Latest research in football - week 5 - 2014

Latest research in football

As previous literature updates, we have performed a PubCrawler search looking for football articles in NCBI Medline (PubMed) and GenBank databases.

Following studies were retrieved for this week:


#1 Neck strength imbalance correlates with increased head acceleration in soccer heading
Authors: Dezman ZD, Ledet EH, Kerr HA.
Reference: Sports Health. 2013 Jul;5(4):320-6. doi: 10.1177/1941738113480935.
Summary: Soccer heading is using the head to directly contact the ball, often to advance the ball down the field or score. It is a skill fundamental to the game, yet it has come under scrutiny. Repeated subclinical effects of heading may compound over time, resulting in neurologic deficits. Greater head accelerations are linked to brain injury. Developing an understanding of how the neck muscles help stabilize and reduce head acceleration during impact may help prevent brain injury. It was hypothesized that neck strength imbalance correlates to increasing head acceleration during impact while heading a soccer ball. Sixteen Division I and II collegiate soccer players headed a ball in a controlled indoor laboratory setting while player motions were recorded by a 14-camera Vicon MX motion capture system. Neck flexor and extensor strength of each player was measured using a spring-type clinical dynamometer.  Players were served soccer balls by hand at a mean velocity of 4.29 m/s (±0.74 m/s). Players returned the ball to the server using a heading maneuver at a mean velocity of 5.48 m/s (±1.18 m/s). Mean neck strength difference was positively correlated with angular head acceleration (rho = 0.497; P = 0.05), with a trend toward significance for linear head acceleration (rho = 0.485; P = 0.057). This study suggests that symmetrical strength in neck flexors and extensors reduces head acceleration experienced during low-velocity heading in experienced collegiate players. Balanced neck strength may reduce head acceleration cumulative subclinical injury. Since neck strength is a measureable and amenable strength training intervention, this may represent a modifiable intrinsic risk factor for injury.

#2 Case-Study: Muscle Atrophy and Hypertrophy in a Premier League Soccer Player During Rehabilitation From ACL Injury
Authors: Milsom J, Barreria P, Burgess DJ, Iqbal Z, Morton JP.
Reference: Int J Sport Nutr Exerc Metab. 2014 Jan 17. [Epub ahead of print]
Summary: The onset of injury and subsequent period of immobilisation and disuse present major challenges to maintenance of skeletal muscle mass and function. Although the characteristics of immobilisation-induced muscle atrophy are well documented in laboratory studies, comparable data from elite athletes in free-living conditions are not readily available. We present a six-month case-study account from a professional soccer player of the English Premier League characterising rates of muscle atrophy and hypertrophy (as assessed by DXA) during immobilisation and rehabilitation after ACL injury. During 8 weeks of inactivity and immobilisation (where the athlete adhered to a 'low carbohydrate-high protein diet'), total body mass decreased by 5 kg attributable to 5.8 kg loss and 0.8 kg gain in lean and fat mass, respectively. Changes in whole body lean mass was attributable to comparable relative decreases in the trunk (12%, 3.8 kg) and immobilised limb (13%, 1.4 kg) whereas the non-immobilised limb exhibited smaller declines (7%, 0.8 kg). In weeks 8-24, the athlete adhered to a 'moderate carbohydrate-high protein diet' combined with structured resistance and field based training for both the lower and upper body that resulted in whole body muscle hypertrophy (varying from 0.5-1 kg per week). Regional hypertrophy was particularly pronounced in the trunk and non-immobilised limb during weeks 8-12 (2.6 kg) and 13-16 (1.3 kg), respectively, whereas the previously immobilised limb exhibited slower but progressive increases in lean mass from week 12-24 (1.2 kg). The athlete presented after the totality of the injured period with an improved anthropometrical and physical profile.

