Latest research in football - week 26 - 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 Football training improves lean body mass in men with prostate cancer undergoing androgen deprivation therapy
Reference: Scand J Med Sci Sports. 2014 Aug;24 Suppl 1:105-12. doi: 10.1111/sms.12260.
Authors: Uth J, Hornstrup T, Schmidt JF, Christensen JF, Frandsen C, Christensen KB, Helge EW, Brasso K, Rørth M, Midtgaard J, Krustrup P.
Summary: Androgen deprivation therapy (ADT) remains a cornerstone in the management of patients with prostate cancer (PCa) despite adverse effects on body composition and functional parameters. We compared the effects of football training with standard care in PCa patients managed with ADT (> 6 months). Fifty-seven men aged 67 (range: 43-74) were randomly assigned to a football group (FG, n = 29) or a usual care control group (CON, n = 28). The primary outcome was change in lean body mass (LBM) assessed by dual-energy X-ray absorptiometry scanning. Secondary outcomes included changes in knee-extensor muscle strength (one repetition maximum), fat percentage, and maximal oxygen uptake (VO2max ). Mean heart rate during training was 137.7 (standard deviation 13.7) bpm or 84.6 (3.9)% HRmax. In FG, LBM increased by 0.5 kg [95% confidence interval (CI) 0.1-0.9; P = 0.02] with no change in CON (mean group difference 0.7 kg; 95% CI 0.1-1.2; P = 0.02). Also, muscle strength increased in FG (8.9 kg; 95% CI 6.0-11.8; P < 0.001) with no change in CON (mean group difference 6.7 kg; 95% CI 2.8-10.7; P < 0.001). In FG, VO2max increased (1.0 mL/kg/min; 95% CI 0.2-1.9; P = 0.02) and fat percentage tended to decrease (0.7%; 95%CI 1.3-0.0; P = 0.06), but these changes were not significantly different from CON. In conclusion, football training over 12 weeks improved LBM and muscle strength compared with usual care in men with prostate cancer receiving ADT.

#2 Positive effects of football on fitness, lipid profile, and insulin resistance in Brazilian patients with type 2 diabetes
Reference: Scand J Med Sci Sports. 2014 Aug;24 Suppl 1:57-65. doi: 10.1111/sms.12258.
Authors: de Sousa MV, Fukui R, Krustrup P, Pereira RM, Silva PR, Rodrigues AC, de Andrade JL, Hernandez AJ, da Silva ME.
Summary: We evaluated the effects of recreational football training combined with calorie-restricted diet (football + diet) vs calorie-restricted diet alone (diet) on aerobic fitness, lipid profile, and insulin resistance indicators in type 2 diabetes (T2D) patients. Forty-four T2D patients aged 48-68 years (27 females, 17 males) were randomly allocated to the football + diet group (FDG; n = 22) or to the diet group (DG; n = 22), of whom 19 FDG and 15 DG subjects completed the study. The football training was performed for 3 × 40 min/week for 12 weeks. Dual-energy X-ray absorptiometry scanning, treadmill testing, and fasting blood samplings were performed pre and post-intervention. After 12 weeks, maximal oxygen uptake (VO2max ) was elevated (P < 0.05) by 10 ± 4% in FDG but not in DG (-3 ± 4%, P < 0.05). After 12 weeks, reductions in blood triglycerides (0.4 ± 0.1 mmol/L), total cholesterol (0.6 ± 0.2 mmol/L), low-density lipoprotein, and very low-density lipoprotein levels were observed only in FDG. Fat mass decreased (P < 0.05) by 3.4 ± 0.4 kg in FDG and 3.7 ± 0.4 kg in DG. The lower (P < 0.05) glucagon and homeostatic model assessment of insulin resistance indicated an improvement in insulin sensitivity in FDG. In conclusion, football combined with restricted diet was effective in enhancing VO2max , reducing total cholesterol and triglycerides, and increasing insulin sensitivity, potentially providing better tools for the prevention of T2D complications than diet alone.

