Within-Subject Principal Component Analysis of External Training Load and Intensity Measures in Youth Soccer Training.

ABSTRACT: Marynowicz, J, Lango, M, Horna, D, Kikut, K, Konefal, M, Chmura, P, and Andrzejewski, M. Within-participant principal component analysis of external training load and intensity measures in youth soccer training. J Strength Cond Res 37(12): 2411-2416, 2023-The aim of this study was to identify which combination of external training load (EL) and external intensity (EI) metrics during youth soccer training sessions captured similar or unique information. Data were collected from 18 youth soccer players during an 18-week in-season competition period using a 10-Hz global positioning system, rating of perceived exertion (RPE), and session-RPE (sRPE). External training load measures included total distance (TD, in meters), PlayerLoad (PL, in arbitrary units), high-speed running distance (HSR, in meters), and number of accelerations (ACC, n). All EL metrics were also divided by session duration (minutes) to obtain EI values. A total of 804 training observations were undertaken (43 ± 17 sessions per player). The analysis was performed by use of the principal component analysis technique. The first principal component (PC) captured 49-70% and 68-89% of the total variance in EI and EL, respectively. The findings show that from the 5 EI metrics, most of the information can be explained by either TD per minute or PL per minute, with a loading from 0.87 to 0.98 and from 0.76 to 0.95, respectively. The majority of EL information can be explained by PL (loading: 0.93-0.98), TD (loading: 0.95-0.99), ACC (loading: 0.71-0.91), or sRPE (loading: 0.70-0.93). The second PC for EL metrics is most strongly correlated with HSR, with loadings from 0.53 to 0.84. The results suggest that the majority of the information contained in the EL variables can be captured in 1 PC without losing much information. The findings suggest that stakeholders who intend to provide a fast and holistic view of EL information in a daily training environment should report TD, PL, ACC, or sRPE plus HSR to coaching staff as a metrics that provides additional unique information.

Factors affecting match running performance in elite soccer: Analysis of UEFA Champions League matches.

This study aimed to examine the independent effect of different match-related factors on match running performance (MRP) in elite soccer. Players' MRPs (n = 244) were collected during UEFA Champions League (UCL) group stage matches in the 2020-21 season. All MRP data were collected by the semi-automatic optical system InStat Fitness (InStat Limited, Limerick, Republic of Ireland). Match-related factors included match outcome, team quality, match location, opponent quality and difference in team quality, while MRP included cumulative and relative measures of total distance (TD and R-TD), low-intensity running (LIR and R-LIR) (≤ 4 m/s), moderate-intensity running (MIR and R-MIR) (4-5.5 m/s) and high-intensity running (HIR and R-HIR) (≥ 5.5 m/s). Linear mixed models were used to examine the collective effect of match-related factors on MRPs when controlling for between-player, between-playing position and between-team variation. The main findings were that match outcome was associated with reduced HIR (d = -0.38, p = 0.04), match location was associated with increased TD, R-TD, LIR and R-LIR (d = 0.54-0.87, all p < 0.01), while team quality, opponent quality and difference in team quality were not associated with MRP. These results show that (i) winning UCL matches was not strongly influenced by players' physical performance, (ii) away UCL matches were characterized by a slower match pace and greater match volume, and (iii) players' physical performance was similar irrespective of playing either in or against high- or low-quality teams. The findings from this study may help soccer coaches to ensure optimal physical preparation of players in elite soccer.

The effect of ball possession on physical and technical performance in UEFA Champions league matches.

This study aimed to examine the effects of low-percentage ball possession teams (LPBPT) and high-percentage ball possession teams (HPBPT) on the physical and technical performance of UEFA Champions League (UCL) players. All data were obtained from group stage matches of UCL during the 2020/21 season using a semi-automatic optical tracking system. Linear mixed model was fitted with contextual variables as covariates. Wide midfielders and forwards in LPBPT covered more total distance, low-intensity running, and achieved greater average speed than in HPBPT (all large effect sizes [ES]). Central defenders and fullbacks covered more high-intensity running (small ES), while CMs covered more sprinting (medium ES) in HPBPT than in LPBPT. Players on all playing positions produced greater number of passes and successful passes in HPBPT than in LPBPT (large ES), except forwards who produced more passes in LPBPT than in HPBPT (small ES). Both physical and technical performance were highly dependent on ball possession percentages, with evident position-specific changes, indicating that the effect of ball possession is highly position-dependent. These findings provide information for soccer coaches on physical and technical demands across teams with varying percentage ball possession, which could be used to individualise training programs based on playing style and position.

