Impact of COVID-19 lockdown on match activity and physical performance in professional football referees

To investigate the effect of COVID-19 lockdown on match-play metrics in professional football referees during official matches of the Spanish professional leagues. Forty-two professional football referees from the First (n = 20) and Second Division (n = 22) were monitored during 564 official games using Global Positioning System (GPS) technology. Data of matches before lockdown were compared to matches after resumption of the competition. Compared to pre-lockdown, in the referees of the First Division there was a decrease in the total running distance and the distance covered at all speed thresholds > 6 km · h^-1 after lockdown (P < .05). In the Second Division referees, the post-lockdown measurement only showed a decrease in the running distance at 21–24 km · h^-1 (P < .05), with no changes in the other speed thresholds. The post-lockdown measurement showed an increased distance covered at < 6 km · h^-1 and the number of accelerations for both First and Second Division referees (P < .05). Referees’ match activity was reduced due to the COVID-19 lockdown, while the effect on running parameters was more pronounced in First Division referees.     

Monitoring external load in elite male handball players depending on playing positions

Monitoring workload is critical for elite training and competition, as well as preventing potential sports injuries. The assessment of external load in team sports has been provided with new technologies that help coaches to individualize training and optimize their team’s playing system. In this study we characterized the physical demands of an elite handball team during an entire sports season. Novel data are reported for each playing position of this highly strenuous body-contact team sport. Sixteen world top players (5 wings, 2 centre backs, 6 backs, 3 line players) were equipped with a local positioning system (WIMU PRO) during fourteen official Spanish first league matches. Playing time, total distance covered at different running speeds, and acceleration variables were monitored. During a handball match, wings cover the greater distance by high-speed running (> 5.0 m·s^-1): 410.3 ± 193.2 m, and by sprint (> 6.7 m·s^-1): 98.0 ± 75.4 m. Centre backs perform the following playing position that supports the highest speed intensities during the matches: high-speed running: 243.2 ± 130.2 m; sprint: 62.0 ± 54.2 m. Centre backs also register the largest number of high-intensity decelerations (n = 142.7 ± 59.5) compared to wings (n = 112.9 ± 56.0), backs (n = 105.2 ± 49.2) and line players: 99.6 ± 28.9). This study provides helpful information for professional coaches and their technical staff to optimize training load and individualize the physical demands of their elite male handball players depending on each playing position.     

Most running demand passages of match play in youth soccer congestion period

The objective of this study was to determine whether there is a decrease in the physical performance of the players in the most demanding passages (MDP) during periods of competition congestion. The study involved 15 under-19 players, belonging to a club in Spain’s first division (age: 18.1 ± 0.8 years, weight: 70.2 ± 4.9 kg and height: 1.78 ± 0.06 m), who were monitored during 23 national and international official matches in the 2018/19 season. The Youth League matches were played between two matches in the national championship in six different weeks. The league matches corresponded to the first 17 matches of the league championship, the period in which the 6 matches in the Youth League were played. The two physical variables analysed were total distance (TD) and distance at > 21 km·h^-1 (TD21). Using the rolling average, four time windows were taken (1, 3, 5 and 10 min), and the values were relativized to the minute (m·min^-1). The main results were that: there were more MDP in the first halves than in the second halves of all the time windows; 2) the central match in the week (Youth League) was the most demanding one; and 3) the players maintained the TD and TD21 in the MDP in the third match compared to the first. The results of this study could provide trainers with information on the need to design training tasks that simulate the demands of competition in relation to the TD and the TD21 according to different time windows.     

