Latest research in football - week 36 - 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 Utility of the anterior reach Y-BALANCE test as an injury risk screening tool in elite male youth soccer players
Reference: Phys Ther Sport. 2020 Jul 10;45:103-110. doi: 10.1016/j.ptsp.2020.06.002. Online ahead of print.
Authors: Paul J Read, Jon L Oliver, Gregory D Myer, Abdulaziz Farooq, Mark De Ste Croix, Rhodri S Lloyd
Summary: The aim was to examine growth and maturation trends in dynamic balance using the anterior reach Y-Balance test, and its utility as an injury risk screening tool. 346 players grouped as pre, circa or post peak height velocity (PHV) participated in this study. Pre-season anterior reach absolute and relative Y-Balance test scores and seasonal prospective lower extremity injury monitoring were used as outcome measures. Absolute reach distances were greatest post-PHV (p < 0.05). Relative to leg length, pre-PHV achieved the highest scores and increased between-limb differences. Significant associations between injury and anterior reach scores were present in pre (OR: 0.94, CI: 0.91-0.98, p < 0.05) and circa-PHV (OR: 1.05, 95% CI: 1.05-1.10, p < 0.05). Increased age (OR: 1.49, 95% CI: 1.04-2.13, p < 0.05) and height (OR: 1.06, 95% CI: 0.99-1.13, p = 0.82) were risk factors post-PHV. No differences in injury occurrence were shown between players with absolute reach difference >4 cm in any group. Anterior reach scores increased injury risk, but associations were small and inconsistent. The Y-Balance should be used with caution as a screening tool in this cohort.

#2 Competitive evaluation in male elite junior soccer players: entire match, replaced, and substitute players
Reference: J Exerc Rehabil. 2020 Jun 30;16(3):286-292. doi: 10.12965/jer.2040358.179. eCollection 2020 Jun.
Authors: Adriano Titton
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Summary: The purpose of this study was to analyze the mood states, recovery, displacement patterns, and rating of perceived exertion of elite junior soccer players during a national competition, considering substitutions in the matches. Before the games, the mood states and total quality recovery (TQR) were evaluated. During the games, the total distance (TD), low-speed distance (LSD), and high-speed distance were monitored. At the end of the matches, the rating of perceived exertion scale was used. The average and standard deviation were used to compare the match stages, soccer positions and influence of the substitutions. The significance level adopted was 5%. In relation to the mood states, fatigue presented higher values (P<0.05) for entire match and substitute players, and in the TQR, substitute players presented better recovery (P<0.05) than entire match and replaced players. In the TD, shorter distances covered were observed (P<0.05) in the first half, and the average of the midfielders was longer (P<0.05) than that of the defenders. In the LSD, the midfielders covered longer distances (P<0.05) than the strikers and defenders. It is possible to conclude that the substitutions have an impact on the player positions, match stages and maintenance of the intensity of the players.

#3 Drug use and abuse and the risk of adverse events in soccer players: results from a survey in Italian second league players
Reference: Eur Ann Allergy Clin Immunol. 2020 Jul 30. doi: 10.23822/EurAnnACI.1764-1489.163. Online ahead of print.
Authors: F W Rossi, F Napolitano , V Pucino , G Capua , D Bianchedi , F Braconaro, A de Paulis
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Summary: Drug use in athletes has been frequently investigated in the last three decades, especially regarding its misuse for doping. However little is known about the use of permitted drugs for medical purposes and less studies have investigated the relationship between adverse drugs reactions (ADRs) and sports. An observational cross-sectional investigation analyzing a group of second league soccer players (the second-highest division in Italy) was performed. Anamnestic and physical examinations as well as a validated questionnaire (AQUA©) were performed in a group of 378 Italian second league soccer players. Most players (91.8%) reported the use of NSAIDs in the previous year, and one third of them were regular users. Analgesics were used in 64% of the players, while 52.1% had taken antibiotics in the previous year. 29.20% of players used intraarticular treatments in the previous year. In 7,4% of players, an ADRs was reported: 3,47% reacted to NSAIDs, 2,6% to antibiotics, 1,05% to analgesics and 1 of them to supplements. For intra-articular injections, only 2 players experienced ADRs. One quarter of players experienced reactions as urticaria-angioedema syndrome or more severe conditions as bronchospasm or anaphylaxys. This study shows that drug misuse/abuse in soccer is a real matter of debate, especially with regards to NSAIDs, exposing athletes to predictable and/or unpredictable risks for their health.