Changes of physical match performance after the COVID-19 lockdown in professional soccer players according to their playing position.

The aim of this study was to evaluate the impact of the pandemic lockdown, which included training cessation and home-based training, on physical performance in professional soccer players from the Polish Ekstraklasa according to their playing position. The research was based on 3137 players' individual match performance observations during the 2019/2020 season divided into before (26 matchdays) and after (11 matchdays) lockdown periods. The data were collected using the computerised multiple-camera optical tracking system TRACAB (ChryronHego VID, New York, NY) with a sampling frequency of 25 Hz. Independently of playing position, a significant (p < 0.001) reduction in season resumption metrics of total distance (-0.9%), jogging (-1.6%), running (-3.4%) and high-speed running (-2.5%), with a contemporaneous increase in walking distance (1.4%), was noted in relation to pre-lockdown performance. A reduction in high-speed running was observed in central defenders (p < 0.05), central midfielders (p < 0.01) and forwards (p < 0.05). No significant decrease in sprinting or maximal running velocity was observed. The COVID-19 lockdown negatively influenced the physical performance in professional soccer players.

Direction of travel of time zones crossed and results achieved by soccer players. The road from the 2018 FIFA World Cup to UEFA EURO 2020.

The study detailed here has sought to assess the physical and technical activity engaged in by football players in the light of the direction of travel in which time zones were crossed as players transferred from training centres to match venues, in the context of matches played at the 2018 FIFA World Cup in Russia. The material consisted of 945 observations of 340 players. Analysed: total distances covered [km], distances covered with high-intensity running (20-25 km/h) [m], numbers of sprints, numbers of shots, numbers of passes, pass accuracy [%] and the official ranking of national teams. Three categories of time-zone shift (training centre → match venue) were taken account of, i.e. (1) West→East (WE), (2) Same Zone (SZ) and (3) East→West (EW). Analysis of results revealed that players in the EW and SZ categories were able to achieve results significantly better than those moving WE (total distances covered H = 11.815(2); p = 0.003; numbers of passes H = 7.630(2); p = 0.022), and this in relation to team placings in the end-of-tournament ranking (H = 18.099(2); p = 0.001). The results will be valuable in searching places for training centres during future FIFA World Cup and UEFA European Championship competitions.

The influence of thermal stress on the physical and technical activities of soccer players: lessons from the 2018 FIFA World Cup in Russia.

The present study attempts to assess changes in soccer players' physical and technical activity profiles due to thermal stress, measured with the Universal Thermal Climate Index (UTCI), in training centres and during matches of the 2018 FIFA World Cup in Russia. The study also verifies the theoretical models of soccer players' physiological parameters. The study sample consisted of 945 observations of 340 players of national teams taking part in the World Cup in Russia. The measured variables included physical activities: total distance covered, distances covered with an intensity of 20-25 km/h, number of sprints; technical activities: number of shots, number of passes, pass accuracy and physiological indicators: evaporative water loss and heart rate. In addition, the final ranking places of each national team were also used in the study. The UTCI was calculated based on meteorological data recorded at training centres and during matches. The UTCI records were then classified into two ranges: NTS-no thermal stress (UTCI 9-26 °C) and TS-thermal stress (UTCI > 26 °C). Climatic conditions at soccer training centres assessed as involving "no thermal stress" are found to be more beneficial for increasing the total distance covered and the number of sprints performed by players during a match. The theoretical models for determining soccer players' physiological parameters used in the study reduce the players' heart rate effort and evaporative water loss, which is in line with findings in studies by other authors. The climatic conditions at soccer training centres and during tournament matches should be taken into account in planning preparations for future World Cup tournaments, especially those in hotter countries.

