Professional Soccer Team Research Articles

Relationship between testosterone and cortisol with anthropometric characteristics in professional male soccer players

Pre-season training has been demonstrated to modify the physical fitness and hormone levels in professional soccer players. The present study aimed to analyze the relationships between testosterone and cortisol with anthropometric characteristics in a professional male soccer team after the pre-season period. Fourteen volunteer professional male soccer players participated in this study. Significant decreases in anthropometric characteristics were found. For biochemical measures, cortisol (13) =-5.25, p=.001, d=-.27), testosterone (t (13) =-8.10, p=.001, d=-.65) and C/T ratio (t (13) =-4.07, p=.001, d =-0.2) significantly increased after the pre-season period. Moreover, moderate negative relationships were observed between the percentage of change in body weight, r=0.61, p=.01, body fat percentage, r=.53, p=.04, and testosterone. The present study revealed that the improvements in body composition after intense training in the pre-season period could stimulate anabolic activities such as increases in muscle mass, which is an important result in terms of quality of performance and prevention of injury risk, especially throughout the competitive soccer season. Testosterone and cortisol should be considered for future research as stress and recovery state indicators. In fact, professional soccer staff can use these parameters in combination with other indicators to optimize workloads and avoid overreaching and overtraining. Keywords: Testosterone; cortisol; professional soccer players; performance; physical fitness

Is Travel Associated With Match Performance in Elite North American Professional Soccer? An Exploratory Study.

Travel fatigue impacts cognitive and physiologic systems, but its association with elite soccer match performance is unclear. In this retrospective observational study, we aimed to explore the association between travel and match outcomes in elite North American soccer. Travel data and match outcomes(team points or goals scored and conceded) and physical performance outcomes from 26 elite professional soccer teams and their players were analyzed (148 matches [team-based data] and 1252 player matches from 297 players; age 22.7 [4.5]y). Player- and match-level correlations between performance measures and both acute and cumulated travel metrics were analyzed. Cumulative travel metrics were positively associated with team (travel distance [r = .20; 95% CI, .03-.25], travel time [r = .20; .06-.37], and time away [r = .20; .06-.37]) and individual player (travel distance, [r = .14; .08-.19], travel time [r = .17-.23], and time away [r = .13; .07-.18]) high-intensity running. Cumulative time away was negatively associated with team points (r = -.14; -.28 to -.001) and positively associated with goals conceded (r = .14; .01-.27); no clear association between acute travel metrics and match outcomes or physical performance was observed. As travel cumulated, away teams and their players ran more but for less reward (team points), although the magnitude of these associations was small. These data are exploratory and do not imply acausal relationship; however, further research should consider cumulation of travel.

Relative age effect in Mexican professional and youth soccer

In youth football, categories are defined by the players’ year of birth. In one category, there can be an age difference of almost 12 months, which may manifest itself in considerable physical differences. The impact of this "relative age" is reflected in elite teams by an overrepresentation of players born in the first months of the year, called "Relative Age Effect" (RAE). In the present study, this bias was analyzed among the 4499 Mexican players (3531 men, 968 women), registered by the 18 professional clubs for the 2022 season in men’s First Division, their U20, U18, U17, U16, U14 categories, women's First Division, and their U17 categories. From every player were collected: birthday, playing position, minutes played for their teams, and their teams’ final rank in the National Championships. In all categories, except women's First Division, a statistically significant RAE was found, whose size was greater in the lower categories than in the major ones. The playing positions that presented a higher size of RAE were not the same in the different categories. A positive correlation was found between RAE and individual and team performances. These results indicate the need to take a deeper look at the selection and development processes of talented players in Mexico, because players initially favored by their greater relative age do not reach the professional soccer teams in the same proportion.

A comparative analysis of weekly internal and external workloads between starting and non-starting professional soccer players: A retrospective 21-week examination.

