Physical and perceptual-cognitive demands of top-class refereeing in association football

The aim of this study was to examine the physical and perceptual-cognitive demands imposed on UEFA top-class referees and assistant referees during the final round of the Euro 2000 Championship. To investigate the physical workload, the heart rates during matches were monitored by short-range radio telemetry and translated to different workloads expressed as a percentage of maximal heart rate. For measurement of the perceptual-cognitive workload, video-recordings of games were used to obtain the average number of observable decisions taken by a referee. On average, referees and assistant referees performed the matches at 85±5% and 77±7% of their maximal heart rate, respectively. Over the 31 games, the mean number of observable decisions was 137 (range 104–162), 64% of which were based on communication with the assistant referees and/or the fourth official. To optimize the physical preparation of top-class match officials, the results of this study support the application of intensive and intermittent training sessions, which should place priority on high-intensity aerobic stimuli. In addition, video training is discussed as an additional method for improving match officials' decision making.     

Activity profile and physiological demands of top-class soccer assistant refereeing in relation to training status

To determine the movement patterns and physiological demands of top-class soccer assistant referees, we performed computerized time-motion analysis and measured heart rate and blood lactate concentration in 15 assistant referees during 22 competitive matches in the top Danish league. To relate match performance to the physical capability of the assistant referees, they performed a 3 x 30 m sprint protocol before and after matches and a laboratory treadmill test within 3 weeks of the games. The mean total distance covered by the top-class assistant referees was 7.28 (range 5.78-8.16) km, of which 1.15 (0.86-1.44) km was high-intensity running and 1.16 (0.12-2.34) km was sideways running. The amount of high-intensity running during a game was correlated with performance of repeated sprints (r = 0.80, P < 0.05). Mean heart rate was 137 (117-159) beats x min(-1), corresponding to 73% (60-88%) of maximal heart rate and 65% (53-80%) of maximal oxygen uptake. Blood lactate concentration was 4.7 (1.6-11.0) and 4.8 (1.1-13.7) mmol x 1(-1) after the first and second half, respectively. Sprinting performance was poorer (P < 0.05) after than before the games. The peak distance to the offside line was greater (P < 0.05) in the second than the first half (7 +/- 1 vs 5 +/- 0 m). Our results show that: (1) top-class assistant soccer refereeing is characterized by brief intense bouts of forward and sideways running interspersed with long periods of low activity; (2) top-class soccer assistant referees have moderate aerobic energy production during games with episodes of high aerobic and anaerobic energy turnover; (3) assistant referees' performance of repeated sprints correlates with the amount of high-intensity running performed in a game; and (4) sprint performance decreases towards the end of a game, which appears to affect assistant referees' ability to keep up with play.     

Activity profile and physiological demands of top-class soccer assistant refereeing in relation to training status

To determine the movement patterns and physiological demands of top-class soccer assistant referees, we performed computerized time-motion analysis and measured heart rate and blood lactate concentration in 15 assistant referees during 22 competitive matches in the top Danish league. To relate match performance to the physical capability of the assistant referees, they performed a 3 2 30 m sprint protocol before and after matches and a laboratory treadmill test within 3 weeks of the games. The mean total distance covered by the top-class assistant referees was 7.28 (range 5.78-8.16) km, of which 1.15 (0.86-1.44) km was high-intensity running and 1.16 (0.12-2.34) km was sideways running. The amount of high-intensity running during a game was correlated with performance of repeated sprints (r = 0.80, P ? 0.05). Mean heart rate was 137 (117-159) beats · min^-1 , corresponding to 73% (60-88%) of maximal heart rate and 65% (53-80%) of maximal oxygen uptake. Blood lactate concentration was 4.7 (1.6-11.0) and 4.8 (1.1-13.7) mmol · l -1 after the first and second half, respectively. Sprinting performance was poorer (P ? 0.05) after than before the games. The peak distance to the offside line was greater (P ? 0.05) in the second than the first half (7 - 1 vs 5 - 0 m). Our results show that: (1) top-class assistant soccer refereeing is characterized by brief intense bouts of forward and sideways running interspersed with long periods of low activity; (2) top-class soccer assistant referees have moderate aerobic energy production during games with episodes of high aerobic and anaerobic energy turnover; (3) assistant referees' performance of repeated sprints correlates with the amount of high-intensity running performed in a game; and (4) sprint performance decreases towards the end of a game, which appears to affect assistant referees' ability to keep up with play.     

