The Effects of a Supramaximal Intermittent Training Program on Aerobic and Anaerobic Running Measures in Junior Male Soccer Players.

This study investigated the effectiveness of supplementing regular preseason soccer training with a supramaximal intermittent shuttle-run training (ISRT) model prescribed from Carminatti's Test peak speed (PST-CAR) in aerobic performance-related indices and sprinting speed in male junior soccer players. Twenty-three national-level soccer players (mean ± SD; age 18.07 ± 0.9 y, body height 1.76 ± 0.65 m, body mass 71.9 ± 8.7 kg) were assigned to either an experimental group (EG; n = 13) performing ISRT + soccer training or a control group (CG; n = 10) that followed regular preseason soccer training alone. The following tests were applied before and after the eight-week training intervention: (i) incremental treadmill tests (VO2max and lactate minimum speed - LMS); (ii) linear 30-m sprint test and Carminatti's Test (PST-CAR). Results indicated larger gains for the EG in LMS (Δ = 9.53% vs. 2.82%) and PST-CAR (Δ = 5.50% vs. 2.10%) than in the CG. Furthermore, changes in VO2max produced higher effect size (d) values for the EG (Δ = 6.67%; d = 0.59) than the CG (Δ = 1.88%; d = 0.18). Both groups improved (p = 0.002) their flying 20-m sprint speed (EG: Δ = 1.01%; CG: Δ = 1.56%). However, small decreases were observed for 10-m sprint speed in the CG (Δ = -2.19%; d = -0.44), while only trivial changes were noticed for the EG (Δ = -0.50%; d = -0.16). Our data support that additional supramaximal ISRT is an effective training stimulus to enhance aerobic performance-related indices and promote small improvements in maximal running speed without impairing the soccer players' acceleration capacity. This study also shows that PST-CAR can be useful for individualizing running intensity in supramaximal ISRT modes.

The selection advantages associated with advanced biological maturation vary according to playing position in national-level youth soccer.

This study investigated the extent to which biological maturation selection biases existed according to playing position in national-level youth soccer. A total of 159 players from the U13 to U16 age groups in the Football Association of Ireland's national talent pathway and international representative squads had their relative biological maturity status assessed using the Khamis-Roche method for the percentage of predicted adult height at the time of observation. Players were categorised as goalkeeper (GK), central defender (CD), full-back (FB), centre defensive midfielder (CDM), centre midfielder (CM), centre attacking midfielder (CAM), wide midfielder (WM) or centre forward (CF). A series of one-sampled means t-tests were used to examine the degree to which biological maturation selection biases existed across playing positions. A non-parametric Kruskal-Wallis test was used to evaluate inter-positional differences. A small to very large selection bias in favour of early maturing players existed for GK (D = 0.7), CD (D = 1.65), FB (D = 0.49), CM (D = 0.62), WM (D = 0.78), and CF (D = 0.76) (p < 0.05). Maturational selection biases did not exist for CDM or CAM. Moreover, CD were significantly more advanced in maturation compared to FB, CDM and CAM (p < 0.05). This study supports the contention that maturation selection biases exist in youth soccer, but the magnitude of this bias is highly dependent upon playing position. The very strong maturity selection biases at the national level evidenced in this investigation highlight the need for Football Associations to explore strategies, such as futures programmes, to help to retain talented, yet late maturing athletes.

Relationships between training load, peak height velocity, muscle soreness and fatigue status in elite-level young soccer players: a competition season study.

BACKGROUND: This study aimed to compare training load parameters, delayed onset muscle soreness (DOMS), and fatigue status between season periods (1st and 2nd halves) in U14 soccer players and to analyze the relationships between training load parameters based on season periods (1st and 2nd halves) with peak height velocity (PHV), DOMS, and fatigue status in under-14 (U14) young elite soccer players. Additionally, it was intended to analyze if fatigue, DOMS and PHV could explain training load parameters across the season. METHODS: Twenty U14 players that competed in the national league participated in this study. The players were monitored during the whole season (26 weeks), and evaluations were carried out at the end of the in-season. Anthropometric and body composition parameters and the maturity offset of each player were utilized to compute each player's age at PHV. Players reported their levels of DOMS and fatigue status using Hooper index questionnaires. The internal load was monitored using the rating of perceived exertion (RPE). Acute weekly internal load (AW), chronic weekly internal load (CW), acute: chronic workload ratio (ACWR), training monotony (TM), and training strain (TS) were also obtained. RESULTS: The main results showed that TM was higher in the 2nd half, while CW, AW and DOMS were higher in the 1st half of the season. Moreover, the main correlations showed a positive correlation between PHV and TS (2nd half of the season) and between fatigue and TM (1st half of the season). CONCLUSION: In conclusion, variations in well-being status and PHV cannot explain the variations in internal training loads in elite U14 soccer players. In addition, internal training load indices during the first half of the competitive season can promote a fundamental base for progression loads during the second period of the competitive season.

