Latest research in football - week 8 - 2020

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 Oxygen therapy in patients with ST elevation myocardial infarction based on the culprit vessel: results from the randomized controlled SOCCER trial
Reference: BMC Emerg Med. 2020 Feb 18;20(1):12. doi: 10.1186/s12873-020-00309-y.
Authors: Mokhtari A, Akbarzadeh M, Sparv D, Bhiladvala P, Arheden H, Erlinge D, Khoshnood A
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Summary: Oxygen (O2) treatment has been a cornerstone in the treatment of patients with myocardial infarction. Recent studies, however, state that supplemental O2 therapy may have no effect or harmful effects in these patients. The aim of this study was thus to evaluate the effect of O2 therapy in patients with ST Elevation Myocardial Infarction (STEMI) based on the culprit vessel; Left Anterior Descending Artery (LAD) or Non-LAD. This was a two-center, investigator-initiated, single-blind, parallel-group, randomized controlled trial at the Skåne university hospital, Sweden. A simple computer-generated randomization was used. Patients were either randomized to standard care with O2 therapy (10 l/min) or air until the end of the primary percutaneous coronary intervention. The patients underwent a Cardiac Magnetic Resonance Imaging (CMRI) days 2-6. The main outcome measures were Myocardium at Risk (MaR), Infarct Size (IS) and Myocardial Salvage Index (MSI) as measured by CMRI, and median high-sensitive troponin T (hs-cTnT). A total of 229 patients were assessed for eligibility, and 160 of them were randomized to the oxygen or air arm. Because of primarily technical problems with the CMRI, 95 patients were included in the final analyses; 46 in the oxygen arm and 49 in the air arm. There were no significant differences between patients with LAD and Non-LAD as culprit vessel with regard to their allocation (oxygen or air) with regards to MSI, MaR, IS and hs-cTnT. The results indicate that the location of the culprit vessel has probably no effect on the role of supplemental oxygen therapy in STEMI patients.

#2 ALCAPA syndrome in an asymptomatic young soccer player
Reference: Turk Gogus Kalp Damar Cerrahisi Derg. 2019 Jun 14;27(3):388-391. doi: 10.5606/tgkdc.dergisi.2019.16320. eCollection 2019 Jul.
Authors: Ramoğlu MG, Bulut MO, Epçaçan S, Dedemoğlu M
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Summary: Anomalous origin of left coronary artery from pulmonary artery syndrome is a rare, but severe congenital cardiac malformation. It is an important cause of dilated cardiomyopathy and left heart failure during infancy and, if left untreated, the prognosis is poor with an overall mortality rate over 90%. About 15% of patients can survive beyond the first year of life, depending on the development of collateral circulation and may present with angina, dyspnea, syncope, and arrhythmias. Myocardial infarction and sudden cardiac death may be the only and the first symptom in some cases. The treatment of choice for this syndrome is urgent surgical intervention with favorable long-term outcomes. Herein, we present an asymptomatic adolescent active sportsman who was diagnosed with anomalous origin of left coronary artery from pulmonary artery syndrome and underwent a successful surgery.

#3 Does Recreational Soccer Change Metabolic Syndrome Status in Obese Adolescents? A Pilot Study
Reference: Res Q Exerc Sport. 2020 Feb 21:1-9. doi: 10.1080/02701367.2019.1711007. [Epub ahead of print]
Authors: Vasconcellos F, Cunha FA, Gonet DT, Farinatti PTV
Summary: The purpose was to evaluate whether a soccer program (RSP) might lower risk factors related to metabolic syndrome (MetS) in obese adolescents. A 12-week randomized controlled trial [RSP: n = 6 (2 girls), age = 13.9 ± 1.6 yr, body mass index = 30.5 ± 2.1 kg/m2; Control: n = 7 (2 girls); age = 14.7 ± 2.3 yr, body mass index: 30.8 ± 3.1 kg/m2] was conducted. Participants underwent anthropometric, body fractioning, blood pressure, lipid profile, and glucose tolerance assessments at baseline and post-intervention. MetS status was determined based on waist circumference and at least two additional criteria: high blood pressure, hypertriglyceridemia, dyslipidemia, and hyperglycemia. RSP included eutrophic and overweight adolescents and consisted of small-sided games (85 ± 4% maximal heart rate) performed three times/week. High-density lipoprotein increased [(HDL) ∆15.5 ± 5.2 mg·dL-1; p = .01] and triglycerides lowered [(TG) ∆-34.7 ± 7.1 mg·dL-1; p = .02] after RSP intervention. Between-group differences were also detected for changes in HDL (∆13.0 ± 6.1 mg·dL-1; p = .04) and TG (∆-47.1 ± 7.7 mg·dL-1; p = .05). The presence of MetS lowered in RSP (5 in 6 participants; p = .02), but not Control (1 in 7 participants; p = .32). A 12-week RSP was effective to reduce MetS risk factors and status in obese adolescents.