Physiological demands of top-class soccer refereeing in relation to physical capacity: effect of intense intermittent exercise training.

To examine the activity profile and physiological demands of top-class soccer refereeing, we performed computerized time-motion analyses and measured the heart rate and blood lactate concentration of 27 referees during 43 competitive matches in the two top Danish leagues. To relate match performance to physical capacity and training, several physiological tests were performed before and after intermittent exercise training. Total distance covered was 10.07+/-0.13 km (mean +/- s(x)), of which 1.67+/-0.08 km was high-intensity running. High-intensity running and backwards running decreased (P < 0.05) in the second half. Mean heart rate was 162+/-2 beats min(-1) (85+/-1% of maximal heart rate) and the mean blood lactate concentration was 4.9+/-0.3 (range 1.7-14.0) mmol x l(-1). The amount of high-intensity running during a match was related to the Yo-Yo intermittent recovery test (r2 = 0.57; P<0.05) and the 12 min run (r2 = 0.21; P<0.05). After intermittent training (n = 8), distance covered during high-intensity running was greater (2.06+/-0.13 vs 1.69+/-0.08 km; P< 0.05) and mean heart rate was lower (159+/-1 vs 164+/-2 beats x min(-1); P< 0.05) than before training. The results of the present study demonstrate that: (1) top-class soccer referees have significant aerobic energy expenditure throughout a game and episodes of considerable anaerobic energy turnover; (2) the ability to perform high-intensity running is reduced towards the end of matches; (3) the Yo-Yo intermittent recovery test can be used to evaluate referees' match performance; and (4) intense intermittent exercise training improves referees' performance capacity during a game.     

Physiological demands of top-class soccer refereeing in relation to physical capacity: effect of intense intermittent exercise training

To examine the activity profile and physiological demands of top-class soccer refereeing, we performed computerized time-motion analyses and measured the heart rate and blood lactate concentration of 27 referees during 43 competitive matches in the two top Danish leagues. To relate match performance to physical capacity and training, several physiological tests were performed before and after intermittent exercise training. Total distance covered was 10.07 - 0.13 km (mean - s x ), of which 1.67 - 0.08 km was high-intensity running. High-intensity running and backwards running decreased (P ? 0.05) in the second half. Mean heart rate was 162 - 2 beats· min -1 (85 - 1% of maximal heart rate) and the mean blood lactate concentration was 4.9 - 0.3 (range 1.7-14.0) mmol·l -1 . The amount of high-intensity running during a match was related to the Yo-Yo intermittent recovery test ( r 2 = 0.57; P ? 0.05) and the 12 min run ( r 2 = 0.21; P ? 0.05). After intermittent training ( n = 8), distance covered during high-intensity running was greater (2.06 - 0.13 vs 1.69 - 0.08 km; P ? 0.05) and mean heart rate was lower (159 - 1 vs 164 - 2 beats· min -1 ; P ? 0.05) than before training. The results of the present study demonstrate that: (1) top-class soccer referees have significant aerobic energy expenditure throughout a game and episodes of considerable anaerobic energy turnover; (2) the ability to perform high-intensity running is reduced towards the end of matches; (3) the Yo-Yo intermittent recovery test can be used to evaluate referees' match performance; and (4) intense intermittent exercise training improves referees' performance capacity during a game.     