#3 The effects of exertion on the postural stability in young soccer players
Authors: Arliani GG1, Almeida GP1, Dos Santos CV2, Venturini AM1, Astur Dda C1, Cohen M1.
Reference: Acta Ortop Bras. 2013 May;21(3):155-8. doi: 10.1590/S1413-78522013000300005.
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Summary: The purpose was to analyze the effects of physical exertion during a soccer match on the functional capacity and stability of the lower limbs of young soccer players. We analyzed 10 soccer players who underwent functional capacity assessment of the lower limbs by a Hop Test protocol and evaluation of the level of postural stability in the Biodex Stability System (Biodex, Inc., Shirley, NY) before and immediately after a friendly game lasting 45 minutes.  After the match, there was a decrease in overall stability index (F(1,23) = 7.29 P = .024) and anterior posterior index (APSI) (F(1,23) = 5.53 P = .043). Fatigue in the dominant limb was responsible for the significant deficit in OSI (F(1,23) = 3.16, P = .047) and APSI (F(1,23) = 3:49, P = .029), while the non-dominant limb did not cause any change in the pre and post-game. A football match can cause decreased stability and functional capacity of the lower limbs in young players. Level of Evidence III, Pre-test and Post-test Study (Case-control) .

#4 High intensity training and salivary immunoglobulin-a response in professional top-level soccer players: Effect of training intensity
Authors: Owen AL, Wong DP, Dunlop G, Groussard C, Kebsi W, Dellal A, Morgans R, Zouhal H.
Reference: J Strength Cond Res. 2014 Jan 19. [Epub ahead of print]
Summary: This study aimed 1)- to test the hypothesis that salivary immunoglobulin A (s-IgA) would vary with training intensity sessions (low intensity [LI] vs. high intensity sessions [HI]) during a traditional training program divided in 4 training periods and 2)- to identify key variables (e.g. GPS data, RPE, training duration) which could affect s-IgA.Saliva samples of 10 elite professional soccer players were collected a)- before the investigation started to establish the baseline level, b)-before and after each 4 training sessions (LI vs. HI). Training intensity was monitored as internal (via heart rate responses and RPE) and external (via GPS) loads.HI sessions were associated with higher external load (GPS) and with higher RPE. Baseline and Pre-Training s-IgA did not differ between the 4 training sessions both for HI and LI. Post-Training s-IgA were not different (in absolute value and in percentage of change) between HI and LI sessions at the first three periods. However, at the fourth period, s-IgA concentration for HI session was significantly lower (p<0.05) than the LI session. The percentage change between s-IgA post-training and s-IgA baseline concentrations differ significantly (p<0.05) between HI and LI training sessions. Significant correlations between s-IgA and training intensity were also noted. HI soccer training sessions might cause a significant decrease in s-IgA values during the post-exercise window as compared with LI sessions. This study encourages coaches to monitor s-IgA in routine particularly during HI training periods to take precautions to avoid upper respiratory tract infection in highly trained soccer players.

#5 Concussion Among Female Middle-School Soccer Players
Authors: O'Kane JW, Spieker A, Levy MR, Neradilek M, Polissar NL, Schiff MA.
Reference: JAMA Pediatr. 2014 Jan 20. doi: 10.1001/jamapediatrics.2013.4518. [Epub ahead of print]
Summary: Despite recent increased awareness about sports concussions, little research has evaluated concussions among middle-school athletes. The purpose of the study was to evaluate the frequency and duration of concussions in female youth soccer players and to determine if concussions result in stopping play and seeking medical care. 4 soccer clubs from the Puget Sound region of Washington State, involving 351 elite female soccer players, aged 11 to 14 years, from 33 randomly selected youth soccer teams participated in this study. Of the players contacted, 83.1% participated and 92.4% completed the study. Concussion cumulative incidence, incidence rate, and description of the number, type, and duration of symptoms were used as outcome measures. We inquired weekly about concussion symptoms and, if present, the symptom type and duration, the event resulting in symptom onset, and whether the player sought medical attention or played while symptomatic. RESULTS Among the 351 soccer players, there were 59 concussions with 43 742 athletic exposure hours. Cumulative concussion incidence was 13.0% per season, and the incidence rate was 1.2 per 1000 athletic exposure hours (95% CI, 0.9-1.6). Symptoms lasted a median of 4.0 days (mean, 9.4 days). Heading the ball accounted for 30.5% of concussions. Players with the following symptoms had a longer recover time than players without these symptoms: light sensitivity (16.0 vs 3.0 days, P = .001), emotional lability (15.0 vs 3.5 days, P = .002), noise sensitivity (12.0 vs 3.0 days, P = .004), memory loss (9.0 vs 4.0 days, P = .04), nausea (9.0 vs 3.0 days, P = .02), and concentration problems (7.0 vs 2.0 days, P = .02). Most players (58.6%) continued to play with symptoms, with almost half (44.1%) seeking medical attention. Concussion rates in young female soccer players are greater than those reported in older age groups, and most of those concussed report playing with symptoms. Heading the ball is a frequent precipitating event. Awareness of recommendations to not play and seek medical attention is lacking for this age group.