#4 Return to play after three ipsilateral anterior cruciate ligament reconstructions in an elite soccer player: A case report
Reference: Int J Surg Case Rep. 2020 Feb 19;68:1-3. doi: 10.1016/j.ijscr.2020.02.027. [Epub ahead of print]
Authors: Noronha JC, Oliveira JP, Brito J
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Summary: Despite the reasonable success of ACL reconstruction, some athletes are not able to regain the level of play they once had. Here, we report the case of a 32-year-old male professional soccer player who sustained an ACL injury in his right knee. The patient had a history of two prior ipsilateral ACL injuries, which was reconstructed with ipsilateral hamstring autograft (first surgery) and ipsilateral patellar tendon autograft (revision surgery). Imaging examination revealed a small narrowing of the medial femoro-tibial compartment, a complete ACL rupture, partial medial meniscectomy, small cartilage lesions in the medial condyle, a 7° varus knee, an enlarged tibial tunnel, and a femoral tunnel positioned high above the intercondylar roof. A one-step re-revision surgery using a fresh-frozen, cadaveric, non-irradiated Achilles tendon allograft was planned. After surgery, physiotherapy was conducted once per day during 4 months. The patient started running at the 6th month, and returned to full training 8 months after surgery. The player returned to full competitive play 9 months after surgery and has been competing for the last 36 months at the highest level of play without any limitation, inflammation, pain, or perception of instability. In professional sports, when re-revision ACL reconstruction is indicated and the patient expects to return to competition, surgery should not be delayed. In these cases, the usefulness of Achilles tendon allograft should be taken into consideration for re-revision ACL reconstruction.

#5 The Association Between Interlimb Asymmetry and Athletic Performance Tasks: A Season-Long Study in Elite Academy Soccer Players
Reference: J Strength Cond Res. 2020 Feb 27. doi: 10.1519/JSC.0000000000003526. [Epub ahead of print]
Authors: Bishop C, Read P, Bromley T, Brazier J, Jarvis P, Chavda S, Turner A
Summary: The aims of this study were to determine the association between asymmetry and measures of speed and change of direction speed (CODS) performance throughout a competitive soccer season and, determine whether any observed changes in asymmetry were associated with changes in speed and CODS performance. Eighteen elite male under-23 academy soccer players performed unilateral countermovement jumps, unilateral drop jumps (DJ), 10- and 30-m sprints, and 505 CODS tests at pre, mid, and end of season. No significant relationships were evident during preseason or midseason between asymmetry and speed or CODS performance. Significant correlations were shown at the end of season between DJ height asymmetry and 10-m sprint time (ρ = 0.62; p = 0.006) and 505 time on the right limb (ρ = 0.65; p = 0.003). No significant correlations between changes in asymmetry and changes in speed or CODS were evident at any time point. Although numerous studies have reported associations between asymmetry and reduced athletic performance, it seems that these associations with speed and CODS do not track consistently over time. Thus, suggestions for the reduction of asymmetry that may indirectly enhance athletic performance cannot be made.