Activity profile of top-class association football referees in relation to fitness-test performance and match standard

The aim of this study was to examine the kinematic activity profiles, cardiovascular responses and physical fitness of top-class football referees (n=11) during the FIFA Confederations Cup 2005. Computerised match-analyses (n=9) were performed with a two-dimensional photogrammetric video system, and the cardiovascular demand imposed on the referees (n=12) was measured using heart rate recordings. Total distance covered was 10,218, s=643 m of which 3531, s=510 m was covered at high intensities (>3.6 m.s(-1)). Both total distance covered (r2=0.59; P=0.02) and high-intensity activities (r2=0.44; P=0.05) were related to the distance covered by the ball in the same match. The referees ran at high speed 37% further (P=0.01) in the actual tournament than during under-17 top-level officiating. After the 5-min interval during which high-speed running peaked, in the following 5 min the performance was reduced by 19% (P=0.01) in relation to the mean of the game. Mean heart rate was 161, s=9 b.min(-1) (86, s=3% of maximal heart rate (HRmax)). Mean heart rate (expressed as percentage of HRmax) was related in part (r2=0.36; P<0.01) to the number of high-intensity activities performed in the same 5-min interval. The results of this study show that: (1) kinematic activity profiles of top-class referees can be influenced by the distance covered by the ball; (2) the amount of high-speed running (>5 m.s(-1)) best describes the physical performance of referees; (3) heart rate recording can be a useful tool to determine the most intense periods of a match and (4) the new fitness tests adopted by FIFA were poor predictors of match activities.     

Activity profile of top-class association football referees in relation to performance in selected physical tests

Abstract

The aims of the present study were (1) to analyse the physical demands of top-class referees and (2) to compare their official FIFA fitness test results with physical performance during a match. The work rate profiles of 11 international referees were assessed during 12 competitive matches at the 2003 FIFA Under-17 World Cup and then analysed using a bi-dimensional photogrammetric video analysis system based on direct lineal transformation (DLT) algorithms. In the first 15 min of matches, the referees were more active, performing more high-intensity exercise (P < 0.01) than in the first 15 min of the second half. During the second half of matches, the referees covered a shorter distance (P < 0.01), spent more time standing still (P < 0.05), and covered less ground cruising (P < 0.05), sprinting (P < 0.05), and moving backwards (P < 0.001) than in the first half. Also in the second 45 min, the distance of referees from infringements increased (P < 0.05) in the left attacking zone of the filed. There was also a decrease (P < 0.05) in performance in the period following the most high-intensity activity, compared with the mean for the 90 min. Time spent performing high-intensity activities during a match was not related to performance in the 12-min run (r ² = 0.30; P < 0.05), the 200-m sprint (r ² = 0.05; P < 0.05), or the 50-m sprint (r ² = 0.001; P < 0.05). The results of this study show that: (1) top-class referees experienced fatigue at different stages of the match, and (2) the typical field tests used by FIFA (two 50-m and 200-m sprints, followed by a 12-min run) are not correlated with match activities.     

Activity profile of top-class association football referees in relation to performance in selected physical tests

The aims of the present study were (1) to analyse the physical demands of top-class referees and (2) to compare their official FIFA fitness test results with physical performance during a match. The work rate profiles of 11 international referees were assessed during 12 competitive matches at the 2003 FIFA Under-17 World Cup and then analysed using a bi-dimensional photogrammetric video analysis system based on direct lineal transformation (DLT) algorithms. In the first 15 min of matches, the referees were more active, performing more high-intensity exercise (P < 0.01) than in the first 15 min of the second half. During the second half of matches, the referees covered a shorter distance (P < 0.01), spent more time standing still (P < 0.05), and covered less ground cruising (P < 0.05), sprinting (P < 0.05), and moving backwards (P < 0.001) than in the first half. Also in the second 45 min, the distance of referees from infringements increased (P < 0.05) in the left attacking zone of the filed. There was also a decrease (P < 0.05) in performance in the period following the most high-intensity activity, compared with the mean for the 90 min. Time spent performing high-intensity activities during a match was not related to performance in the 12-min run (r(2) = 0.30; P < 0.05), the 200-m sprint (r(2) = 0.05; P < 0.05), or the 50-m sprint (r(2) = 0.001; P < 0.05). The results of this study show that: (1) top-class referees experienced fatigue at different stages of the match, and (2) the typical field tests used by FIFA (two 50-m and 200-m sprints, followed by a 12-min run) are not correlated with match activities.     

