Latest research in football - week 25 - 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 Factors associated with injuries among first-division Rwandan female soccer players
Reference: Afr Health Sci. 2013 Dec;13(4):1021-6. doi: 10.4314/ahs.v13i4.23.
Authors: Niyonsenga J, Phillips J.
Summary: Female soccer has grown tremendously in the last decade. Studies have suggested that female soccer players are more susceptible to injuries than their male counterparts, and their vulnerability is due mainly to intrinsic factors such as their anatomical and physiological structure. To establish factors associated with soccer injuries among first-division Rwandan female soccer players. In a descriptive cross-sectional study, self-administered questionnaires were used to investigate factors associated with injuries among soccer players. Almost half of the 300 participants (45%) indicated having been injured in the three seasons prior to the study. More than half (52.6%) were recurrent injuries. The ankle was the most common body part injured. Intrinsic factors associated with injuries were age, excessive ankle range of motion, pre-menstrual symptoms, and previous injury (p-value < 0.05). Extrinsic factors associated with injuries were use of oral contraceptive pills, (OCP), competition level, use of protective equipment, and player's position. The large number of recurring injuries was notable, emphasizing the importance of prevention strategies and access to adequately trained medical personnel as research has shown a significant reduction in the prevalence of recurring injuries after the introduction of effective prevention programmes.

#2 Carbohydrate Ingestion Before and During Soccer Match Play and Blood Glucose and Lactate Concentrations
Reference: J Athl Train. 2014 Jun 16. [Epub ahead of print]
Authors: Russell M, Benton D, Kingsley M.
Summary: The ingestion of carbohydrate (CHO) before and during exercise and at halftime is commonly recommended to soccer players for maintaining blood glucose concentrations throughout match play. However, an exercise-induced rebound glycemic response has been observed in the early stages of the second half of simulated soccer-specific exercise when CHO-electrolyte beverages were consumed regularly. Therefore, the metabolic effects of CHO beverage consumption throughout soccer match play remain unclear. The purpose was to investigate the blood glucose and blood lactate responses to CHOs ingested before and during soccer match play. Ten male outfield academy soccer players (age = 15.6 ± 0.2 years, height = 1.74 ± 0.02 m, mass = 65.3 ± 1.9 kg, estimated maximal oxygen consumption = 58.4 ± 0.8 mL·kg-1·min-1) were used. Players received a 6% CHO-electrolyte solution or an electrolyte (placebo) solution 2 hours before kickoff, before each half (within 10 minutes), and every 15 minutes throughout exercise. Blood samples were obtained at rest, every 15 minutes during the match (first half: 0-15, 15-30, and 30-45 minutes; second half: 45-60, 60-75, and 75-90 minutes) and 10 minutes into the halftime break. Metabolic responses (blood glucose and blood lactate concentrations) and markers of exercise intensity (heart rate) were recorded. Supplementation influenced the blood glucose response to exercise (time × treatment interaction effect: P ≤ .05), such that glucose concentrations were higher at 30 to 45 minutes in the CHO than in the placebo condition. However, in the second half, blood glucose concentrations were similar between conditions because of transient reductions from peak values occurring in both trials at halftime. Blood lactate concentrations were elevated above those at rest in the first 15 minutes of exercise (time-of-sample effect: P < .001) and remained elevated throughout exercise. Supplementation did not influence the pattern of response (time × treatment interaction effect: P = .49). Ingestion of a 6% CHO-electrolyte beverage before and during soccer match play did not benefit blood glucose concentrations throughout the second half of exercise.

#3 The effect of coach and player injury knowledge, attitudes and beliefs on adherence to the FIFA 11+ programme in female youth soccer
Reference: Br J Sports Med. 2014 Jun 13. pii: bjsports-2014-093543. doi: 10.1136/bjsports-2014-093543. [Epub ahead of print]
Authors: McKay CD, Steffen K, Romiti M, Finch CF, Emery CA.
Summary: Injury knowledge and beliefs influence uptake of prevention programmes, but the relationship between knowledge, beliefs and adherence remains unclear. The aim was to describe injury knowledge and beliefs among youth female soccer coaches and players, and to identify the relationship between these factors, different delivery strategies of the FIFA 11+ programme. A subcohort analysis from a cluster-randomised controlled trial of 31 female soccer teams (coaches n=29, players (ages 13-18) n=258). Preseason and postseason questionnaires were used to assess knowledge and beliefs. Teams recorded FIFA 11+ adherence during the season. At baseline, 62.8% (95% CI 48.4% to 77.3%) of coaches and 75.8% (95% CI 71.5% to 80.1%) of players considered 'inadequate warm-up' a risk factor for injury. There was no effect of delivery method (OR=1.1; 95% CI 0.8 to 1.5) or adherence (OR=1.0; 95% CI 0.9 to 1.1) on this belief. At baseline, 13.8% (95% CI 1.3% to 26.4%) of coaches believed a warm-up could prevent muscle injuries, but none believed it could prevent knee and ankle injuries. For players, 9.7% (95% CI 6.1% to 13.3%), 4.7% (95% CI 2.1% to 7.3%) and 4.7% (95% CI 2.1% to 7.3%) believed a warm-up would prevent muscle, knee and ankle injuries, respectively. Years of playing experience were negatively associated with high adherence for coaches (OR=0.93; 0.88 to 0.99) and players (OR=0.92; 0.85 to 0.98). There were gaps in injury knowledge and beliefs, which differed for coaches and players. Beliefs did not significantly affect adherence to the FIFA 11+, suggesting additional motivational factors should be considered.