How did three consecutive matches with extra time affect physical performance? A case study of the 2018 football Men's World Cup.

The purpose of this study was to ascertain the effect of playing three consecutive matches with extra time (ET) on the physical performance of selected Croatian players in their subsequent match, the final of the 2018 Men's World Cup in Russia. The case study consisted of 4 players on the Croatian national team (16 observations) who had played in all three matches up to 120 min. The consecutive full time matches (90 minutes) and extra time (30 minutes) were compared. The analysis was conducted using data collected by an advanced motion analysis system known as STATS and from interviews with the strength and conditioning coach of the Croatian national team. The recorded variables used were: total distance covered [m], distances covered [m] at intensity ranges of 20-25 km/h and above 25 km/h, and number of sprints performed. All the studied parameters systematically increased in each match up to 90 minutes of play, reached their maximum values in the semi-final and then decreased in the final match. Compared to the first extra time period, in the third extra time period the players covered twice as much distance with an intensity of 20-25 km/h and above 25 km/h, and recorded twice as many sprints. This investigation shows that players in central positions on the pitch are able to maintain or even increase high and very high intensity activity in three consecutive matches with extra time. These data complement the developing body of literature relating to the influence of accumulation of match play with extra time periods on high level players.

Anabolic-catabolic hormonal responses in youth soccer players during a half-season.

This study sought to evaluate the hormonal response (i.e. total testosterone, free testosterone, cortisol, and their ratios TT/C and FT/C) in the under-19 youth soccer team (n = 18) throughout a six-month period. All sport medical examinations were conducted four times: before the beginning of the preparation period (T1), just after preparation period (T2), in the middle of the competitive period (T3), and at the end of the season (T4). The cortisol concentration was decreased at the T3 (-16.9%; p = 0.014), then increased at the T2 (16.8%; p = 0.001) and at the T4 (12.7%; p = 0.062), respectively, compared to the initial value. The analyses for total and free testosterone demonstrated no differences between the measurements. Finally, values of the TT/C and FT/C ratios were increased during the T3 (25%; p = 0.017, 24.4%; p = 0.021) in comparison with the initial measurement and decreased at the T4 (-28.9%; p = 0.001, - 30.8%; p = 0.001) in comparison with the T3. The study results showed that the lowest level of peripheral fatigue was recorded in the T3, which may suggest that a correct selection of training loads does not affect the severity of catabolic processes in youth players.

Effects of Plyometrics Training on Muscle Stiffness Changes in Male Volleyball Players.

Dariusz, M, Krzysztof, M, Pawel, C, Edward, S, Marek, K, Tomasz, S, Dorota, B, Rektor, Z, and Jan, C. Effects of plyometrics training on muscle stiffness changes in male volleyball players. J Strength Cond Res 33(4): 910-921, 2019-We investigated whether 6 weeks of specific plyometric training (PT) impacts on changes in muscle stiffness and enhances the vertical jumping ability as the indirect evaluation of the explosive power of the lower extremities of male volleyball players. Sixteen male collegiate volleyball players participated in this experiment. Regular PT was performed twice per week for 60-90 minutes each time. During each PT session, heart rate and muscle stiffness data were collected. Two series of 10 single measurements of each muscle (23 points of the front and back legs) were measured the day before the first enhanced training session and after completing each week of PT. Participants were tested for maximum effort in vertical jumping using the squat jump (SJ) with hands on thighs, countermovement jump (CMJ), and CMJ with a 2-step to 3-step approach. Jumping motor ability tests were completed. Data were collected 1 day before PT. The last measurement was performed 3 days after completing the last week of PT. The 6-week PT program only had an effect on the statistically relevant increase in muscle stiffness in the tibialis anterior (highest value, 593.86 ± 60.24 N·m) and quadriceps. Improvements in the explosive power of leg muscles resulted in a significant increase in the vertical jumping ability; there were improvements in SJ and CMJ (p = 0.0338 and p = 0.0007, respectively). If PT involves a moderate workload and if players never exceed the intensity target of the workout, then less muscle stiffness and muscle soreness may occur.