#3 Football training improves cardiovascular health profile in sedentary, premenopausal hypertensive women
Reference: Scand J Med Sci Sports. 2014 Aug;24 Suppl 1:36-42. doi: 10.1111/sms.12278.
Authors: Mohr M, Lindenskov A, Holm PM, Nielsen HP, Mortensen J, Weihe P, Krustrup P.
Summary: The present study examined the effects of short-term recreational football training on blood pressure (BP), fat mass, and fitness in sedentary, 35-50-year-old premenopausal women with mild hypertension. Forty-one untrained, hypertensive women were randomized into a football training group (n = 21; FTG) and a control group (n = 20; CON). FTG performed 45 ± 1 1-h small-sided football training sessions during the 15-week intervention period. BP, body composition (dual-energy x-ray absorptiometry), blood lipid profile, and fitness level were determined pre- and post-intervention. After 15 weeks, systolic and diastolic BP, respectively, were lowered more (P < 0.05) in FTG (-12 ± 3 and -6 ± 2 mmHg) than in CON (-1 ± 1 and 1 ± 2 mmHg). Total body fat mass decreased more (P < 0.05) in FTG than in CON during the 15-week intervention period (-2.3 ± 0.5 kg vs 0.4 ± 0.3 kg). After 15 weeks, both total cholesterol (-0.4 ± 0.1 mmol/L vs 0.1 ± 0.2 mmol/L) and triglyceride (-0.2 ± 0.1 mmol/L vs 0.3 ± 0.2 mmol/L) were lowered more (P < 0.05) in FTG than in CON. Yo-Yo intermittent endurance level 1 test performance increased more (P < 0.05) in FTG than in CON (111 ± 18% vs 1 ± 3%) during the 15-week intervention period. In conclusion, short-term football training resulted in a marked reduction in BP and induced multiple improvements in fitness and cardiovascular health profile of untrained, premenopausal women with mild hypertension.

#4 Effects of a 5-month football program on perceived psychological status and body composition of overweight boys
Reference: Scand J Med Sci Sports. 2014 Aug;24 Suppl 1:10-6. doi: 10.1111/sms.12268.
Authors: Seabra AC, Seabra AF, Brito J, Krustrup P, Hansen PR, Mota J, Rebelo A, Rêgo C, Malina RM.
Summary: The effects of a 5-month intervention of football instruction and practice on the perceived psychological status and body composition of overweight boys were examined. Twelve boys (8-12 years; body mass index ≥ 85th percentile) participated in a structured 5-month football program, consisting of four weekly 60-90 min sessions with mean heart rate > 80%HRmax [football group (FG)]. A control group (CG) included eight boys of equivalent age from an obesity clinic located in the same area as the school. Both groups participated in two sessions of 45-90-min physical education per week at school. Indicators of perceived psychological status included body image, self-esteem, attraction to participation in physical activity, and perceived physical competence measured with standardized questionnaires. Body composition was evaluated using dual-energy X-ray absorptiometry. From baseline through 5 months, FG improved (P < 0.05) in all indicators of psychological status (%Δ = +11.7 to +29.2%) compared with CG (%Δ = -32.1 to +0.5%). Changes in percentage body fat and lean body mass, however, did not differ between FG and CG. The findings suggest that a 5-month football intervention program was effective in improving the psychological status of overweight boys but did not significantly alter body composition.

