Latest research in football - week 31- 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 Evaluation of Ball Passing and Space Detection Skill in Soccer: Implementation of Two New Soccer Tests
Reference: Res Sports Med. 2020 Jul 1;1-11. doi: 10.1080/15438627.2020.1789133. Online ahead of print.
Authors: Evangelos Bekris, Stylianos Kounalakis, Ioannis Ispirlidis, Athanasios Katis
Summary: The present study examined the validity and reliability of two new soccer tests: the Passing Accuracy Test (PAT), which assesses ball passing accuracy in combination with visual stimulus recognition and the Passing and Visual Recognition test (PVR), which assesses player's space detection skill in a 360 degrees range along with the frequency and the accuracy of ball passing technique. Participants were allocated in four (4) groups based on their age: the Under 11 (U11) group consisted of 101 players, the Under 14 (U14) group consisted of 100 players, the Under 17 (U17) group consisted of 118 players and the Adults (AD) group consisted of 43 players. The typical error, the limits of agreement and the ICC of PAT and PVR test were examined. The results of the study showed high validity and reliability for both tests with the exception in PAT for adult group (ICC = 0.33-0.83; P < 0.05). Therefore, both tests could be valuable tools to assess the accuracy of ball passing technique and the space detection skill in players of different ages.

#2 Talipes Equinus Deformity Caused by Fibrous Gastrocnemius Muscle Contracture After Direct Contusion in Football Players: Report of Two Cases
Reference: J Foot Ankle Surg. Jul-Aug 2020;59(4):816-820. doi: 10.1053/j.jfas.2019.10.004.
Authors: Yoichi Kaneuchi, Ken-Ichi Otoshi, Michiyuki Hakozaki, Kazuo Watanabe, Shin-Ichi Konno
Summary: Two main causes of gastrocnemius contracture have been considered: 1) congenital deformities in pediatric patients, such as limb-length discrepancy, cerebral palsy, flatfoot, and clubfoot; and 2) secondary conditions such as immobilization for trauma or a nonfunctional limb. Talipes equinus deformity caused by fibrous gastrocnemius contracture after a direct muscle contusion is extremely rare. We describe 2 cases of talipes equinus deformity caused by fibrous gastrocnemius muscle contracture after a direct contusion in football players. Both of the players had a talipes equinus deformity with a severe restriction of ankle dorsiflexion, and a cord-like structure was observed at the proximal part of the lateral gastrocnemius head. Both patients' histological examinations revealed fibrous tendon-like tissue within the structure. After discission of the cord-like structures, the restriction of ankle dorsiflexion was completely resolved, and the patients were able to fully return to playing football without any discomfort in their calves.

#3 Training Soccer Skills to Adolescents With Autism Spectrum Disorder via Peer-Mediated Behavioral Skills Training
Reference: Behav Anal Pract. 2019 Aug 19;13(2):454-461. doi: 10.1007/s40617-019-00381-2.
Authors: Caitlyn Chambers, Keith C Radley
Summary: Peer-mediated interventions have been identified as efficient means of promoting the acquisition of skills of students with autism spectrum disorder (ASD). Limited research, however, has evaluated the utility of such procedures for promoting recreational skills that may allow for greater interaction with peers. The purpose of the current study was to evaluate the effectiveness of peer-mediated behavioral skills training on the acquisition of discrete soccer skills of 3 students with ASD. Following the implementation of the intervention, all participants demonstrated substantial improvements in the accuracy of the target soccer skills.

#4 Relationships Between Controlling Interpersonal Coaching Style, Basic Psychological Need Thwarting, and Burnout, in Adolescent Soccer Players
Reference: Int J Environ Res Public Health. 2020 Jul 7;17(13):E4909. doi: 10.3390/ijerph17134909.
Authors: Verónica Morales-Sánchez, Miriam Crespillo-Jurado, David Jiménez-López, Juan P Morillo-Baro, Antonio Hernández-Mendo, Rafael E Reigal 
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Summary: The aim of this paper is to analyze the relationships between a controlling interpersonal style, psychological need thwarting and burnout in adolescent soccer players and to test a structural equation model to analyze whether (a) a controlling interpersonal style is a predictor of psychological need thwarting and whether (b) psychological need thwarting is a predictor of burnout. A total of 103 male soccer players between the ages of 12 and 17 participated in the research (M = 14.91; SD = 5.56). The Controlling Coach Behaviors Scale, the Psychological Need Thwarting Scale, and the Athlete Burnout Questionnaire were used to evaluate the variables under study. The analyses revealed significant relationships between a controlling interpersonal style, psychological need thwarting and burnout. Furthermore, the proposed structural equations model, using the partial least squares (PLS) method, showed that a controlling style is a positive predictor of basic psychological need thwarting and that the latter is a predictor of burnout, as well as revealing an indirect relationship between a controlling style and burnout. This indirect effect of the controlling style variable on burnout can be enhanced (or attenuated) by the basic psychological need thwarting variable, which acts as a modulator.