#4 Variable long-term developmental trajectories of short sprint speed and jumping height in English Premier League academy soccer players: An applied case study
Reference: J Sports Sci. 2020 Jul 29;1-7. doi: 10.1080/02640414.2020.1792689. Online ahead of print.
Authors: Jason Moran, Kevin Paxton, Ben Jones, Urs Granacher, Gavin Rh Sandercock, Edward Hope, Rodrigo Ramirez-Campillo
Summary: Growth and maturation affect long term physical performance, making the appraisal of athletic ability difficult. We sought to longitudinally track youth soccer players to assess the developmental trajectory of athletic performance over a 6-year period in an English Premier League academy. Age-specific z-scores were calculated for sprint and jump performance from a sample of male youth soccer players (n = 140). A case study approach was used to analyse the longitudinal curves of the six players with the longest tenure. The trajectories of the sprint times of players 1 and 3 were characterised by a marked difference in respective performance levels up until peak height velocity (PHV) when player 1 achieved a substantial increase in sprint speed and player 3 experienced a large decrease. Player 5 was consistently a better performer than player 2 until PHV when the sprint and jump performance of the former markedly decreased and he was overtaken by the latter. Fluctuations in players' physical performance can occur quickly and in drastic fashion. Coaches must be aware that suppressed, or inflated, performance could be temporary and selection and deselection decisions should not be made based on information gathered over a short time period.

#5 School-based soccer practice is an effective strategy to improve cardiovascular and metabolic risk factors in overweight children
Reference: Prog Cardiovasc Dis. 2020 Jul 25;S0033-0620(20)30144-4. doi: 10.1016/j.pcad.2020.07.007. Online ahead of print.
Authors: André Seabra, João Brito, Pedro Figueiredo, Liliana Beirão, Ana Seabra, Maria José Carvalho, Sandra Abreu, Susana Vale, Augusto Pedretti, Henrique Nascimento, Luís Belo, Carla Rêgo
Summary: We examined the effects of a 6-month school-based soccer programme on cardiovascular (CV) and metabolic risk factors in overweight children. Methods: 40 boys [8-12 years; body mass index (BMI) >2 standard deviations of WHO reference values] participated in complementary school-based physical education classes (two sessions per week, 45-90 min each). The participants were divided into a soccer group (SG; n = 20) and a control group (CG; n = 20). The SG intervention involved 3 extra-curricular school-based soccer sessions per week, 60-90 min each. The intervention lasted for 6-months. All measurements were taken at baseline and after 6-months. From baseline to 6-months, the SG significantly improved (p < .05) BMI z-score, waist circumference, waist-to-height ratio, percentage of fat mass, percentage of fat-free mass, diastolic blood pressure, total cholesterol, triglycerides, low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol, but no such improvements were observed for the CG. After the intervention, the prevalence of soccer participants with normal waist-to-height ratio (30 vs. 5%; p = .037), systolic blood pressure (90 vs. 55%; p = .039), total cholesterol (80 vs. 65%; p = .035) and LDL-C (90 vs. 75%; p = .012) were significantly higher than at baseline. The findings suggest that a 6-month school-based soccer intervention program represents an effective strategy to reduce CV and metabolic risk factors in overweight children prepared to take part in a soccer program.

#6 Dribbling speed predicts goal-scoring success in a soccer training game
Reference: Scand J Med Sci Sports. 2020 Jul 27. doi: 10.1111/sms.13782. Online ahead of print.
Authors: Robbie S Wilson, Nicholas M A Smith, Nicolau Melo de Souza, Felipe Arruda Moura
Summary: The aim of this study was to explore the underlying bases of goal-scoring ability of junior soccer players. Male players (mean age 17.2 years, SD = 1.3) were recruited from an elite Brazilian football academy. We assessed each individual's dribbling and sprinting speed along five 30 m paths varying in curvature from 0 to 1.37 radians.m-1. We also quantified each player's ability to dribble the ball through a series of 15 cones using six different techniques. Dribbling, sprinting and technical dribbling were then compared with an individual's goal-scoring ability as assessed when competing against one defender and a goalkeeper protecting a full-sized goal (N = 20-48 attempts/ individual). Goal-scoring success was significantly positively associated with their sprint speed (r = 0.60; P = 0.014), dribbling speed (r = 0.81; P < 0.0001) and technical dribbling (r = 0.49; P = 0.022). An individual's percentage of shots saved was only significantly associated with their dribbling speed (r = -0.81; P < 0.001), with faster dribblers less likely to have their shots saved. Based on the full multivariate model for goal-scoring success (adjusted r2 = 0.60; P < 0.001), dribbling speed was the only significant correlate (t = 3.51; P < 0.001). Our study demonstrates that our metric of dribbling speed, as measured along curved paths, was associated with goal-scoring success. Future studies should focus on specific training regimes aimed at improving dribbling ability, and measuring any impact on the creation of goal-scoring opportunities and number of goals scored.