#4 Psychometric properties of the motor diagnostics in the German football talent identification and development programme
Reference: J Sports Sci. 2014 Jun 20:1-15. [Epub ahead of print]
Authors: Höner O, Votteler A, Schmid M, Schultz F, Roth K.
Summary: The utilisation of motor performance tests for talent identification in youth sports is discussed intensively in talent research. This article examines the reliability, differential stability and validity of the motor diagnostics conducted nationwide by the German football talent identification and development programme and provides reference values for a standardised interpretation of the diagnostics results. Highly selected players (the top 4% of their age groups, U12-U15) took part in the diagnostics at 17 measurement points between spring 2004 and spring 2012 (N = 68,158). The heterogeneous test battery measured speed abilities and football-specific technical skills (sprint, agility, dribbling, ball control, shooting, juggling). For all measurement points, the overall score and the speed tests showed high internal consistency, high test-retest reliability and satisfying differential stability. The diagnostics demonstrated satisfying factorial-related validity with plausible and stable loadings on the two empirical factors "speed" and "technical skills". The score, and the technical skills dribbling and juggling, differentiated the most among players of different performance levels and thus showed the highest criterion-related validity. Satisfactory psychometric properties for the diagnostics are an important prerequisite for a scientifically sound rating of players' actual motor performance and for the future examination of the prognostic validity for success in adulthood.

#5 Executive summary: Football for health - prevention and treatment of non-communicable diseases across the lifespan through football
Reference: Scand J Med Sci Sports. 2014 Aug;24 Suppl 1:147-50. doi: 10.1111/sms.12271.
Authors: Bangsbo J, Junge A, Dvorak J, Krustrup P.
Summary: This supplement contains 16 original articles describing how football conducted as small sided games affects fitness and health of untrained individuals across the lifespan. The intermittent nature of football and high exercise intensity result in a broad range of effects. The heart changes its structure and improves its function. Blood pressure is markedly reduced with the mean arterial blood pressure being lowered by ~10 mmHg for hypertensive men and women training 2-3 times/week for 12-26 weeks. Triglycerides and cholesterol are lowered and body fat declines, especially in middle-aged men and women with type 2 diabetes. Furthermore, muscle mass and bone mineral density increases in a number of participant groups, including 65-75-year-old men. The functional capacity is elevated with increases in VO2 max of 10-15%, and 50-100% improvements in the capacity to perform intermittent work within 16 weeks. These effects apply irrespective of whether the participants are young, overweight, elderly or suffering from a disease. The studies clearly show that the participants enjoy playing football and form special relationships with their team mates. Thus, football is a healthy activity, providing a unique opportunity to increase recruitment and adherence to physical activity in a hitherto underserved population, and to treat and rehabilitate patients with hypertension, type 2 diabetes and prostate cancer.

#6 Football Fitness - a new version of football? A concept for adult players in Danish football clubs
Reference: Scand J Med Sci Sports. 2014 Aug;24 Suppl 1:138-46. doi: 10.1111/sms.12276.
Authors: Bennike S, Wikman JM, Ottesen LS.
Summary: This article explores a new Danish football-based activity for health called Football Fitness (FF). Data are from quantitative and qualitative methods, and the theoretical framework for the analysis of the organizational form of FF is the theory of path dependency (Mahoney) and first- and second-order change (Watzlawick et al.). Theories of Pestoff concerning differences between state, market, and the civil society and theories of voluntary associations in a Danish context (Kaspersen & Ottesen; Ibsen & Seippel) are applied. This article indicates how FF is a result of the changing landscape of sport and argues that it can be beneficial to target sports organizations and include the expertise of non-profit sports clubs if the goal is to raise the physical activity level of the local community and make these long lasting. But the organizations need to consider how this is to be done. FF, established by the Danish Football Association (FA) and managed by the voluntary clubs, is one example in a Danish context. Data indicate that FF is beneficial to the clubs involved in a number of ways. Among other things, it attracts new user groups and improves the club environment, including social activities and parental environment.

