Latest research in football - week 30 - 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 Effects of Three Different Stretching Protocols on Hamstring Muscle Flexibility in Professional Soccer Players: A Randomized Study 

Reference: J Sports Med Phys Fitness. 2020 Jul;60(7):999-1004. doi: 10.23736/S0022-4707.20.10562-0. 

Authors: Vincenzo Manzi, Ferdinando Iellamo, Anas R Alashram, Rosario D'onofrio, Elvira Padua, Maurizio Casasco, Giuseppe Annino

Summary: The current study aimed to investigate and compare the influences of global postural rieducation techniques (GPR), stretching exercises on a whole-body vibration platform (WBV), and static stretching exercises on hamstrings flexibility in elite soccer players. 24 professional soccer players were randomly assigned to either global postural re-education (N.=8), stretching on whole-body vibration group (N.=8) or static stretching (N.=8), during the first 4 weeks of the precompetitive season. Assessment of hamstring muscle flexibility was performed using a straight leg raise test. All participants were assessed three times: at baseline, at the end of the study protocol and 14 days after the end of the study protocol. The short-term increase in hamstring muscle flexibility was observed in all 3 groups, without significant differences among groups. However, after 14 days from the end of the interventions only the WBV group maintained the flexibility level achieved just at the end of the protocol with no significant changes in both legs whereas a significant decrease in the SLRT in GPR and SS groups, in right and left legs (GPR, P=0.002; P=0.015; SS, P=0.0001; P=0.0001), was observed. These results would suggest that GPR, static stretching on whole-body vibration and static stretching techniques all improve hamstring muscle flexibility, but only stretching on WBV maintains the effect over time in professional soccer players. 



#2 Soccer Player With Unusual Right Shoulder and Arm Pain and Swelling 

Reference: J Prim Health Care. 2020 Jun;12(2):181-183. doi: 10.1071/HC19101. 

Authors: Alan Zakaria , Jasper Gill, Livia Maruoka Nishi, Jeff Nadwodny, George G A Pujalte

Summary: Paget-Schroetter syndrome, or effort thrombosis, refers to a deep venous thrombosis in an upper extremity. It is most commonly located in the axillary or subclavian veins and is associated with vigorous repetitive movements and anatomic abnormalities. This case study describes an 18-year-old Division 1 soccer player who presented with worsening axillary swelling and pain. He was found to have subclavian stenosis at the level of the thoracic inlet between the clavicle and first rib, with deep venous thrombosis in his right axillary, subclavian, proximal brachial, and basilic veins. It was diagnosed with ultrasound and confirmed with venography. He was treated initially with enoxaparin and warfarin before having mechanical thrombolysis, balloon venoplasty, infusion of tissue plasminogen activator, and a right first rib resection. CONCLUSION As Paget-Schroetter syndrome is rare, early recognition and management leads to fewer long-lasting sequelae and less morbidity. Left untreated, it can result in pulmonary embolism and residual upper extremity obstruction. 



#3 Variations of Estimated Maximal Aerobic Speed in Children Soccer Players and Its Associations With the Accumulated Training Load: Comparisons Between Non, Low and High Responders 

Reference: Physiol Behav. 2020 Jun 25;224:113030. doi: 10.1016/j.physbeh.2020.113030. Online ahead of print. 

Authors: Filipe Manuel Clemente, Ana Filipa Silva, Ana Ruivo Alves, Pantelis Theodoros Nikolaidis, Rodrigo Ramirez-Campillo, Ricardo Lima, Mustafa Sö?üt, Thomas Rosemann, Beat Knechtle

Summary: The aim of this study was twofold: (i) to examine the variations of estimated maximal aerobic speed between non, low and high responders and (ii) to analyze the relationships between accumulated training load parameters and variations of maximal aerobic speed in children soccer players. Forty-four male soccer players were assessed three times during the early and mid-season (second to fifth month of the season) and were monitored daily over the period of analysis using the rating of perceived exertion (RPE), recording the training duration (in min) and calculating the session-RPE (sRPE). Pairwise comparisons revealed that maximal aerobic speed (MAS) was greater for the third assessment than the first (p-value [p] = 0.003; standardized effect of Cohen [d] = 0.355) and second (p = 0.013; d = 0.193) assessments. Large correlations were found between MAS and accumulated RPE, accumulated time, and accumulated sRPE. Moreover, non, low and high responders differed in ?MAS (p<0.001) with the last group presenting the largest improvement in MAS. Results suggest that children with lower MAS baseline levels will improve more this capacity over the early and mid-season period compared to children with better baseline levels. Moreover, associations between accumulated training load and MAS were found, suggesting that the training effort can be related with aerobic capacity changes. 



#4 Association Between the ACE I/D Polymorphism and Muscle Injuries in Italian and Japanese Elite Football Players 

Reference: J Sports Sci. 2020 Jul 2;1-7. doi: 10.1080/02640414.2020.1787683. Online ahead of print. 

