Soccer

This study compared the effects of whole body vibration (WBV) and a field-based re-warm-up during half-time (HT) on subsequent physical performance measures during a simulated soccer game. Ten semi-professional male soccer players performed 90-min fixed-intensity soccer simulations (SAFT 90 ), using a multi-directional course. During the HT period players either remained seated (CON), or performed intermittent agility exercise (IAE), or WBV. At regular intervals during SAFT 90 , vastus lateralis temperature (T m ) was recorded, and players also performed maximal countermovement jumps (CMJ), 10-m sprints, and knee flexion and extension contractions. At the start of the second half, sprint Scand J Med

PURPOSE: The purpose of this investigation was to quantify maximal aerobic power (VO2max) in soccer as a function of performance level, position, age, and time of season. In addition, the authors examined the evolution of VO2max among professional players over a 23-y period.METHODS: 1545 male soccer players (22 ± 4 y, 76 ± 8 kg, 181 ± 6 cm) were tested for VO2max at the Norwegian Olympic Training Center between 1989 and 2012.RESULTS: No differences in VO2max were observed among national-team players, 1st- and 2nd-division players, and juniors. Midfielders had higher VO2max than defenders, forwards, and goalkeepers (P < .05). Players <18 y of age had ~3% higher VO2max than 23- to 26-y-old players (P = .016). The players had 1.6% and 2.1% lower VO2max during off-season than preseason (P = .046) and in season (P = .021), respectively. Relative to body mass, VO2max among the professional players in this study has not improved over time. Professional players tested during 2006-2012 actually had 3.2% lower VO2max than those tested from 2000 to 2006 (P = .001).CONCLUSIONS: This study provides effect-magnitude estimates for the influence of performance level, player position, age, and season time on VO2max in men's elite soccer. The findings from a robust data set indicate that VO2max values ~62-64 mL · kg-1 · min-1 fulfill the demands for aerobic capacity in men's professional soccer and that VO2max is not a clearly distinguishing variable separating players of different standards.

Ferrete, C, Requena, B, Suarez-Arrones, L, and Sá ez de Villarreal, E. Effect of strength and high-intensity training on jumping, sprinting, and intermittent endurance performance in prepubertal soccer players. J Strength Cond Res 28(2): 413-422, 2014-The purpose of this study was to examine the effects of a 26-week on-field combined strength and high-intensity training on the physical performance capacity among prepubertal soccer players who were undertaking a competitive phase of training. Twenty-four prepubertal soccer players between the age of 8 and 9 years were randomly assigned to 2 groups: a control (C; n = 13) and an experimental group (S; n = 11). Both groups performed an identical soccer-training program, whereas the S group also performed combined strength and high-intensity training before the soccer-specific training. The 15-m sprint time (seconds), countermovement jump (CMJ) displacement, Yo-Yo intermittent endurance test (Yo-Yo IE), and Sit and Reach flexibility were each measured before (baseline) and after 9 (T2), 18 (T3), and 26 weeks (posttest) of training. There were no significant differences between the groups in any of the variables tested at baseline. After 26 weeks, significant improvements were found in the CMJ (6.72%; effect size [ES] = 0.37), Yo-Yo IE (49.57%, ES = 1.39), and Flexibility (7.26%; ES = 0.37) variables for the S group. Conversely, significant decreases were noted for the CMJ (210.82%; ES = 0.61) and flexibility (213.09%; ES = 0.94) variables in the C group. A significant negative correlation was found between 15-m sprint time and CMJ (r = 20.77) and Yo-Yo IE (r = 20.77) in the S group. Specific combined strength and high-intensity training in prepubertal soccer players for 26 weeks produced a positive effect on performance qualities highly specific to soccer. Therefore, we propose modifications to current training methodology for prepubertal soccer players to include strength and high-intensity training for athlete preparation in this sport.