#7 Physiological response and activity profile in recreational small-sided football: No effect of the number of players
Reference: Scand J Med Sci Sports. 2014 Aug;24 Suppl 1:130-7. doi: 10.1111/sms.12232.
Authors: Randers MB, Nielsen JJ, Bangsbo J, Krustrup P.
Summary: We examined the effect of the number of players on the activity profile and physiological response to small-sided recreational football games with fixed relative pitch size. Twelve untrained men (age: 33.0 ± 6.4 (± standard deviation) years, fat%: 22.4 ± 6.1%, VO2 max: 43.3 ± 5.2 mL/min/kg) completed three football sessions of 4 times 12 min with 3v3, 5v5, or 7v7 in a randomized order. Pitch sizes were 80 m(2) per player. Activity profile (10 Hz global positioning system), heart rate (HR), and rating of perceived exertion (RPE) were measured, and blood samples were collected before and during games. Average HR was 84.1 ± 3.9, 84.5 ± 5.0, and 82.8 ± 5.1 %HRmax for 3v3, 5v5, and 7v7, respectively, with no difference between game formats. High blood lactate (5.9 ± 2.9, 5.9 ± 2.4, and 5.5 ± 2.9 mmol/L) and plasma NH3 concentrations (124 ± 48, 112 ± 38, and 126 ± 55 μmol/L, respectively) were observed during 3v3, 5v5, and 7v7, respectively, with no difference between formats. Similar total distance (3676 ± 478, 3524 ± 467, and 3577 ± 500 m), high-intensity distance (349 ± 145, 406 ± 134, and 409 ± 165 m), and RPE (4.7 ± 1.6, 4.9 ± 2.1, and 4.6 ± 1.8) were also observed. The number of intense accelerations (500 ± 139 vs 459 ± 143 and 396 ± 144) were higher (P < 0.05) during 3v3 than 5v5 and 7v7. In conclusion, the intensity is high during small-sided recreational football games, with similar physiological responses for 6-14 players when pitch size is adapted, providing further evidence that effective recreational football training is easy to organize.

#8 Street football is a feasible health-enhancing activity for homeless men: Biochemical bone marker profile and balance improved
Reference: Scand J Med Sci Sports. 2014 Aug;24 Suppl 1:122-9. doi: 10.1111/sms.12244.
Authors: Helge EW, Randers MB, Hornstrup T, Nielsen JJ, Blackwell J, Jackman SR, Krustrup P.
Summary: This case-control study investigated the feasibility of street football as a health-enhancing activity for homeless men, specifically the musculoskeletal effects of 12 weeks of training. Twenty-two homeless men participated in the football group (FG) and 10 served as controls (C). Plasma osteocalcin, TRACP5b, leptin, and postural balance were measured, and whole-body DXA scanning was performed. The attendance rate was 75% (2.2 ± 0.7 sessions per week). During 60 min of training, the total distance covered was 5534 ± 610 m, with 1040 ± 353, 2744 ± 671, and 864 ± 224 m covered by high-intensity, low-intensity, and backwards/sideways running, respectively. In FG, osteocalcin increased by 27% from 20.1 ± 11.1 to 25.6 ± 11.8 ng/mL (P = 0.007). Postural balance increased by 39% (P = 0.004) and 46% (P = 0.006) in right and left leg. Trunk bone mineral density increased by 1.0% from 0.959 ± 0.095 to 0.969 ± 0.090 g/cm(2) (P = 0.02). No effects were observed in C. In conclusion, street football appears to be a feasible training activity with musculoskeletal health benefits for homeless men. The attendance rate and the training intensity were high, and 12 weeks of training resulted in a substantial anabolic response in bone metabolism. Postural balance improved markedly, and the overall risk of falling, and hospitalization due to sudden trauma, could be reduced by street football for homeless men.

#9 "All boys and men can play football": A qualitative investigation of recreational football in prostate cancer patients
Reference: Scand J Med Sci Sports. 2014 Aug;24 Suppl 1:113-21. doi: 10.1111/sms.12193.
Authors: Bruun DM, Krustrup P, Hornstrup T, Uth J, Brasso K, Rørth M, Christensen JF, Midtgaard J.
Summary: Evidence is accumulating that exercise-based rehabilitation improves physical capacity and quality of life in cancer survivors. However, recruitment and persistence of male cancer patients in rehabilitation and physical activity are low and novel health promotion strategies are warranted. The purpose of this study was to gain an understanding of the meaning of recreational football as a team and interaction-oriented health-promoting activity in men with prostate cancer (n = 26). Qualitative data were collected through six focus group interviews (n = 4-6) and 20 h of participant observations. The two data sets were analyzed using framework analysis. The analysis produced 11 subthemes that were structured into three overarching themes: (a) motivational drivers; (b) united in sport; and (c) confirmation of own capacity. The findings indicated that participants regarded football as a welcome opportunity to regain control and acquire a sense of responsibility for own health without assuming the patient role, and football training legitimized and promoted mutual caring behavior in a male-oriented context. In conclusion, the study suggests that football, due to its cultural representation of masculine ideals, may be a potent and unique strategy for increasing recruitment and adherence to physical activity in prostate cancer patients.


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