Latest research in football - week 7 - 2023

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 Video Analytics in Elite Soccer: A Distributed Computing Perspective

Reference: Proc IEEE Sens Array Multichannel Signal Process Workshop. 2022 Jun;2022:221-225.  doi: 10.1109/SAM53842.2022.9827827. Epub 2022 Jul 22.

Authors: Debesh Jha, Ashish Rauniyar, Håvard D Johansen, Dag Johansen, Michael A Riegler, Pål Halvorsen, Ulas Bagci

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Summary: Ubiquitous sensors and Internet of Things (IoT) technologies have revolutionized the sports industry, providing new methodologies for planning, effective coordination of training, and match analysis post game. New methods, including machine learning, image and video processing, have been developed for performance evaluation, allowing the analyst to track the performance of a player in real-time. Following FIFA's 2015 approval of electronics performance and tracking system during games, performance data of a single player or the entire team is allowed to be collected using GPS-based wearables. Data from practice sessions outside the sporting arena is being collected in greater numbers than ever before. Realizing the significance of data in professional soccer, this paper presents video analytics, examines recent state-of-the-art literature in elite soccer, and summarizes existing real-time video analytics algorithms. We also discuss real-time crowdsourcing of the obtained data, tactical and technical performance, distributed computing and its importance in video analytics and propose a future research perspective.



#2 An assist for cognitive diagnostics in soccer (Part II): Development and validation of a task to measure working memory in a soccer-specific setting

Reference: Front Psychol. 2023 Jan 23;13:1026017. doi: 10.3389/fpsyg.2022.1026017. eCollection 2022.

Authors: Simon Knöbel, Franziska Lautenbach

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Summary: Cognitive diagnostics is of increasing interest to researchers and practitioners in the context of talent identification and performance enhancement in professional soccer. Research addressing the relevance of cognitive skills for sports performance has been based on the cognitive component approach (i.e., general cognitive processes) and the expert performance approach (i.e., sport-specific cognitive processes). Following the aim to combine the strengths of both approaches, we have previously developed and validated tasks to measure inhibition and cognitive flexibility in a soccer-specific setting, including a soccer-specific motor response. In line with the broad consistency on three core executive functions, this further development of diagnosing executive functions is to be completed with a task for the assessment of working memory. For this purpose, 60 amateur players with a soccer experience of at least one competitive season (M age = 25.95, SD age = 4.59) first conducted a computer-based version of the n-back (3-back) task followed by a 3-back task that required a soccer-specific motor response (i.e., pass) performed in a soccer-specific setting (i.e., SoccerBot100). Results show good reliability for both tasks. With regard to convergent validity, significant correlations between the computerized and soccer-specific task could be determined in target trials for response time (r = 0.446) and accuracy (r = 0.401). Thus, the soccer-specific n-back task can be considered a potentially valid instrument for assessing working memory and potentially allows soccer clubs to diagnose the three core executive functions in a consistent soccer-specific setting.



#3 Dietary supplements and beverages: Knowledge, attitudes, and practices among semi-professional soccer players in KwaZulu-Natal, South Africa

Reference: S Afr J Sports Med. 2022 Jan 1;34(1):v34i1a14018. doi: 10.17159/2078-516X/2022/v34i1a14018. eCollection 2022.