Physical and metabolic demands of training and match-play in the elite football player

In soccer, the players perform intermittent work. Despite the players performing low-intensity activities for more than 70% of the game, heart rate and body temperature measurements suggest that the average oxygen uptake for elite soccer players is around 70% of maximum (VO(2max). This may be partly explained by the 150 - 250 brief intense actions a top-class player performs during a game, which also indicates that the rates of creatine phosphate (CP) utilization and glycolysis are frequently high during a game. Muscle glycogen is probably the most important substrate for energy production, and fatigue towards the end of a game may be related to depletion of glycogen in some muscle fibres. Blood free-fatty acids (FFAs) increase progressively during a game, partly compensating for the progressive lowering of muscle glycogen. Fatigue also occurs temporarily during matches, but it is still unclear what causes the reduced ability to perform maximally. There are major individual differences in the physical demands of players during a game related to physical capacity and tactical role in the team. These differences should be taken into account when planning the training and nutritional strategies of top-class players, who require a significant energy intake during a week.     

Video-based training to improve perceptual-cognitive decision-making performance of Australian football umpires

Decision-making is a central component of the in-game performance of Australian football umpires; however, current umpire training focuses largely on physiological development with decision-making skills development conducted via explicit lecture-style meetings with limited practice devoted to making actual decisions. Therefore, this study investigated the efficacy of a video-based training programme, aimed to provide a greater amount of contextualised visual experiences without explicit instruction, to improve decision-making skills of umpires. Australian football umpires (n = 52) were recruited from metropolitan and regional Division 1 competitions. Participants were randomly assigned to an intervention or control group and classified according to previous umpire game experience (i.e., experienced; less experienced). The intervention group completed a 12-week video-based decision-making training programme, with decision-making performance assessed at pre-training, and 1-week retention and 3-week retention periods. The control group did not complete any video-based training. Results indicated a significant Group (intervention; Control) × Test interaction (F(1, 100) = 3.98; P = 0.02, partial ?² = 0.074), with follow-up pairwise comparisons indicating significant within-group differences over time for the intervention group. In addition, decision-making performance of the less experienced umpires in the intervention group significantly improved (F(2, 40) = 5.03, P = 0.01, partial ?² = 0.201). Thus, video-based training programmes may be a viable adjunct to current training programmes to hasten decision-making development, especially for less experienced umpires.     

Effect of positioning on the accuracy of decision making of association football top-class referees and assistant referees during competitive matches

Abstract The aim of this study was to examine the effect of positioning on the correctness of decision making of top-class referees and assistant referees during international games. Match analyses were carried out during the Fédération Internationale de Football Association (FIFA) Confederations Cup 2009 and 380 foul play incidents and 165 offside situations were examined. The error percentage for the referees when indicating the incidents averaged 14%. The lowest error percentage occurred in the central area of the field, where the collaboration of the assistant referee is limited, and was achieved when indicating the incidents from a distance of 11-15?m, whereas this percentage peaked (23%) in the last 15-min match period. The error rate for the assistant referees was 13%. Distance of the assistant referee to the offside line did not have an impact on the quality of the offside decision. The risk of making incorrect decisions was reduced when the assistant referees viewed the offside situations from an angle between 46 and 60°. Incorrect offside decisions occurred twice as often in the second as in the first half of the games. Perceptual-cognitive training sessions specific to the requirements of the game should be implemented in the weekly schedule of football officials to reduce the overall error rate.     