#6 Detraining in young soccer players
Authors: Melchiorri G, Ronconi M, Triossi T, Viero V, De Sanctis D, Tancredi V, Salvati A, Padua E, Alvero Cruz JR

Reference: J Sports Med Phys Fitness. 2014 Feb;54(1):27-33.
Summary: Background: Two types of detraining can be described: short-term detraining with a period of less than 4 weeks, and long-term detraining (period longer than 4 weeks). The purpose of this study is to verify the presence and eventually the magnitude of physiological cardiorespiratory changes in young team sport players after a period of long-term detraining. Methods: Fourteen young soccer players (15±1 year) were studied with two incremental tests at the end of the regular season and after a six-week total break period from training activities. Physiological variables were evaluated: heart rate (HR), oxygen uptake (VO2), volume of ventilation (VE), aerobic (VA) and anaerobic (Van) running speed at thresholds and maximum effort were recorded. Results: This study shows the magnitude of the physiological changes in young players after a period of long-term detraining. The results showed significant decreases at the end of the detraining period of VO2 at VA of 22.7% (44.54±4.56 vs. 34.41±4.57 mL/kg/min, P<0.05), of 25.8% of VO2 at VAn (54.60±5.81 vs. 40.48±5.07 mL/kg/min, P<0.05) and of 21.2% in VO2max (62.83±5.77 vs. 49.46±6.51 mL/kg/min, P<0.05). Speed at VA (11.5±0.96 vs. 10.7±0.97 km/h; P<0.05), speed at VAn (15.3±1.05 vs. 14.2±1.48 km/h; P<0.05), peak running speed (18.8±1.20 vs. 17.2±1.1 km/h; P<0.05). Conclusion: It is likely that alteration of metabolic parameters may significantly affect the range of physical condition and especially, aerobic-anaerobic resistance and maintenance training would be advisable in young athletes during the transition period. Given the relevance of worsening demonstrated by our data, coaches should avoid very long periods of complete rest (no more than 15 days) at the end of the season.

#7 Association between traditional standing vertical jumps and a soccer-specific vertical jump
Authors: Requena B, Garcia I, Requena F, Bressel E, Saez-Saez de Villarreal E, Cronin J.
Reference: Eur J Sport Sci. 2014 Jan;14 Suppl 1:S398-405. doi: 10.1080/17461391.2012.708790. Epub 2012 Jul 27.
Summary: The present study aimed to determine the relationships between a soccer-specific vertical jump (ssVJ) test, that included common elements of a soccer VJ (e.g. run-up and intention to head), and three traditional VJ tests using elite soccer players. A secondary purpose of this study was to determine the reliability of the VJs used in the analysis. A randomised order and counterbalanced design was used to assess the relationships between these VJs [countermovement jump (CMJ), drop jump for height (DJh), drop jump for maximum height and minimum ground contact time (DJh/t) and the ssVJ]. Take-off velocity, contact time and flight time were the dependent variables of interest and compared between jumps. Intra-class correlation coefficient (ICC) and coefficient of variation (CV) were used as measures of inter-session reliability. All VJ tests were found to have high ICCs (0.89-0.99) and acceptable within-subject CVs (<7.5%). All the ssVJ dependent variables were not significantly related (r<0.44) with similar variables from the CMJ and DJh tests and only moderately related (r=~0.49) with the DJh/t test variables. In addition, the DJh/t variables were not significantly correlated (r<0.47) with DJh and CMJ test variables. In conclusion, it would seem that the proposed ssVJ test and CMJ or DJh tests assess different leg qualities and thought should be given before using them interchangeably to assess or develop the same performance measures (i.e. velocity at take-off or jump height).