Authors: S Nyawose, R Naidoo, N Naumovski, A J McKune

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Summary: The ingestion of dietary supplements and beverages is prevalent in soccer, at the amateur and professional level. The absence of professional advice at non-professional level makes amateur soccer players susceptible to ingesting unsafe supplements. The aim was to determine the knowledge, attitudes and practices of ABC Motsepe League (semi-professional) players in KwaZulu-Natal regarding the use of dietary supplements and beverages. Three hundred and forty-three soccer players participated in a cross-sectional study. Knowledge, attitudes and practices were determined using a questionnaire. Researchers visited twelve teams. On the day of the visit to each team, information sheets and questionnaires were given to participants. Questionnaires were collected immediately following completion. Descriptive statistics were used, including means and standard deviations, where applicable. Inferential statistics, Chi-square and binomial tests were used to analyse the results. Statistical significance was set at p < 0.05. Sports beverages were the most recommended and commonly used, followed by energy beverages. Dietary supplements were the least-known used. Participants used beverages and dietary supplements to assist in providing more energy (67%), improve health (65%) and improve performance (55%) (p<0.001). Seventy-three percent of participants lacked knowledge about the anti-doping policy (p<0.001), with 87% having never attended a workshop on the safe use of supplements and beverages, or anti-doping awareness campaigns (p<0.001). Thirty-eight percent had not heard of the South African Institute for Drug-Free Sport (SAIDS), and 84% were not familiar with the yearly updated World Anti-Doping Agency's (WADA) prohibited list (p<0.001). Of the 59% who did not take dietary supplements or beverages, 75% had insufficient information regarding them (p<0.001), 66% indicated that dietary supplements and beverages were costly (p=0.001), and 55% indicated they did not need dietary supplements and beverages (p=0.32). There is a need for an educational programme on the safe use of dietary supplements, and sports and energy beverages among KwaZulu-Natal semi-professional soccer players.



#4 Cognitive function in soccer athletes determined by sleep disruption and self-reported health, yet not by decision-reinvestment

Reference: Front Neurol. 2023 Feb 6;13:872761. doi: 10.3389/fneur.2022.872761. eCollection 2022.

Authors: Jasmin Pourhassan, Jane Sarginson, Wolfgang Hitzl, Kneginja Richter

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Summary: Sleep disruption (SD) increases sympathetic activity and cortisol secretion, and delays cognitive functions such as reaction-time (RT). Sympathetic activity of disturbed sleepers, is similar to those of so-called decision-reinvesters. Decision-reinvestment refers to traits in individuals with greater tendency to ruminate and reinvest in their decisions, with significant decrease in both motor-control and cognitive performance. Decision-making quality is a crucial attribute to athletic performance which relies on RT. Consequently, SD affects pitch-performance negatively, particularly in decision-reinvesters. This observational pilot-study examined the relationship between SD and cognitive function, perceived health, as well as reinvestment strategies. The hypothesis was that athletes with lower SD perceive their health better, report lower stress levels, perform better in cognitive tasks, and show lower tendency for decision-reinvestment. Twenty-one football player recorded their sleep with fit-trackers for 7 nights. Participants self-reported their mental and physical health, decision-reinvestment strategy, sleep behaviour, and perceived stress levels. Athletes then performed a set of cognitive tests to examine memory function (Backwards Corsi), selective attention (STROOP), and cognitive flexibility (Wisconsin Card Sorting Test, WCST). Normality was tested with a Shapiro-Wilk test, and analysed with a Pearson's or Spearman's correlation test. Significant correlation appeared between extended sleep-interruptions and Backwards Corsi RT, r = 0.66, p = 0.010, as further in total sleep time and wellbeing r = 0.50, p = 0.029. A negative correlation exist in regard of pain scores and Backwards Corsi scores r = -0.57, p = 0.110. Physical health correlated with error-rates in the WCST, r = 0.69, p ≤ 0.001. Also, reinvestment negatively correlated with physical health, r = -0.80, p ≤ 0.001. Wellbeing relies on total sleep-time. Athletes with extended sleep-interruptions are slower in recalling memory, and those with greater reported pain have lower memory scores. Participants who rate physical health greater, have more error-rates in the WCST; indicating that cognitive flexibility is enhanced in individuals with inferior perceived health. However, individuals with lower physical health scores also have greater tendency to ruminate and reinvest in decisions, suggesting interrelation between reinvestment and physical health.



#5 External load profile during different sport-specific activities in semi-professional soccer players

Reference: BMC Sports Sci Med Rehabil. 2023 Feb 22;15(1):22. doi: 10.1186/s13102-023-00633-3.