Aims of the present investigation encompassed: (i) the quantification of training and match loads experienced by starters and non-starters within a professional soccer team; (ii) the identification of variations in these loads across different training modalities, namely, Preparation Training (PT), Match and Match Compensation Training (M&MCT), and their cumulative sum (Total Load; TL); and (iii) the formulation of guidelines aimed at harmonizing the weekly workloads between the groups. Internal and external load of training sessions (n = 97), competitive matches (n = 21) and running based sessions (n = 4) were recorded for 21 weeks to investigate possible heterogeneity between starters and non-starters across PT, M&MCT and TL. During PT, time spent in heart rate zone 5 (HRZ5) was increased for non-starters (+46.1%). During M&MCT, lower loads for non-starters were found in the rate of perceived exertion (sRPE) (-45.6%), HRZ4 (-54%) and HRZ5 (-77.8%), total distance (TD) (-37%), number of sprints (-58.1%), distance in speed zone 1 (-51.1%), zone 3 (-61.5%) and zone 4 (-59.8%) (SZ1, SZ3&4) and all acceleration and deceleration zones (Acc1-4; Dec1-4) (Acc1: -53.1%; Acc2: -56.3%; Acc3: -59.2%; Acc4: 57.8%) (Dec1: -45.9%; Dec2: -55.2%; Dec3: -63.2%; Dec4: -67.7%). Regarding TL, the non-starters' loads remain lower compared to starters for sRPE (-19.2%), HRZ4 (-21.6%) and HRZ5 (-41.4%), number of sprints (-26.7%), SZ3 (-34.2%), Acc3 (-24.4%), Acc4 (-26.1%), Dec2 (-18.7%), Dec3 (-24%) and Dec4 (-31.2%). By implementing a running-based regimen on matchday and MCT the day after (MD+1), TD, distances in SZ1, SZ2, SZ4, SZ5, and counts of accelerations in Acc1&2, as well as Dec1, were effectively replicated for non-starters. All other variables remained unaligned for the non-starters. Given the prevalent emphasis on Small-Sided Games (SSGs) during MCT at MD+1, the incorporation of an additional running-based session for non-starters on MD is advised to address gaps in TD, sprint counts, and high-intensity load variables, such as HRZ4&5 and SZ 3 to 5.

Performance in professional soccer players: normative data and benchmarks from official matches for metabolic power and high-intensity activities.

The opportunity to compare data among players using normative data and benchmarks may represent a helpful tool for coaches to assess the players' physical performance easily and quickly. This study aimed to create normative data and benchmarks that can be exploited to compare professional soccer players' physical capacity competing in the Premier Division Championship (series A). Match data from six professional soccer teams competing in the Premier Division championship (Serie A and Italy Cup matches) were collected during the entire season. Players (N.=112) were divided based on the role positioning as follows: forwards and wingers (FW), midfielders (MF), side-backs (SB), and center-backs (CB). All the teams analyzed competed with a 4-3-3 formation, and only players who played for the entire match (85-95 minutes) were considered. The video analysis system STATS SportVU was used to collect the data during official matches. Average metabolic power (AP) was considered to estimate the energy cost. The number of power events (PE), distance (m) covered at more than 25 W/kg (D25), and finally, the distance covered at v>25 km/h (VHS) were considered as high-intensity assessments. Standardized T-scores (scaled from 0 to 100) were calculated for each role and variable. T-score data was used to create performance bands combined with qualitative description (ranging from extremely poor to excellent), and a traffic light system approach was implemented to simplify the data's interpretation. The results could be used to compare different athletes' performance quickly and effectively, to detect symptoms of overtraining, and to give helpful insights to coaches on what the training should be focused on.

The Influence of the Playing Surface on Workload Response in Spanish Professional Male Soccer Players.