The determinants of the intention to continue voluntary football refereeing

Competitive sports require a regulating body of referees to enforce the rules for the effective operation of the game. However, the number of referees is generally decreasing, leading to organisational problems at the amateur level. The purpose of this research is to identify the factors that determine the intention to continue voluntary refereeing in the context of football in Germany. Combining several concepts as predictors, including both the antecedents and the experience of volunteering, in this study, the authors extend the understanding about volunteers’ intentions to continue their activity and address the research gap regarding the analyses of specific volunteer groups such as referees. By means of an online questionnaire, the authors surveyed voluntary football referees in Germany (n = 4541). Regression analysis reveals the motive of self-orientation, respect shown by athletes, coaches, and spectators towards referees, compatibility of refereeing with one’s occupational and private life, perceived organisational support, and referees’ satisfaction to predict referees’ positive intention to continue with their activity. Simultaneously, experiences of offences during refereeing negatively influence this intention, and younger referees show higher intentions to continue their activity than do older referees. Because volunteer recruitment and retention are expensive, the findings of this study facilitate the improvement of effective retention strategies for the federations responsible for referees.     

Season-of-birth bias in association football

In this longitudinal study, we assessed the frequency of birth dates for boys selected for the Football Association National School. Birthdays were divided into three periods of the year: January to April, May to August and September to December. We compared data over a 5 year period and concluded that there is indeed a bias towards selecting older children. Furthermore, analysis of separate data revealed a shift of bias when comparing two different start dates, namely September and January. Our findings show that the youngest children from the January start date (born September to December) are selected significantly more often than the youngest children from the September start date (born May to August). Interestingly, even when the influence of body mass was reduced, the selection bias towards the older players remained.     

Season-of-birth bias in association football

In this longitudinal study, we assessed the frequency of birth dates for boys selected for the Football Association National School. Birthdays were divided into three periods of the year: January to April, May to August and September to December. We compared data over a 5 year period and concluded that there is indeed a bias towards selecting older children. Furthermore, analysis of separate data revealed a shift of bias when comparing two different start dates, namely September and January. Our findings show that the youngest children from the January start date (born September to December) are selected significantly more often than the youngest children from the September start date (born May to August). Interestingly, even when the influence of body mass was reduced, the selection bias towards the older players remained.     

Women's football: Player characteristics and demands of the game

The number of scientific investigations on women's football specific to the topics of player characteristics and demands of the game has considerably increased in recent years due to the increased popularity of the women's game worldwide, although they are not yet as numerous as in the case of men's football. To date, only two scientific publications have attempted to review the main findings of studies published in this area. However, one of them was published about 20 years ago, when women's football was still in its infancy and there were only a few studies to report on. The other review was more recent. Nonetheless, its main focus was on the game and training demands of senior elite female players. Thus, information on female footballers of lower competitive levels and younger age groups was not included. Consequently, an updated review is needed in this area. The present article therefore aims to provide an overview of a series of studies that have been published so far on the specific characteristics of female football players and the demands of match-play. Mean values reported in the literature for age (12–27 years), body height (155–174 cm), body mass (48–72 kg), percent body fat (13%–29%), maximal oxygen uptake (45.1–55.5 mL/kg/min), Yo-Yo Intermittent Recovery Test Level 1 (780–1379 m), maximum heart rate (189–202 bpm), 30 m sprint times (4.34–4.96 s), and counter-movement jump or vertical jump (28–50 cm) vary mostly according to the players' competitive level and positional role. There are also some special considerations that coaches and other practitioners should be aware of when working with female athletes such as the menstrual cycle, potential pregnancy and lactation, common injury risks (particularly knee and head injuries) and health concerns (e.g., female athlete triad, iron deficiency, and anemia) that may affect players' football performance, health or return to play. Reported mean values for total distance covered (4–13 km), distance covered at high-speed (0.2–1.7 km), average/peak heart rate (74%–87%/94%–99% HR_max), average/peak oxygen uptake (52%–77%/96%–98% VO_2max), and blood lactate (2.2–7.3 mmol/L) during women's football match-play vary according to the players' competitive level and positional role. Methodological differences may account for the discrepancy of the reported values as well. Finally, this review also aims to identify literature gaps that require further scientific research in women's football and to derive a few practical recommendations. The information presented in this report provides an objective point of reference about player characteristics and game demands at various levels of women's football, which can help coaches and sport scientists to design more effective training programs and science-based strategies for the further improvement of players' football performance, health, game standards, and positive image of this sport.     