The effects of defensive style and final game outcome on the external training load of professional basketball players

This study aimed to analyse the influence of different contextual factors (i.e., defensive style and game outcome) on basketball players’ external load during games-based drills using ultrawideband (UWB) technology. Fourteen male professional basketball players belonging to an elite reserve Spanish club (ACB) participated in this study. The games-based drills consisted of one bout of 10 min played 5vs5 in which players were instructed to use man-to-man defence (MMD) and/or zone defence (ZD). In addition, the final game outcome (i.e., winning or losing) of the game-based drill was registered. External load variables per minute were recorded: total distance covered, distance covered in different speed zones, distance covered while accelerating and decelerating, maximum speed, steps, jumps and player load. A two-way ANOVA with the Tukey post hoc test was used to assess the impact of defensive style and final game outcome and the interaction of both factors on the external load encountered by basketball players. No meaningful differences (unclear) were found in the external loads between playing with MMD and with ZD and between winning and losing teams except for greater distance at high-speed running (18.0–24.0 km·h^-1) in winning teams (p < 0.05, ES = 0.68, moderate). A significant interaction between defensive style and final game outcome was found for high decelerations (> -2 m·s^-2) (p = 0.041; ES = 0.70) and jumps (p = 0.037; ES = 0.68). These results could potentially help coaching staff in prescribing an appropriate workload during basketball-specific game-based drills, and ultimately enhance the match performance.     

Movement Demands of Elite Under-20s and Senior International Rugby Union Players

This study compared the movement demands of elite international Under-20 age grade (U20s) and senior international rugby union players during competitive tournament match play. Forty elite professional players from an U20 and 27 elite professional senior players from international performance squads were monitored using 10Hz global positioning systems (GPS) during 15 (U20s) and 8 (senior) international tournament matches during the 2014 and 2015 seasons. Data on distances, velocities, accelerations, decelerations, high metabolic load (HML) distance and efforts, and number of sprints were derived. Data files from players who played over 60 min (n = 258) were separated firstly into Forwards and Backs, and more specifically into six positional groups; FR–Front Row (prop & hooker), SR–Second Row, BR–Back Row (Flankers & No.8), HB–Half Backs (scrum half & outside half), MF–Midfield (centres), B3 –Back Three (wings & full back) for match analysis. Linear mixed models revealed significant differences between U20 and senior teams in both the forwards and backs. In the forwards the seniors covered greater HML distance (736.4 ± 280.3 vs 701.3 ± 198.7m, p = 0.01) and severe decelerations (2.38 ± 2.2 vs 2.28 ± 1.65, p = 0.05) compared to the U20s, but performed less relative HSR (3.1 ± 1.6 vs 3.2 ± 1.5, p < 0.01), moderate (19.4 ± 10.5 vs 23.6 ± 10.5, p = 0.01) and high accelerations (2.2 ± 1.9 vs 4.3 ± 2.7, p < 0.01) and sprint•min^-1 (0.11 ± 0.06 vs 0.11 ± 0.05, p < 0.01). Senior backs covered a greater relative distance (73.3 ± 8.1 vs 69.1 ± 7.6 m•min^-1, p < 0.01), greater High Metabolic Load (HML) distance (1138.0 ± 233.5 vs 1060.4 ± 218.1m, p < 0.01), HML efforts (112.7 ± 22.2 vs 98.8 ± 21.7, p < 0.01) and heavy decelerations (9.9 ± 4.3 vs 9.5 ± 4.4, p = 0.04) than the U20s backs. However, the U20s backs performed more relative HSR (7.3 ± 2.1 vs 7.2 ± 2.1, p <0.01) and sprint•min^-1 (0.26 ± 0.07 vs 0.25 ± 0.07, p < 0.01). Further investigation highlighted differences between the 6 positional groups of the teams. The positional groups that differed the most on the variables measured were the FR and MF groups, with the U20s FR having higher outputs on HSR, moderate & high accelerations, moderate, high & severe decelerations, HML distance, HML efforts, and sprints•min^-1. For the MF group the senior players produced greater values for relative distance covered, HSR, moderate decelerations, HML distance and sprint•min^-1. The BR position group was most similar with the only differences seen on heavy accelerations (U20s higher) and moderate decelerations (seniors higher). Findings demonstrate that U20s internationals appear to be an adequate ‘stepping stone’ for preparing players for movement characteristics found senior International rugby, however, the current study highlight for the first time that certain positional groups may require more time to be able to match the movement demands required at a higher playing level than others. Conditioning staff must also bear in mind that the U20s players whilst maintaining or improving match movement capabilities may require to gain substantial mass in some positions to match their senior counterparts.     