#8 Long-Term Practice Induced Plasticity in the Primary Motor Cortex Innervating the Ankle Flexor in Football Juggling Experts
Authors: Hirano M, Kubota S, Morishita T, Uehara K, Fujimoto S, Funase K.
Reference: Motor Control. 2014 Jan 21. [Epub ahead of print]
Summary: The aim of this study was to investigate the plasticity of M1 innervating the tibialis anterior muscle (TA) induced by the long-term practice of football juggling using a transcranial magnetic stimulation (TMS) technique. Ten football juggling experts and ten novices participated in this study. Motor evoked potentials (MEP) and the H-reflex were recorded from the right TA during isometric dorsiflexion at 10% of maximum voluntary contraction. The MEP input-output curve of the experts was steeper than that of the novices, and reduced short-interval intracortical inhibition and long-interval intracortical inhibition were observed in the experts. In contrast, the ratio of Hmax to Mmax did not differ between the groups. Our results show that football juggling experts displayed enhanced excitability in the M1 innervating the TA, which was induced by the long-term practice of the ankle movements required to perform football juggling well.

#9 A gender-sensitised weight loss and healthy living programme for overweight and obese men delivered by Scottish Premier League football clubs (FFIT): a pragmatic randomised controlled trial
Authors: Hunt K, Wyke S, Gray CM, Anderson AS, Brady A, Bunn C, Donnan PT, Fenwick E, Grieve E, Leishman J, Miller E, Mutrie N, Rauchhaus P, White A, Treweek S.
Reference: Lancet. 2014 Jan 20. pii: S0140-6736(13)62420-4. doi: 10.1016/S0140-6736(13)62420-4. Summary: The prevalence of male obesity is increasing but few men take part in weight loss programmes. We assessed the effect of a weight loss and healthy living programme on weight loss in football (soccer) fans. We did a two-group, pragmatic, randomised controlled trial of 747 male football fans aged 35-65 years with a body-mass index (BMI) of 28 kg/m2 or higher from 13 Scottish professional football clubs. Participants were randomly assigned with SAS (version 9·2, block size 2-9) in a 1:1 ratio, stratified by club, to a weight loss programme delivered by community coaching staff in 12 sessions held every week. The intervention group started a weight loss programme within 3 weeks, and the comparison group were put on a 12 month waiting list. All participants received a weight management booklet. Primary outcome was mean difference in weight loss between groups at 12 months, expressed as absolute weight and a percentage of their baseline weight. Primary outcome assessment was masked. Analyses were based on intention to treat. The trial is registered with Current Controlled Trials, number ISRCTN32677491. 374 men were allocated to the intervention group and 374 to the comparison group. 333 (89%) of the intervention group and 355 (95%) of the comparison group completed 12 month assessments. At 12 months the mean difference in weight loss between groups, adjusted for baseline weight and club, was 4·94 kg (95% CI 3·95-5·94) and percentage weight loss, similarly adjusted, was 4·36% (3·64-5·08), both in favour of the intervention (p<0·0001). Eight serious adverse events were reported, five in the intervention group (lost consciousness due to drugs for pre-existing angina, gallbladder removal, hospital admission with suspected heart attack, ruptured gut, and ruptured Achilles tendon) and three in the comparison group (transient ischaemic attack, and two deaths). Of these, two adverse events were reported as related to participation in the programme (gallbladder removal and ruptured Achilles tendon). The FFIT programme can help a large proportion of men to lose a clinically important amount of weight; it offers one effective strategy to challenge male obesity. Scottish Government and The UK Football Pools funded delivery of the programme through a grant to the Scottish Premier League Trust. The National Institute for Health Research Public Health Research Programme funded the assessment (09/3010/06).