The aim of the study was to determine the relationships between maximal oxygen uptake (VO(2max)) in a maximal treadmill run and the aerobic endurance performance in the 20-m multistage shuttle run (MST) test, with the performance indices obtained in the running repeated sprint ability (rRSA) test, in elite youth soccer players. Thirty-seven adolescent male outfield players performed on separate days and in random order the treadmill run test and the MST, to obtain their measured VO(2max) and aerobic endurance performance (via the number of completed shuttles in the MST), respectively. Players also completed the rRSA test of 6x20-m all-out sprints, interspersed with 20 s of active recovery. There was a significant moderate correlation between measured VO(2max) (in L . min(-1) and mL . kg(-1) . min(-1)) and MST results (r=0.43 and 0.54, P&lt;0.05, respectively). There was no significant correlation between measured VO(2max) and aerobic endurance performance with any of the performance...

The aim of this research is to understand the experience of the football sector on the use of artificial turf (satisfaction, safety, sporting feature, or the advantages and disadvantages). The study was conducted on a random selection of 627 male participants (404 amateur/semi-professional footballers, 101 coaches and 122 referees) that regularly train/compete on artificial turf in Spanish football leagues. The

The Oslo Sports Trauma Research Center (OSTRC) back injury prevention program (IPP) is an evidence-based injury prevention exercise designed to prevent back pain and other related injuries. The aim of this study was to assess the implementation of the OSTRC Back IPP among professional basketball, handball, soccer, and volleyball players in the Gulf Cooperation Council (GCC) countries. The survey was developed by the study authors and it consisted of two sections: the socio-demographic and questionnaire assess the implementation of OSTRC Back IPP. A total of 360 athletes responded to the survey (response rate was 93.75%). The mean (±SD) of the total implementation score was 6.6 (±1.8) out of 13. Jumping lunges exercise was the highest implemented exercise, making up 56.1% of the participated players, followed by the side plank and jump turns 53.3% and 53.1%, respectively. In contrast, the lowest implemented exercise was the rotational strength exercise which accounts for 46.4%. There were no statistically significant differences between the GCC countries in the implementation of all exercises except for the side lunges exercise. The rate of implementation of the OSTRC Back IPP among players was low in the GCC countries.

Objective The objective of this study is to describe the results of arthroscopic debridement for talar lesions in a population of soccer players. Patients Patients were sixteen soccer players with osteochondral talar lesions, treated surgically between 1999 and 2004. Interventions All patients were diagnosed clinically. Complementary imaging studies included X-ray, scintigraphy, and magnetic resonance imaging. All patients underwent arthroscopic debridement. Main outcome measurements At 3.56 years of follow up, patient status was assessed using a visual analog scale (VAS) and the Ogilvie-Harris scale. The mean time to return to sports at the same level as that before the start of symptoms was evaluated. Results The Ogilvie-Harris score showed 81.75% excellent results and 18.25% good results. The VAS score was 0.26 (0-2.2). Among the total, 93.75% of patients resumed sports activities at the same level as that before surgery. Conclusions Arthroscopic debridement of talar osteochondral lesions in soccer players provides excellent results. We consider this option the treatment of choice in this population.

The primary purpose of this study was to investigate the strength and anthropometric characteristics of elite and semi-elite tenpin bowlers as compared to non-bowlers, and to establish whether it was possible to discriminate playing level through selected predictor variables. Elite and semi-elite bowlers were distinguished by their bowling score average (BS ave), with participants scoring 200 pin falls and above assigned to the elite group. Eighteen elite bowlers (M=10, F=8; BS ave 213.2± 6.80), 12 semi-elite bowlers (M=7, F=5; BS ave 181.3± 9.36) and 33 sedentary university students (M=14, F=19) were recruited. Anthropometric measurements were taken and isometric arm strength was recorded. Between-group differences were identified through a two-way ANOVA, while discriminant analysis was used to predict group membership. For anthropometric characteristics, the results indicated that the elite bowlers were heavier, had longer lower leg and hand length and had a wider arm span as compared to the non-bowlers. The elite group also had stronger forearm/wrist internal rotation compared to non-bowlers. In addition, the male elite group were stronger than the non-bowling group for arm flexion. There appeared to be a 54% success rate for predicting group membership from selected anthropometric and strength discriminating variables, with forearm/wrist internal rotation strength being the best discriminating variable. It is suggested that coaches should benefit by selecting larger built bowlers with long limbs. Furthermore, bowlers could potentially gain by paying extra attention to increasing the strength levels of forearm/wrist internal rotators and arm flexors during training. These findings also provide normative data for elite and semi-elite bowlers.