Movement Demands of Elite U20 International Rugby Union Players

The purpose of this study was to quantify movement demands of elite international age grade (U20) rugby union players during competitive tournament match play. Forty elite professional players from an U20 international performance squad were monitored using 10Hz global positioning systems (GPS) during 15 international tournament matches during the 2014/15 and 2015/16 seasons. Data on distances, velocities, accelerations, decelerations, high metabolic load (HML) distance and efforts, and number of sprints were derived. Data files from players who played over 60 min (n = 161) were separated firstly into Forwards and Backs, and more specifically into six positional groups; FR—Front Row (prop & hooker), SR—Second Row, BR—Back Row (Flankers & No.8), HB—Half Backs (scrum half & outside half), MF—Midfield (centres), B3 –Back Three (wings & full back) for match analysis. Analysis revealed significant differences between forwards and backs positions. Backs scored higher on all variables measured with the exception of number of moderate accelerations, decelerations (no difference). The centres covered the greatest total distance with the front row covering the least (6.51 ± 0.71 vs 4.97 ± 0.75 km, p < 0.001). The front row also covered the least high speed running (HSR) distance compared to the back three (211.6 ± 112.7 vs 728.4 ± 150.2 m, p < 0.001) who covered the most HSR distance, affirming that backs cover greater distances but forwards have greater contact loads. These findings highlight for the first time differences in the movement characteristics of elite age grade rugby union players specific to positional roles.     

Physical match performance of Japanese top-level futsal players in different categories and playing positions

To examine the substitution characteristics during official matches and the physical match performances of Japanese top-level futsal players in different categories and playing positions. Overall, 79 adult (age: 28.4 ± 4.6 years) and 59 youth (age: 17.1 ± 0.7 years) futsal players were classified into three groups based on the playing position (Pivot, Winger, and Defender). Physical match performance was assessed using active profiles from the semi-automatic tracking system. Speed and total distance covered were analysed for the in-play time. The in-play time was categorized based on the teams’ ball possession status. The average total playing time per substitution was significantly higher in the youth (6.2 ± 2.1 min) than in the adult players (3.8 ± 1.1 min; p < 0.05). Furthermore, the proportion of high intensity exercise during matches was significantly higher in adults (43.2 ± 5.2%) than in youth players (37.2 ± 5.4%; p < 0.05). There was no significant difference in the average total distance covered between different playing positions. However, the average total distance covered with ball possession by Pivot (140 ± 15 m/min) was significantly lower than that by Winger (151 ± 15 m/min; p < 0.05) in adult players. Furthermore, the proportion of high intensity exercise without ball possession as Defender (36.7 ± 6.1%) was lower than that as Winger (41.9 ± 6.1%; p < 0.05) in adults but not in the youth players. Adult futsal players have higher physiological demands than youth players. The physical match performances vary between playing positions with or without ball possession. These results could be useful for youth development and position-specific training information.     

Economical Speed and Energetically Optimal Transition Speed Evaluated by Gross and Net Oxygen Cost of Transport at Different Gradients