#10 Concussion Surveillance: Do Low Concussion Rates in the Qatar Professional Football League Reflect a True Difference or Emphasize Challenges in Knowledge Translation?
Authors: Eirale C, Tol JL, Targett S, Holmich P, Chalabi H.
Reference: Clin J Sport Med. 2014 Jan 21. [Epub ahead of print]
Summary: To investigate concussion epidemiology in the first football (soccer) division of Qatar. Professional First Division Football League of Qatar participated in this study.  Daily collection of training and match exposure from August 2008 until April 2012 by club medical staff. Head injuries during training and match play were recorded on standardized injury cards. Injury incidence was calculated as number of injuries per hour exposed to risk and expressed as rate per 1000 hours was used as outcome measures. The incidence of concussions in professional club football in Qatar is 0.016 (0.000-0.033) per 1000 hours of exposure. The concussion incidence is only 25% of that in the previous European studies using the same time loss injury definition. This raises the possibility that concussions are underreported. Further research is necessary. In the meantime, concussion education of players, club medical, and support staff is warranted, in keeping with the Zurich concussion consensus call for the need for an increase in knowledge translation.This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License, where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially.

#11 Comparison of home advantage in men's and women's football leagues in Europe
Authors: Pollard R, Gómez MA.
Reference: Eur J Sport Sci. 2014 Jan;14 Suppl 1:S77-83. doi: 10.1080/17461391.2011.651490. Epub 2012 Mar 1.
Summary: Most research into home advantage is based on men's sports. This article analyses home advantage in the women's domestic football leagues of Europe and makes a comparison with the corresponding men's football leagues. A total of 47,042 games were included. From 2004 to 2010, home advantage existed in the domestic women's soccer leagues of all 26 European countries analysed, ranging from 51.0% to 58.8% and averaging 54.2%. In every country, this was less than the corresponding men's home advantage which averaged 60.0%. Crowd effects, both on players and referees, and different gender perceptions of territorial protection are plausible reasons for the differences found. Using a regression model that controlled for the competitive balance of each league, as well as for crowd size, the Gender Gap Index, which quantifies the status of women in each country, was a significant predictor of the difference between men's and women's home advantage. As the status of women becomes closer to that of men within a country, the difference in home advantage is less between the men's and women's football leagues.

#12 Length, width and centroid distance as measures of teams tactical performance in youth football
Authors: Folgado H, Lemmink KA, Frencken W, Sampaio J.
Reference: Eur J Sport Sci. 2014 Jan;14 Suppl 1:S487-92. doi: 10.1080/17461391.2012.730060. Epub 2012 Oct 12.
Summary: Small-sided games are commonly used in training and teaching contexts of football. However, few studies have focused on the tactical implications of this type of drills. The aim of this study is to identify how tactical collective behaviour varies with age in different small-sided game formats. We investigated the in-game field position in three different age groups of youth football players [under-9 (n=10; age = 8.5±0.53), under-11 (n=10; age = 10.4±0.52) and under-13 (n=10; age = 12.7±0.48)], participating in two different small-sided game conditions (GK + 3×3 + GK and GK + 4×4 + GK). A team variable was created based on the players' length per width ratio (lpwratio), and a match variable was calculated as the distance between the centroid of the two teams. Results show that team variable values were influenced by the age of the players, as younger teams tend to present a higher value of lpwratio in their dispersion on the pitch. The variability of this variable also showed a decrease for teams with older players, suggesting a more consistent application of the width (stretching and creating space) and concentration (compressing into a confined area) principles of play and reflecting a higher level of collective tactical behaviour. Match variable showed a larger centroid distance for the older age groups in comparison with the younger players in the GK + 3×3 + GK, while all age groups demonstrated similar large centroid distances in the GK + 4×4 + GK game format. These results suggest that length and width ratio and centroid distance are useful measures of tactical performance in small-sided games in youth football.

