Latest research in football - week 27 - 2016

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

Following studies were retrieved for this week:

#1 Injuries during football tournaments in 45,000 children and adolescents
Reference: Eur J Sport Sci. 2016 Jul 20:1-9. [Epub ahead of print]
Authors: Kolstrup LA, Koopmann KU, Nygaard UH, Nygaard RH, Agger P
Summary: Four percent of the world's population, or 265 million people, play football, and many players are injured every year. The present study investigated more than 1800 injuries in over 45,000 youth players participating in three consecutive international football tournaments in Denmark in 2012-2014. The aim was to investigate the injury types and locations in children and adolescent football players and the differences between genders and age groups (11-15 and 16-19 years of age). An overall injury rate of 15.3 per 1000 player hours was found. The most common injury location was lower extremities (66.7%), and the most common injury type was contusion (24.4%). Girls had a relative risk of injury of 1.5 compared with boys, p < .001, and they had a higher proportion of injuries to knee and lower leg, 23.8%, than boys, 19.0%, p < .01. Boys had a higher proportion of fracture, 6.8%, as opposed to 3.3% among girls, p < .001. In conclusion, we found the youngest girls to have a higher incidence of almost all injury categories than any other group. In general, the incidence of injury decreased with age. The study provides a detailed insight into the injuries that may be expected at a large youth football tournament. These findings are of great value for organizations and healthcare professionals planning similar events and for planning injury prevention strategies, which would be of special interest in the youngest female players in general.

#2 The relationship between game-based performance indicators and developmental level in junior Australian football: Implications for coaching
Reference: J Sports Sci. 2016 Jul 20:1-5. [Epub ahead of print]
Authors: Woods CT, Bruce L, Veale JP, Robertson S
Summary: Identifying performance differences between juniors at different stages of a talent pathway may assist with the development of prospective talent. This study investigated the relationship between game-based performance indicators and developmental level in junior Australian football (AF). Players were categorised into 2 groups according to developmental level; U16 and U18. Physical and technical skill performance indicators were collated for all U16 (n = 200) and U18 (n = 244) participants of their respective 2014 national championships. Data were acquired from all 28 games (12 U16, 16 U18); resulting in 1360 player observations (568 U16, 792 U18). Microtechnology and a commercial provider facilitated the quantification of 15 performance indicators. Generalised estimating equations (GEEs) modelled the extent to which these performance indicators were associated with developmental level. The GEE model revealed that "contested marks" and "contested possessions" had the strongest association with the U16 level, while "total marks" and "clearances" had the strongest association with the U18 level. The remaining performance indicators were not developmentally discriminant. These results indicate that there are distinctive features of gameplay more associated with the U16 and U18 levels in AF. Coaches may wish to consider these results when constructing training drills designed to minimise developmental gaps.

#3 Evaluating a Nationwide Recreational Football Intervention: Recruitment, Attendance, Adherence, Exercise Intensity, and Health Effects
Reference: Biomed Res Int. 2016;2016:7231545. doi: 10.1155/2016/7231545. Epub 2016 Jun 29.
Authors: Fløtum LA, Ottesen LS, Krustrup P, Mohr M
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Summary: The present study evaluated a nationwide exercise intervention with Football Fitness in a small-scale society. In all, 741 adult participants (20-72 yrs) were successfully recruited for Football Fitness training in local football clubs, corresponding to 2.1% of the adult population. A preintervention test battery including resting heart rate (RHR), blood pressure, and body mass measurements along with performance tests (Yo-Yo Intermittent Endurance level 1 (Yo-Yo IE1), the Arrowhead Agility Test, and the Flamingo Balance Test) were performed (n = 502). Training attendance (n = 310) was 1.6 ± 0.2 sessions per week (range: 0.6-2.9), corresponding to 28.8 ± 1.0 sessions during the 18 wk intervention period. After 18 wks mean arterial pressure (MAP) was -2.7 ± 0.7 mmHg lower (P < 0.05; n = 151) with even greater (P < 0.05) reductions for those with baseline MAP values >99 mmHg (-5.6 ± 1.5 mmHg; n = 50). RHR was lowered (P < 0.05) by 6 bpm after intervention (77 ± 1 to 71 ± 1 bpm). Yo-Yo IE1 performance increased by 41% (540 ± 27 to 752 ± 45 m), while agility and postural balance were improved (P < 0.05) by ~6 and ~45%, respectively. In conclusion, Football Fitness was shown to be a successful health-promoting nationwide training intervention for adult participants with an extraordinary recruitment, a high attendance rate, moderate adherence, high exercise intensity, and marked benefits in cardiovascular health profile and fitness.