This study aimed to quantify the influence of the playing surface on workload-related variables (i.e., external load, Rate of perceived exertion (RPE), and mental load) in training sessions with a Spanish professional soccer team. Twenty professional male players from the same soccer team were involved. A total of thirty training sessions related to the preseason period were included. All the players completed training sessions on three playing surfaces: natural turf of poor quality, natural turf of high quality, and third-generation artificial turf. Monitoring during sessions involved assessing internal load (i.e., RPE and mental load) via self-reported questionnaires, and external load using Global Positioning System devices. Linear mixed models showed that RPE was significantly higher on natural turf of high quality than on natural turf of poor quality (p < 0.001). Total distance, relative total distance, the number of accelerations, decelerations, and high metabolic load distance were significantly lower on third-generation artificial turf compared to natural turf of poor quality (p < 0.001) and high quality (p < 0.001). In addition, high-speed running, sprint running distances, and the number of sprints reached higher values on third-generation artificial turf compared to the other two playing surfaces. These findings highlight the need for coaches to consider the type of training surface in soccer to optimize training load planning and prevent injuries.

Research on Tactical Executive Ability of College Men's Football Team

By using the methods of literature and video observation, this paper studies the tactical executive ability of the men's football team in colleges and universities through various forms of observation, this paper combs out the factors that affect the tactical executive ability of the men's football team, and makes a comprehensive analysis of the factors, and obtains the problems caused by the factors. In view of the problems and the present situation, this paper puts forward some countermeasures to affect the tactical execution ability of the professional men's soccer team in Gongga Cup, aiming at improving its tactical execution ability and tactical accomplishment.

Examining switching intention in professional sport: a push-pull-mooring perspective

PurposeDrawing upon a push-pull-mooring model and the literature on behavioral loyalty, this research aims to examine the underlying factors and mechanisms that influence switching intention in the context of professional sport in Japan.Design/methodology/approachUsing a two-wave survey design (pregame and postgame surveys), we collected data from 367 fans of a professional soccer team in Japan. Our data included three push factors (quality, satisfaction, and perceived value of the current favorite team), a pull factor (alternative team attractiveness), a mooring factor (team identification), and behavioral loyalty and switching intention to the alternative team. We used structural equation modeling to test our hypotheses.FindingsA mediation analysis revealed that perceived value of an individual’s current favorite team was negatively associated with behavioral loyalty to an alternative team, whereas attractiveness of the alternative team was positively associated with behavioral loyalty, which, in turn, resulted in fans’ switching intention. Latent moderated structural equation modeling further revealed the negative moderating effect of team identification with the current team on the relationship between behavioral loyalty and switching intention.Originality/valueThe findings provide new evidence about the role of behavioral loyalty in understanding sport consumers’ switching intention and highlight the importance of team identification that can foster a sustainable and long-term relationship between fans and their favorite sport teams.

Comparing locomotor intensity indicators in soccer training and competition across contextual factors: a study of replaced coaches in a Portuguese professional 1st league team

This study aims to examine, for each head coach (HC) replaced, the association between training intensity and physical performances obtained in games. Furthermore, the study investigated how contextual factors influence locomotor and mechanical performance association. External load variables were collected using Global Positioning System (GPS) devices across the 4 weeks and 4 games before and after the replacement in a professional adult male soccer team. Six different HC records were analysed (48.8 ± 7.4 years of age; 11.2 ± 3.9 years as an HC) during a three-season span (2020/21–2022/2023). There were marked differences within player variability across the two coaching regimes. Game loads didn't reflect training-related performance, with differences ranging from −71.4% to −9.9%. Players under the outgoing coaches have greater coverage of meters per minute. Meters per minute, distance covered over 18 km/h and high-speed running (all in training) are found to be significant variables influenced by contextual factors. Within-subject and time, training loads did not reflect game-related loads/performances, with starters showing higher deficits (ranging from −79.0 to −14.5). The study suggests that changes in soccer HC can affect players' training intensity and game performance, influenced by various contextual factors and not directly correlated. This type of information might be very suitable to improve training load periodization and programming. For further research avenues, could be the study of the variation of the psychological states of the players at the time of the dismissal and hiring of the HCs, associating them with the physiological performance at the same moments.