#13 Artificial turf surfaces: Perception of safety, sporting feature, satisfaction and preference of football users
Authors: Burillo P, Gallardo L, Felipe JL, Gallardo AM.
Reference: Eur J Sport Sci. 2014 Jan;14 Suppl 1:S437-47. doi: 10.1080/17461391.2012.713005. Epub 2012 Aug 10.
Summary: 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 results of the skin abrasion, muscle strain and the possibility of sustaining an injury, on a Likert-type 10-point interval scale, gave a perception of 'somewhat dissatisfied' for the participants. The main advantages of artificial turf were their sports features, the evenness of the surface and the good state of conservation. Participants were satisfied with the artificial turf surface. Approximately three out of four participants gave an overall ranking of highly satisfied. The players were significantly less satisfied than the coaches and referees. The overall satisfaction with artificial turf fields was strongly influenced by previous experience, particularly those who had previously played on dirt pitches. These results highlight the versatility of artificial turf to adapt to any circumstance or requirement for local sport and top-level professional competitions alike.

#14 Effects of a defender on run-up velocity and ball speed when crossing a football
Authors: Orth D, Davids K, Araújo D, Renshaw I, Passos P.

Reference: Eur J Sport Sci. 2014 Jan;14 Suppl 1:S316-23. doi: 10.1080/17461391.2012.696712. Epub 2012 Jul 6.
Summary: This study evaluated effects of defensive pressure on running velocity in footballers during the approach to kick a stationary football. Approach velocity and ball speed/accuracy data were recorded from eight football youth academy participants (15.25, SD=0.46 yrs). Participants were required to run to a football to cross it to a receiver to score against a goal-keeper. Defensive pressure was manipulated across three counterbalanced conditions: defender-absent (DA); defender-far (DF) and defender-near (DN). Pass accuracy (percentages of a total of 32 trials with 95% confidence limits in parenthesis) did not significantly reduce under changing defensive pressure: DA, 78% (55-100%); DF, 78% (61-96%); DN, 59% (40-79%). Ball speed (m·s(-1)) significantly reduced as defensive pressure was included and increased: DA, 23.10 (22.38-23.83); DF, 20.40 (19.69-21.11); DN, 19.22 (18.51-19.93). When defensive pressure was introduced, average running velocity of attackers did not change significantly: DA versus DF (m·s(-1)), 5.40 (5.30-5.51) versus 5.41 (5.34-5.48). Scaling defender starting positions closer to the start position of the attacker (DN) significantly increased average running velocity relative to the DA and DF conditions, 5.60 (5.50-5.71). In the final approach footfalls, all conditions significantly differed: DA, 5.69 (5.35-6.03); DF, 6 .22 (5.93-6.50); DN, 6.52 (6.23-6.80). Data suggested that approach velocity is constrained by both presence and initial distance of the defender during task performance. Implications are that the expression of kicking behaviour is specific to a performance context and some movement regulation features will not emerge unless a defender is present as a task constraint in practice.

#15 Variation in the ACE, PPARGC1A and PPARA genes in Lithuanian football players
Authors: Gineviciene V, Jakaitiene A, Tubelis L, Kucinskas V.