Authors: Guglielmo Pillitteri, Valerio Giustino, Marco Petrucci, Alessio Rossi, Marianna Bellafiore, Ewan Thomas, Angelo Iovane, Antonino Bianco, Antonio Palma, Giuseppe Battaglia

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Summary: Global Positioning System (GPS) devices are widely used in soccer for monitoring external load (EL) indicators with the aim of maximizing sports performance.The aim of this study was to investigate the EL indicators differences in players of different playing positions (i.e., central backs, external strikers, fullbacks, midfielders, strikers, wide midfielder) between and within different sport-specific tasks and official matches. 1932 observations from 28 semi-professional soccer players (age: 25 ± 6 years, height: 183 ± 6 cm, weight: 75.2 ± 7 kg) were collected through GPS devices (Qstarz BT-Q1000EX, 10 Hz) during the season 2019-2020. Participants were monitored during Official Match (OM), Friendly Matches (FM), Small Sided Games (SSG), and Match-Based Exercises (MBE). Metabolic (i.e., metabolic power, percentage of metabolic power > 35w, number of intense actions per minute, distance per minute, passive recovery time per minute) and neuromuscular indicators (i.e., percentage of intense accelerations, percentage of intense decelerations, change of direction per min > 30°) were recorded during each task. Statistically significant differences were detected in EL indicators between playing positions within each task and between tasks. In particular, results from the two-way ANOVA tests showed significant interaction, but with small effect size, in all the EL indicators between playing positions for each task and within tasks. Moreover, statistical differences, but with small effect size, between playing positions were detected in each task and for each EL indicator. Finally, the strongest statistical differences (with large effect size) were detected between tasks for each EL indicator. Details of the Tukey post-hoc analysis reporting the pairwise comparisons within and between tasks with playing positions are also provided. In semi-professional soccer players, different metabolic and neuromuscular performance were detected in different playing position between and within different tasks and official matches. Coaches should consider the different physical responses related to different physical tasks and playing position to design the most appropriate training program.



#6 Soccer and Benign Paroxysmal Positional Vertigo

Reference: Case Rep Otolaryngol. 2023 Feb 14;2023:3744863. doi: 10.1155/2023/3744863. eCollection 2023.

Authors: Nikolaj Warming, Stephanie Balslev Andersen, Dan Dupont Hougaard

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Summary: Benign paroxysmal positional vertigo (BPPV) is the most common cause of vertigo among adults. The etiology of BPPV is unknown in approximately 50 percent of cases. This condition is also termed primary BPPV, if the etiology is unknown, and secondary BPPV if patients have identified predisposing factors. A few studies suggest that there is a correlation between the development of BPPV and specific sports. A 19-year-old male presented with recurrent episodes of vertigo during soccer play. Eight months prior to referral, the patient was involved in a car accident with a mild head trauma. The patient was later diagnosed with BPPV several times. Soccer might be a plausible BPPV trigger, especially if there is a prehistory of head trauma. This is most likely due to the demands of the game such as the change of directions, repetitive head impacts (headers or head collisions), accelerations/decelerations, jumps, foot landings, and rapid head movements.



#7 Match Load Physical Demands in U-19 Professional Soccer Players Assessed by a Wearable Inertial Sensor

Reference: J Funct Morphol Kinesiol. 2023 Feb 7;8(1):22. doi: 10.3390/jfmk8010022.

Authors: Guglielmo Pillitteri, Valerio Giustino, Marco Petrucci, Alessio Rossi, Ignazio Leale, Marianna Bellafiore, Ewan Thomas, Angelo Iovane, Antonio Palma, Giuseppe Battaglia

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Summary: Wearable inertial sensors are poorly used in soccer to monitor external load (EL) indicators. However, these devices could be useful for improving sports performance and potentially reducing the risk of injury. The aim of this study was to investigate the EL indicators (i.e., cinematic, mechanical, and metabolic) differences between playing positions (i.e., central backs, external strikers, fullbacks, midfielders, and wide midfielder) during the first half time of four official matches (OMs). 13 young professional soccer players (Under-19; age: 18.5 ± 0.4 years; height: 177 ± 6 cm; weight: 67 ± 4.8 kg) were monitored through a wearable inertial sensor (TalentPlayers TPDev, firmware version 1.3) during the season 2021-2022. Participants' EL indicators were recorded during the first half time of four OMs. Significant differences were detected in all the EL indicators between playing positions except for two of them (i.e., distance traveled in the various metabolic power zones (<10 w) and the number of direction changes to the right >30° and with speed >2 m). Pairwise comparisons showed differences in EL indicators between playing positions. Young professional soccer players showed different loads and performances during OMs in relation to playing positions. Coaches should consider the different physical demands related to playing positions in order to design the most appropriate training program.