Authors: Myosotis Massidda, Eri Myamoto-Mikami, Hiroshi Kumagai, Hayato Ikeda, Yu Shimasaki, Masafumi Yoshimura, Paolo Cugia, Francesco Piras, Marco Scorcu, Naoki Kikuchi , Carla Maria Calò, Noriyuki Fuku 

Summary: ACE I/D polymorphism has been recently associated with the susceptibility to inflammation and muscle damage after exercise. The aim of this study was to understand the association between the ACE I/D polymorphism and muscle injuries in a large cohort of elite football players from two different countries. Seven hundred and ten male elite football players from Italy (n = 341) and Japan (n = 369) were recruited for the study. Genomic DNA was extracted from either the buccal epithelium or saliva using a standard protocol. Structural-mechanical injuries and functional muscle disorders were recorded from 2009 to 2018. A meta-analysis was performed using Review Manager 5.3.5. In the Japanese cohort, the ACE I/D polymorphism was significantly associated with muscle injury using the D-dominant model (OR: 0.48, 95% CI: 0.24-0.97, P = 0.040). The meta-analysis showed that in the pooled model (Italian and Japanese populations), the frequencies of the DD+ID genotypes were significantly lower in the injured groups than in non-injured groups (OR: 0.61, 95% CI: 0.38-0.98, P = 0.04) with a low degree of heterogeneity (I2 = 0%). Our findings suggest that the ACE I/D polymorphism could influence the susceptibility to developing muscle injuries among football players. 



#5 Effects of Daily Probiotics Supplementation on Anxiety Induced Physiological Parameters among competetive Football Players

Reference: Nutrients. 2020 Jun 29;12(7):E1920. doi: 10.3390/nu12071920.  

Authors: A M G C P Adikari, Mahenderan Appukutty, Garry Kuan

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Summary: Competitive football players who undergo strenuous training and frequent competitions are more vulnerable to psychological disorders. Probiotics are capable of reducing these psychological disorders. The present study aimed to determine the effect of daily probiotics supplementation on anxiety induced physiological parameters among competitive football players. The randomized, double-blinded, placebo-controlled trial was conducted on 20 male footballers who received either probiotics (Lactobacillus Casei Shirota strain 3 × 1010 colony forming units (CFU) or a placebo drink over eight weeks. Portable biofeedback devices were used to measure the electroencephalography, heart rate, and electrodermal responses along with cognitive tests at the baseline, week 4, and week 8. Data were statistically analyzed using mixed factorial ANOVA and results revealed that there is no significant difference between the probiotic and placebo groups for heart rate (61.90 bpm ± 5.84 vs. 67.67 bpm ± 8.42, p = 0.09) and electrodermal responses (0.27 µS ± 0.19 vs. 0.41 µS ± 0.12, p = 0.07) after eight weeks. Similarly, brain waves showed no significant changes during the study period except for the theta wave and delta wave at week 4 (p < 0.05). The cognitive test reaction time (digit vigilance test) showed significant improvement in the probiotic group compared to the placebo (p < 0.05). In conclusion, these findings suggest that daily probiotics supplementation may have the potential to modulate the brain waves namely, theta (relaxation) and delta (attention) for better training, brain function, and psychological improvement to exercise. Further research is needed to elucidate the mechanism of current findings. 



#6 Injuries and Functional Performance Status in Young Elite Football Players: A Prospective 2-year Monitoring 

Reference: J Sports Med Phys Fitness. 2020 Jun 30. doi: 10.23736/S0022-4707.20.10886-7. Online ahead of print. 

Authors: Johanna Sieland, Frieder Krause, Kristin Kalo, Jan Wilke, Lutz Vogt, Winfried Banzer, Daniel Niederer

Summary: Motor function, such as strength asymmetries of the lower extremities and impaired dynamic stability, have a predictive value for the risk of injury. The present study aimed to reveal potential associations between injury and motor performance. Two hundred five (205) male youth elite (association) football (soccer) players (mean ± standard deviation: 13.5 ± 4.5 years, 57.2 ± 30.2 kg, 168 ± 35 cm) were included. A test battery was conducted twice per season, over two consecutive seasons (four times). Mobility (Sit and Reach Test, SnR), dynamic stability (Single Leg Hop for Distance, SLHD), linear sprinting speed (10 m, 30 m [s]), agility (Zig-Zag test with and without dribbling a ball [s]), jump performance (Counter Movement Jump (CMJ) and Drop Jump (DJ) [cm]) and Maximal Isometric Voluntary Force (MIVF [N]) of the knee extensors and flexors were assessed. All injuries occurring over the two-year period, as well as training and competition exposure time, were collected and used as grouping variables for statistical difference testing. One hundred twenty five (125) injuries in 93 players occurred (an injury incidence of 2.7/1000 hours of exposure). Age was associated with injury incidence (r=.191; p=.006). Neither DJ, CMJ, SnR nor agility performance were statistically different between injured and non-injured participants (p>.05). Group differences did occur for sprint and strength (p=.011; p=.016), but these lapsed after the inclusion of age as a covariate. Only for SLHD symmetry was a non-significant trend evident after the correction for age (p=.08). The occurrence of musculoskeletal injuries in junior football players are, probably, not related to baseline motor function. Group differences between injured and non-injured youth elite football players are mostly explained by age. Only the symmetry in SLHD could be a potential risk factor for injuries and merits further investigation. 