#5 Structural and functional cardiac adaptations to a 10-week school-based football intervention for 9-10-year-old children
Reference: Scand J Med Sci Sports. 2014 Aug;24 Suppl 1:4-9. doi: 10.1111/sms.12277.
Authors: Krustrup P, Hansen PR, Nielsen CM, Larsen MN, Randers MB, Manniche V, Hansen L, Dvorak J, Bangsbo J.
Summary: The present study investigated the cardiac effects of a 10-week football training intervention for school children aged 9-10 years using comprehensive transthoracic echocardiography as a part of a larger ongoing study. A total of 97 pupils from four school classes were cluster-randomized into a control group that maintained their usual activities (CON; two classes, n = 51, 21 boys and 30 girls) and a football training group that performed an additional 3 × 40 min of small-sided football training per week (FT; two classes, n = 46, 23 boys and 23 girls). No baseline differences were observed in age, body composition, or echocardiographic variables between FT and CON. After the 10-week intervention, left ventricular posterior wall diameter was increased in FT compared with CON [0.4 ± 0.7 vs -0.1 ± 0.6 (± SD) mm; P < 0.01] as was the interventricular septum thickness (0.2 ± 0.7 vs -0.2 ± 0.8 mm; P < 0.001). Global isovolumetric relaxation time increased more in FT than in CON (3.8 ± 10.4 vs -0.9 ± 6.6 ms, P < 0.05) while the change in ventricular systolic ejection fraction tended to be higher (1.4 ± 8.0 vs -1.1 ± 5.5%; P = 0.08). No changes were observed in resting heart rate or blood pressure. In conclusion, a short-term, school-based intervention comprising small-sided football sessions resulted in significant structural and functional cardiac adaptations in pre-adolescent children.

#6 More Than Meets the Eye: A Rapidly Progressive Skin Infection in a Football Player
Reference: Clin J Sport Med. 2014 Jun 17. [Epub ahead of print]
Authors: Geissler KE, Borchers JR.
Summary: Fournier gangrene (FG) is a rare polymicrobial infection of perineum that carries a high mortality rate. Survival depends on rapid identification of the infection with early and extensive debridement of necrotic tissue. We present a case of an otherwise healthy American football offensive lineman who was initially hospitalized for gluteal abscess and advancing cellulitis. The patient was discovered to have FG during intraoperative debridement of the abscess and was subsequently treated with several weeks of broad-spectrum antibiotics. This case highlights the importance that team physicians play in the identification and appropriate management of potentially life-threatening infections.

#7 Motivational patterns as an instrument for predicting success in promising young football players
Reference: J Sports Sci. 2014 Jun 18:1-9. [Epub ahead of print]
Authors: Zuber C, Zibung M, Conzelmann A.
Summary: Psychological characteristics are crucial to identifying talents, which is why these are being incorporated in today's multidimensional talent models. In addition to multidimensionality, talent studies are increasingly drawing on holistic theories of development, leading to the use of person-oriented approaches. The present study adopts such an approach by looking at the influence that motivational characteristics have on the development of performance, in a person-oriented way. For this purpose, it looks at how the constructs achievement motive, achievement goal orientation and self-determination interact with one another, what patterns they form and how these patterns are linked to subsequent sports success. Ninety-seven top young football players were questioned twice. Another year later, it was enquired which of these players had been selected for the U15 national team. At both measuring points, four patterns were identified, which displayed a high degree of structural and individual stability. As expected, the highly intrinsically achievement-oriented players were significantly more likely to move up into the U15 national team. The results point to the importance of favourable patterns of motivational variables in the form of specific types, for medium-term performance development among promising football talents, and thus provide valuable clues for the selection and promotion of those.