#8 Reliability of the Coimbra Reactive Agility Soccer Test (CRAST)

Reference: J Funct Morphol Kinesiol. 2023 Jan 18;8(1):11. doi: 10.3390/jfmk8010011.

Authors: António Nóbrega, Hugo Sarmento, Vasco Vaz, Vítor Gouveia, Joel Barrera, Andreia Martins, Tomás Santos, João Pedro Duarte

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Summary: Agility is a fitness-skill-related component that should be a part of the standard physiological testing for soccer players and one of the key performance indicators in soccer. The present study aimed to assess the reliability of the CRAST as a research tool in the study of soccer skills. Twenty-one university soccer players (chronological age: 19.3 ± 1.4 years; body mass: 69.6 ± 8.2 kg; stature: 173.5 ± 6.5 cm; federated training experience: 9.7 ± 3.6 years) volunteered for the testing protocol. The CRAST requires players to complete random courses six times as quickly as possible. In addition, the CRAST requires players to control and dribble the markers (four different colors: green, yellow, blue, and red). The soccer players completed three trials, each separated by one week. The first trial accounted for familiarization; the second and third were considered for analysis. The correlation for overall performance was very strong. The reliability of the CRAST was slightly better for total time than that for the penalty score (0.95 vs. 0.93). The TEM and the associated CV range of 7.04%-7.54% were for the penalty score and the total time, respectively. For both measurements, the ICC values also represent excellent reliability, as both values were over 0.900. The CRAST is a reliable protocol for assessing agility in soccer players.



#9 Majority of competitive soccer players return to soccer following hip arthroscopy for femoroacetabular impingement: female and older aged players are less likely to return to soccer

Reference: Knee Surg Sports Traumatol Arthrosc. 2023 Feb 21. doi: 10.1007/s00167-023-07349-4.

Authors: Niv Marom, Reena Olsen, Joost A Burger, Matthew S Dooley, Struan H Coleman, Anil S Ranawat, Bryan T Kelly, Danyal H Nawabi

Summary: The aim was to determine return to soccer rates and soccer performance in a large cohort of competitive soccer players after hip arthroscopic surgery for the treatment of femoroacetabular impingement (FAI) and to identify possible risk factors associated with not returning to soccer. An institutional hip preservation registry was retrospectively reviewed for patients identified as competitive soccer players who underwent primary hip arthroscopy for FAI performed between 2010 and 2017. Patient demographics and injury characteristics as well as clinical and radiographic findings were recorded. All patients were contacted for return to soccer information using a soccer-specific return to play questionnaire. Multivariable logistic regression analysis was used to identify potential risk factors for not returning to soccer. Eighty-seven competitive soccer players (119 hips) were included. 32 players (37%) underwent simultaneous or staged bilateral hip arthroscopy. The mean age at surgery was 21.6 ± 7.0 years. Overall, 65 players (74.7%) returned to soccer, of which 43 players (49% of all included players) returned to pre-injury level of play or better. Most common reasons for not returning to soccer were pain or discomfort (50%) followed by fear of re-injury (31.8%). The mean time to return to soccer was 33.1 ± 26.3 weeks. Among 22 players who did not return to soccer, 14 (63.6%) reported satisfaction from surgery. Multivariable logistic regression analysis revealed female players (odds ratio [OR] = 0.27; confidence interval [CI] = 0.083 to 0.872; p = 0.029) and older aged players (OR = 0.895; 95% CI = 0.832 to 0.963; p = 0.003) were less likely to return to soccer. Bilateral surgery was not found to be a risk factor. Hip arthroscopic treatment for FAI in symptomatic competitive soccer players allowed three-quarters of them to return to soccer. Despite not returning to soccer, two-thirds of players who did not return to soccer were satisfied with their outcome. Female and older aged players were less likely to return to soccer. These data can better guide clinicians and soccer players with realistic expectations related to the arthroscopic management of symptomatic FAI.



#10 An overview of injury prevention for soccer players in Pakistan: A sports rehab perspective

Reference: J Pak Med Assoc. 2023;73(1(B)):435-437. doi: 10.47391/JPMA.15-23.