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Carbohydrate and caffeine are known to independently improve certain aspects of athletic performance. However, less is understood about physiological and performance outcomes when these compounds are coingested in a rehydration and carbohydrate-replacement strategy. The aim of this study was to examine the influence of adding a moderate dose of caffeine to a carbohydrate solution during prolonged soccer activity. Fifteen male soccer players performed two 90-min intermittent shuttle-running trials. They ingested a carbohydrate-electrolyte solution (CON) providing a total of 1.8 g/kg body mass (BM) of carbohydrate or a similar solution with added caffeine (CAF; 3.7 mg/kg BM). Solutions were ingested 1 hr before exercise and every 15 min during the protocol. Soccer passing skill and countermovement-jump height (CMJ) were quantified before exercise and regularly during exercise. Sprinting performance, heart rate, blood lactate concentration (La) and the subjective experiences of partici...

Due to increasing prevalence of the COVID-19 virus, athletes were unable to train optimally. This study aimed to determine the differences in aerobic capacity, body mass, and body mass index in soccer players as the effect of lockdown due to the COVID-19 pandemic. Methodology: Fourteen male participants were recruited from the university soccer team. Anthropometric characteristics were as follows: age = 20.75 ± 1.48 years, height = 174.35 ± 5.59 cm, body mass = 68.95 ± 6.17 kg, and body mass index = 21.92 ± 0.94 kg/m 2. Single-group pretest and posttest designs were selected to conduct this study. A multistage fitness test determined aerobic capacity. ANOVA test was used to identify aerobic capacity, body mass, and body mass index differences between pretest and posttest on university soccer players. Results: The pretest and posttest were similar in anthropometric characteristics, and there were no significant differences in age (P = 0.382), height (P = 0.106), and body mass (P = 0.068). Our findings showed significant differences between pretest and posttest for aerobic capacity (P = 0.042) and body mass index (P = 0.037) in university soccer players. Conclusion: We conclude that there was a significant effect of the COVID-19 pandemic on the soccer player's aerobic capacity and body mass index. These findings may have implications, namely, as functional test's organization, administration, and outcomes while testing the players. Team coaches, trainers, and physiologists must consider the effects of lockdown on the players' performance while preparing players for competition. Further researchers should be established to modify other types of tests, conduct studies with a larger sample and population, and add other variables.

Nicholas Blincoe’s More Noble Than War: A Soccer History of Israel-Palestine (Bold Type Books, 2019) is a beautifully narrated and written history of a century of conflict between pre-state Jews and Palestinians and Israeli Jews and Israeli Palestinians after the establishment of the state. It is a story that goes far beyond the history of the conflict, the mirror images of developments in Jewish and Palestinian society, and the internecine ideological infighting and power struggles within the two communities. It paints in graphic detail the incestuous and inseparable relationship between sports and politics and the importance of soccer, particularly in the Middle East and North Africa, in identity and nation formation as well as nation building. It also demonstrates in graphic detail how first Jews and then Palestinians exploited soccer to first achieve international recognition of their struggles and then as nations by dispatching teams to tour other countries and being granted membership in world soccer body FIFA. In doing so, Israelis and Palestinians set an example that decades later became a key pillar of the Algerian liberation struggle in the 1950s and 1960s with the National Liberation Front (FLN)’s creation of its own national soccer team that put its fight for independence on the world map. The skeletal facts of Blincoe’s tale have long been known. The significance of Blincoe’s contribution is that he puts flesh on the skeleton by weaving the facts into a meticulously researched and reported, easily accessible narrative in which he brings key players and ideological trends to life. It’s a tale that is all fact but reads like a thriller.