The oxygen cost of transport per unit distance (CoT; mL·kg^-1·km^-1) shows a U-shaped curve as a function of walking speed (v), which includes a particular walking speed minimizing the CoT, so called economical speed (ES). The CoT-v relationship in running is approximately linear. These distinctive walking and running CoT-v relationships give an intersection between U-shaped and linear CoT relationships, termed the energetically optimal transition speed (EOTS). This study investigated the effects of subtracting the standing oxygen cost for calculating the CoT and its relevant effects on the ES and EOTS at the level and gradient slopes (±5%) in eleven male trained athletes. The percent effects of subtracting the standing oxygen cost (4.8 ± 0.4 mL·kg^-1·min^-1) on the CoT were significantly greater as the walking speed was slower, but it was not significant at faster running speeds over 9.4 km·h^-1. The percent effect was significantly dependent on the gradient (downhill > level > uphill, P < 0.001). The net ES (level 4.09 ± 0.31, uphill 4.22 ± 0.37, and downhill 4.16 ± 0.44 km·h^-1) was approximately 20% slower than the gross ES (level 5.15 ± 0.18, uphill 5.27 ± 0.20, and downhill 5.37 ± 0.22 km·h^-1, P < 0.001). Both net and gross ES were not significantly dependent on the gradient. In contrast, the gross EOTS was slower than the net EOTS at the level (7.49 ± 0.32 vs. 7.63 ± 0.36 km·h^-1, P = 0.003) and downhill gradients (7.78 ± 0.33 vs. 8.01 ± 0.41 km·h^-1, P < 0.001), but not at the uphill gradient (7.55 ± 0.37 vs. 7.63 ± 0.51 km·h^-1, P = 0.080). Note that those percent differences were less than 2.9%. Given these results, a subtraction of the standing oxygen cost should be carefully considered depending on the purpose of each study.     

Effect of training day,match, and length of the microcycle on workload periodization in professional soccer players: a full-season study

The aims of this study were to: (a) describe and compare the volume and intensity from the workload of professional soccer players between training and MD, and (b) analyse the effect that the length of the microcycle had on the workload. A cohort study was designed for a full season in La Liga 123. Wearable tracking systems collected the distance covered in meters (m), total number of high-intensity accelerations (ACC_HIGH) and decelerations (DEC_HIGH), total number of high-speed running actions (HSRA), high-speed running distance (HSRD), high metabolic load distance (HMLD), and player load (PL) from training days (MD+1, MD-4, MD-3, MD-2, and MD-1) and MD. Significant differences were found between training and MD workload, MD workload being the most demanding for all intensity and volume variables (F = 36.35–753.94; p < 0.01; w_p² = 0.21–0.85). The greatest training intensity and volume were found on MD-4 and MD-3 (p < 0.05). In addition, a novel finding was that the length of the microcycle had a significant effect on the workload both in volume and intensity (F = 4.84–14.19; p < 0.01; w_p² = 0.03–0.09), except for relative ACC_HIGH, DEC_HIGH, and HMLD. Although MD-4 and MD-3 were the most suitable days for loading the players, the results showed that MD elicited a unique stimulus in terms of volume and intensity. Consequently, coaches need to include specific training drills to adapt the players for the competitive demands. Finally, special focus should be placed on MD from short and regular microcycles (5-day, 6-day, or 7-day microcycles) since declines in physical performance were observed in comparison with long microcycles (8-day or 9-day microcycles).     

Session-to-session variations in external load measures during small-sided games in professional soccer players

The aims of this study were 1) to analyse session-to-session variations in different external load measures and 2) to examine differences in within-session intervals across different small-sided game (SSG) formats in professional players. Twenty professional soccer players (mean ± SD; age 28.1 ± 4.6 years, height 176.7 ± 4.9 cm, body mass 72.0 ± 7.8 kg, and body fat 10.3 ± 3.8%) participated in 3v3, 4v4, and 6v6 SSGs under different conditions (i.e., touch limitations and presence of goalkeepers vs. free touch and ball possession drill) over three sessions. Selected external load measures—including total distance (TD), high-intensity running (HIR, distance covered > 14.4 km^.h^-1), high-speed running (HSR, distance covered > 19.8 km^.h^-1), and mechanical work (MW, accelerations and deceleration > 2.2 m^.s²)—were recorded using GPS technology during all SSG sessions. Small to large standardized typical errors were observed in session-to-session variations of selected measures across SSGs. TD^.min^-1 showed less variability, having a coefficient of variation (CV) of 2.2 to 4.6%, while all other selected external load measures had CV values ranging from 7.2% to 29.4%. Trivial differences were observed between intervals in TD^.min^-1 and HIR^.min^-1 for all SSGs, as well as in HSR^.min^-1 and MW^.min^-1 for most SSG formats. No reductions or incremental trends in session-to-session variations were observed when employing touch limitations or adding goalkeepers. The increased noise observed in higher speed zones (e.g., high-speed running) suggests a need for more controlled, running-based conditional drills if the aim is greater consistency in these measures.     