Authors: Muhammad Furqan Hassan, Furqan Ahmed Siddiqi, Muhammad Salman Bashir, Farooq Azam Rathore

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Summary: Soccer (football) is one of the most popular weight-bearing sports in the world, which involves activities such as jumping, running and turning. Soccer related injuries have the highest incidence in all sports and are more common in young amateur players. The most important modifiable risk factors include neuromuscular control, postural stability, hamstring strength and core dysfunction. The International Federation of Football Association introduced FIFA 11+; an injury prevention programme for reduction in the rate of injuries in amateur and young soccer players. It focusses on the training of dynamic, static and reactive neuromuscular control, proper posture, balance, agility and control of the body. This training protocol is not being used in Pakistan at amateur level who neither possess the resources, nor the knowledge or proper guidance in risk factor assessment, prevention, and subsequent sport injury management. In addition, the physicians and rehabilitation community are not much familiar with it except for those directly involved in sports rehabilitation. This review highlights the importance of including FIFA 11+ training programme in the curriculum and faculty training.



#11 Effects of Combined Horizontal Plyometric and Change of Direction Training on Anaerobic Parameters in Youth Soccer Players

Reference: Sports (Basel). 2023 Jan 26;11(2):27. doi: 10.3390/sports11020027.

Authors: Yiannis Michailidis, Panagiotis Venegas, Thomas Metaxas

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Summary: The aim of this study is to investigate whether the combination of soccer training, plyometric training (PT), and change of direction (COD) exercises would enhance anaerobic performance to a greater extent than training on its own in youth U17 soccer players. Twenty youth players participated in this study. Players were randomly separated into two groups: the control group (CG, n = 9) and the intervention group (EX), which performed extra PT and COD exercises (EX, n = 11). The duration of the training program was six weeks. Sprint 10 m, 30 m, countermovement jump (CMJ), single leg countermovement jump (CMJ right and left), squat jump (SJ), 505 test, and Illinois agility test were measured pre and post of the training program. The performance in the 505 test improved for the EX group (right leg: p = 0.031, left leg: p = 0.004). In addition, Illinois test performance increased in the EX group (2.9%, p = 0.019). The performances of the two groups differed significantly in the Illinois agility test (p = 0.001). This study supports that a short-term combined program of PT and COD exercises can improve change of direction ability in youth U17 soccer players. The lack of effect of the intervention program on sprint and jump performance may be due to the type and volume of plyometric exercises used. The results reflect the training principle of specialization of stimulus. The improvement in performance was presented in tests that had similar characteristics to training stimuli.



#12 Protein Intake in NCAA Division 1 Soccer Players: Assessment of Daily Amounts, Distribution Patterns, and Leucine Levels as a Quality Indicator

Reference: Sports (Basel). 2023 Feb 14;11(2):45. doi: 10.3390/sports11020045.

Authors: Jun Kwon, Morgan M Nishisaka, Alexandra F McGrath, Aleksandra S Kristo, Angelos K Sikalidis, Scott K Reaves

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Summary: Dietary protein is required to support recovery and adaptation following exercise training. While prior research demonstrates that many athletes meet total daily protein needs, intake seems to be predominantly skewed toward the evening meal. An even distribution of protein doses of ≥0.24 g/kg BW consumed throughout the course of a day is theorized to confer greater skeletal muscle anabolism outcomes compared to a skewed pattern of intake. Protein quality is also an important dietary consideration for athletes, with the amino acid leucine seemingly serving as the primary driver of the postprandial anabolic response. The present study investigates protein consumption characteristics among a cohort of NCAA D1 soccer players and evaluates differences between male and female athletes. Athletes were instructed to complete 3-day food diaries, which were subsequently analyzed and compared to UEFA expert group-issued nutrition guidelines for soccer players. Breakfast, lunch, and dinner accounted for 81.4% of the total daily dietary protein intake. Most athletes (77.8%) ingested optimum amounts of protein at dinner but not at breakfast (11.1%) or lunch (47.2%). In addition, statistically significant sex-based differences in daily dietary protein intake, meal-specific protein amounts, and protein quality measures were detected. Findings indicate suboptimal dietary protein intake practices among the collegiate soccer athletes.