#4 Study protocol of European Fans in Training (EuroFIT): a four-country randomised controlled trial of a lifestyle program for men delivered in elite football clubs
Reference: BMC Public Health. 2016 Jul 19;16(1):598. doi: 10.1186/s12889-016-3255-y.
Authors: van Nassau F, van der Ploeg HP, Abrahamsen F, Andersen E, Anderson AS, Bosmans JE, Bunn C, Chalmers M, Clissmann C, Gill JM, Gray CM, Hunt K, Jelsma JG, La Guardia JG, Lemyre PN, Loudon DW, Macaulay L, Maxwell DJ, McConnachie A, Martin A, Mourselas N, Mutrie N, Nijhuis-van der Sanden R, O'Brien K, Pereira HV, Philpott M, Roberts GC, Rooksby J, Rost M, Røynesdal Ø, Sattar N, Silva MN, Sorensen M, Teixeira PJ, Treweek S, van Achterberg T, van de Glind I, van Mechelen W, Wyke S
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Summary: Lifestyle interventions targeting physical activity, sedentary time and dietary behaviours have the potential to initiate and support behavioural change and result in public health gain. Although men have often been reluctant to engage in such lifestyle programs, many are at high risk of several chronic conditions. We have developed an evidence and theory-based, gender sensitised, health and lifestyle program (European Fans in Training (EuroFIT)), which is designed to attract men through the loyalty they feel to the football club they support. This paper describes the study protocol to evaluate the effectiveness and cost-effectiveness of the EuroFIT program in supporting men to improve their level of physical activity and reduce sedentary behaviour over 12 months. The EuroFIT study is a pragmatic, two-arm, randomised controlled trial conducted in 15 football clubs in the Netherlands, Norway, Portugal and the UK (England). One-thousand men, aged 30 to 65 years, with a self-reported Body Mass Index (BMI) ≥27 kg/m(2) will be recruited and individually randomised. The primary outcomes are objectively-assessed changes in total physical activity (steps per day) and total sedentary time (minutes per day) at 12 months after baseline assessment. Secondary outcomes are weight, BMI, waist circumference, resting systolic and diastolic blood pressure, cardio-metabolic blood biomarkers, food intake, self-reported physical activity and sedentary time, wellbeing, self-esteem, vitality and quality of life. Cost-effectiveness will be assessed and a process evaluation conducted. The EuroFIT program will be delivered over 12 weekly, 90-minute sessions that combine classroom discussion with graded physical activity in the setting of the football club. Classroom sessions provide participants with a toolbox of behaviour change techniques to initiate and sustain long-term lifestyle changes. The coaches will receive two days of training to enable them to create a positive social environment that supports men in engaging in sustained behaviour change. The EuroFIT trial will provide evidence on the effectiveness and cost-effectiveness of the EuroFIT program delivered by football clubs to their male fans, and will offer insight into factors associated with success in making sustained changes to physical activity, sedentary behaviour, and secondary outcomes, such as diet.

#5 Rehabilitation after first-time anterior cruciate ligament injury and reconstruction in female football players: a study of resilience factors
Reference: BMC Sports Sci Med Rehabil. 2016 Jul 16;8:20. doi: 10.1186/s13102-016-0046-9. eCollection 2016.
Authors: Johnson U, Ivarsson A, Karlsson J, Hägglund M, Waldén M, Börjesson M
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Summary: Most of the research in the area of psychosocial factors in rehabilitation after sports injuries has focused on risk behaviors, while relatively few studies have focused on behaviors that facilitate rehabilitation. The objective of our study was to understand the psychosocial features that characterize elite female football players who express a resilient behaviour during rehabilitation after a first-time anterior cruciate ligament (ACL) injury and reconstruction. A qualitative method was used based on individual in-person interviews and video communication of players who incurred a first-time ACL tear during the 2012 season of the Swedish Women's Elite Football League. In total, 13 players had a first-time ACL and were interviewed post-season. The interviews were followed by a thematic content analysis. Based on this, eight players were identified as showing resilient behaviors during their rehabilitation and were included in the final analysis. Three core themes representing psychosocial factors that help players cope successfully with rehabilitation were identified: (I) constructive communication and rich interaction with significant others; (II) strong belief in the importance and efficacy of one's own actions; and (III) the ability to set reasonable goals. The findings suggest three core themes of psychosocial factors that characterize first-time ACL-injured elite female football players showing resilience during rehabilitation after ACL reconstruction. Suggestions for medical teams about ways to support communication, self-efficacy, and goal-setting during the rehabilitation process, are provided.