Player Migration and Soccer Performance.

The aim of this study is to examine the relationship between migrating soccer players and the annual ranking of the national teams according to the World Football Elo Rating. The sample includes annual data for 243 countries over the period 1994-2018. Migration is captured with the number of migrating players by country in the "big-five" leagues. The causal relationship between the two variables is examined by using Granger causality test. Four control variables are included: the political regime, per capita income, population, and regional soccer confederations. It was hypothesized that (i) the better the ranking of the national teams in the Elo rating, the higher the number of migrating players in the "big-five" leagues (shop-window hypotheses) and that (ii) while the shop-window effect takes place in the short-run, the annual Elo rating of a national team is positively affected by expatriate players in the medium or long-run, but not in the short-run (blending hypotheses). The results shed light on two crucial issues. First, causality mainly goes from national soccer performance to migrating soccer players rather than the other way around. Second, the timing of the two effects is quite different. While those players giving an outstanding performance when their national team is doing well are immediately bought by clubs from more highly ranked leagues (the shop-window effect), it takes at least 4 years for the additional skills acquired by migrated players to have a positive effect on the national soccer performance (the blending effect).

Data-Driven Visual Performance Analysis in Soccer: An Exploratory Prototype.

In soccer, understanding of collective tactical behavior has become an integral part in sports analysis at elite levels. Evolution of technology allows collection of increasingly larger and more specific data sets related to sport activities in cost-effective and accessible manner. All this information is minutely scrutinized by thousands of analysts around the globe in search of answers that can in the long-term help increase the performance of individuals or teams in their respective competitions. As the volume of data increases in size, so does the complexity of the problem and the need for suitable tools that leverage the cognitive load involved in the investigation. It is proven that visualization and computer-vision techniques, correctly applied to the context of a problem, help data analysts focus on the relevant information at each stage of the process, and generally lead to a better understanding of the facts that lie behind the data. In the current study, we presented a software prototype capable of assisting researchers and performance analysts in their duty of studying group collective behavior in soccer games and trainings. We used geospatial data acquired from a professional match to demonstrate its capabilities in two different case studies. Furthermore, we successfully proved the efficiency of the different visualization techniques implemented in the prototype and demonstrated how visual analysis can effectively improve some of the basic tasks employed by sports experts on their daily work, complementing more traditional approaches.

Small-Sided Games in Elite Soccer: Does One Size Fit All?

PURPOSE: To compare the peak intensity of typical small-sided games (SSGs) with those of official matches in terms of running demands and mechanical work (MechW) over different rolling average durations and playing positions. METHODS: Data were collected in 21 players (25 [5] y, 181 [7] cm, and 77 [7] kg) belonging to an elite French football team. SSG data were collected over 2 seasons during typical training sessions (249 files, 12 [4] per player) and official matches (n = 12). Players' locomotor activity was recorded using 5-Hz Global Positioning System. Total distance (m), high-speed distance (HS, distance above 14.4 km·h-1, m), and MechW (a.u.) were analyzed during different rolling average periods (1-15 min). The SSGs examined were 4v4+goalkeepers (GKs), 6v6+GKs, 8v8+GKs, and 10v10+GKs. RESULTS: Peak total distance and HS during 4v4, 6v6, and 8v8 were likely-to-most likely lower than during matches (effect size: -0.59 [±0.38] to -7.36 [±1.20]). MechW during 4v4 was likely-to-most likely higher than during matches (1-4 min; 0.61 [±0.77] to 2.30 [±0.64]). Relative to their match demands, central defenders performed more HS than other positions (0.63 [±0.81] to 1.61 [±0.52]) during 6v6. Similarly, central midfielders performed less MechW than the other positions during 6v6 (0.68 [±0.72] to 1.34 [±0.99]) and 8v8 (0.73 [±0.50] to 1.39 [±0.32]). CONCLUSION: Peak locomotor intensity can be modulated during SSGs of various formats and durations to either overload or underload match demands, with 4v4 placing the greatest and the least emphasis on MechW and HS, respectively. Additionally, in relation to match demands central defenders and central midfielders tend to be the most and least overloaded during SSGs, respectively.