Reference: Eur J Sport Sci. 2014 Jan;14 Suppl 1:S289-95. doi: 10.1080/17461391.2012.691117. Epub 2012 May 31.
Summary:  The aim of this study was to determine the impact of ACE (I/D), PPARGC1A (G/A) and PPARA (G/C) polymorphisms on footballers performance among 199 Lithuanian professional footballers and 167 sedentary, healthy men (controls). Genotyping was performed using polymerase chain reaction and restriction fragment length polymorphism methods on DNA from leucocytes. Results revealed that the angiotensin-1-coverting enzyme gene (ACE) genotype distribution was significantly different between total football players group (II 23.6%, ID 46.7% and DD 29.6%) and the controls (II 24.6%, ID 29.9% and DD 45.5%; P=0.002). Although investigating PPARGC1A (G/A) and PPARA (G/C) polymorphisms no significant results were obtained in the total football players group, however, significant differences were determined between forwards and controls [PPARGC1A: GG 54.6%, GA 29.5%, AA 15.9% vs. GG 49.7%, GA 44.3% and AA 6.0% (P = 0.044); PPARA: GG 52.3%, GC 40.9%, CC 6.8% vs. GG 72.4%, GC 24.6% and CC 3.0% (P = 0.034)]. In the whole cohort, the odds ratio of the genotype [ACE ID + PPARA GG] being a footballer was 1.69 (95% CI 1.04-2.74), and of [ACE ID + PPARGC1A GG] 1.93 (95% CI 1.10-3.37) and of [ACE II + PPARA GC] 2.83 (95% CI 1.02-7.91) compared to controls. It was revealed that ACE ID genotype together with PPARA GG and PPARGC1A GG as well as ACE II genotype with PPARA GC is probably the 'preferable genotype' for footballers. Summing up, the present study suggests that the ACE, PPARGC1A and PPARA polymorphisms genotypes are associated, separately and in combination, with Lithuanian footballers' performance.

#16 Home advantage and referee bias in European football
Author: Goumas C.
Reference: Eur J Sport Sci. 2014 Jan;14 Suppl 1:S243-9. doi: 10.1080/17461391.2012.686062. Epub 2012 May 21.
Summary: Abstract Home advantage is well documented in a wide range of team sports including association football (soccer). Home team crowd support has been shown to be a likely causal factor and its influence on referee decision-making appears to play a significant role. Match data from the 2009/2010 and 2010/2011 seasons of the Union of European Football Associations (UEFA) Champions League and Europa League were used to investigate referee bias in terms of the association between match location (home vs. away) and disciplinary sanctions used by football referees. The adjusted mean number of yellow cards received by home and away teams and the ratios of these means were estimated from Poisson regression models. After controlling for within-match measures of attacking dominance referees in the Champions League and Europa League issued 25% (p<0.001) and 10% (p=0.002) more yellow cards, respectively, to away teams than to home teams. The higher level of home team bias in the Champions League appeared to be mainly due to higher crowd densities. In a combined analysis of both UEFA leagues the magnitude of referee bias increased with increasing crowd density (p<0.001). Crowd size and crowd proximity were not associated with referee bias after controlling for crowd density. These results provide further evidence that crowd support influences referee decisions. Failure to control for within-match team performance may over-estimate the extent of referee bias in terms of the number of disciplinary sanctions used.

#17 Foul or dive? Motor contributions to judging ambiguous foul situations in football
Authors: Renden PG, Kerstens S, Oudejans RR, Cañal-Bruland R.
Reference: Eur J Sport Sci. 2014 Jan;14 Suppl 1:S221-7. doi: 10.1080/17461391.2012.683813. Epub 2012 May 31.
Summary: Football (soccer) referees frequently face situations in which they have to distinguish dives and fouls. Yet, little is known about the contributing factors that characterise the ability to judge these ambiguous situations correctly. To this end, in the current article we tested the hypothesis that motor experience of observers contributes to the visual identification of deceptive actions. Thereto, we asked skilled football referees, skilled football players, wheelchair bounded football fans (thus with limited motor experience) and novices to judge whether potential tackle situations in football were either fouls or dives. Results revealed that the referees (accuracy 72.2%, s=6.2) and players (accuracy 72.0%, s=6.4) were better at discriminating fouls and dives than the fans (accuracy 61.1%, s=7.2) and the novices (accuracy 57.4%, s=7.0) (P < 0.001). The results seem to point to an added value of motor experience in detecting deceptive movements.