#6 Calf injuries in professional football: Treat the patient or the scan? - A case study
Reference: Phys Ther Sport. 2016 Jan 31;21:63-67. doi: 10.1016/j.ptsp.2016.01.004. [Epub ahead of print]
Authors: Barreira P, Kassarjian A, Araújo JP, Ferreira R, Espregueira Mendes J
Summary: The aim was to describe a case of a professional football player with significant imaging findings despite a rather innocuous clinical presentation with gradual onset of calf pain and who was able to continue training and playing with minor medical intervention. To discuss some of the limitations of existing muscle injury grading systems and their potential to cover the full range of injury presentations for calf injuries. A professional football player was assessed by physical examination, clinical testing and imaging (MRI) after a gradual onset of a calf injury. After returning to training and competition, a follow-up of his symptoms was performed with regular ultrasound imaging assessments. A professional football player (35 years, 1.90 m, 88 kg) male, African, striker, playing in the Professional Arabian Gulf League. The discordance between the clinical presentation and the imaging findings resulted in a challenging situation regarding the decision of whether to allow the player to train and compete. In addition, existing muscle injury grading systems do not seem to cover the full range of injuries seen in clinical practice.

#7 The effect of hypermobility on the incidence of injury in professional football: A multi-site cohort study
Reference: Phys Ther Sport. 2015 Dec 30;21:7-13. doi: 10.1016/j.ptsp.2015.12.006. [Epub ahead of print]
Authors: Konopinski M, Graham I, Johnson MI, Jones G
Summary: A recent study demonstrated joint hypermobility increased the incidence of injury in an elite football team utilising a univariate statistical model. The objective was to compare injury incidence between hypermobile and non-hypermobile elite football players incorporating a multi-site design and multivariate inferential statistics. 80 players comprising 3 English Championship football teams were followed prospectively during the 2012-2013 season. Joint hypermobility was assessed according to the 9-point Beighton Criteria at the start of the study period. A cut-off score of ≥4 categorised a participant as hypermobile. Player exposure and time-loss injuries were recorded throughout. Mean and standard deviation incidence of injuries was 9.2 ± 10.8 injuries/1000 h. The prevalence of hypermobility was 8.8%. Hypermobiles had a tendency for higher injury incidence (mean [95% confidence interval] difference, 5.2 [0.9-2.7] injuries/1000 h; p = 0.06). Cox regression analyses found training exposure to be highly significant in terms of injury risk (p < 0.001) for all participants. Non-hypermobiles had a lower injury risk (p = 0.11), according to the Cox model, which is suggestive but not conclusive that hypermobility predisposes injury risk. Hypermobility showed a trend towards increased risk of injury. Training exposure is a significant injury risk factor in elite football.

#8 Chronic Traumatic Encephalopathy Presenting as Alzheimer's Disease in a Retired Soccer Player
Reference: J Alzheimers Dis. 2016 Jul 29. [Epub ahead of print]
Authors: Grinberg LT, Anghinah R, Nascimento CF, Amaro E, Leite RP, Martin MD, Naslavsky MS, Takada LT, Filho WJ, Pasqualucci CA, Nitrini R
Summary: The relationship between soccer and chronic traumatic encephalopathy (CTE) is not well established. Clinicopathological correlation in an 83-year-old retired center-back soccer player, with no history of concussion, manifesting typical Alzheimer-type dementia. Examination revealed mixed pathology including widespread CTE, moderate Alzheimer's disease, hippocampal sclerosis, and TDP-43 proteinopathy. This case adds to a few CTE cases described in soccer players. Furthermore, it corroborates that CTE may present clinically as typical Alzheimer-type dementia. Further studies investigating the extent to which soccer is a risk for CTE are needed.

