Latest research in football - week 29 - 2015

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 Salivary hormones and IgA in relation to physical performance in football
Reference: J Sports Sci. 2015 Jul 6:1-8. [Epub ahead of print]
Authors: Peñailillo L, Maya L, Niño G, Torres H, Zbinden-Foncea H.
Summary: Salivary biomarkers have shown to be useful to assess physiological stress in football, but their relationship with physical performance is unknown. The aims of this study were to investigate the effect of a football match on salivary cortisol, testosterone and immunoglobulin A (IgA) concentrations in elite footballers, and to examine the relationship of physical performance during the match to these biomarkers. Nine elite football players were assessed before, during and after a friendly international match. Physical performance during the match was measured by time-motion analysis, whilst salivary cortisol, testosterone and IgA were measured before and 10 min post-match. The results showed that players covered an average of 9463 ± 458 m during the match. Salivary cortisol did not change post-match. Testosterone and IgA concentrations decreased by 30.6% and 74.5%, respectively. The testosterone/cortisol (T/C) ratio decreased by 64.2% after the match. Changes in testosterone concentrations correlated (r = 0.85) with distance covered. Pre- and post-match testosterone levels correlated with post-match IgA concentrations (r = 0.8 and 0.89, respectively). These results suggest that a football match induces catabolic stress as indicated by the decreased T/C ratio. It seems that footballers with smaller decreases in testosterone levels covered more distance and decreased their immune function less.

#2 Cortisol, testosterone and mood state variation during an official female football competition
Reference: J Sports Med Phys Fitness. 2015 Jul 8. [Epub ahead of print]
Authors: Casanova N, Palmeira-de-Oliveira A, Pereira A, Crisóstomo LD, Travassos B, Costa AM.
Summary: Endogenous hormones are essential on the control of physiological reactions and adaptations during sport performance. This study aims to compare the mood state and the salivary levels of cortisol and testosterone during an official female association football tournament. Twenty female football players (22.85 ± 4.2 yrs) from the Portuguese women's national team were included in the study. Mood, salivary cortisol and testosterone levels were examined in five moments over the championship (M1, neutral measures; M2-M5, on every match day). Saliva samples were collected before breakfast and immediately after each match. Mood was measured by the profile of mood states questionnaire (POMS); hormone levels were measure by immunoassay methods. Iceberg Profiles of POMS were observed during all the moments of evaluation (M2-M5), showing a decrease in vigor and an increase in tension and depression in both team defeats (M2 and M5). There is no relationship between the hormones levels and the outcome of the competition, once cortisol and testosterone decrease from pre-match to post-match in both wins (M2 and M5) and defeats (M3 and M4). For testosterone the observed decrease is significantly different (p<0.05) before and after all matches. Our results show a pattern in mood states behavior. Cortisol and testosterone decrease after match and throughout the tournament, independently of the match outcome. The absence of hormone flutuations related to competiton performance points out that top-level professional football players training systematically and regularly seem to be very well adapted to competition stress effect.

#3 Responses to a 120 min reserve team soccer match: a case study focusing on the demands of extra time
Reference: J Sports Sci. 2015 Jul 6:1-7. [Epub ahead of print]
Authors: Russell M, Sparkes W, Northeast J, Kilduff LP.
Summary: The movement demands of the soccer extra time period are unknown despite the importance of this period of play. Data are presented for five English Premier League reserve team players who wore GPS (10 Hz) monitors during an official soccer match that required extra time to be played. Countermovement jump performance (peak power output (PPO) and jump height) and creatine kinase (CK) concentrations were assessed before (-24 h; baseline) and after (+24 h, +48 h) match play. Players covered 14,106 ± 859 m (109 ± 7 m·min-1) throughout the game. From 90 to 120 min, 3213 ± 286 m were covered and 12 ± 6 sprints, 221 ± 14 accelerations and 207 ± 16 decelerations occurred. From 105 to 120 min, acceleration and deceleration parameters reduced by >10% compared to the opening 15 min. At +24 h and +48 h, PPO reduced by 416.1 ± 199.9 W (10.9% ± 4.4%) and 155.1 ± 34.8 W (4.1% ± 0.8%), jump heights decreased by 0.064 ± 0.046 m (17.8% ± 11.2%) and 0.025 ± 0.009 m (7.4% ± 3.2%), whereas CK increased by 586.6 ± 85.1 μ·l-1 (236% ± 92%) and 266.8 ± 134.7 μ·l-1 (107% ± 89%) versus baseline, respectively. Physical performance markers reduced throughout match play and countermovement jump performance was impaired, while CK remained elevated, for at least 48 h after the game. Interventions which maintain performance throughout a game and which enhance recovery in the days after 120 min of soccer match play warrant further investigation.