Are there meaningful changes in the performance of professional soccer teams from the first half of the match to the second? Evidence from the data of eight consecutive seasons of the Chinese Super League

ABSTRACT In the aim to better understanding the dynamic of performance changes between the first and second halves of professional soccer teams, statistics of 1899 matches from 2012 to 2019 of the Chinese Super League (CSL) were collected and analysed. The generalised mixed linear modelling was used to estimate the mean change of each of 40 physical and technical performance-related parameters of soccer teams from the first half of the match to the second, controlling the effects of match status, match location, team strength and opponent strength. Results showed that, out of the selected 40 parameters, only goals (first half vs second half M ± SD: 0.60 ± 0.76 vs 0.82 ± 0.92, ES; ±99% confidence limits: 0.21; ±0.05), shots (5.7 ± 2.8 vs 6.8 ± 3.3, 0.34; ±0.05), individual possession in the attacking third (55 ± 21 vs 62 ± 25, 0.31; ±0.05), cross (9.7 ± 4.6 vs 10.9 ± 5.8, 0.24; ±0.06) and yellow cards (0.75 ± 0.84 vs 1.24 ± 1.07, 0.45; ±0.06) showed substantially increment from the first half to the second, other parameters presented only trivial changes. Hence, it is concluded that the physical performance of soccer teams in the second half did not show meaningful change, while technical actions related to attacking tended to increase. The findings can offer soccer coaches valuable insights into when and how to adjust their tactics, manage their players, thus can maintain or enhance the team’s match performance.

Weekly Programming of Hamstring-Related Training Contents in European Professional Soccer.

Hamstring injuries in soccer continue to be a challenge for professionals who work with soccer players daily. Although its origin is multifactorial, the proper management of neuromuscular fatigue during the training microcycle is a very important factor to consider. There are no clear guidelines regarding the weekly distribution of certain exercises that demand the hamstrings. The main objective of this study was to describe the usual training practices of professional European soccer teams. An international observational survey design was applied to some of the strength and conditioning coaches of professional soccer teams. The survey included different neuromuscular demanding exercises for the hamstrings. For each exercise, the strength and conditioning coaches had to respond in relation to their frequency of use and timepoint depending on the day of the weekly microcycle. Although there is no strong consensus in this regard, there does seem to be a trend when applying certain exercises, especially on the days matchday-4 and matchday-3.

Comparisons of external load variables among periods, playing status, and positions in professional soccer team: A case study

The aims of this study were to compare weekly variations of training monotony (TM) and training strain (TS) among periods of the season, playing status and playing positions in professional soccer athletes. Nineteen male professional soccer players were monitored daily over a 43-week period for their total distance, sprint distance (&gt;23 km h−1), acceleration (Acc, &gt;4 m s−2), and decelerations numbers (Dec, &gt;−4 m s−2). Players were divided in groups of 10 starters and 9 non-starters; and by three central defenders (CD), four wide defenders (WD), four central midfielders (CM), four wide midfielders (WM), and four strikers (ST). Season data was divided in pre-, early-, mid-, and end-season. There were significant differences for TM through sprint distance between playing positions in mid- and full-season. In mid-season, sprint distance was meaningfully greater for CD than WD ( p = 0.006; g = 1.74 [0.06, 3.95]), CM ( p = 0.002; g = 2.04 [0.28, 4.46]), WM ( p = 0.005; g = 1.78 [0.09, 4.02]), and ST ( p = 0.002; g = 2.05 [0.28, 4.46]). Regarding full-season, TM of sprint distance was significantly greater for CD than WD ( p = 0.031; g = 1.59 [−0.04, 3.73]), CM ( p = 0.011; g = 1.83 [0.13, 4.11]), and ST ( p = 0.023; g = 1.52 [−0.10, 3.59]). The study revealed that TM and TS of sprint distance in mid-season was meaningfully greater for CD than for WD, CM, WM, and ST. No differences between starters and non-starters were found.

Effects of Contextual Variables on Match Load in a Professional Soccer Team Attending to the Different Season Periods.