#6 The prevalence of disordered eating in elite male and female soccer players
Reference: Eat Weight Disord. 2020 Feb 27. doi: 10.1007/s40519-020-00872-0. [Epub ahead of print]
Authors: Abbott W, Brett A, Brownlee TE, Hammond KM, Harper LD, Naughton RJ, Anderson L, Munson EH, Sharkey JV, Randell RK, Clifford T
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Summary: The purpose was to examine the prevalence of disordered eating (DE) in elite male and female soccer players and the influence of perfectionism. Using a cross-sectional design, elite male (n = 137) and female (n = 70) soccer players and non-athlete controls (n = 179) completed the clinical perfectionism questionnaire (CPQ-12) and the eating attitudes test (EAT-26) to assess perfectionism and DE risk, respectively. Male soccer players had higher EAT-26 scores than controls (10.4 ± 9.9 vs. 6.8 ± 6.7; P = 0.001), but there were no differences in the prevalence of clinical levels of DE (EAT-26 score ≥ 20) (15 vs. 5%, respectively; X2 = 0.079) The proportion of females with DE risk was higher in controls [EAT-26: 13.9 ± 11.6 (25% of population)] than female players [EAT-26: 10.0 ± 9.0% (11% of population)] (X2 = 0.001). With linear regression, perfectionism explained 20% of the variation in DE risk in males (P = 0.001); in females, athletic status (player vs. control) and perfectionism were significant predictors of DE risk, explaining 21% of the variation (P = 0.001). Male reserve team players had higher EAT-26 (+ 3.5) and perfectionism (+ 2.7) scores than first-team players (P < 0.05). There were no differences in the prevalence of DE risk between the male and female soccer players (X2 = 0.595). The prevalence of DE risk was not different in elite male and female soccer players; in fact, the prevalence was greatest in non-athlete female controls. Perfectionism is a significant predictor of DE risk in males and females.

#7 Effect of Forefoot and Midfoot Bending Stiffness on Agility Performance and Foot Biomechanics in Soccer
Reference: J Appl Biomech. 2020 Feb 25:1-7. doi: 10.1123/jab.2019-0115. [Epub ahead of print]
Authors: Brinkmann DJ, Koerger H, Gollhofer A, Gehring D
Summary: Footwear bending stiffness is known to positively affect performance in agility maneuvers due to improved energy storage and propulsion based on a stiffer foot-shoe complex. However, the functional properties of the forefoot and midfoot differ. Therefore, the present study investigates the effect of the interface of longitudinal bending stiffness and the ratio of forefoot to midfoot bending stiffness on agility performance and foot biomechanics. A total of 18 male soccer players performed 2 agility tasks in footwear conditions that were systematically modified in forefoot and midfoot bending stiffness. Results revealed that higher longitudinal bending stiffness caused more foot exorotation at the initial ground contact (P < .05), less torsion (P < .001), and an anterior shift in the point of force application during push off (P = .01). In addition, the authors observed decreased forefoot bending (P < .05) and increased torsion (P < .01) in footwear with a higher forefoot-midfoot ratio. Finally, the agility performance was significantly impaired by 1.3% in the condition with the highest forefoot-midfoot ratio (P < .01). The high forefoot-midfoot ratio, that is, a stiff forefoot in combination with a soft midfoot, seemed to shift the flex line from anterior to posterior that may explain the performance impairment.

#8 Twelve eyes see more than eight. Referee bias and the introduction of additional assistant referees in soccer
Reference: PLoS One. 2020 Feb 26;15(2):e0227758. doi: 10.1371/journal.pone.0227758. eCollection 2020.
Authors: Albanese A, Baert S, Verstraeten O
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Summary: This study is the first to investigate whether the introduction of additional assistant referees in the UEFA Europa League (2009-2010 season) and the UEFA Champions League (2010-2011 season) was associated with lower referee bias in terms of home and "big" team favouritism. To this end, we analyse a unique database with pre- and within-game characteristics of all games in seven recent seasons in these leagues by means of bivariate probit regression models. We find evidence for substantial referee bias before the introduction of additional referees, while no such evidence is found after the introduction. Furthermore, additional assistants go hand in hand with more yellow cards for both home and away teams. We show that these findings are robust to multiple operationalisations of referee bias and that they are not just picking up a general time evolution towards less referee bias or the effect of parallel reforms.