#4 Iron status markers are only transiently affected by a football game
Reference: J Sports Sci. 2015 Jul 13:1-12. [Epub ahead of print]
Authors: Jamurtas AZ, Douroudos II, Deli CK, Draganidis D, Chatzinikolaou A, Mohr M, Avloniti A, Barbero-Álvarez JC, Margonis K, Mavropalias G, Stampoulis T, Giannakidou D, Flouris AD, Koutedakis Y, Fatouros IG.
Summary: We examined the temporal variation of iron's status markers during a 60 h period following a football game. Thirty-four male football players were randomly assigned to a control group (CG, N = 14, participated only in measurements and training) or an experimental group (EG, N = 20, took part in a football game one week after the completion of the competitive season). All participants trained regularly for two consecutive days after the game. Training and game load was monitored with high time-resolution global positioning system (GPS) devices. Blood samples were collected and muscle damage markers and repeated sprint ability (RSA) were assessed pre-game and at 2 h, 12 h 36 h and 60 h post-game. No changes were noted in CG. Iron concentration decreased (P < 0.05) 2 h post-game and normalised thereafter whereas total iron binding capacity increased (P < 0.05) 12-60 h of recovery (P < 0.05). Erythrocytes, haemoglobin (HGB) concentration, plasma volume, haematocrit, mean cell volume, mean cell HGB, mean cell HGB concentration, red cell width-SD, red cell width-CV, ferritin concentration and transferrin saturation remained unaltered during the intervention period. Creatine kinase activity and muscle soreness increased (P < 0.05) throughout recovery in EG. RSA declined (P < 0.05) until 36 h of recovery and normalised thereafter. Our data demonstrate that iron status markers are only transiently affected by a football game.

#5 Self-reported previous knee injury and low knee function increase knee injury risk in adolescent female football
Reference: Scand J Med Sci Sports. 2015 Jul 15. doi: 10.1111/sms.12521. [Epub ahead of print]
Authors: Clausen MB, Tang L, Zebis MK, Krustrup P, Hölmich P, Wedderkopp N, Andersen LL, Christensen KB, Møller M, Thorborg K
Summary: Knee injuries are common in adolescent female football. Self-reported previous knee injury and low Knee injury and Osteoarthritis Outcome Score (KOOS) are proposed to predict future knee injuries, but evidence regarding this in adolescent female football is scarce. The aim of this study was to investigate self-reported previous knee injury and low KOOS subscale score as risk factors for future knee injuries in adolescent female football. A sample of 326 adolescent female football players, aged 15-18, without knee injury at baseline, were included. Data on self-reported previous knee injury and KOOS questionnaires were collected at baseline. Time-loss knee injuries and football exposures were reported weekly by answers to standardized text-message questions, followed by injury telephone interviews. A priori, self-reported previous knee injury and low KOOS subscale scores (< 80 points) were chosen as independent variables in the risk factor analyses. The study showed that self-reported previous knee injury significantly increased the risk of time-loss knee injury [relative risk (RR): 3.65, 95% confidence (CI) 1.73-7.68; P < 0.001]. Risk of time-loss knee injury was also significantly increased in players with low KOOS subscale scores (< 80 points) in Activities of Daily Living (RR: 5.0), Sport/Recreational (RR: 2.2) and Quality of Life (RR: 3.0) (P < 0.05). In conclusion, self-reported previous knee injury and low scores in three KOOS subscales significantly increase the risk of future time-loss knee injury in adolescent female football.