#13 Weekly screening of youth male football players: a 14-week longitudinal investigation of interactions between groin pain and long lever adductor squeeze strength

Reference: J Sci Med Sport. 2023 Feb 10;S1440-2440(23)00031-2. doi: 10.1016/j.jsams.2023.02.003.

Authors: Matthew D DeLang, J Craig Garrison, Joseph P Hannon, Lasse Ishøi, Kristian Thorborg

Summary: The aim was o explore relationships between groin pain and adductor squeeze strength in male academy football players over a 14-week period. Weekly monitoring of youth male football players consisted of reporting groin pain and testing long lever adductor squeeze strength. Players who reported groin pain at any time during the study period were stratified into the "groin pain" group while players who did not report pain remained in the "no groin pain" group. Baseline squeeze strength was retrospectively compared between groups. Players that developed groin pain were examined via repeated measures ANOVA at four timepoints: baseline, last squeeze before pain, pain onset, and return to pain-free. 53 players were included (age 14.4 ± 1.6 years). Baseline squeeze strength was not different between players in the "groin pain" (n = 29, 4.35 ± 0.89 N/kg) versus "no groin pain" group (n = 24, 4.33 ± 0.90 N/kg, p = 0.83). At a group level, players with no groin pain maintained similar adductor squeeze strength throughout 14 weeks (p > 0.05). Compared to baseline (4.33 ± 0.90 N/kg), players with groin pain had decreased adductor squeeze strength at the last squeeze before pain (3.91 ± 0.85 N/kg, p = 0.003) and at pain onset (3.58 ± 0.78 N/kg, p < 0.001). Adductor squeeze strength at the point where pain subsided (4.06 ± 0.95 N/kg) was not different from baseline (p = 0.14). Decreases in adductor squeeze strength manifest one-week prior to groin pain onset and further decrease at pain onset. Weekly adductor squeeze strength may be an early detector for groin pain in youth male football players.



#14 Effect of Increasing the Number of Substitutions on Physical Performance during Periods of Congested Fixtures in Football

Reference: Sports (Basel). 2023 Jan 19;11(2):25. doi: 10.3390/sports11020025.

Authors: Abraham García-Aliaga, Adrián Martín-Castellanos, Moisés Marquina Nieto, Diego Muriarte Solana, Ricardo Resta, Roberto López Del Campo, Daniel Mon-López, Ignacio Refoyo

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Summary: (I) This study aimed to evaluate the impact on physical demands induced by FIFA's new rule implemented based on the number of substitutions caused by COVID-19. (II) Sixty-six matches were analysed in peak periods (microcycles of three matches in a week) in the competition period before and after the pandemic. The variables collected were organised by team (22 from LaLigaTM SmartBank 2019-2020) for a total of 132 team records and 1077 player performance reports using a multi-camera tracking system and Mediacoach® software. Physical performance variables were analysed in the first half, second half and whole match, thus determining the individual and collective performances of the team. (III) This study shows how, despite the increase in substitutions allowed with the new rule, physical performance increased in some variables in the congested periods (e.g., total distance run and distance run in the first and second halves). Additionally, the players' physical performance involved in a substitution was greater than it was for players who completed the game. (IV) The new substitution rule helps to maintain and even improve physical performance. This measure could improve intensity levels in both individual and team performance. It could even safeguard the physical integrity of the players by reducing the risk of injury, as fewer players have to play the full match.



#15 Measuring direct and indirect tendon parameters to characterize the proximal tendinous complex of the rectus femoris in football and futsal players

Reference: Front Physiol. 2023 Feb 7;14:986872. doi: 10.3389/fphys.2023.986872. eCollection 2023.

Authors: Sandra Mechó, Raquel Lisbona Ortega, Ricard Pruna, Lexa Nescolarde Selva, Jordi Morillas Pérez, Alfonso Rodríguez-Baeza, Javier Martínez Agea, Ricard Pérez-Andrés