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A developmental model of subjective group dynamics suggests that social identity is sustained first by intergroup biases and later by intragroup biases. In this study 476 English children 5 to 11 years old evaluated the English and German soccer teams, and judged in-group or out-group members whose attitudes toward the teams was normative versus antinormative. Children of all ages expressed intergroup bias. Differential evaluation against in-group deviants and in favor of out-group deviants strengthened with age. Understanding of targets' relative acceptability (differential inclusion) among in-group and out-group members mediated the effects of age and intergroup bias on intragroup bias. Identification with the in-group moderated the effects only among older children.

Este trabalho propõe um estudo contextual das crônicas do Jornal dos Sports acerca da atuação da seleção brasileira nas Copas do Mundo de Futebol realizadas na década de 1950. O sentido em analisar o discurso dos cronistas sobre a participação do Brasil nas Copas ocorridas durante a década de 1950 é o de procurar entender como a interseção entre o contexto político nacional, jornalismo, identidade e futebol colaborou na construção discursiva de um imaginário acerca da seleção e da nação. Com esta investigação, que levou em consideração para a análise questões estruturais mais amplas do campo político e midiático tensionadas pela autonomia discursiva dos cronistas, foi possível compreender que a relevância que ainda hoje é dada a uma ou outra participação do selecionado nas Copas realizadas na década de 1950 está, entre outros motivos, relacionada ao imaginário construído por estas crônicas, que produziram sentidos que vem sendo herdados de geração em geração.

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Deception remains a hotly debated topic in evolutionary and behavioural research. Our understanding of what impedes or facilitates the use and detection of deceptive signals in humans is still largely limited to studies of verbal deception under laboratory conditions. Recent theoretical models of non-human behaviour have suggested that the potential outcome for deceivers and the ability of receivers to discriminate signals can effectively maintain their honesty. In this paper, we empirically test these predictions in a real-world case of human deception, simulation in soccer. In support of theoretical predictions in signalling theory, we show that cost-free deceit by soccer players decreases as the potential outcome for the signaller becomes more costly. We further show that the ability of receivers (referees) to detect deceptive signals may limit the prevalence of deception by soccer players. Our study provides empirical support to recent theoretical models in signalling theory, and identifies conditions that may facilitate human deception and hinder its detection.

The present study investigated whether football has favorable effects in the treatment of mild-to-moderate arterial hypertension in untrained middle-aged men. Twenty-five untrained males aged 31-54 year with mild-to-moderate hypertension were randomized to a football training group (FTG, two 1-h sessions per week) and a control group receiving physician-guided traditional recommendations on cardiovascular risk factor modification (doctoral advice group, DAG). After 3 months, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were lowered (Po0.05) by 12 AE 3 and 7 AE 1 mmHg in FTG, respectively, whereas no significant changes were observed for DAG, with the 3 months values being lower (Po0.05) in FTG than DAG (SBP: 138 AE 2 vs 148 AE 2 mmHg; DBP: 84 AE 2 vs 92 AE 2 mmHg). The resting heart rate was lowered (Po0.05) by 12 AE 2 b.p.m. in FTG after 3 months (67 AE 3 vs 79 AE 3 b.p.m.), whereas no change was observed for DAG. After 3 months, FTG had higher (Po0.05) VO 2max (8 AE 2%; 35.0 AE 1.6 vs 32.5 AE 1.3 mL/min/kg) and lower (Po0.05) fat mass (1.7 AE 0.6 kg), whereas no change was observed for DAG. In conclusion, football training is an attractive non-pharmacological supplement to the treatment of mild-to-moderate arterial hypertension in untrained middle-aged men.

The aim of the present study was to examine the influence of first half activity, overall match intensity and seasonal variation on the physical match performances of English Premier League football referees. Match analysis data was collected using the Prozone ® match analysis system from 19 fulltime professional referees during a total of 254 matches in the 2004-2005 season. Physical match performances were classified into three separate categories: 1, total distance covered (TD); 2, high-intensity running distance (running speed > 5.5 m/s, HIR); 3, average distance from infringements (DI). Using these match activity variables the influence of first half TD and HIR distances on second half activities and also the influence of players' match activities upon the referees' physical match performances were examined. The main finding of the present study was that the physical match performances of the referees were partly related to those of the players, in that the referees' HIR correlated with players' HIR (r = 0.43, p < 0.0001, n = 212). Furthermore, first half TD and HIR distances were found to be related to second half coverage in referees (r = 0.47 and r = 0.52, respectively, p < 0.001, n = 254). These results demonstrate a need to assess the overall match intensity prior to examining the physical match performance of the referee. Further examination is required as to whether reduced physical performances in the second half of matches are a consequence of referee fatigue, tactical strategies on behalf of the referee or reduced player match activities resulting in a slower tempo of match.