High Speed Running and Sprinting Profiles of Elite Soccer Players.

Real Madrid was named as the best club of the 20th century by the International Federation of Football History and Statistics. The aim of this study was to compare if players from Real Madrid covered shorter distances than players from the opposing team. One hundred and forty-nine matches including league, cup and UEFA Champions League matches played by the Real Madrid were monitored during the 2001-2002 to the 2006-2007 seasons. Data from both teams (Real Madrid and the opponent) were recorded. Altogether, 2082 physical performance profiles were examined, 1052 from the Real Madrid and 1031 from the opposing team (Central Defenders (CD) = 536, External Defenders (ED) = 491, Central Midfielders (CM) = 544, External Midfielders (EM) = 233, and Forwards (F) = 278). Match performance data were collected using a computerized multiple-camera tracking system (Amisco Pro®, Nice, France). A repeated measures analysis of variance (ANOVA) was performed for distances covered at different intensities (sprinting (>24.0 km/h) and high-speed running (21.1-24.0 km/h) and the number of sprints (21.1-24.0 km/h and >24.0 km/h) during games for each player sectioned under their positional roles. Players from Real Madrid covered shorter distances in high-speed running and sprint than players from the opposing team (p < 0.01). While ED did not show differences in their physical performance, CD (p < 0.05), CM (p < 0.01), EM (p < 0.01) and F (p > 0.01) from Real Madrid covered shorter distances in high-intensity running and sprint and performed less sprints than their counterparts. Finally, no differences were found in the high-intensity running and sprint distances performed by players from Real Madrid depending on the quality of the opposition.

Effects of match situational variables on possession: the case of England Premier League season 2015/16

Aim: The main aim of this study was to identify the effects of match location, quality of opponents and match status on possession during the 2015/16 Season of England Premier League. Methods: Three hundred and eighty matches played by 20 teams were analysed. For each match, two values were recorded, resulting in 760 observations. Results Teams who played at home (51.77 ± 10.22%) presented higher possession values (EF=moderate) than those who played away (48.21 ± 10.30%). Quality of opponents also had a significant difference, as possession was higher (EF=large) when teams played against weak (52.30 ± 9.77%) than strong opponents (46.48 ± 10.38%). The multivariate analysis revealed no interaction between situational variables and possession (p = 0.76). Despite the teams classified as "best-ranking" (1st to 8th position: 50.60 ± 10.35%) presented greater possession (EF=moderate) than "worst-ranking" (9st to 20th position: 47.59 ± 9.74%), no significant differences were found in the comparisons of match status (winner [50.34 ± 10.48%] x drawer [49.95 ± 10.25%] x loser [49.68 ± 10.48%]). Conclusion: General interpretations should be viewed with caution, since this possession can represent an indicator of success for a team but not for others.(AU)

The Influence of Referee Bias on Extra Time in Elite Soccer Matches.

Referees have discretion over the addition of extra time at the end of the soccer game to compensate for lost time due to unusual stoppages. This study assesses if referees favor big teams by shortening close games where the big team is ahead and lengthening close games where the big team is behind. The sample comprises all 380 matches in the Spanish La Liga during the 2014-2015 season. The dependent variable was the extra time the referee decides to add to the second half. The independent variables were the score difference, opponent team's level of play, yellow cards, red cards, player substitutions, average attendance, and fouls committed. Linear regression analysis suggested that the greater the score difference between teams, the less extra time was added by the referee. However, in close games, referees tended to add more time for a higher level team when they were behind and add less time when they were ahead. Red cards and the number of fouls committed increased the extra time.

Developing Legacy: Health Planning in the Host City of Porto Alegre for the 2014 Football World Cup.

AIM: To describe the process adopted to identify, classify, and evaluate legacy of health care planning in the host city of Porto Alegre for the Football World Cup 2014. BACKGROUND: There is an emerging interest in the need to demonstrate a sustainable health legacy from mass gatherings investments. Leaving a public health legacy for future host cities and countries is now an important part of planning for these events. PROCESS: The Ministry of Sports initiated and coordinated the development of projects in the host cities to identify actions, projects, and constructions to be developed to prepare for the World Cup. In Porto Alegre, a common structure was developed by the coordinating team to instruct legacy identification, classification, and evaluation. This structure was based on international documentary analysis (including official reports, policy documents, and web-based resources) and direct communication with recognized experts in the field. FINDINGS AND INTERPRETATION: Sixteen total legacies were identified for health surveillance (5) and health services (11). They were classified according to the strategic area, organizations involved, dimension, typology, planned or unplanned, tangible or intangible, territorial coverage, and situation prior to the World Cup. Possible impacts were then assessed as positive, negative, and potentiating, and mitigating actions were indicated. CONCLUSIONS: The project allowed the identification, classification, and development of health legacy, including risk analysis, surveillance, mitigation measures, and provision of emergency medical care. Although the project intended the development of indicators to measure the identified legacies, evaluation was not possible at the time of publication due to time.