#9 Comparative analysis of the ankle joints in juvenile male soccer players with imaging
Reference: Zhonghua Yi Xue Za Zhi. 2016 Jul 5;96(25):1971-5. doi: 10.3760/cma.j.issn.0376-2491.2016.25.003. [Article in Chinese]
Authors: Huang YB, Zhao YX, Xiao JJ, Li MW, Zhang R, Li SL
Summary: The purpose was to investigate the characteristics of children male soccer players' ankle imaging features. From October 2015 to February 2016, a total of 32 male children players of two soccer clubs in Guangzhou were enrolled in this study.The ages of all cases were from 10 to 14 years, average age was (11.3±0.9) years.A total of 15 male children in region ordinary primary and secondary school students were set as control group, ages were from 10 to 14 years, average age was (12.1±1.2) years. All objects' ankle were examined by X-ray for positive and lateral positions; routine CT scanning and then on the workstation restructuring for axial, coronal and sagittal slices; and examined by MR. MR scan was with special surface coil for ankle joint for horizontal axis T2WI; coronal T1WI; coronary proton density weighted imaging (PWI); sagittal T2WI with fat suppression; sagittal PWI with isotropic and fat suppression sequence of fast field echo. The ankle bone morphological structures were observed on X-ray; the ankle bone mineral density, cortical bone thickness and sesamoid bone quantity was being observed and measured on CT; and the tenosynovitis, Achilles tendinitis, synovitis, and cancellous bone edema signal were observed on MR. For study group, a total of 32 cases and 64 ankles joints were completed by X-ray, CT and MR examination.A total of 15 cases and 30 ankles joints were completed by X-ray in control group, 26 ankle joints were completed by CT scan and 22 ankle joints were completed by MR examination.X-ray examination showed there was no statistically significant difference between the two groups in ankle bone structure.CT showed that navicular bone CT value was (296±82) HU in research group and navicular bone CT value was (266±107) HU in control group, the difference was statistically significant (P=0.03). MR showed the incidence of diseases in research group that the tendon sheath peripheral inflammation was 92.2% (59/64), Achilles tendon lesions was 18.8%(12/64), edema of cancellous bone was 73.4% (47/64) , lateral malleous ligaments injuried was 43.8%(28/64), synovitis or effusion in posterior ankle was 87.5% (56/64). The incidence of diseases in control group was that tendon sheath peripheral inflammation was 31.8%(7/22), Achilles tendon lesions was 0/22, edema of cancellous bone was 0/22, lateral malleous ligaments injuried was 0/22, synovitis or effusion in posterior ankle was 54.5% (12/22). There was statistically significant difference between these two groups (all P<0.05). Compared with the control group, children's male soccer players ankle bone structure, bone cortex thickness and bone mineral density there were no obvious difference. In the tenosynovitis, Achilles tendinitis, synovitis, bone marrow edema, lateral malleous ligaments injuried were significantly higher than the control group.

#10 Effects of a 10-Week Nordic Hamstring Exercise and Russian Belt Training on Posterior Lower Limb Muscle Strength in Elite Junior Soccer Players
Reference: J Strength Cond Res. 2016 Jul 26. [Epub ahead of print]
Authors: Rey E, Paz-Domínguez Á, Porcel-Almendral D, Paredes-Hernández V, Barcala-Furelos R, Abelairas-Gómez C
Summary: The purpose of this study was to assess the effect of two eccentric hamstring training exercises, Nordic hamstring (NHE) and Russian belt (RB), on lower limb strength and bilateral asymmetry using the Single Leg Hamstring Bridge (SLHB) test. Forty-seven elite junior soccer players (age 17.7±0.5 years, height 175.3±3.6 cm, body mass 68.1±7.4 kg) were randomized into one of three groups, the NHE group (n= 16), RB group (n= 15), or the control group (CG) (n= 16). The eccentric training intervention consisted of 27 supervised training sessions over 10 weeks. Within-group analysis showed significant improvements (p<0.001) in right SLHB (+25.52% for NHE and +18.33% for RB) and left SLHB (+28.92% for NHE and +20.08 for RB) from pretest to post-test in NHE and RB. However, no significant pre-post changes were observed for the CG in any variable. In addition, a significant time effect (p= 0.028) was also observed for NHE in bilateral asymmetry decreasing from pre to post-test. In the between-groups analysis, significant better results were found in right SLHB and left SLHB, in the NHE group and RB group in comparison to CG. However, there were no differences between the eccentric training groups (NHE vs RB). The RB seems to be a viable alternative to the NHE to developing posterior lower limb muscle strength based on SLHB.

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