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Summary: The aim was to present unprecedented radiological parameters that characterize the angle between the direct and indirect tendons of the proximal rectus femoris (RF) and its inclinations and to evaluate the population variability according to demographic variables. From September 2019 to July 2021, using MRI multiplanar reconstructions of the proximal thigh/hip, two blinded radiologists measured the direct and indirect tendon angle and the inclination of each tendon in different planes. The intra- and inter-observer agreements were assessed with Bland-Altman analysis and intraclass correlation coefficient (ICC). The correlations between radiological parameters and demographic variables were evaluated using linear regression, Student's t-test, and analysis of variance. We performed 112 thigh/hip MRI scans on 91 football players of different age, gender, and disciplines (football and futsal). For observer 1 (the reference), the mean direct and indirect tendon angle was 56.74° ± 9.37, the mean indirect tendon slope was -7.90° ± 7.49, and the mean direct tendon slope was 22.16° ± 5.88. The three measurements showed inter- and intra-observer agreement (mean differences ∼0). No correlation was observed between age and the parameters. Likewise, no statistically significant differences were found for gender, dominant limb, examined limb, and sport. There is an inter- and intra-observer agreement in the measurements of the direct and indirect tendon angle and the inclination of each tendon. There is population variability in the proximal tendinous complex unrelated to demographic factors. These results allow further detection of morphological patterns that represent a risk factor for lesions in the RF in professional football and futsal players and other sports.



#16 Peak Running Speeds in Professional Male Football: Influence of Division and Playing Position

Reference: J Strength Cond Res. 2023 Mar 1;37(3):636-640. doi: 10.1519/JSC.0000000000004298. Epub 2022 Jul 1.

Authors: Jack T Fahey, Kristian Aldred, Matt Greig, David Rhodes

Summary: Well-established physical demands of competitive professional football facilitate prescription and monitoring of training. However, many factors influence these physical demands with implications for efficacious practice. Match-play data were analyzed over 2 seasons using global positioning systems technology, differentiating English Championship (33 matches) and League One (27 matches) demands. Playing position categorized wide and central defenders and midfielders and forwards. Peak running speeds defined the outcome measure, assessing the influence of the competition level and playing position across 1, 5, and 10-minute rolling average durations using a linear mixed model. Significant effects were detected for the competition level (F1,324.5 = 5.44, p = 0.02) and playing position (F4,328.3 = 89.90, p < 0.001). League One matches demonstrated greater peak running speeds than Championship matches (mean difference = 2.72 m·min-1 [95% confidence intervals: 0.4, 5.0]). No difference was observed between central and wide midfielders (mean difference = 0.62 m·min-1 [95% confidence intervals: -3.1, 4.3]). Wide midfielders presented faster peak running speeds than forwards (mean difference = 18 m·min-1 [95% confidence intervals:14.1, 22.1], p < 0.05), central defenders (mean difference = 25 m·min-1 [95% confidence intervals: 21.7, 29.8], p < 0.05), and wide defenders (mean difference = 12 m·min-1 [95% confidence intervals: 8.2, 16.5], p < 0.05). Interaction effects were found for division*position (F4,328.3 = 2.57, p = 0.038) demonstrating greater running speeds in League One, except for central defenders. Wide midfielders presented greater peak 1-minute running speeds, whereas 5 and 10-minute peak running speeds were greatest in central midfielders. The sensitivity of peak running speeds to competition level and playing position has implications for training prescription, monitoring particularly when transitioning between competition levels, determining and monitoring positional training intensities, and objective targets for progressive overload during rehabilitation.



#17 The pattern of non-contact injuries in a South African professional football team

Reference: S Afr J Sports Med. 2022 Jan 1;34(1):v34i1a13723. doi: 10.17159/2078-516X/2022/v34i1a13723. eCollection 2022.