Young soccer players are usually trained with adult-training methods, even though the physiological adaptations are likely to be very different compared with adults. In contrast, some have suggested training preadolescents only with coordination training. The purpose of this study was to investigate whether coordination or repeated-sprint training better improved speed over 20 m, with and without the ball. Sixteen soccer players (mean age 11+/-0.5 y) were randomly assigned to a sprint-training group (STG=7) or a coordination-training group (CTG=9). The STG trained twice a week for 12 wk and performed 20 repetitions of 20- and 10-m sprints; the CTG performed coordination training (eg, speed ladder running) for the same training duration. Maximal jump height, anthropometric measures, and 20-m sprint time, with and without ball, were evaluated before and after the training period. Statistical significance was determined using two-way ANOVA with repeated measure and Pearson test for cor...

Pain thresholds and levels of distress before and in the early postoperative period after anterior cruciate ligament surgery were measured in professional and amateur male soccer players and compared. Between June 2005 and March 2007, 30 soccer players (10 amateur, 20 professional) with acute or chronic tears of the anterior cruciate ligament who were scheduled for a bone-tendon-bone ACL reconstruction procedure were enrolled in the study. Measures of pain intensity, depression and anxiety were assessed 1 day pre-operation and 1 week and 3 weeks post-operation (T1 T2 and T3). Pain was assessed using a visual analog scale (VAS), depression with the Beck Depression Inventory (BDI), and anxiety with both the state and trait forms of the State-Trait Anxiety Inventory (STAI). Scores on the VAS, BDI, and STAI in both groups were analyzed. The mean VAS scores at T1 and T2 in professional players were not significantly higher than those in amateur players (P N 0.05). Professionals had significantly higher BDI scores at T1 and T2 (P b 0.05), but this difference was not significant at T3 (P = 0.12). High depression scores did not correlate with high pain scores.

Background: To investigate the effects of a caffeine-containing energy drink on soccer performance during a simulated game. A second purpose was to assess the post-exercise urine caffeine concentration derived from the energy drink intake. Methodology/Principal Findings: Nineteen semiprofessional soccer players ingested 630652 mL of a commercially available energy drink (sugar-free Red BullH) to provide 3 mg of caffeine per kg of body mass, or a decaffeinated control drink (0 mg/kg). After sixty minutes they performed a 15-s maximal jump test, a repeated sprint test (7630 m; 30 s of active recovery) and played a simulated soccer game. Individual running distance and speed during the game were measured using global positioning satellite (GPS) devices. In comparison to the control drink, the ingestion of the energy drink increased mean jump height in the jump test (34.764.7 v 35.865.5 cm; P,0.05), mean running speed during the sprint test (25.662.1 v 26.361.8 km ? h 21 ; P,0.05) and total distance covered at a speed higher than 13 km ? h 21 during the game (12056289 v 14366326 m; P,0.05). In addition, the energy drink increased the number of sprints during the whole game (30610 v 2468; P,0.05). Post-exercise urine caffeine concentration was higher after the energy drink than after the control drink (4.161.0 v 0.160.1 mg ? mL 21 ; P,0.05). Conclusions/significance: A caffeine-containing energy drink in a dose equivalent to 3 mg/kg increased the ability to repeatedly sprint and the distance covered at high intensity during a simulated soccer game. In addition, the caffeinated energy drink increased jump height which may represent a meaningful improvement for headers or when players are competing for a ball.