Activity profile of international-level soccer referees during competitive matches

The purpose of this study was to investigate the activity profile of soccer referees competing at international level. Thirteen international-level soccer referees (INRG, age 38 +/- 3 years, height 182.0 +/- 6.5 cm, and body mass 78.8 +/- 7.0 kg) were observed during official international matches using a match analysis system (Play Controller, Phromos, Italy) that enabled speeds and times collection for 11 arbitrarily chosen match categories. For comparison, 13 Italian elite-level soccer referees (NRG, age 37 +/- 3 years, height 182.5 +/- 3.5 cm, and body mass 77.1 +/- 6.5 kg) were examined during domestic official first division matches (Serie A). Results showed that NRG covered more distance during matches than the INRG (12,956 +/- 548 m and 11,218 +/- 1,056 m, respectively; p < 0.05). Running faster than 18 km.h(-1), NRG covered more distance than INRG (2,378 +/- 423 m and 1,642 +/- 689 m, respectively; p < 0.05). No between-halves differences in the distance covered at speed faster than 18 km.h(-1) were observed in each group. The main finding of this study is that international-level referees during international competitions are less active than national-level officials directing domestic matches. This unexpected result may suggest the need for specific training for the international referees, as recent reports have shown that better positioning is associated with longer space coverage during competitive matches. Across-halves, high-intensity, space-coverage conservation should be regarded as a peculiarity of the elite-level soccer referee.     

Influence of Yo-Yo IR2 Scores on Internal and External Workloads and Fatigue Responses of Tag Football Players during Tournament Competition

The purpose of this study was to: a) identify changes in jump height and perceived well-being as indirect markers of fatigue, b) determine the internal and external workloads performed by players, and c) examine the influence of Yo-Yo IR2 on changes in jump height, perceived well-being and internal and external workloads during a tag football tournament. Microtechnology devices combined with heart rate (HR) chest straps provided external and internal measures of match work-rate and workload for twelve male tag football players during the 2014 Australian National Championships. Jump height and perceived well-being were assessed prior to and during the tournament as indirect measures of fatigue. Changes in work-rate, workload and fatigue measures between high- and low-fitness groups were examined based on players’ Yo-Yo IR2 score using a median split technique. The low- and high-fitness groups reported similar mean HR, Playerload^TM/min, and distance/min for matches, however the low-fitness group reported higher perceived match-intensities (ES = 0.90–1.35) for several matches. Further, the high-fitness group reported higher measures of tournament workload, including distance (ES = 0.71), Playerload^TM (ES = 0.85) and Edwards’ training impulse (TRIMP) (ES = 1.23) than the low-fitness group. High- and low-fitness groups both showed large decreases (ES = 1.46–1.49) in perceived well-being during the tournament, although jump height did not decrease below pre-tournament values. Increased Yo-Yo IR2 appears to offer a protective effect against player fatigue despite increased workloads during a tag football tournament. It is vital that training programs adequately prepare tag football players for tournament competition to maximise performance and minimise player fatigue.     