#5 The Effects of Physical Fitness on Postactivation Potentiation in Professional Soccer Athletes
Reference: J Strength Cond Res. 2020 Jul 7. doi: 10.1519/JSC.0000000000003711. Online ahead of print.
Authors: Mauro A Guerra Jr, Leonardo C Caldas, Helder L Souza, Jason Tallis, Michael J Duncan, Lucas Guimarães-Ferreira 
Reference: The effects of physical fitness on postactivation potentiation in professional soccer athletes.
Summary: The purpose was to investigate the relationship of the response to postactivation potentiation (PAP) with scores of physical fitness. Twenty-four professional male soccer players undertook tests of agility, muscular power, aerobic capacity, and body composition. Conditioning activities (CAs) were performed consisting of plyometrics exercises and sprints with sled towing. In the first and second sessions, body composition, agility, power, and aerobic capacity were assessed. At the third session, countermovement jumps (CMJ) were performed with 1, 3, and 5 minutes after the execution of the CA. Significant differences were found for CMJ height 1, 3, and 5 minutes after the CA compared with baseline values (3.58, 5.10, 5.48%, respectively). There was a significant positive correlation between the level of general physical fitness and PAP (CMJ height increase) 5 minutes after (r = 0.73). When the athletes were divided into groups with higher and lower physical fitness, the CA caused a significant increase in CMJ height in both groups, but a significant difference (p < 0.05) was observed at all times after PAP induction, with better performance in higher versus lower fitness level. The results suggest that plyometrics exercises associated with sled towing sprints as a CA result in an increase in CMJ performance in athletes and that physical fitness directly influences the PAP occurrence, with higher fit players demonstrating an enhanced PAP response.

#6 High Coenzyme Q10 Plasma Levels Improve Stress and Damage Markers in Professional Soccer Players During Competition
Reference: Int J Vitam Nutr Res. 2020 Jul 8;1-12. doi: 10.1024/0300-9831/a000659. Online ahead of print.
Authors: Ana Sánchez-Cuesta, Ana Belén Cortés-Rodríguez, Ignacio Navas-Enamorado, José Antonio Lekue, Toscana Viar, Martín Axpe, Plácido Navas, Guillermo López-Lluch
Summary: Ubiquinol, the reduced form of Coenzyme Q10 (CoQ10), is a key factor in bioenergetics and antioxidant protection. During competition, professional soccer players suffer from considerable physical stress causing high risk of muscle damage. For athletes, supplementation with several antioxidants, including CoQ10, is widely recommended to avoid oxidative stress and muscle damage. We performed an observational study of plasma parameters associated with CoQ10 levels in professional soccer players of the Spanish First League team Athletic Club de Bilbao over two consecutive seasons (n = 24-25) in order determine their relationship with damage, stress and performance during competition. We analyzed three different moments of the competition: preterm, initial phase and mid phase. Metabolites and factors related with stress (testosterone/cortisol) and muscle damage (creatine kinase) were determined. Physical activity during matches was analyzed over the 2015/16 season in those players participating in complete matches. In the mid phase of competition, CoQ10 levels were higher in 2015/16 (906.8 ± 307.9 vs. 584.3 ± 196.3 pmol/mL, p = 0.0006) High levels of CoQ10 in the hardest phase of competition were associated with a reduction in the levels of the muscle-damage marker creatine kinase (Pearsons' correlation coefficient (r) = - 0.460, p = 0.00168) and a trend for the stress marker cortisol (r = -0.252, p = 0.150). Plasma ubiquinol was also associated with better kidney function (r = -0.287, p = 0.0443 for uric acid). Furthermore, high CoQ10 levels were associated with higher muscle performance during matches. Our results suggest that high levels of plasma CoQ10 can prevent muscle damage, improve kidney function and are associated with higher performance in professional soccer players during competition.

#7 Identification of Ankle Injury Risk Factors in Professional Soccer Players Through a Preseason Functional Assessment
Reference: Orthop J Sports Med. 2020 Jun 24;8(6):2325967120928434. doi: 10.1177/2325967120928434.
Authors: Lucas Sartori Manoel, Marcela Godoy Xixirry, Thabata Pasquini Soeira, Marcelo Camargo Saad, Marcelo Riberto
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Summary: Etiologically, the risk of an ankle injury depends on extrinsic and intrinsic factors, such as muscle strength asymmetry, decreased flexibility, and decreased proprioception, as well as patient age and history of injuries. The purpose of this study was to identify risk factors present in the preseason assessment that may predispose professional soccer players to ankle injuries. We hypothesized that analysis of these parameters could relate the incidence of injuries to the deficits found during the preseason period, enabling the identification of risk factors to predict the occurrence of injuries. A total of 89 professional soccer athletes were evaluated in the preseason period; the evaluation included athlete history and anthropometric data collection, an isokinetic ankle evaluation, and functional tests: the Dorsiflexion Lunge Test and Y-Balance Test (YBT). The athletes were monitored during the competitive period, and the incidence of injuries was surveyed. The association of quantitative variables and injury outcomes was analyzed using the Student t test for independent samples, with P < .05. For the association of categorical variables and injury outcomes, the chi-square test was performed, with P < .05. A higher incidence of ankle injuries was associated with lower YBT scores in the dominant (P = .04) and nondominant (P = .01) limbs. A higher body mass index was also associated with a higher injury occurrence (P = .01).
Functional tests, such as the YBT, are indicated tools for assessing the physical capacities and possible risks of ankle sprains, as they can evaluate the ankle functional capacity in a complex way, identifying athletes more prone to ankle injuries. Athletes' body mass index should also be taken into account to prevent such injuries.