#7 Framing potential for adverse effects of repetitive subconcussive impacts in soccer in the context of athlete and non-athlete controls
Reference: Brain Imaging Behav. 2020 Jul 25. doi: 10.1007/s11682-020-00297-4. Online ahead of print.
Authors: Sara B Strauss, Roman Fleysher, Chloe Ifrah, Liane E Hunter, Kenny Ye, Richard B Lipton, Molly E Zimmerman, Mimi Kim, Walter F Stewart, Michael L Lipton
Summary: The benefits of athletic activity may be attenuated by sport-related head impacts, including soccer-related concussion and subconcussive events. The purpose of this study is to characterize the specific effects of soccer heading on white matter microstructure and cognitive function, independent of concussion, relative to non-athlete controls and relative to active athletes who are not involved in collision sports. 246 amateur soccer players, 72 non-contact/non-collision sports athletes and 110 healthy,non-athlete controls were included in the study, and underwent cognitive testing and 3T diffusion tensor imaging (DTI). Voxelwise linear regression, comparing soccer players and non-contact/non-collision sports athletes healthy,non-athlete controls, identified regions of abnormally low and high fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD) and mean diffusivity (MD) in athlete participants. Generalized estimating equations were used to examine the effects of 2 week and 1 year heading exposure quartile on cognitive performance and on the volume of each high and each low DTI parameter. Athletes with no or lower exposure to repetitive heading exhibited greater expression of low RD, greater expression of high FA and better performance on tasks of attention, processing speed, verbal memory, and working memory compared to non-athletes. Soccer players with the highest exposure to repetitive head impacts, however, did not differ significantly from healthy, non-athletes on either micro-structural features or cognitive performance, findings not explained by concussion history or demographic factors. These results are consistent with the notion that beneficial effects of athletic conditioning or training on brain structure and function may be attenuated by exposure to repeated subconcussive head impacts.

#8 A nutrition education intervention in adolescents who play soccer: The IDEHA-F project
Reference: Psicothema. 2020 Aug;32(3):359-365. doi: 10.7334/psicothema2019.394.
Authors: María M Fernández-Álvarez, Rubén Martín-Payo, Rebeca García-García, Marcelino Cuesta, Sergio Carrasco-Santos
Summary: Diet and physical activity are prioritised in behavioural interventions given their influence on major child health issues. The objective of this study was to assess the feasibility of an educational intervention, based on the Behaviour Change Wheel model, on adherence to healthy eating habits in adolescent soccer players in Asturias, Spain. This pilot study involved 319 soccer players (mean age=14.19 years; SD=1.089), who were distributed into a control group (CG) and an intervention group (IG). The response variables were: the usage rate of, adherence to, and acquisition of knowledge of the Mediterranean diet. The intervention included posters, a web-app, and practical activities. The mean score on the knowledge questionnaire was 2.53 for the CG and 3.42 for the IG (p <.001). A weak direct correlation was observed between diet knowledge and KIDMED scores (r =.222, p =.013). The total pre-test KIDMED (p <.001) and diet knowledge ( p =.05) scores explained approximately 33% of the total post-test KIDMED score. The combined use of posters and a web app as intervention tools have been shown to be feasible in order to provide information on healthy eating habits to adolescents who play soccer and to help them maintain those eating habits.