The Relationship Between Intensity Indicators in Small-Sided Soccer Games.

The aim of the present study was to examine the relationship between different kinds of intensity indicators in small-sided soccer games. This descriptive correlational study included 14 semi-professional male soccer players (21.3 ± 2.3 years, 174 ± 4.0 cm, 73.4 ± 5.1 kg) from the same team. The players were monitored by means of heart rate monitors and GPS devices during 27 small-sided games of nine different formats, yielding a total of 217 recordings. After each game the Borg scale was used to give a rate of perceived exertion (RPE). The internal load indicators were the mean heart rate relative to the individual maximum (%HRmean) and the RPE, while those for the external load were the player load, total distance covered, distance covered in two intensity ranges (>18 km·h-1 and >21 km·h-1), and frequency of effort (in the same two intensity ranges). There was a significant moderate correlation (r=0.506) between the two internal load measurements (%HRmean and RPE). Although there were significant correlations of different degrees between various external load measurements, only the player load was significantly correlated with the internal load indicators (r=0.331 with %HRmean and r=0.218 with RPE). During training programes of this kind, it is necessary to consider a range of intensity indicators so as to obtain complementary information. This will enable coaches to more accurately assess the load imposed on players and therefore optimize the training process.

Mechanical determinants of acceleration and maximal sprinting speed in highly trained young soccer players.

Abstract The aim of the present study was to examine, in highly trained young soccer players, the mechanical horizontal determinants of acceleration (Acc) and maximal sprinting speed (MSS). Eighty-six players (14.1 ± 2.4 year) performed a 40-m sprint to assess Acc and MSS. Speed was measured with a 100-Hz radar, and theoretical maximal velocity (V0), horizontal force (F0) and horizontal power (Pmax) were calculated. Within each age group, players were classified as high Acc/fast MSS (>2% faster than group mean), medium (between -2% and +2%), and low/slow (>2% slower). Acc and MSS were very largely correlated (-0.79; 90% confidence limit [-0.85; -0.71]). The determinants (multiple regression r2 = 0.84 [0.78; 0.89]) of Acc were V0 (partial r: 0.80 [0.72; 0.86]) and F0 (0.57 [0.44; 0.68]); those of MSS (r2 = 0.96 [0.94; 0.97]) were V0 (0.96 [0.94; 0.97]) and Pmax (0.73 [0.63; -0.80]). High/Med have likely greater F0 (Cohen's d: +0.8 [0.0; 1.5]), V0 (+0.6 [-0.1; 1.3]) and Pmax (+0.9 [0.2; 1.7]) than Low/Med. High/Fast have an almost certainly faster V0 (+2.1 [1.5; 2.7]) and a likely greater Pmax (+0.6 [-0.1; 1.3]) than High/Med, with no clear differences in F0 (-0.0 [-0.7; 0.6]). Speed may be a generic quality, but the mechanical horizontal determinants of Acc and MSS differ. While maximal speed training may improve both Acc and MSS, improving horizontal force production capability may be efficient to enhance sprinting performance over short distances.

Football Fitness - a new version of football? A concept for adult players in Danish football clubs.

This article explores a new Danish football-based activity for health called Football Fitness (FF). Data are from quantitative and qualitative methods, and the theoretical framework for the analysis of the organizational form of FF is the theory of path dependency (Mahoney) and first- and second-order change (Watzlawick et al.). Theories of Pestoff concerning differences between state, market, and the civil society and theories of voluntary associations in a Danish context (Kaspersen & Ottesen; Ibsen & Seippel) are applied. This article indicates how FF is a result of the changing landscape of sport and argues that it can be beneficial to target sports organizations and include the expertise of non-profit sports clubs if the goal is to raise the physical activity level of the local community and make these long lasting. But the organizations need to consider how this is to be done. FF, established by the Danish Football Association (FA) and managed by the voluntary clubs, is one example in a Danish context. Data indicate that FF is beneficial to the clubs involved in a number of ways. Among other things, it attracts new user groups and improves the club environment, including social activities and parental environment.