Authors: J Swart, C Varekamp, J Greyling

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Summary: The incidence, pattern and severity of non-contact injuries in European football has been researched extensively. In South African football only two studies have been conducted to date and with disparate outcomes. Further research into injury rates in South African football is therefore warranted. The aim was to determine the incidence and pattern of non-contact injuries in a South African professional football team during the course of a single season (2016-2017) in relation to competition exposure, training load and playing position. Thirty-four male professional football players belonging to a single team competing in the Premier Soccer League (PSL) in South Africa were studied. Non-contact time-loss injuries (total training and match injuries) were recorded. Injury incidence, location, severity, type, and playing position (defender, midfielder, attackers, goalkeepers) during either match play or training were recorded. The non-contact incidence was 52 injuries with an injury rate of 3.74 per 1 000 exposures (training and competition). Competitions resulted in an incidence of 26.4 injuries per 1 000 exposure and training incidence 2.08 injuries per 1 000 exposures. Hamstring, groin and quadriceps injuries were the most frequently injured locations and muscle-tendon injuries accounted for the majority of injuries. The majority of injuries (52%) occurred during match play while 48% occurred during training. The greatest absolute number of injuries were sustained by midfielders (50%), followed by defenders (33%) and attackers (17%). However, relative to player numbers, the greatest number of injuries during match play were for defenders (44%), attackers (32%) and midfielders (24%). During training attackers sustained the most injuries (39%), followed by defenders (31%) and midfielders (30%). Goalkeepers did not sustain any non-contact injuries during the duration of the study. The non-contact injury incidence in South African professional football players is similar to European football players. Hamstrings and groin injuries are predominant and were sustained throughout the competitive season. Defenders sustained the most non-contact injuries within the team relative to exposure time compared to attackers and midfielders. To our knowledge, injuries relative to player position have not been reported previously.



#18 Sport during the COVID-19 bio-bubble: Wellness and opinions in South African elite football

Reference: S Afr J Sports Med. 2022 Jan 1;34(1):v34i1a12528. doi: 10.17159/2078-516X/2022/v34i1a12528. eCollection 2022.

Authors: K Bahdur, L Pillay, D Dell'oca

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Summary: COVID-19 imposed challenges on professional sport, with restrictions leading to the delay in the completion of the South African Premier Soccer League (PSL). Creating a biologically safe environment (BSE) provided a solution enabling the 2019/2020 season to be completed. Evaluating the impact that the BSE had on player wellness and what coping mechanisms were used in the BSE. A questionnaire was distributed to PSL teams on the final weekend in the BSE. It consisted of three validated psychology questionnaires. An additional section focused on the impact and coping strategies during the PSL's BSE. A total of 37 completed questionnaires were analysed. General anxiety (4.7±4.2) and depression levels (4.8±3.9) were at an overall low. The health of the players, as well as separation from and concerns about family, were the greatest contributors to anxiety. Electronic communication with family and friends, social interactions with others in the BSE and time spent on self-reflection were important coping mechanisms for players. As time progressed, they adapted to the BSE. The BSE did not have a negative impact on the anxiety and depression levels of the respondents, with a variety of coping mechanisms key helping them adapt in the BSE.



#19 Injury, illness, and medication use surveillance during the 2020 COSAFA Women's championship: a prospective cohort study of football players from Southern Africa

Reference: Sci Med Footb. 2023 Feb;7(1):74-80. doi: 10.1080/24733938.2021.1971745. Epub 2021 Aug 30.

Authors: Nonhlanhla S Mkumbuzi, Senanile B Dlamini, Fidelis Chibhabha, Fredrick M Govere

Summary: Systematic analyses of injuries, illnesses or medication use and their risk factors among female African athletes are scarce, which has implications for management of these athletes. This prospective cohort study analysed the incidence and characteristics of injuries, illnesses and medication use during the 2020 COSAFA Women's Championship. The medical personnel of all participating teams reported all new injuries, illnesses and medication used by players daily. Sixty-three injuries were reported: 45 match and 18 training injuries; 45.5 (95% CI: 32.2 to 58.8) injuries/1000 match-hours and 21.7 (95% CI: 11.7 to 31.7) injuries/1000 training-hours, respectively. Most (n = 55, 87%) were caused by contact with another player and involved the lower extremity (n = 43; 68%). Fifty-eight illnesses were reported: 44.4 (95% CI: 33.0 to 58.8) illnesses/1000 player-days, mostly diarrhoea (n = 25; 43.1%) and dysmenorrhoea (n = 18; 31%). No cases of COVID-19 were reported. In total, 175 medications were prescribed: 168.8 (95% CI: 143.8 to 193.8) medications/1000 player-days. Non-steroidal anti-inflammatory drugs (NSAIDs) (n = 60; 34.3%) and analgesics (n = 33; 18.9%) were the most commonly prescribed drugs. Incidences of injury and illnesses were high but time loss was low, likely due to high NSAIDs use. Further studies should be conducted in order to inform appropriate prevention or management protocols in this population.


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