The first,second, and third most demanding passages of play in professional soccer: a longitudinal study

The study aimed to compare the physical demands required during the first, second, and third most demanding passages (MDP) of play considering the effect of playing position, type of passage, and passage duration. A longitudinal study for three mesocycles was conducted in a professional soccer team competing in LaLiga123. Tracking systems collected total distance covered (DIS), high-speed running distance (HSRD), sprinting distance (SPD), total of high-intensity accelerations (ACC_HIGH), and total of high-intensity decelerations (DEC_HIGH). The results confirmed that a significant effect of the type of passage (first, second or third MDP of play) on DIS (F_{(1.24, 178.89)} = 115.53; p = 0.01; ηp² = 0.45), HSRD (F_{(1.35, 195.36)} = 422.82; p = 0.01; ηp² = 0.75), SPD (F_{(1.43, 206.59)} = 299.99; p = 0.01; ηp² = 0.68), ACC_HIGH (F_{(1.45, 209.38)} = 268.59; p = 0.01; ηp² = 0.65), and DEC_HIGH (F_{(1.45, 209.38)} = 324.88; p = 0.01; ηp² = 0.69) was found. In addition, a significant interaction between playing position, type and duration of the passage was observed in DIS (F_{(12.60, 453.47)} = 1.98; p = 0.02; ηp² = 0.05) and ACC_HIGH (F_{(13.99, 503.78)} = 1.92; p = 0.03; ηp² = 0.06). In conclusion, significant differences in physical demands between the first, second, and third MDP of play were observed. However, there were some cases (DIS and ACC_HIGH) in which no significant differences were found between these passages. Therefore, coaches should consider not only the magnitude of these peak intensity periods (e.g., distance covered per minute) but also the number of passages that players may experience during match play.     

The Correlation between Running Economy and Maximal Oxygen Uptake: Cross-Sectional and Longitudinal Relationships in Highly Trained Distance Runners

A positive relationship between running economy and maximal oxygen uptake (V̇O_2max) has been postulated in trained athletes, but previous evidence is equivocal and could have been confounded by statistical artefacts. Whether this relationship is preserved in response to running training (changes in running economy and V̇O_2max) has yet to be explored. This study examined the relationships of (i) running economy and V̇O_2max between runners, and (ii) the changes in running economy and V̇O2max that occur within runners in response to habitual training. 168 trained distance runners (males, n = 98, V̇O_2max 73.0 ± 6.3 mL∙kg^-1∙min^-1; females, n = 70, V̇O_2max 65.2 ± 5.9 mL kg^-1∙min^-1) performed a discontinuous submaximal running test to determine running economy (kcal∙km^-1). A continuous incremental treadmill running test to volitional exhaustion was used to determine V̇O_2max 54 participants (males, n = 27; females, n = 27) also completed at least one follow up assessment. Partial correlation analysis revealed small positive relationships between running economy and V̇O_2max (males r = 0.26, females r = 0.25; P<0.006), in addition to moderate positive relationships between the changes in running economy and V̇O_2max in response to habitual training (r = 0.35; P<0.001). In conclusion, the current investigation demonstrates that only a small to moderate relationship exists between running economy and V̇O_2max in highly trained distance runners. With >85% of the variance in these parameters unexplained by this relationship, these findings reaffirm that running economy and V̇O_2max are primarily determined independently.     

Small-sided games in amateur players: rule modification with mini-goals to induce lower external load responses

The aim of this study was to compare the acute physiological (i.e., heart rate-related variables) and neuromuscular responses (i.e., sprint and jump) and time-motion characteristics (i.e., external load variables) when modifying the game design (possession play vs. mini-goals without a goalkeeper) during 4-a-side in amateur senior football players. Male senior football players (n = 16) performed two formats of small-sided games (SSGs) in two different testing sessions (4-a-side with possession play and mini-goals rule). Differences in time-motion characteristics and physiological parameters of players were measured with the Global Positioning System (GPS), and tested before and after (pre- and post-SSG) for neuromuscular assessment. A repeated measures analysis of variance (ANOVA), with Bonferroni post-hoc test, showed that both SSG formats induced changes in sprint performance (before-after comparison) (p ≤ 0.05). Moreover, the results showed that the variables muscle oxygen saturation, rate of perceived exertion, 85–89% heart rate peak, total distance, total distances at low speed, total distances at high speed, m/min, accelerations at low speed, accelerations of ≥ 2.5 m.s^-2, maximal speed, and average speed were statistically significantly different among game conditions. The players’ performances are affected by the inclusion of mini-goals during 4 vs. 4 SSGs. The results provide useful information for training and task design that replicate specific physical demands (i.e., accelerations of ≥ 2.5 m.s^-2, total distances at high speed or total distances at low speed).     