#8 The Secondary School Football Coach's Relationship with the Athletic Trainer and Their Perspectives on Exertional Heat Stroke
Reference: J Athl Train. 2014 Jun 16. [Epub ahead of print]
Authors: Adams WM, Mazerolle SM, Casa DJ, Huggins RA, Burton L.
Summary: Prior researchers have examined the first-aid knowledge and decision making among high school coaches, but little is known about their perceived knowledge of exertional heat stroke (EHS) or their relationships with an athletic trainer (AT). Objective :  To examine secondary school football coaches' perceived knowledge of EHS and their professional relationship with an AT. A Web-based management system was used and Thirty-eight secondary school head football coaches (37 men, 1 woman) participated in this study. Their average age was 47 ± 10 years old, and they had 12 ± 9 years' experience as a head football coach. Participants responded to a series of online questions that were focused on their perceived knowledge of EHS and professional relationships with ATs. Data credibility was established through multiple-analyst triangulation and peer review. We analyzed the data by borrowing from the principles of a general inductive approach. Two dominant themes emerged from the data: perceived self-confidence of the secondary school coach, and the influence of the AT. The first theme highlighted the perceived confidence, due to basic emergency care training, of the coach regarding management of an emergency situation, despite a lack of knowledge. The second theme illustrated the secondary school coach's positive professional relationships with ATs regarding patient care and emergency procedures. Of the coaches who participated, 89% (34 out of 38) indicated positive interactions with their ATs. These secondary school coaches were unaware of the potential causes of EHS or the symptoms associated with EHS, and they had higher perceived levels of self-confidence in management abilities than indicated by their perceived knowledge level. The secondary school football coaches valued and understood the role of the AT regarding patient and emergency care.

#9 Low back pain in young elite field hockey players, football players and speed skaters: Prevalence and risk factors
Reference: J Back Musculoskelet Rehabil. 2014 Jun 24. [Epub ahead of print]
Authors: van Hilst J, Hilgersom NF, Kuilman MC, Kuijer PP, Frings-Dresen MH.
Summary: Low back pain (LBP) hampers performance and experiencing an episode of LBP is strongly associated with recurrent episodes. The prevalence of LBP and associated risk factors among young elite athletes in popular sports in the Netherlands were studied. A questionnaire-based cross-sectional study was performed among 236 young elite athletes aged between 14-25 years in field hockey, football and speed skating. One hundred and eighty one (n=181) athletes responded (response rate 77%). The overall, 12-month prevalence of LBP for the three sports was 60%: field hockey 56%, football 64% and speed skating 60%. Satisfaction with their own performance (OR=0.5 95%CI:0.3-0.9) and with the coaching staff (OR=0.5, 95%CI:0.4-0.8) were associated with a lower occurrence of LBP in field hockey. No sport-related risk factors were found in football. In speed skating more training hours (OR=1.1, 95%CI:1.0-1.2), performance of Pilates (OR=4.1, 95%CI:1.1-15.7) and more time spent on warming up (OR=1.1, 95%CI:1.0-1.1) were associated with the occurrence of LBP.CONCLUSIONS: Prevalence of LBP among young elite athletes compared to the general age-related population was 3--5 times higher. Sport-related risk factors of LBP were found in field hockey and in speed skating.

#10 Effect of DHA on plasma fatty acid availability and oxidative stress during training season and football exercise
Reference: Food Funct. 2014 Jun 23. [Epub ahead of print]
Authors: Martorell M, Capó X, Sureda A, Batle JM, Llompart I, Argelich E, Tur JA, Pons A.
Summary: The aim was to determine the effects of a diet supplemented with 1.14 g per day of docosahexaenoic acid (DHA) for eight weeks on the plasma oxidative balance and anti-inflammatory markers after training and acute exercise. Fifteen volunteer male football players were randomly assigned to placebo or experimental and supplemented groups. Blood samples were taken under resting conditions at the beginning and after eight weeks of training under resting and post-exercise conditions. The experimental beverage increased the plasma DHA availability in non-esterified fatty acids (NEFAs) and triglyceride fatty acids (TGFAs) and increased the polyunsaturated fatty acid (PUFA) fraction of NEFAs but had no effects on the biomarkers for oxidative balance in plasma. During training, plasma protein markers of oxidative damage, the haemolysis degree and the antioxidant enzyme activities increased, but did not affect lipid oxidative damage. Training season and DHA influenced the circulating levels of prostaglandin E2 (PGE2). Acute exercise did not alter the basal levels of plasma markers for oxidative and nitrosative damage of proteins and lipids, and the antioxidant enzyme activities, although DHA-diet supplementation significantly increased the PGE2 in plasma after acute exercise. In conclusion, the training season and acute exercise, but not the DHA diet supplementation, altered the pattern of plasma oxidative damage, as the antioxidant system proved sufficient to prevent the oxidative damage induced by the acute exercise in well-trained footballers. The DHA-diet supplementation increased the prostaglandin PGE2 plasma evidencing anti-inflammatory effects of DHA to control inflammation after acute exercise.