Evolution of technical activity in various playing positions, in relation to match outcomes in professional soccer.

The study presented below aimed to examine the position-specific evolution of technical activity among soccer players and how it is related to match outcomes over three consecutive domestic seasons in Germany's Bundesliga. The research was based on a sample of 13,032 individual match observations of 556 soccer players during the 2014/2015, 2015/2016 and 2016/2017 seasons. These players were classified into five positional roles: central defenders (CD), full-backs (FB), central midfielders (CM), wide midfielders (WM) and forwards (F). The activity of the players was analysed using the Impire AG motion analysis system. Our study indicates that over the course of the three seasons: 1) the total numbers of shots by CMs decreased in the case of won or drawn matches; 2) the number of passes by CD players increased in matches won, and by CM and WM players in matches won, drawn and lost, whereas percentage pass accuracy increased at the CM position in won and drawn matches; 3) players at each position engaged in a substantially smaller number of duels, no matter what the match outcome, while the percentage of encounters won in subsequent seasons decreased among CD, and increased among WM in matches won and at F positions in both won and drawn matches. This research clearly shows that the evolution of technique among professional soccer players is heading in the direction of increased accuracy, with a simultaneous stabilisation of, or even a decline in, the number of activities engaged in.

Match outcome and running performance in different intensity ranges among elite soccer players.

The monitoring of players' work-rate profiles during competition is now feasible through computer-aided motion analysis. The aim of the present study was to examine how various playing positions and match outcomes (i.e. won, drawn, lost) affect the total distance, and the distances covered at different intensities, by soccer players in Germany's Bundesliga. Match performance data were collected for 556 soccer players competing in the Bundesliga during the 2014/15, 2015/16 and 2016/17 domestic seasons. A total of 13 039 individual match observations were made of outfield players (goalkeepers excluded). The analysis was carried out using an IMPIRE AG motion analysis system, with records of all players' movements in all the 918 matches. The recorded variables included total distance covered [km] and distance covered at intensities in the ranges below 11 km/h, 11-14 km/h, 14-17 km/h, 17-21 km/h, 21-24 km/h, and above 24 km/h. In won matches, as opposed to drawn and lost matches, the wide midfielders and forwards ran a significantly longer distance, primarily covered at intensities of 21-23.99 and above 24 km/h (p ≤ 0.05). The analysis of full-backs, central defenders and central midfielders in won matches - as opposed to drawn and lost matches - in turn reveals that players ran a significantly shorter distance, most likely to be covered at intensities of 17-20.99 and 21-23.99 km/h (p ≤ 0.05). The results of the present study emphasise the importance of match outcome and playing positions during the assessment of physical aspects of soccer performance.

Physical activity profile of 2014 FIFA World Cup players, with regard to different ranges of air temperature and relative humidity.

The present study attempts to assess changes in soccer players' physical activity profiles under the simultaneous influence of the different combinations of ambient temperature and relative humidity characterising matches of the 2014 FIFA World Cup hosted by Brazil. The study material consisted of observations of 340 players representing 32 national teams taking part in the tournament. The measured indices included total distances covered; distances covered with low, moderate, or high intensity; numbers of sprints performed, and peak running speeds achieved. The analysis was carried out using FIFA official match data from the Castrol Performance Index system. Ultimately, consideration was given to a combination of three air temperature ranges, i.e. below 22 °C, 22-28 °C, and above 28 °C; and two relative humidity ranges below 60 % and above 60 %. The greatest average distance recorded (10.54 ± 0.91 km) covered by players at an air temperature below 22 °C and a relative humidity below 60 %, while the shortest (9.83 ± 1.08 km) characterised the same air temperature range, but conditions of relative humidity above 60 % (p ≤ 0.001). Two-way ANOVA revealed significant differences (p ≤ 0.001) in numbers of sprints performed by players, depending on whether the air temperature range was below 22 °C (40.48 ± 11.17) or above 28 °C (30.72 ± 9.40), but only where the relative humidity was at the same time below 60 %. Results presented indicate that the conditions most comfortable for physical activity on the part of players occur at 22 °C, and with relative humidity under 60 %.