Training sessions with tackles impair upper-limb neuromuscular function in elite rugby union

The aim of this study was to investigate the response to non-tackle and tackle field-based training on upper- and lower-limb neuromuscular function in elite rugby union players. Nine elite senior elite rugby union players (mean age = 21 ± 2 years; height = 184 ± 7 cm; body mass 91.0 ± 9 kg) were evaluated before and immediately following 17 training sessions. A total of 306 assessments were performed. Data on neuromuscular function of plyometric push-up and countermovement jump were calculated from force signals using inverse dynamics. The change from pre- to post-session was investigated across non-tackle and tackle training using a linear mixed model. Considering upper-limb neuromuscular function, peak concentric power [P = 0.024; ES = 0.33 95%CI (0.04, 0.62)] was significantly lower after tackle compared to non-tackle training. In addition, peak countermovement jump eccentric power was significantly lower after non-tackle compared to tackle training [P = 0.044; ES = -0.4 95%CI (-0.69, -0.1)] in lower-limb neuromuscular function. Overall, the results indicated that the type of training influences upper- and lower-limb neuromuscular function differently immediately after training. Indeed, due to physical contact, the upper-body neuromuscular function increased during tackle training. In contrast, lower-body neuromuscular function emerged only in non-tackle training, due to the greater distance covered during this type of training session. Coaches and practitioners should plan adequate weekly training sessions according to this information.     

Competing with Lower Level Opponents Decreases Intra-Team Movement Synchronization and Time-Motion Demands during Pre-Season Soccer Matches

This study aimed to quantify the time-motion demands and intra-team movement synchronization during the pre-season matches of a professional soccer team according to the opposition level. Positional data from 20 players were captured during the first half of six pre-season matches of a Portuguese first league team. Time-motion demands were measured by the total distance covered and distance covered at different speed categories. Intra-team coordination was measured by calculating the relative phase of all pairs of outfield players. Afterwards, the percentage of time spent in the −30° to 30° bin (near-in-phase mode of coordination) was calculated for each dyad as a measure of space-time movement synchronization. Movement synchronization data were analyzed for the whole team, according to each dyad average speed and by groups of similar dyadic synchronization tendencies. Then, these data were compared according to the opponent team level (first league; second league; amateurs). Time-motion demands showed no differences in total distance covered per opposition levels, while matches opposing teams of superior level revealed more distance covered at very high intensity. Competing against superior level teams implied more time in synchronized behavior for the overall displacements and displacements at higher intensities. These findings suggest that playing against higher-level opponents (1^st league teams) increased time-motion demands at high intensities in tandem with intra-team movement synchronization tendencies.     

Activity Profiles and Physiological Responses of Representative Tag Football Players in Relation to Playing Position and Physical Fitness

This study determined the physical fitness, match-activity profiles and physiological responses of representative tag football players and examined the relationship between physical fitness and the match-activity profile. Microtechnology devices and heart rate (HR) chest straps were used to determine the match-activity profiles of sixteen tag football players for five matches during the 2014 Australian National Championships. The relationships between lower body muscular power, straight line running speed and Yo-Yo intermittent recovery test level 2 (Yo-Yo IR2) and the match-activity profile were examined using Pearson’s correlation coefficients. Outside players had greater lower body muscular power (ES = 0.98) and straight line running speed (ES = 1.03–1.18) than inside players, and also covered greater very high-speed running (VHSR) distance/min (ES = 0.67) and reached higher peak running speeds (ES = 0.95) during matches. Inside and outside players performed a similar number of repeated high-intensity effort (RHIE) bouts and reported similar mean and maximum efforts per RHIE bout. However, there were differences between playing positions for mean and maximal RHIE effort durations (ES = 0.69–1.15) and mean RHIE bout recovery (ES = 0.56). Inside and outside players also reported small to moderate differences (ES = 0.43–0.80) for times spent in each HR zone. There were a number of moderate to very large correlations between physical fitness measures and match-activity profile variables. This study found lower body muscular power, straight line running speed and Yo-Yo IR2 to be related to the match-activities of representative tag football players, although differences between inside and outside players suggest that athlete testing and training practices should be modified for different playing positions.     