#7 Cross-Cultural Exploration of Baseline ImPACT Quick Test Performance Among Football Athletes in Zambia 

Reference: Phys Sportsmed. 2020 Jun 30. doi: 10.1080/00913847.2020.1790983. Online ahead of print. 

Authors: Jessica Wallace, Philip Schatz, Davie Mulenga, Mark Lovell, Gabriel Muyinda, Kachinga Agrippa Sichizya, Joseph Mulenga, Tracey Covassin

Summary: Concussion is a global sport injury; however, this public health issue has yet to be studied across Africa. It is unknown if tests such as the Immediate Post-Concussion Assessment and Cognitive Test (ImPACT) Quick Test (QT) are culturally appropriate for implementation as part of a concussion screening protocol in Zambia or other African nations. Study objectives included: 1) establish that Zambian athletes are able to complete the iPad-based ImPACT QT with respect to language or cultural barriers that may exist, and 2) document baseline neurocognitive percentile ranks among Zambian football athletes on the ImPACT QT. This study was completed with adult premiere league football athletes in Zambia (n=125) aged 24.48±5.41. Participants completed the ImPACT QT neurocognitive assessment prior to a preseason practice. Outcome measures were average performance on 3 factor scores: Motor Speed, Memory, and Attention Tracker, presented as percentile ranks using normative data built-into the ImPACT QT. Zambian athletes scored nearly two standard deviations below the mean on Motor Speed (7th percentile), using North American normative data. However, performance on Attention Tracker (44th percentile) and Memory (56th percentile) was within the average range. Results of the current study show that Zambian athletes are able to complete the ImPACT QT, despite any language or cultural differences that may exist. In addition, preliminary percentile ranks suggest Zambian football athletes have average scores on Attention and Memory and below average scores on Motor Speed. These data are the first to explore Zambian athletes' performance on a cognitive concussion measure. 



#8 Age-related and Training-Induced Changes in Morphological Characteristics of Young Elite Male Soccer Players 

Reference: J Sports Med Phys Fitness. 2020 Jun 30. doi: 10.23736/S0022-4707.20.11119-8. Online ahead of print. 

Authors: Nikolaos Androulakis, Nikolaos Koundourakis, Christos Tsiakiris, George Notas 

Summary: In soccer, morphological characteristics of young players are particularly important as they have a significant impact on the performance of many technical-tactical elements. Our aim in this study was to investigate whether soccer specific training on its own or combined with strength training can influence the morphological characteristics, of young soccer players and if so, to establish which age is more appropriate for interventions through individualized training. The study sample consisted of 61 young male soccer players, members of two under 17 (U171 and U172) and two under 19 (U191 andU192) teams. U171 (n= 17, consists of ages: 15.1±0.6) and U191 (n=14, consists of ages 17.3±0.5 years) teams performed only soccer specific training whilst U172 (n= 18, consists of ages 15.0±0.4 years) and U192 (n=12 consists of ages 17.1±0.7 years) teams had two extra strength trainings per week. Anthropometric measurements were performed at the beginning and at the end of the 10-months session. Lean body mass was increased whilst body fat decreased at the end of the study in all teams (p<0.001). No significant changes were found regarding endomorphic and ectomorphic outcome. Mesomorphic outcome was significantly increased only in U172 team (p<0.001). Our data supports that earlier interventions (between ages 15-17 years) in the training routine may be more effective in order to achieve anatomical and morphological characteristics most favorable for soccer. 



#9 Design and Validation of the Instrument for the Measurement of Learning and Performance in Football

Reference: Int J Environ Res Public Health. 2020 Jun 27;17(13):E4629. doi: 10.3390/ijerph17134629. 

Authors: Juan M García-Ceberino, Antonio Antúnez, Sergio J Ibáñez, Sebastián Feu

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Summary: The assessment of tactical-technical knowledge of football is essential to develop optimal and integral teaching processes for students. Therefore, the aim of this study was to design and validate an instrument so that teachers, coaches, and researchers can observe and codify both the tactical behaviors and technical skills performed by the students in the game of football. The design and validation of the instrument were carried out in four phases: a) review of the literature and previous instruments; b) design of the Instrument for the Measurement of Learning and Performance in Football (IMLPFoot). It assesses all the offensive and defensive play actions, with and without the ball, as well as their three components (decision-making, technical execution, and final result); c) sample selection of experts (N = 12); and d) quantitative (Likert-type scale from 1 to 10) and qualitative assessment of degree the pertinence, unambiguity, and importance of each of the 33 items included in the IMLPFoot. Aiken's V coefficient was used to determine content validity. Likewise, internal consistency was calculated using Cronbach's ? coefficient. The results showed demanding levels of validity (V ? 0.77), internal consistency (? = 0.983), inter-rater, and intra-rater reliability. Therefore, it is a valid and reliable instrument that makes possible a complete assessment of football in physical education classes and/or in the sports context (out-of-school football). 


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