Match running performance preceding scoring and conceding a goal in men's professional soccer.

This study aimed to investigate the potential differences in the match running performance of professional soccer players 5 min. before scoring and conceding a goal in the Polish Ekstraklasa. The sample consisted of 278 matches with 570 goals scored during official matches of the 2022/23 Polish Ekstraklasa season. All data was collected utilising the computerised multiple-camera optical tracking system TRACAB. Total distance covered (TD), standing distance (StD; < 0.72 km h-1), walking distance (WD; 0.73-7.2 km h-1), jogging distance (JG; 7.21-14.4 km h-1), running distance (RD; 14.41-19.8 km h-1), high-speed running distance (HSR; 19.81-25.2 km h-1) and sprinting distance (SprD; > 25.2 km h-1) were analysed in 5-min intervals prior to a goal scored for both teams. The employed linear mixed models showed that all examined match-running performance metrics were higher in teams that scored a goal compared to teams that conceded a goal. Within 5 min before scoring a goal in Polish Ekstraklasa matches, the scoring team produced significantly greater TD (∆ 95%CI 256.8-300.4 m; p = 0.001), WD (∆ 95%CI 52.3-95.8 m; p = 0.001), JG (∆ 95%CI 100.5-144.1 m; p = 0.001) and RD (∆ 95%CI 16.2-59.8 m; p = 0.001) compared to the conceding team, although no differences were found for HSR and SprD. These results demonstrate the enhanced identification potential of key physical performance factors influencing goal scoring in the Polish Ekstraklasa, thereby optimising the training process and improving overall performance. To enhance the effectiveness of soccer training, coaching and performance staff should consider this study's findings, that indicate an increase in the volume of medium- and low-intensity running efforts preceding a goal.

In which rounds were the most rotations of key players made, and how did this affect physical activity? Analysis of the eight best teams of the 2018 FIFA world cup Russia.

BACKGROUND: Team management, especially player selection, rotation, and availability, are critical issues when dealing with the high demands of modern training and gameplay. As such, research continuously seeks ways to improve these actions or implement new ideas to gain a competitive advantage through the rotation of players in the starting line-up. The current study aimed to examine the rounds of the 2018 FIFA World Cup Russia in which the most rotations of key players were made and how this affected physical activity. METHODS: The sample consisted of 110 players from the top eight teams in the 2018 World Cup Russia who played entire matches for up to 90 min in seven consecutive games. All players were divided into key players (KPs, n = 58) and non-key players (NKPs, n = 52). The analysis used data collected by an advanced motion analysis system known as STATS®, with physical activity variables analyzed, including total distance covered (TDC), distance covered with high intensity over 20 km/h (HIR), and the number of sprints undertaken. In statistical analysis, differences between categories and consecutive matches were calculated using the Kruskal-Wallis H test, and if a significant effect size was found, a multiple comparisons p values test was performed. RESULTS: The best teams at the 2018 FIFA World Cup Russia used the most KP rotations with NKPs in the third match of the group stage. In addition, this was even more visible among more successful teams than less successful teams. The rotation strategy among the best eight teams allowed them to maintain the physical activity of KPs and NKPs in all rounds of the tournament. CONCLUSIONS: Coaches and coaching staff should incorporate squad rotation that includes a large group of players in their team management to improve their success. Team management expertise in player rotation during matches played over congested schedules at top tournaments maintains high levels of physical activity indicators (TDC, HIR, and sprints).

Long-Term Trends in Shooting Performance in the NBA: An Analysis of Two- and Three-Point Shooting across 40 Consecutive Seasons.