#18 Physical match performance of youth football players in relation to physical capacity
Authors: Rebelo A, Brito J, Seabra A, Oliveira J, Krustrup P.
Reference: Eur J Sport Sci. 2014 Jan;14 Suppl 1:S148-56. doi: 10.1080/17461391.2012.664171. Epub 2012 Mar 19.
Summary: The aims of the study were to (1) analyse the activity profile of youth football players during competitive matches, and (2) examine the relationship between physical match performance and intermittent exercise performance as well as [Formula: see text]. Thirty youth male football players, aged 14-17 years, carried out a laboratory treadmill test for determination of [Formula: see text] as well as the Yo-Yo intermittent recovery level 1 (Yo-Yo IR1) and Yo-Yo intermittent endurance level 2 (Yo-Yo IE2) tests. Time-motion analysis and heart rate (HR) recordings were performed during two competitive matches per player. Distance covered during the match was 6311±948 (range: 4435-8098) m, of which 12% were high-intensity activities (HIA; 759±437 [374-2062] m), and 5% was backwards running (309±205 [12-776] m). Mean match HR was 168±12 (140-187) bpm, corresponding to 85% (69-91) of maximum HR. The total distance covered in the last 13.3-min period of the match was 40%, 26% and 17% lower than in the first, second and fourth 13.3-min periods of the match, respectively (P<0.05). The distance covered in backwards running decreased by 31% and 37% from the first to the last 13.3-min periods of the first and second half, respectively (P<0.05). The Yo-Yo IR1 was significantly associated with the time spent with sprinting during the match (r=0.63; P=0.002) and during the last 13.3-min period (r=0.63; P=0.022). Both Yo-Yo IR1 and Yo-Yo IE2 were correlated with the time spent with match HIA (r=0.56 and r=0.57, respectively; P<0.05). No significant relationship was observed between [Formula: see text] and match time-motion variables (r=-0.13-0.25; P>0.05) or Yo-Yo test performances (r=0.09-0.26; P>0.05). In conclusion, youth football players have a high heart-rate loading during match play and a decreased running performance towards the end of the game. The intermittent exercise capacity, as determined in the Yo-Yo IR1 test, appears to be a valid indicator of high-intensity exercise performance in youth matches.

#19 Do weight management programmes delivered at professional football clubs attract and engage high risk men? A mixed-methods study
Authors: Hunt K, Gray CM, Maclean A, Smillie S, Bunn C, Wyke S.
Reference: BMC Public Health. 2014 Jan 21;14(1):50. doi: 10.1186/1471-2458-14-50.
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Summary: The prevalence of obesity in men in the UK is amongst the highest in Europe but men are less likely than women to use existing weight loss programmes. Developing weight management programmes which are appealing and acceptable to men is a public health priority. Football Fans in Training (FFIT), a men-only weight management programme delivered to groups of men at top professional football clubs, encourages men to lose weight by working with, not against, cultural ideals of masculinity. To inform further development of interventions in football club settings, the current study explored who is attracted to FFIT and why overweight/obese men choose to take part. A mixed-methods study analysing baseline data on 747 men aged 35-65 years with BMI ≥ 28 kg/m2 who were participants in a randomised controlled trial of FFIT, and data from 13 focus group discussions with 63 men who had attended the programme was used in this study.  Objectively-measured mean body mass index was 35.3 kg/m2 (sd 4.9). Overall over 90% of participants were at very high or extremely high risk of future ill-health. Around three-quarters of participants in all age groups were at 'very high' risk of type 2 diabetes, hypertension and cardiovascular disease (72%, 73% and 80% of men aged 35-44, 45-54 and 55-64 years respectively). A further 21%, 16% and 13% were at 'extremely high' risk. Qualitative data revealed that the powerful 'draw' of the football club attracted men otherwise reluctant to attend existing weight management programmes. The location and style of delivery of early FFIT sessions fostered team spirit; men appreciated being with others 'like them' and the opportunity to undertake weight management in circumstances that enhanced physical and symbolic proximity to something they valued highly, the football club. The delivery of a weight management intervention via professional football clubs attracted men at high risk of ill-health. The setting enabled men to join a weight management programme in circumstances that felt 'right' rather than threatening to themselves as men. FFIT is an example of how to facilitate health promotion activities in a way that is consistent with, rather than challenging to, common ideals of masculinity.

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