#6 Examining the potential public health benefit of offering STI testing to men in amateur football clubs: evidence from cross-sectional surveys
Reference: BMC Public Health. 2015 Jul 17;15(1):676. doi: 10.1186/s12889-015-1951-7.
Authors: Mercer CH, Fuller SS, Saunders JM, Muniina P, Copas AJ, Hart GJ, Sutcliffe LJ, Johnson AM, Cassell JA, Estcourt CS
Summary: In Britain, young people continue to bear the burden of sexually transmitted infections (STIs) so efforts are required, especially among men, to encourage STI testing. The SPORTSMART study trialled an intervention that sought to achieve this by offering chlamydia and gonorrhoea test-kits to men attending amateur football clubs between October and December 2012. With football the highest participation team sport among men in England, this paper examines the potential public health benefit of offering STI testing to men in this setting by assessing their sociodemographic characteristics, sexual behaviours, and healthcare behaviour and comparing them to men in the general population. Data were collected from 192 (male) members of 6 football clubs in London, United Kingdom, aged 18-44 years via a 20-item pen-and-paper self-completion questionnaire administered 2 weeks after the intervention. These were compared to data collected from 409 men of a similar age who were resident in London when interviewed during 2010-2012 for the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3), a national probability survey that used computer-assisted-personal-interviewing with computer-assisted-self-interview. Age standardisation and multivariable regression were used to account for sociodemographic differences between the surveys. Relative to men in the general population, SPORTSMART men were younger (32.8 % vs. 21.7 % aged under 25 y), and more likely to report (all past year) at least 2 sexual partners (adjusted odds ratio, AOR: 3.25, 95 % CI: 2.15-4.92), concurrent partners (AOR: 2.05, 95 % CI: 1.39-3.02), and non-use of condoms (AOR: 2.17, 95 % CI: 1.39-3.41). No difference was observed in STI/HIV risk perception (AOR for reporting "not at all at risk" of STIs: 1.25, 95 % CI: 0.76-2.04; of HIV: AOR: 1.54, 95 % CI: 0.93-2.55), nor in reporting STI testing in the past year (AOR: 0.83, 95 % CI: 0.44-1.54), which was reported by only one in six men. Relative to young men in the general population, football club members who completed the SPORTSMART survey reported greater sexual risk behaviour but similar STI/HIV risk perception and STI testing history. Offering STI testing in amateur football clubs may therefore widen access to STI testing and health promotion messages for men at higher STI risk, which, given the minority currently testing and the popularity of football in England, should yield both individual and public health benefit.

#6 Need of cardiopulmonary resuscitation training in the sport of soccer. Literature Review
Reference: Enferm Clin. 2015 Jul 7. pii: S1130-8621(15)00077-7. doi: 10.1016/j.enfcli.2015.05.004. [Epub ahead of print] [Article in Spanish]
Authors: Guerra-Martín MD, Martínez-Montilla JM, Amador-Marín B
Summary: In Spain there are around 25,000 cardiac arrests, many of them in the presence of non-medical personnel. In less than 25% of the cardio-respiratory arrests witnessed, witnesses began cardiopulmonary resuscitation. Soccer is a contact sport with multiple physical characteristics and requirements which pushes your body to the limit, thus leading to a higher chance of developing multiple lesions, including cardio-respiratory arrest. Therefore, our goal was to know the actual situation on training in basic life support in soccer. A literature review was performed on different databases both national (IME, CUIDEN, ENCUENTR@, ENFERMERÍA AL DÍA, ISOC) and international (PUBMED, SCOPUS, CINAHL), with different MESH descriptors related to the topic. A total of 395 references were identified. 17 studies were selected; 8 of them had like main theme cardiopulmonary resuscitation and the remaining 9 spoke on the use of semi-automatic defibrillators. There is a paucity of research on this topic in soccer. This strikes our attention because in this area there could be situations requiring immediate rescue action. Therefore, we emphasize the importance of early cardio-respiratory resuscitation because training in basic life support and semi-automatic defibrillators in soccer are fundamental.