#9 Significant differences in dietary intake of NCAA Division III soccer players compared to recommended levels
Reference: J Am Coll Health. 2020 Feb 26:1-8. doi: 10.1080/07448481.2020.1728279. [Epub ahead of print]
Authors: Gomez-Hixson K, Biagioni E, Brown ML
Summary: This study evaluated dietary intake patterns of NCAA Division III soccer players compared to recommended levels. NCAA Division III soccer players (n = 75) participated in this study. Actual dietary intake was determined by the analysis of a 3-day food record. Results indicate that total energy, carbohydrate, and dietary fiber intake was significantly below the recommended levels. In addition, added sugar and total fat consumption were significantly above recommended levels. Potassium, magnesium, and vitamin D levels were consumed in levels significantly below the recommended levels. Sodium, iron, and vitamin C were consumed in significantly higher levels than the recommended target. Female athletes had significantly higher intakes of added sugar, saturated fat and vitamin C compared to male athletes. Female athletes had significantly lower intakes of calcium, potassium, sodium, iron, magnesium and vitamin D compared to male athletes. Based on the results of the present study, increased efforts should be put into development of nutrition education programs for NCAA Division III athletes.

#10 Concussion incidence and recovery in Swedish elite soccer - prolonged recovery in female players
Reference: Scand J Med Sci Sports. 2020 Feb 26. doi: 10.1111/sms.13644. [Epub ahead of print]
Authors: Vedung F, Hänni S, Tegner Y, Johansson J, Marklund N
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Summary: Sport-related concussions are an increasingly recognized health problem. Soccer is the most popular sport in the world although recent studies on concussion incidence are scarce. Here, a nation-wide prospective study on concussion incidence, symptom severity, risk factors, gender differences and return-to-play after concussion was performed in 51 Swedish elite soccer teams during the 2017 season. In the first and second soccer leagues for men and women, a Sport Concussion Assessment Tool (SCAT) -based questionnaire study was performed at pre-season (baseline) and from 48h up to three months post-concussion. We followed 959 players (389 women, 570 men) for 25146 player game hours (9867 h for women, 15279 h for men). Concussion incidence (n= 36) was 1.19/1000 player game hours (females 1.22/1000 h, males 1.18/1000 h; p= 0.85). Twenty-seven percent (females 8%, males 40%) of players continued to play immediately after the concussion. When compared to male players, female players had worse initial symptom severity scores (median and IQR 30 (17-50.5) vs. 11 (4-26.25), p=0.02) and longer return to play (p=0.02). Risk factors for concussion were baseline symptoms and previous concussion. In Swedish elite soccer, the concussion incidence was 1.19/1000 without gender differences. Most players recovered to play within four weeks post-injury. Almost one third of players continued to play at time of concussion. Female players had worse initial symptoms and longer return-to-play time than males, and a prolonged recovery beyond three months was only observed among female players.

#11 The Impact of Sleep on the Relationship between Soccer Heading Exposure and Neuropsychological Function in College-Age Soccer Players
Reference: J Int Neuropsychol Soc. 2020 Feb 26:1-12. doi: 10.1017/S1355617720000211. [Epub ahead of print]
Authors: Levitch CF, McConathey E, Aghvinian M, Himmelstein M, Lipton ML, Zimmerman ME
Summary: Soccer is the most popular sport worldwide and is the only sport where athletes purposely use their head to deflect the ball during play, termed "heading" the ball. These repetitive head impacts (RHI) are associated with worse neuropsychological function; however, factors that can increase risk of injury following exposure to such head impacts have been largely unexamined. The present study provided a novel examination of the modifying role of sleep on the relationship between RHI exposure and neuropsychological function in college-age soccer players. Fifty varsity and intramural college soccer players completed questionnaires assessing recent and long-term heading exposure, a self-report measure of sleep function, and a battery of neuropsychological tests. A high level of recent heading exposure was significantly associated with poorer processing speed, independent of concussion history. With reduced sleep duration, a high level of recent heading exposure was related to worse sustained attention. However, with greater hours of sleep duration, heading exposure was related to preserved neuropsychological outcome in sustained attention. We replicated our earlier finding of an association between recent head impact exposure and worse processing speed in an independent sample. In addition, we found that sleep may serve as a risk or protective factor for soccer players following extensive exposure to head impacts. Ultimately, this study furthers the understanding of factors impacting neuropsychological function in soccer players and provides empirical support for sleep interventions to help ensure safer soccer play and recovery from injury.

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