unexamined. This paper simultaneously evaluates the external load (EL) and internal load (IL) for different time frames in combination with presession wellness to predict future perceived wellness using machine learning techniques.

METHODS

Training and match data were collected from a professional soccer team. The EL was measured using global positioning system technology and accelerometry. The IL was obtained using the rating of perceived exertion multiplied by duration. Predictive models were constructed using gradient-boosted regression trees (GBRT) and one naive baseline method. The individual predictions of future wellness items (ie, fatigue, sleep quality, general muscle soreness, stress levels, and mood) were based on a set of EL and IL indicators in combination with presession wellness. The EL and IL were computed for acute and cumulative time frames. The GBRT model's performance on predicting the reported future wellness was compared with the naive baseline's performance by means of absolute prediction error and effect size.

RESULTS

The GBRT model outperformed the baseline for the wellness items such as fatigue, general muscle soreness, stress levels, and mood. In addition, only the combination of EL, IL, and presession perceived wellness resulted in nontrivial effects for predicting future wellness. Including the cumulative load did not improve the predictive performances.

CONCLUSIONS

The findings may indicate the importance of including both acute load and presession perceived wellness in a broad monitoring approach in professional soccer.

Match-Play and Performance Test Responses of Soccer Goalkeepers: A Review of Current Literature

Goalkeepers are typically the last defensive line for soccer teams aiming to minimise goals being conceded, with match rules permitting ball handling within a specific area. Goalkeepers are also involved in initiating some offensive plays, and typically remain in close proximity to the goal line while covering ~ 50% of the match distances of outfield players; hence, the competitive and training demands of goalkeepers are unique to their specialised position. Indeed, isolated performance tests differentiate goalkeepers from outfield players in multiple variables. With a view to informing future research, this review summarised currently available literature reporting goalkeeper responses to: (1) match play (movement and skilled/technical demands) and (2) isolated performance assessments (strength, power, speed, aerobic capacity, joint range of motion). Literature searching and screening processes yielded 26 eligible records and highlighted that goalkeepers covered ~ 4-6 km on match day whilst spending ~ 98% of time at low-movement intensities. The most decisive moments are the 2-10 saves·match^-1 performed, which often involve explosive actions (e.g. dives, jumps). Whilst no between-half performance decrements have been observed in professional goalkeepers, possible transient changes over shorter match epochs remain unclear. Isolated performance tests confirm divergent profiles between goalkeepers and outfield players (i.e. superior jump performance, reduced [Formula: see text]_2max values, slower sprint times), and the training of soccer goalkeepers is typically completed separately from outfield positions with a focus primarily on technical or explosive drills performed within confined spaces. Additional work is needed to examine the physiological responses to goalkeeper-specific training and match activities to determine the efficacy of current preparatory strategies.

The team's influence on physical and technical demands of elite goalkeepers in LaLiga: a longitudinal study in professional soccer

This study examined physical and technical demands and the influence of the team's level on elite goalkeepers' performance during six consecutive seasons in Spanish Professional Soccer League. The goalkeepers' performance data were obtained by analyzing a total of 3,874 matches using a multiple-camera computerized tracking system. The physical and technical match variables registered were: distance traveled; distance Sprinted and the number of sprints; total number of passes; successful passes; pass percentage; recovered balls; lost balls; ratio lost balls: recovered balls, and number of saves. The results showed that the number of saves made has shown a significant reduction (p < 0.001). When comparing between the teams' level, the goalkeepers of the worst classified teams showed a greater distance traveled by sprint (+3.72 m, IC95%: 1.00-6.44, ES: 0.41, p = 0.008). In conclusion, the results the influence of the team's level on the technical and physical parameters of the goalkeepers during the last six seasons.

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.

Physical and technical differences between domestic and foreign soccer players according to playing positions in the China Super League

Physical demands and technical skills of different playing positions within soccer match-play have been rarely studied in competitions from Asia that have unique restrictions that limit the number of foreign players per team. Therefore, the aims of this study were to identify the technical and physical differences between domestic and foreign soccer players according to playing-positions in the China Super League (CSL); and to classify domestic and foreign players (best/worst) based on their match performance characteristics. Data were provided by Amisco Sports Analysis Services (n = 3468 observations). Discriminant and ANOVA analyses showed important differences between domestic and foreign players in the CSL in terms of physical and technical performance indicators for various playing positions. The unique match performance profiles of domestic and foreign players within the CSL highlighted important features for coaches and managers to improve the recruitment process within a league that implements a restrictive foreign player policy.

The association between physical performance and match-play activities of field and assistants soccer referees

The aims of this study were to compare the external and internal match responses and fitness performance of national field referees (FRs) and assistant referees (ARs), and to examine the relationships between these fitness measures and physical and physiological responses during match play. Forty-four national soccer match officials (e.g. FRs and ARs) participated in this study. The distance covered and the VO_2max in Yo-Yo Intermittent recovery test (YYIR1) and the 30 m sprint test correlated with high speed and high intensity activities during match play in FRs (r = -0.48-0.63, moderate to large, very likely to most likely, p < 0.05). In addition, YYIR1 performance was related to high accelerations (r = 0.41, moderate, likely, p < 0.05) and high decelerations (r = 0.44, moderate, very likely, p < 0.05) for FRs. Better sprint and cardiovascular fitness could be relevant to the performance of FRs during match play.