#7 Effect of Astaxanthin Supplementation on Salivary IgA, Oxidative Stress, and Inflammation in Young Soccer Players
Reference: Evid Based Complement Alternat Med. 2015;2015:783761. doi: 10.1155/2015/783761. Epub 2015 Jun18.
Authors: Baralic I, Andjelkovic M, Djordjevic B, Dikic N, Radivojevic N, Suzin-Zivkovic V, Radojevic-Skodric S, Pejic
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Summary: The physiologic stress induced by physical activity is reflected in immune system perturbations, oxidative stress, muscle injury, and inflammation. We investigated the effect of astaxanthin (Asx) supplementation on salivary IgA (sIgA) and oxidative stress status in plasma, along with changes in biochemical parameters and total/differential white cell counts. Forty trained male soccer players were randomly assigned to Asx and placebo groups. Asx group was supplemented with 4 mg of Asx. Saliva and blood samples were collected at the baseline and after 90 days of supplementation in preexercise conditions. We observed a rise of sIgA levels at rest after 90 days of Asx supplementation, which was accompanied with a decrease in prooxidant-antioxidant balance. The plasma muscle enzymes levels were reduced significantly by Asx supplementation and by regular training. The increase in neutrophil count and hs-CRP level was found only in placebo group, indicating a significant blunting of the systemic inflammatory response in the subjects taking Asx. This study indicates that Asx supplementation improves sIgA response and attenuates muscle damage, thus preventing inflammation induced by rigorous physical training. Our findings also point that Asx could show significant physiologic modulation in individuals with mucosal immunity impairment or under conditions of increased oxidative stress and inflammation.

#8 An Evidence-Based Discussion of Heading the Ball and Concussions in High School Soccer
Reference: JAMA Pediatr. 2015 Jul 13. doi: 10.1001/jamapediatrics.2015.1062. [Epub ahead of print]
Authors: Comstock RD, Currie DW, Pierpoint LA, Grubenhoff JA, Fields SK
Summary: Soccer, originally introduced as a safer sport for children and adolescents, has seen a rapid increase in popularity in the United States over the past 3 decades. Recently, concerns have been raised regarding the safety of soccer ball heading (when an athlete attempts to play the ball in the air with his or her head) given the rise in concussion rates, with some calling for a ban on heading among soccer players younger than 14 years. To evaluate trends over time in boys' and girls' soccer concussions, to identify injury mechanisms commonly leading to concussions, to delineate soccer-specific activities during which most concussions occur, to detail heading-related soccer concussion mechanisms, and to compare concussion symptom patterns by injury mechanism. Retrospective analysis of longitudinal surveillance data collected from 2005-2006 through 2013-2014 in a large, nationally representative sample of US high schools. Participants were boys and girls who were high school soccer players. Concussions sustained during high school-sanctioned soccer games and practices. Mechanism and sport-specific activity of concussion. Overall, 627 concussions were sustained during 1 393 753 athlete exposures (AEs) among girls (4.50 concussions per 10 000 AEs), and 442 concussions were sustained during 1 592 238 AEs among boys (2.78 concussions per 10 000 AEs). For boys (68.8%) and girls (51.3%), contact with another player was the most common concussion mechanism. Heading was the most common soccer-specific activity, responsible for 30.6% of boys' concussions and 25.3% of girls' concussions. Contact with another player was the most common mechanism of injury in heading-related concussions among boys (78.1%) and girls (61.9%). There were few differences in concussion symptom patterns by injury mechanism. Although heading is the most common activity associated with concussions, the most frequent mechanism was athlete-athlete contact. Such information is needed to drive evidence-based, targeted prevention efforts to effectively reduce soccer-related concussions. Although banning heading from youth soccer would likely prevent some concussions, reducing athlete-athlete contact across all phases of play would likely be a more effective way to prevent concussions as well as other injuries.

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