#8 Effects of Different Solutions Consumed During Exercise on Cognitive Function of Male College Soccer Players
Reference: J Exerc Sci Fit. 2020 Sep;18(3):155-161. doi: 10.1016/j.jesf.2020.06.003. Epub 2020 Jun 20.
Authors: Feng-Hua Sun, Simon B Cooper, Frank Chak-Fung Tse
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Summary: The present study aimed to investigate the effects of three solutions, i.e. carbohydrate-electrolyte-solution (CES), carbohydrate-electrolyte-protein-solution (CEPS), and placebo (PLA), on cognitive function of college soccer players. Sixteen male college soccer players completed three main trials in a randomized cross-over study design. In each main trial, participants completed 90 min Loughborough Intermittent Shuttle Test (LIST) protocol and consumed one of three solutions. The cognitive function tests were performed; blood glucose and lactate concentrations, and several subjective measurements were also recorded in each trial. Compared with pre-exercise level, the accuracy of Rapid Visual Information Processing test (RVIPT) and the response time in Visual Search Test (VST, complex level) after LIST improved in CES and CEPS trials, but not in PLA trial. However, the accuracy of VST (complex level) decreased in both CES and CEPS trials, compared with PLA trial. CEPS consumption improved accuracy in VST (simple level), compared with CES consumption. Blood glucose concentrations were well maintained in CEPS trial, but not in CES and PLA trials. It seems that both CES and CEPS consumption show certain benefits on some aspects of cognitive function in male college soccer players in Hong Kong. However, these effects may be specific to the cognitive domain tested.

#9 Youth Soccer Parents' Attitudes and Perceptions About Concussions
Reference: J Adolesc Health. 2020 Jul 4;S1054-139X(20)30218-4. doi: 10.1016/j.jadohealth.2020.04.029. Online ahead of print.
Authors: Sungwon Kim, Daniel P Connaughton
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Summary: Parents are important figures in properly managing youth sport concussions. Although media attention has predominantly centered on concussions in contact/collision sports, evidence suggests that the concussion rate in soccer is comparable to those found in contact/collision sports. Given the high rate of concussions in youth soccer, this study aimed to examine parents of youth soccer athletes' attitudes and perceptions about concussions and associated factors. A cross-sectional study was conducted by surveying parents of youth soccer athletesfrom the five largest organized youth soccer programs across the U.S. The researchers developed a questionnaire after an extensive literature review and by modifying previously used instruments. Overall, 419 parents completed the survey. The vast majority (85%) agreed that a concussion is a serious injury, but only 27.9% believed that their child could suffer a concussion during the next season. Parents were most concerned about permanent brain damage when their child suffers a concussion. The vast majority (4.37 ± .89) perceived concussion reporting as an important injury prevention strategy. Greater appreciation and perceived risk about concussions was found particularly among parents who received concussion education and those who had witnessed or heard about a concussive incidence(s). Findings suggest that youth soccer parents have high appreciation and perceived risk about concussions. However, the need for more targeted education was noted, as improvements to better manage and reduce concussions can be made. Future research should continue examining youth sport parents' belief and understanding about concussions as well as factors affecting them.

#10 Fatigue Increases in Resting Muscle Oxygen Consumption After a Women's Soccer Match
Reference: Int J Sports Med. 2020 Jul 7. doi: 10.1055/a-1177-0849. Online ahead of print.
Authors: Aldo Alfonso Vasquez Bonilla, Rafael Timon, Alba Camacho-Cardeñosa, Marta Camacho-Cardeñosa, Samantha Guerrero, Guillermo Olcina
Summary: Currently, near infrared spectroscopy has a clear potential to explain the mechanisms of fatigue by assessing muscle oxygenation. The objective of the study was to observe the changes in muscle oxygen consumption after an official women's soccer match. The sample was 14 players who competing in the second division of Spain of women's soccer. They were evaluated before, immediately after and 24 h after the official match. Biochemical parameters were measured in blood plasma (BUN, GOT, LDH, CPK). The jumping in countermovement, perceived exertion and perceived muscle pain were also assessed. The muscle oxygen consumption and muscle oxygen saturation were evaluated in the gastrocnemius muscle with an arterial occlusion test. ANOVA of repeated measures, Pearson's correlation and Hopkins' statistics were applied to measure the magnitudes of change and effect size. There was observed an increase in kinetics of SmO2 at 24 h after the official match, using arterial occlusion. In addition, it was found that the increase in muscle oxygenation correlated with fatigue indicators, such as the increases in LDH, perceived muscle pain and the decrease in countermovement. It is confirmed that a women's soccer match produced an increase of resting muscle oxygenation in 24 h after the official match.

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