This study aimed to analyze the effects of contextual variables (i.e., match location and match outcome) and season periods on match load (i.e., internal and external load) in professional Brazilian soccer players. Thirty-six professional players from the same soccer team participated in this study. The season was split into four phases: matches 1-16 (i.e., Phase 1 = P1); matches 17-32 (i.e., Phase 2 = P2); matches 33-48, (i.e., Phase 3 = P3); matches 49-65 (i.e., Phase 4 = P4). Considering match outcome, when the team wins, Cognitive load, Emotional load, and Affective load were significantly higher in away vs. home matches (p < 0.05). Considering season phases, in P3, Mental Fatigue was significantly higher in drawing than in losing matches (p < 0.05). Additionally, considering the match outcome, when the team lost, Total Distance (TD)/min and TD > 19 km·h-1/min were significantly lower in P1 than P2 (p < 0.001), P3 (p < 0.001), and P4 (p < 0.001). These results suggest to strength and conditioning coaches the need to consider the outcome and location of the previous game when planning the week, as well as the phase of the season they are in to reduce fatigue and injury risk.

Are physiological, physical, wellness and load decisive markers of starting players? A case study from a professional male soccer team

The study aim was to compare physiological, physical, accumulated wellness and load markers within a European professional soccer team between starters and non-starters. Ten starters (age: 25.1 ± 2.2 years; experience: 7.3 ± 2.3 years) and eight non-starters (age: 26.1 ± 4.6; years’ experience: 8.3 ± 4.1 years) participated in the study. The study was conducted across 20 weeks where 75 training sessions and 15 matches occurred. Wellness (fatigue, quality of sleep, muscle soreness, stress and mood) and load (rating of perceived exertion (RPE), accelerations, decelerations, high-speed running and sprinting) measures were observed. Physiological evaluation consisted of a 1200 m maximum effort shuttle test while physical capacity assessment included isokinetic strength, jump ability and balance tests. Isokinetic tests were used to assess peak torque of both legs (extension and flexion at 60◦/s and 180◦/s), single squat jump and single hop jump were utilized to assess jump ability and Y-balance tests were employed to examine balance. Starters presented significantly higher values for peak torque extension of the non-dominant leg compared to non-starters (p = 0.038, effect size (ES) = 0.996), while non-starters showed higher values for both Y-balance postero-medial and postero-lateral (p = 0.009, ES = −1.309 and p = 0.021, ES = −1.133, respectively). Accumulated duration and RPE were lower for non-starters than starters (p ≤ 0.001, ES = 1.268, and p = 0.022, ES = 1.123, respectively). The physiological and physical tests conducted in this study do not seem to determine the starting status of players, considering that only one test revealed significantly higher values for starters. Despite the lower training and match duration for non-starters, this showed that it is possible to accumulate identical load while managing wellness regardless of starting status.

Social Return on Investment (SROI) of a Japanese Professional Soccer Team’s Social Business Activities

Social Return on Investment (SROI) of a Japanese Professional Soccer Team’s Social Business Activities

The Effects of Pre-Season and Relationships with Physical, Physiological, Body Composition, and Load Markers: A Case Study Comparing Starters versus Non-Starters from an Elite Female Professional Soccer Team.

Background and Objectives: Research on female soccer players that analyzes playing status is scarce and has previously only examined load monitoring, while other markers, such as physical (i.e., strength, power, and agility), physiological (i.e., maximal oxygen uptake), and body composition (i.e., body fat mass, fat-free mass, body water, and phase angle) markers, warrant further investigation. Thus, the study aims were to (a) compare physical, physiological, body composition, and load markers between starters and non-starters; (b) compare measurements pre- and post-training intervention (five weeks); and (c) analyze any relationships between physical, physiological, body composition, and load markers in an elite female soccer team. Materials and Methods: Fourteen first-team players participated in the study (age 23.29 ± 3.19 years, weight 59.14 ± 6.87 kg, height 1.66 ± 0.08 m). Several physical (n = 15), physiological (n = 1), body composition (n = 11), and load markers (n = 14) were collected. In addition, participants were sub-divided into starters (n = 7) and non-starters (n = 7). Results: No differences were revealed between starters and non-starters in any of the examined variables. Moreover, following the training intervention, a significantly lower value was found for total body water/fat-free mass ratio (p = 0.043; ES = 0.582). In addition, there were several correlations detected between load and physical/physiological markers (n = 28); load and body composition markers (n = 6); physical/physiological and body composition markers (n = 34); and physical and physiological markers (n = 42). Conclusions: In conclusion, only a slight tendency of higher load values for starters than non-starters was observed. In addition, no differences in physical, physiological, and body composition markers were found between starters and non-starters, possibly suggesting that five weeks were not enough to improve such variables. Finally, the present results provide novel information assessing the effects of the pre-season in elite female Portuguese soccer players and contribute to a better understanding of the associations between different types of measurements.