This study aims to depict two-point and three-point shooting trends and explore their influence on game outcomes in the NBA across 40 consecutive seasons. Therefore, the following game-related statistics were considered: total points per game (PPG), games played (GP), field goals made (FGM), field goal attempts (FGA), field goal percentage (FG%), two-point field goals made (2PM), two-point field goal attempts (2PA), two-point field goal percentage (2P%), three-point field goals made (3PM), three-point field goal attempts (3PA), three-point field goal percentage (3P%), and a three-point field goal to two-point field goal ratio (3P/2P). The fixed-base indexes and inter-decade ANOVAs or Friedman tests were used as the main statistical tools. The number of 3PA significantly increased over time, while the number of 2PA decreased. A significant increase in 3P% was also observed, whereas 2P% remained relatively stable over the analyzed period. This study also revealed a higher number of ball possessions and more points scored per game, especially in the last decade of NBA competition.

The effects of high-intensity interval training at the anaerobic and psychomotor fatigue thresholds on physiological parameters in young soccer players: a prospective study.

This study aimed to investigate the effects of a 4-week specific high-intensity interval training (HIIT) program performed between the anaerobic threshold (ANT) and the psychomotor fatigue threshold (PFT) on physiological parameters in 14 professional soccer players at the under-17 level. The first and second stages of the research protocol included a treadmill running exercise with increasing load and six 3-min four-versus-four games of soccer with a 3-min break between games. Players then participated in a training microcycle involving three specific HIIT exercises twice per week for 4 weeks, after which they repeated stages one and two, followed by an assessment of changes. The measurement of lactate (LA) determined ANT, whereas the choice reaction time (CRT) indicated PFT among other selected physiological parameters. The repeated-measure analysis of variance (ANOVA) compared mean values for the examined variables using Bonferroni post hoc test. It demonstrated significantly increased maximal oxygen consumption (VO2 max) from 45.9 ± 3.0 to 48.7 ± 2.6 at the ANT and from 49.1 ± 3.4 to 52.0 ± 3.6 on the PFT after 4 weeks of training. A significant increase in the running speed (RS) at both thresholds and heart rate (HR) at the ANT (p ≤ 0.05) was also recorded. Moreover, the players exceeded their intensity of effort during ANT while playing four-versus-four soccer matches, but they did not reach intensity during PFT. In conclusion, the findings of the study demonstrated that both thresholds shifted toward higher loads and the proposed specific HIIT effectively increased the exercise capacity of soccer players.

Effects of short bout small-sided game training on acid-based balance markers in youth male soccer players.

This study aimed to compare the effects of 1 × 1 small-sided games (SSGs) with different bout durations on external (ETL) and internal training loads (ITL) in youth soccer players. Twenty U18 players were divided into two groups performing six 1 × 1 SSGs with 30 and 45 s bout durations on a playing field of 10 by 15 m. ITL indices, including the percentage of maximum heart rate (HR), blood lactate (BLa) level, pH, bicarbonate (HCO3-) level, and base excess (BE) level, were measured at rest, after each SSG bout, and 15 and 30 min after the entire exercise protocol. ETL (Global Positioning System metrics) was recorded during all six SSG bouts. The analysis showed that the 45 s SSGs had a greater volume (large effect) but a lower training intensity (small to large effect) than the 30 s SSGs. A significant time effect (p < 0.05) was observed in all ITL indices and a significant group effect (F1, 18 = 8.84, p = 0.0082, ƞ2 = 0.33) in the HCO3- level only. Finally, the changes in the HR and HCO3- level were smaller in the 45 s SSGs than in the 30 s SSGs. In conclusion, 30-s games, characterized by a higher intensity of training effort, are more physiologically demanding than 45-s games. Secondly during short-bout SSG training the HR and BLa level have limited diagnostic value for ITL. Extending ITL monitoring using other indicators, such as the HCO3- and BE levels, appears reasonable.

The effect of team formation on match running performance in UEFA Champions League matches: implications for position-specific conditioning.