Effect of formation,ball in play and ball possession on peak demands in elite soccer

This study examined the most demanding passages of match play (MDP) and the effects of playing formation, ball-in-play (BiP) time and ball possession on the 1-min peak (1-min_peak) demand in elite soccer. During 18 official matches, 305 individual samples from 223 Italian Serie A soccer players were collected. MDP and 1-min_peak were calculated across playing position (central defenders, wide defenders, central midfielders, wide midfielders, wide forwards and forwards). Maximum relative (m·min^-1) total distance (TD), high-speed running (HSR), very high-speed running (VHSR), sprint (SPR), acceleration/deceleration (Acc/Dec), estimated metabolic power (P_met) and high-metabolic load (HML) distance were calculated across different durations (1–5, 10, 90 min) using a rolling method. Additionally, 1-min_peak demand was compared across playing formation (3-4-1-2, 3-4-2-1, 3-5-2, 4-3-3, 4-4-2), BiP and ball/no-ball possession cycles. MDP showed large to verylarge [effect-size (ES): 1.20/4.06] differences between 1-min_peak vs all durations for each parameter. In 1-min_peak, central midfielders and wide midfielders achieved greater TD and HSR (ES:0.43/1.13) while wide midfielders and wide forwards showed greater SPR and Acc/Dec (ES:0.30/1.15) than other positions. For VHSR, SPR and Acc/Dec 1-min_peak showed fourfold higher locomotor requirements than 90-min. 1-min_peak for Acc/Dec was highest in 4-3-3 for forwards, central and wide midfielders. 1-min_Peak was lower during peak BiP (BiP_peak) for HSR, VHSR and Acc/Dec (ES: -2.57/-1.42). Comparing with vs without ball possession, BiP_peak was greater (ES: 0.06/1.48) in forwards and wide forwards and lower (ES: -2.12/-0.07) in central defenders and wide defenders. Positional differences in MDP, 1-min_peak and BiP_peak were observed. Soccer-specific drills should account for positional differences when conditioning players for the peak demands. This may help practitioners to bridge the training/match gap.     

Effects of congested match periods on acceleration and deceleration profiles in professional soccer

The aim of the present study was to analyse the influence of congested periods of matches on the acceleration (Acc) and deceleration (Dec) profiles of elite soccer players. Twenty-three elite male professional soccer players participated in the study across 31 official matches. Assessed periods included: (i) congested periods (three to four days between games), and (ii) non-congested periods (more than four days between games). Physical activity during matches was recorded during games using a 10Hz global positioning system device, coupled with a 100 Hz accelerometer, and was analysed according to the periods. Maximal Acc- (73.2 ± 20.3 vs. 84.918.5 m), high Acc- (244.0 ± 49.5 vs. 267.0 ± 37.8 m), maximal Dec- (139.0 ± 44.8 vs. 152.039.3 m) and the total decelerating- distance (5132 ± 690 vs. 5245 ± 552 m) were lower in congested than in non-congested periods (p < 0.05, effect size 0.31–0.70). Neither a main effect of playing position nor a period*playing position interaction on Acc and Dec were observed (p > 0.05). It was concluded that Acc and Dec match activities were significantly affected during congested periods compared to non-congested highlighting a possible fatigue accumulation being responsible for the observed decrement in physical activity. Monitoring Acc and Dec metrics throughout particular periods of congested fixtures amongst professional soccer teams is advised and may be a way to assess physical and fatigue status.