对中国足球协会会员协会实体化改革的研究

从如何进一步深化中国足球管理体制改革的角度出发，采用文献资料法、专家访谈法、比较研究法、逻辑推理法等社会学研究方法，深入细致了解了中国足球协会各会员协会发展现状，分析了中国足球协会会员协会实体化改革所取得的成绩和存在的问题，并结合国外足球协会管理经验，提出了我国足球协会实体化改革的发展对策。     

Activity profile and physical demands of football referees and assistant referees in international games

Abstract

Time-motion analyses and physiological measurements were performed to investigate the physiological demands of football referees (n = 15) and assistant referees (n = 15) in international games and to examine whether high-intensity running (HIR) correlates to the referees' ability to keep up with play. Total distance covered (10.27 ± 0.90 vs. 6.76 ± 0.83 km) and HIR (1.92 ± 0.58 vs. 0.97 ± 0.22 km) was higher (P < 0.05) for referees than assistant referees, while sprinting distance was not different. Referees covered 0.89 ± 0.37 km by backwards running and assistant referees covered 1.54 ± 0.66 km by sideways running. Mean heart rate was higher (P < 0.05) for referees than assistant referees (150 ± 3 vs. 123 ± 3 b.p.m.), whereas blood lactate was not different. Backwards/sideways running decreased (P < 0.05) from the first to the last 15-min period for referees (49%) and assistant referees (42%), whereas HIR was unaltered. HIR was inversely correlated with the five highest distances from infringements in both halves (r = ?0.60 and ?0.58, P < 0.05). In conclusion, international match officials carry out an important amount of HIR throughout games, while low-intensity and unorthodox running activities are reduced during games. Referees performing the most high-intensity work are better to keep up with play. The match activities differ significantly between referees and assistant referees, which should be considered in training and testing procedures.     

Worldwide regional variations in home advantage in association football

Abstract

Home advantage plays an important part in determining the result of a game of football. Its existence and magnitude is well documented in England, but its causes are still not completely understood. In this study, reliable estimates of home advantage are calculated for the domestic leagues of all countries of Europe and South America, as well as a selection of countries from other continents. The results of all games during the last six seasons are used for each of these 72 countries. In Europe, home advantage in the Balkan countries, especially Bosnia and Albania, is much higher than average. It is generally lower than average in northern Europe, from the Baltic republics, through Scandinavia to the British Isles. In South America, home advantage is high in the Andean countries and lower elsewhere, especially in Uruguay. Home advantage is not unusually high or low in any of the countries from other continents. A multiple regression model for the 51 European countries, which included variables for geographical location, crowd effects and travel, accounted for 76.7% of the variability in home advantage. The large geographical variations can be interpreted in terms of territoriality being a contributing factor to home advantage.     

Decision-making skills and deliberate practice in elite association football referees

We examined sport expertise as a function of role. In study 1, referees were better than players in a video-based decision-making task. This provides evidence that there are role-specific skills within one domain or sport. In study 2, we examined the training activities that could be influential in the development of skills in sports officials. Elite association football (soccer) referees retrospectively reported time spent in and perceptions of training activities for three periods: their first year of formal refereeing, 1998 (before formal training programmes were available), and the current year (2003). This allowed us to examine an area of skill with a limited culture of practice, where performance simulations with direct feedback are usually not feasible. The results showed that referees specialize early and, as they develop, they engage in greater volumes and types of training. Competitive match refereeing is considered a relevant activity for skill acquisition that does not fit Ericsson and colleagues' (1993) original definition of deliberate practice. Our findings indicate that actual performance is a significant activity for skill acquisition and refinement.