This study aimed to determine the effect of team formation on position-specific match running performance (MRP) at highest-level football. Players' MRP (n = 226) was observed in four team formations: 3-5-2 (n = 24), 4-4-2 (n = 44), 4-2-3-1 (n = 77) and 4-3-3 (n = 81). Central defenders in the 3-5-2 formation achieved a greater amount of high-intensity running distance than in the 4-3-3 formation (mean difference (MD) [95% confidence interval] = 144 m [12, 267], medium ES). Fullbacks in the 4-4-2 formation covered less total distance than in 3-5-2 (MD = -762 m [-1431, -94], large ES) and 4-2-3-1 (MD = -662 m [-1055, -269], medium ES). Central midfielders' total distance in the 4-4-2 formation was lower than that in the 3-5-2 (MD = -645 m [-79, -1211], medium ES) and 4-3-3 (MD = -656 m [-1181, -132], medium ES) formations. Wide midfielders' walking distance in the 4-4-2 formation was lower than that in the 4-3-3 (MD = -484 m [-742, -226], very large ES) and 4-2-3-1 (MD = -535 m [-789, -282], very large ES) formations. Forwards' high-intensity running in the 4-2-3-1 formation was lower than that in the 4-3-3 (MD = -363 m [-613, -112], large ES) and 4-4-2 (MD = -396 m, [-688, -103], large ES) formations. These findings show that conditioning programs for players on all playing positions should be tailored according to the formations of their teams. .

Do players competing in the UEFA Champions League maintain running performance until the end of the match? Positional analysis between halves and 5-minute intervals.

BACKGROUND: This investigation aimed to analyze differences in running performances amongst playing positions between the first and second halves of soccer matches and at 5-minute intervals during matches. METHODS: Data were collected from 179 soccer players during 20 UEFA Champions League (UCL) 2020/2021 group stage matches. Data were examined using the InStat Fitness semi-automatic video system. Eight variables were selected to quantify players' running performance (RP). Players were categorized based on positional groups: central defenders (CD), fullbacks (FB), central midfielders (CM), wide midfielders (WM), and forwards (FW). Univariate differences in RP were analyzed using ANOVA and the t-test for dependent samples and multivariate differences were identified using canonical discriminant analysis. RESULTS: The main findings were that all positions achieved significantly higher average speeds and walking distances in the first half of the match than in the second half. Furthermore, analysis of positions showed that CM covered more distance than CD in all 5-minute intervals. In addition, WM performed more high-intensity running than CD in all 5-minute intervals and FW performed more high-intensity running than all other playing positions. CONCLUSIONS: The findings from the present study should help coaches design training exercises that are specific to parts of a match. Moreover, the findings can help provide better understanding of match demands and individualization of training. Analysis of 5-minute intervals may also help coaches understand the stages of a match where player substitutions will be most effective.

The seven phases of match status differentiate the running performance of soccer players in UEFA Champions League.

The purpose of this research was to investigate the running performance of professional soccer players in relation to seven phases which resulted in the changing or maintaining the match status in the UEFA Champion League games during season 2020/2021. Moreover, we aimed to define which match status phases occur at the earliest stage of regular game time. This study involved professional soccer players from 24 teams participating in the group stage of UEFA Champions League in season 2020/21. The match status was divided into seven phases that result in changing or maintaining the match outcome: DW (Drawing to Winning); LD (Losing to Drawing); WW (Winning to Winning); DD (Drawing to Drawing); LL (Losing to Losing); DL (Drawing to Losing); WD (Winning to Drawing). Such running performance variables as: total distance covered (TDC) and distance covered in high-intensity running (HIR) were analyzed. Players participating in the UEFA Champions League matches cover the longest TDC in DW, DL and DD phases. TDC in these stages was between 111 and 123 m min-1. The highest HIR was recorded during phases: DW, DL and LL (range between 9.91 and 10.82 m min-1). In contrast, the lowest total distance and distance in HIR is covered during WD phase (only 105.57 ± 1.89 m min-1 and 7.34 m min-1 respectively). On average, phases resulting in the change of the match status occur during the first half, while all phases maintaining the result in the second half. Coaching staffs should consider registering and analysing the physical match performance in relation to described seven match status phases. Such information allows to prepare team-specific training drills, that players should perform more often in order to change or maintain the status of the game.