The popularity and professionalism of female soccer has increased markedly in recent years, with elite players now employed on either a professional or semi-professional basis. The previous review of the physiological demands of female soccer was undertaken two decades ago when the sport was in its relative infancy. Increased research coupled with greater training and competition demands warrants an updated review to consider the effect on physical performance and injury patterns. The physical demands of match-play along with the influence of factors such as the standard of competition, playing position and fatigue have been explored. Total distance covered for elite female players is approximately 10 km, with 1.7 km completed at high-speed (>18 km.h -1 ). Elite players complete 28% more high-speed running and 24% more sprinting than moderate level players. Decrements in high-speed running distance have been reported between and within halves, which may indicate an inability to maintain highintensity activity. Although physical capacity of female players is the most thoroughly researched area comparisons are difficult due to differing protocols. Elite players exhibit maximal oxygen uptake (VO2max) values of 49.4 -57.6 ml.kg -1 .min -1 , Yo Yo Intermittent Endurance test level 2 (YYIE2) scores of 1774 ± 532 m (mean ± SD) and 20 m sprint times of 3.17 ± 0.03 s (mean ± SD). Reasons for the increased prevalence of anterior cruciate ligament injuries in females (2-6 times greater than males) are discussed with anatomical, biomechanical loading and neuromuscular activation differences being cited in the literature. This review presents an in-depth contemporary examination of the applied physiology of the female soccer player.

The top players in an elite soccer team volunteered as subjects in a study to determine intramuscular glycogen concentrations after a regular season match, and whether optimal glycogen levels could be re-attained prior to the team's next match. Fifteen players were biopsied in the M. vastus lateralis following a regular season game (Day I). Of these, eight were biopsied 24 h later in the evening of a free day during which no training session was held (Day II), and again 24 h later after a very light training session (Day III). Muscle glycogen concentrations for the eight players averaged (+ SD) 45.9 + 7.9, 68.9 + 2.7, and 72.8 + 8.3 mmol glucose units x kg -1 wet muscle weight on Day I, Day II, and Day III respectively. Dietary records were analysed during a week of peak season competition and training. The average daily total energy consumption and total quantity of carbohydrates consumed were less than what is normally consumed by athletes in similar sports. The inability of the players to maintain even normal, resting levels of muscle glycogen is probably related to their dietary practices.

Konrad Heitkamp was taken aback by the extraordinary ordinariness present in the lobby of the Zurich hotel. In November of 1943, life in Zurich seemed unperturbed by the fact that the countries surrounding Switzerland were embroiled in one of the most devastating wars in the history of the world. Heitkamp realized that as the coach of the FC Bayern München soccer team, he was one of the privileged few who could bask in this oasis of normalcy for a few days before he would have to head back home to Munich. He surveyed the lobby and began waving his hand at some of his players standing across the vestibule. Hopefully, the Gestapo men watching him thought of this as an innocuous gesture, a soccer team coach acknowledging the arrival of his players and performing a headcount. But he could not bank on it.

Purpose: This study aimed to examine changes in sagittal (APLAX), frontal (VVLAX), and transverse (IERLAX) plane knee laxity in men and women during an intermittent exercise protocol (IEP) simulating the intensity and duration of a soccer match.

Studies regarding ankle and foot overuse injuries are quite diverse in research methodology, data reporting, and outcomes. The aims of this systematic review were to analyze the methodology of published studies regarding ankle and foot overuse injuries in different sports disciplines and to summarize epidemiological data of ankle and foot overuse injuries. Four electronic databases, PubMed (MEDLINE), EMBASE, CINAHL, and SPORTDiscus(®) were systematically searched up to June 2011. A total of 89 articles on 23 sports disciplines were included in this review. Soccer, running, and gymnastics were the most frequently studied sports. Achilles tendinopathy, plantar fasciitis, and stress fracture were the most frequently studied injuries. Study design and reporting methods were heterogeneous. Most studies suffered from a weak methodology and poor reporting. The most common weaknesses were lack of a clear case definition, describing assessment procedures and reporting sample characteristics....