Physical predictors for retention and dismissal of professional soccer head coaches: an analysis of locomotor variables using logistic regression pipeline.

Soccer has enormous global popularity, increasing pressure on clubs to optimize performance. In failure, the tendency is to replace the Head coach (HC). This study aimed to check the physical effects of mid-season replacements of HCs, investigating which external load variables can predict retention or dismissal. The data was collected in training and matches of a professional adult male soccer team during three complete seasons (2020/21-2022/2023). The sample included 6 different HCs (48.8 ± 7.4 years of age; 11.2 ± 3.9 years as a HC). The 4 weeks and 4 games before and after the replacement of HCs were analysed. External load variables were collected with Global Positioning System (GPS) devices. A logistic regression (LR) model was developed to classify the HCs' retention or dismissal. A sensitivity analysis was also conducted to determine the specific locomotive variables that could predict the likelihood of HC retention or dismissal. In competition, locomotor performance was better under the dismissed HCs, whereas the new HC had better values during training. The LR model demonstrated a good prediction accuracy of 80% with a recall and precision of 85% and 78%, respectively, amongst other model performance indicators. Meters per minute in games was the only significant variable that could serve as a potential physical marker to signal performance decline and predict the potential dismissal of an HC with an odd ratio of 32.4%. An in-depth analysis and further studies are needed to understand other factors' effects on HC replacement or retention.

The relationships between relative age effect, personality constructs and achievement level in soccer.

Youth soccer academies are challenged with the constant recruitment process of young talented players to select those who will achieve long-term success as an athlete. Youth soccer academies strive to enhance the physical and technical skill development as well as personality development of talented players because psychological characteristics play a crucial role in players' future success in their transition to professional soccer. The least mature players and relatively young players may have a greater need to possess superior technical/tactical or psycho-behavioral skills than those relatively older counterparts because of the higher selection rates of early maturing players. Due to RAEs, a significant decrease in the overall quality of professional soccer teams might be observed because of the loss of talent of physically smaller, but psychologically stronger and more versatile relatively young players who possess proper technical and tactical attributes at an early age. The first objective of this study was to examine any possible relationship between RAE and personality constructs. A second objective was to identify factors and effects that can help in the further improvement of talent selection and equal opportunities for elite youth soccer players based on their underlying RAE. The third objective was to consider the impact of RAE on long-term career development. In this retrospective observational study, 151 elite youth soccer players between 15 and 18 years of age were first grouped in birth quartiles. Personality constructs were then assessed, using a combination of observations, interviews, and a self-assessment questionnaire. Next competition level after 8 years was evaluated to identify RAEs, differences in personality characteristics and opportunities to reach professional soccer player status between relatively older vs. younger players. A clear significant RAE was observed for the whole database (Q1 = 38.4% vs. Q4 = 13.9%) with OR of 2.61 (χ2 = 19.46, p < 0.01, r = -0.85). Relatively young players had higher median scores on personality constructs such as self-confidence (p = 0.04), while relatively old players had higher median scores on personality constructs such as team orientation (p = 0.03). In the long term, more players of the youngest birth quartile were signed as professional players (76.2%), compared with relatively old players (46.6%). 65.0% of the 20 players had the highest total score on personality constructs developed as a professional soccer player, vs. 35.0% of the 20 players with the lowest scores. In conclusion, this study showed not only further evidence of the RAE but also provided evidence supporting "the underdog hypothesis" in national elite youth teams. Relatively young players were also more likely to get higher value senior professional contracts in the long term. We propose that this may be due to the relatively young players developing superior psychological skills and technical expertise to compensate for their early physical disadvantage. This in turn suggests the need for greater awareness of the importance of personality constructs in the future development of youth elite soccer players. Therefore, the crux of the issue is how youth soccer academies elicit the "best of both worlds" ie. moderating RAE whilst also gaining the benefits of the underdog hypothesis by creating the right environment for every player to develop to their full potential in elite youth soccer academies.