Changes in repeated-sprint performance in relation to change in locomotor profile in highly-trained young soccer players.

The aim of this study was to examine the effects of changes in maximal aerobic (MAS) and sprinting (MSS) speeds and the anaerobic reserve (ASR) on repeated-sprint performance. Two hundred and seventy highly-trained soccer players (14.5 ± 1.6 year) completed three times per season (over 5 years) a maximal incremental running test to approach MAS, a 40-m sprint with 10-m splits to assess MSS and a repeated-sprint test (10 × 30-m sprints), where best (RSb) and mean (RSm) sprint times, and percentage of speed decrement (%Dec) were calculated. ASR was calculated as MSS-MAS. While ∆RSb were related to ∆MSS and ∆body mass (r(2) = 0.42, 90%CL[0.34;0.49] for the overall multiple regression, n = 334), ∆RSm was also correlated with ∆MAS and ∆sum of 7 skinfolds (r(2) = 0.43 [0.35;0.50], n = 334). There was a small and positive association between ∆%Dec and ∆MAS (r(2) = 0.02 [-0.07;0.11], n = 334). Substantial ∆MSS and ∆MAS had a predictive value of 70 and 55% for ∆RSm, respectively. Finally, ∆ASR per se was not predictive of ∆RSm (Cohen's = +0.8 to -0.3 with increased ASR), but the greater magnitude of ∆RSm improvement was observed when MSS, MAS and ASR increased together (0.8 vs. +0.4 with ASR increased vs. not, additionally to MSS and MAS). Low-cost field tests aimed at assessing maximal sprinting and aerobic speeds can be used to monitor ∆RS performance.

Epidemiology of injuries in First Division Spanish football.

The aim was to examine the injuries sustained by Spanish football players in the First Division and to compare injury-related variables in the context of both competition and training. The injury data were prospectively collected from 16 teams (427 players) using a specific web-based survey during the 2008/2009 season. A total of 1293 injuries were identified (145 were recurring injuries). The overall injury incidence was 5.65 injuries per 1000 h of exposure. Injuries were much more common during competition than during training (43.53 vs. 3.55 injuries per 1000 h of exposure, P < 0.05). Most of the injuries (89.6%) involved the lower extremities, and overuse (65.7%) was the main cause. Muscle and tendon injuries were the most common types of injury (53.8%) among the players. The incidence of training injuries was greater during the pre-season and tended to decrease throughout the season, while the incidence of competition injuries increased throughout the season (all P < 0.05). In conclusion, the results of this study suggest the need for injury prevention protocols in the First Division of the Spanish Football League to reduce the number of overuse injuries in the muscles and tendons in the lower extremities. In addition, special attention should be paid during the pre-season and the competitive phase II (the last four months of the season) in order to prevent training and competition injuries, respectively.

Impact of the 2010 FIFA (Federation Internationale de Football Association) World Cup on Pediatric Injury and Mortality in Cape Town, South Africa.

OBJECTIVE: To examine how a mass-gathering event (the Federation Internationale de Football Association World Cup, 2010, South Africa) impacts trauma and mortality in the pediatric (≤ 18 years) population. STUDY DESIGN: We investigated pediatric emergency visits at Cape Town's 3 largest public trauma centers and 3 private hospital groups, as well as deaths investigated by the 3 city mortuaries. We compared the 31 days of World Cup with equivalent periods from 2007-2009, and with the 2 weeks before and after the event. We also looked at the World Cup period in isolation and compared days with and without games in Cape Town. RESULTS: There was significantly decreased pediatric trauma volume during the World Cup, approximately 2/100,000 (37%) fewer injuries per day, compared with 2009 and to both pre- and post-World Cup control periods (P < .001). This decrease occurred within a majority of injury subtypes, but did not change mortality. There were temporal fluctuations in emergency visits corresponding with local match start time, with fewer all-cause emergency visits during the 5 hours surrounding this time (-16.4%, P = .01), followed by a subsequent spike (+26.2%, P = .02). There was an increase in trauma 12 hours following matches (+15.6%, P = .06). CONCLUSIONS: In Cape Town, during the 2010 Federation Internationale de Football Association World Cup, there were fewer emergency department visits for traumatic injury. Furthermore, there were fewer all-cause pediatric emergency department visits during hometown matches. These results will assist in planning for future mass-gathering events.