#9 A Longitudinal Analysis of the Executive Functions in High-Level Soccer Players
Reference: J Sport Exerc Psychol. 2020 Jul 25;1-9. doi: 10.1123/jsep.2019-0312. Online ahead of print.
Authors: Adam Beavan, Vincent Chin, Louise M Ryan, Jan Spielmann, Jan Mayer , Sabrina Skorski, Tim Meyer , Job Fransen
Summary: Assessments of executive functions (EFs) with varying levels of perceptual information or action fidelity are common talent-diagnostic tools in soccer, yet their validity still has to be established. Therefore, a longitudinal development of EFs in high-level players to understand their relationship with increased exposure to training is required. A total of 304 high-performing male youth soccer players (10-21 years old) in Germany were assessed across three seasons on various sport-specific and non-sport-specific cognitive functioning assessments. The posterior means (90% highest posterior density) of random slopes indicated that both abilities predominantly developed between 10 and 15 years of age. A plateau was apparent for domain-specific abilities during adolescence, whereas domain-generic abilities improved into young adulthood. The developmental trajectories of soccer players' EFs follow the general populations' despite long-term exposure to soccer-specific training and game play. This brings into question the relationship between high-level experience and EFs and renders including EFs in talent identification questionable.

#10 Assessment of diet quality and physical activity of soccer players aged 13 to 16, from the Principality of Asturias, Spain
Reference: An Pediatr (Barc). 2020 Jul 21;S1695-4033(20)30224-1. doi: 10.1016/j.anpedi.2020.05.024. Online ahead of print. [Article in Spanish]
Authors: María Del Mar Fernández-Álvarez, Rubén Martín-Payo, Edurne Zabaleta-Del-Olmo, Rebeca García-García, Marcelino Cuesta-Izquierdo, Xana González-Méndez
Summary: Diet and physical activity are factors that have key roles in childhood overweight and obesity prevention. Appropriate assessment of these factors is an essential task in public health. The main aims of the study are to assess body composition, physical activity, and adherence to Mediterranean diet of soccer players, aged 13 to 16 years old in Asturias, Spain. It also aims to evaluate the relationships between diet, physical activity, body composition, and personal characteristics. A cross-sectional descriptive survey approach was used involving children (n=303) with a mean age of 14.15 years (SD=1.06), and using the KIDMED and PAQ-A questionnaires to assess adherence to Mediterranean diet and level of physical activity, respectively. Body composition was represented using the participants' body mass index. Approximately 23.1% of the participants were overweight or obese. With regards to adherence to Mediterranean diet, 54.8% of the participants had medium adherence, while 8.9% had low adherence. PAQ-A mean score was 2.69 (SD=0.47). Excess weight was associated with being a goalkeeper (P=.001), higher PAQ-A (P=.011), and lower KIDMED scores (P=.032). Correlation analysis showed an inverse association between age and PAQ-A score (r=-0.122), and a direct association between KIDMED and PAQ-A scores (r=0.152). Participants had an adequate level of physical activity. However, they had an obesogenic profile similar to that of their age population, who were not soccer players. Actions to improve adherence to healthy diet practices are highly recommended.

#11 Effects of Match-Related Contextual Factors on Weekly Load Responses in Professional Brazilian Soccer Players
Reference: Int J Environ Res Public Health. 2020 Jul 17;17(14):E5163. doi: 10.3390/ijerph17145163.
Authors: Luiz Guilherme Cruz Gonçalves, Carlos Augusto Kalva-Filho, Fábio Yuzo Nakamura, Vincenzo Rago, José Afonso, Bruno Luiz de Souza Bedo , Rodrigo Aquino
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Summary: This study aimed to quantify the weekly training load distributions according to match location, opponent standard, and match outcome in professional soccer players. Rate-of-perceived-exertion-based training load (sRPE) and distance- and accelerometry-based measures were monitored daily during 52 training sessions and 11 matches performed by 23 players. Athletes who played ≥ 60 min during non-congested weeks were considered for data analysis. The training days close to away matches (e.g., one day before the match = MD-1) presented greater sRPE, distance-based volume measures, and mechanical work (player load) compared to the training days close to home matches (p = 0.001-0.002; effect size (ES) = medium-large). The most distant days of the home matches (e.g., five days before the match = MD-5) presented higher internal and external loads than before away matches (p = 0.002-0.003, ES = medium). Higher sRPE, distance-based volume measures, and mechanical work were found during the middle of the week (e.g., three days before the match, MD-3) before playing against bottom vs. medium-ranking teams (p = 0.001-0.01, ES = small-medium). These metrics were lower in MD-5 before matches against bottom vs. medium-ranking opponents (p = 0.001, ES = medium). Higher values of all external load measures were observed during the training session before winning matches (MD-1) compared to a draw or loss (p < 0.001-0.001, ES = medium-large). In conclusion, the training load distribution throughout the week varied considerably according to match-contextual factors.

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