The effect of COVID-19 lockdown on ball possession performance in Spanish professional soccer leagues

ABSTRACT This research analysed the influence of lockdown and interruption of competitions due to COVID-19 on different ball possession-related variables. Also, match location and the differences between divisions were considering between the pre- and post-lockdown. A total of 144,689 records from 842 soccer matches during the 2019/20 season of the First (n = 380) and Second Spanish Division (n = 462) were collected. Match data were collected using the ChryonHego video-tracking system. Pre-lockdown (1st–27th matchday in First Division and 1st–31st matchday in Second Spanish Division) and post-lockdown periods (28th–38th matchday in First Division and 32nd–42nd matchday in Second Spanish Division) were compared. The match location contextual-related variable was also considered for the analysis. Linear mixed models showed that the number of outplayed players by ball possession (3.1%), successful passes (17.5%) and total passes (18.9%) increased during the post-lockdown period (p < .001). In addition, match location and league significantly influenced the successful and total passes in all situations (p < .001), increasing in the post-lockdown period. In conclusion, the lockdown period has led changes in the ball possession of the soccer teams. These results help to understand the impact that a particular and unusual situation as the interruption of the league due to COVID-19 lockdown had on the performance of professional soccer teams.

Are non-starters accumulating enough load compared with starters? Examining load, wellness, and training/match ratios of a European professional soccer team

BackgroundThe aims of the study were to: (i) compare accumulated load and wellness between starters and non-starters of a European professional soccer team; (ii) analyze the relationships between wellness and load measures and; (iii) compare training/match ratio (TMr) of external and internal load between starters and non-starters.MethodsTen players were considered starters while seven were classified as non-starters over a 16-week period in which six training sessions and match day (MD) were considered in each weekly micro-cycle. The following measures were used: wellness (fatigue, quality of sleep, muscle soreness, stress, and mood); load (rated of perceived exertion (RPE), session-RPE (s-RPE), high-speed running (HSR), sprinting, accelerations (ACC) and decelerations (DEC)). Accumulated wellness/load were calculated by summing all training and match sessions, while TMr was calculated by dividing accumulated training load by match data for all load measures and each player. Mann–Whitney U test was used for wellness variables, while independent T-test was used for the remaining variables to compare groups. Moreover, relationships among variables were explored using the Spearman’s Rho correlation coefficient.ResultsThe main results showed that non-starters presented higher significant values for fatigue (p < 0.019; g = 0.24) and lower significant values for duration (p < 0.006; ES = 1.81) and s-RPE (p < 0.001; ES = 2.69) when compared to starters. Moreover, positive and very large correlation was found between quality of sleep and RPE, while negative and very large correlation were found between stress and deceleration, and mood and deceleration (all, p < 0.05). Finally, non-starters presented higher values in all TMr than starters, namely, RPE (p = 0.001; g = 1.96), s-RPE (p = 0.002; g = 1.77), HSR (p = 0.001; g = 2.02), sprinting (p = 0.002; g = 4.23), accelerations (p = 0.001; g = 2.72), decelerations (p < 0.001; g = 3.44), and duration (p = 0.003; g = 2.27).ConclusionsIn conclusion, this study showed that non-starters produced higher TMr in all examined variables despite the lower match and training durations when compared with starters, suggesting that physical load was adjusted appropriately. Additionally, higher RPE was associated with improved sleep while higher number of decelerations were associated with decreased wellness, namely, stress and mood for non-starters.