#11 Prevalence of abnormal ECGs in male soccer players decreases with the Seattle criteria, but is still high
Reference: Scand J Med Sci Sports. 2014 Jun 24. doi: 10.1111/sms.12274. [Epub ahead of print]
Authors: Berge HM, Gjesdal K, Andersen TE, Solberg EE, Steine K.
Summary: Electrocardiogram (ECG) and echocardiography are mandatory in preparticipation cardiac screening in soccer players. Abnormal ECG findings usually require follow-up investigations. The main aim of this study was to compare the prevalence of abnormal ECG findings in male professional soccer players according to European Society of Cardiology's (ESC) recommendations and the Seattle criteria, and to assess the need for echocardiography. ECGs from 587 of 595 (99%) players were recorded with ClickECG, and measurements were derived with visually adjusted on-screen calipers on the computer-based averaged PQRST complex. Echocardiographic recordings were performed with Vivid 7/i and categorized according to reference values for athlete's heart. After the initial screening, 32 (5.5%) players were recommended for follow-up. The prevalence of abnormal ECGs was 29.3% vs 11.2% according to the ESC's recommendations and the Seattle criteria, respectively. None of the players with abnormal ECGs only according to the ESC's recommendations had abnormal echocardiograms. Echocardiography alone detected one player with abnormalities (athlete's heart). The Seattle criteria reduced the number of athletes with abnormal ECGs considerably compared with the ESC recommendations. Based on echocardiographic evaluations, this increased the specificity of the Seattle criteria, without increasing the number of false-negative ECGs. The need for mandatory echocardiography in soccer players seems limited.

#12 Estimated metabolic and mechanical demands during different small-sided games in elite soccer players
Reference: Hum Mov Sci. 2014 Jun 23;36C:123-133. doi: 10.1016/j.humov.2014.05.006. [Epub ahead of print]
Authors: Gaudino P, Alberti G, Iaia FM.
Summary: The present study examined the extent to which game format (possession play, SSG-P and game with regular goals and goalkeepers, SSG-G) and the number of players (5, 7 and 10 a-side) influence the physical demands of small-sided soccer games (SSGs) in elite soccer players. Training data were collected during the in-season period from 26 English Premier League outfield players using global positioning system technology. Total distance covered, distance at different speed categories and maximal speed were calculated. In addition, we focused on changes in velocity by reporting the number of accelerations and decelerations carried out during the SSGs (divided in two categories: moderate and high) and the absolute maximal values of acceleration and deceleration achieved. By taking into account these parameters besides speed and distance values, estimated energy expenditure and average metabolic power and distance covered at different metabolic power categories were calculated. All variables were normalized by time (i.e., 4min). The main findings were that the total distance, distances run at high speed (>14.4kmh-1) as well as absolute maximum velocity, maximum acceleration and maximum deceleration increased with pitch size (10v10>7v7>5v5; p<.05). Furthermore, total distance, very high (19.8-25.2kmh-1) and maximal (>25.2kmh-1) speed distances, absolute maximal velocity and maximum acceleration and deceleration were higher in SSG-G than in SSG-P (p<.001). On the other hand, the number of moderate (2-3ms-2) accelerations and decelerations as well as the total number of changes in velocity were greater as the pitch dimensions decreased (i.e., 5v5>7v7>10v10; p<.001) in both SSG-G and SSG-P. In addition, predicted energy cost, average metabolic power and distance covered at every metabolic power categories were higher in SSG-P compared to SSG-G and in big than in small pitch areas (p<.05). A detailed analysis of these drills is pivotal in contemporary football as it enables an in depth understanding of the workload imposed on each player which consequently has practical implications for the prescription of the adequate type and amount of stimulus during exercise training.


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