Introduction: The aim of this study was to determine if using a direct kinematic (DK) or inverse kinematic (IK) modelling approach can influence the estimation of knee joint kinematics, kinetics and ACL injury risk classification during unanticipated side-cutting. Methods: Three-dimensional motion and force data of 34 amateur Australian rules footballers conducting unanticipated side-cutting manoeuvres were collected. The model used during the DK modelling approach was an eight segment lower body model with the hip, knee and ankle free to move in six degrees-of-freedom. During the IK modelling approach the same eight segment model was used, however translational constraints were imposed on the hip, knee and ankle joints. The similarity between kinematic and kinetic waveforms was evaluated using root mean square error and one-dimensional statistical parametric mapping (SPM1D). Classification of an athlete's ACL injury risk was determined by correlating their peak knee moments with a pre-defined injury risk threshold. Results: The greatest RMSE occurred in the frontal plane joint angles (RMSE: 10.86) and moments (RMSE: 0.67±0.18 N·m·kg -1 ), which were also shown to be significantly different in the SPM1D analysis. Both DK and IK modelling approaches classified the same athletes as being at 'high risk' of ACL injury. Conclusions: The choice of a DK or IK modelling approach affected frontal plane estimates of knee joint angles and peak knee moments during the weight acceptance phase of unanticipated side-cutting. However, both modelling approaches were similar in their classification of an athlete's ACL injury risk.

The physiological characteristics of football referees have received an increasing amount of focus in the scientific literature over the past decade. Studies have examined referee profiles, both physiological and anthropometric, 19 as well as the movement patterns and physiological load experienced during actual match play. Match analysis by D'Ottavio and Castagna 7 demonstrated that referees cover a mean ± SD distance, over the course of an average 95-minute match, of 11469 ± 983 m, with walking constituting 957 m, 4174 m of low-intensity running, 2585 m of medium-intensity running, and a total of 1556 m of highintensity running. Running at maximal speed accounted for 608 m, and nonorthodox directional modes-that is, sideways and backward running-accounted for 181 m and 1315 m, respectively. 7 Heart rate recordings collected during matches demonstrated that the mean cardiovascular strain imposed on referees during match is approximately 85% of maximal heart rate (HR max ). 9,11,21 However, as referees have been reported to spend approximately 75% of their total match time either standing, walking, or jogging, 11 the amount of high-intensity activity, performed at speeds of more than 15 km/hour during a match, is a better indicator of the physical demands of matches. Given the high physical load imposed on top-class referees during actual match play, 7,9,11 fitness levels need to be sufficient enough for the referees to be able to cope with the demands of their games through keeping up with play at all times and ensuring optimal viewing positions. This in itself is a challenge. However, when combined with the fact that referees are on average 10 to 15 years older than their playing counterparts 6,7,9 and aging has a negative effect on fitness levels, 20,23 referees have to work extremely hard in training to ensure that they attain, and maintain, an appropriate level of fitness. Also, in most countries referees Background: In comparison to the amount of literature that has examined the match demands of football refereeing, there has been little attempt to assess the impact of high-intensity training.

The soccer ''penalty shootout'' in the knock-out phase of major international tournaments is one of the most dramatic events in international soccer. The outcome of these kicks is typically attributed to factors such as psychology (e.g. coping with stress), skill (e.g. kicking technique), physiology (e.g. overcoming the fatigue of 120 min play), and chance (e.g. in what direction the goalkeeper moves). The purpose of this study was to use internet game record data to estimate the relative importance of these performance components for the outcome of penalty kicks in international matches. Data were collected from soccer statistics internet sites on all 41 penalty shootouts and 409 kicks taken in the World Cup, European Championships, and Copa America between 1976 and 2004. The results showed that the importance of the kicks (indicative of stress) was negatively related to the outcomes of the kicks, whereas skill and fatigue were less, or not, related to outcome. It was concluded that psychological components are most influential for the outcome of penalty kicks. We recommend that practitioners work with players to reduce the perceived importance of each kick.

Sports Geographer BJ Pheasant has calculated the ratios of needed incoming male college freshman soccer players versus the number of 12th grade boys soccer players in each state. The ratio shows the number of players from each U18 club team needed to play in college soccer to fill the incoming freshman class in each state. 

The calculations use data from the US Census Bureau, USYS, NCAA, NAIA and Gotsoccer among others in its research.