Latest research in football - week 32 - 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 Exposure assessment for repeated sub-concussive head impacts in soccer: The HEalth and Ageing Data IN the Game of football (HEADING) study

Reference: Int J Hyg Environ Health. 2023 Aug 6;253:114235. doi: 10.1016/j.ijheh.2023.114235.

Authors: Ioannis Basinas, Damien M McElvenny, Finley Brooker, Steven Robertson, Yvonne van Hoecke, Simon Kemp, Neil Pearce, Valentina Gallo, John W Cherrie

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Summary: The purpose of this paper was to develop exposure estimates for repetitive sub-concussive head impacts (RSHI) for use in epidemiological analyses. We used a questionnaire to collect lifetime history of heading and other head contacts associated with training and playing football from 159 former footballers all members of the English professional football association. We used linear mixed effect regression with player as the random effect, to model the number of headers, blows to the head and head-to-head impacts as a function of potential exposure affecting factors, which were treated as the fixed effects. Exposure affecting factors included playing position, league, context of play (game vs training) and decade of play. Age at time of response to the questionnaire was also included in the models. In model results, playing position was important, with RSHIs being highest among defenders and lowest among goalkeepers. Players headed the ball more during games than in training, and when playing in amateur or youth leagues compared with semi-professional or professional leagues. The average number of reported head impacts declined linearly throughout the observation period (1949-2015). The derived final model for headers explained 43%, 9% and 36% of the between player, within player and total variance in exposure, respectively with good precision and predictive performance. These findings are generally in agreement with previously published results pointing towards the models forming a valid method for estimating exposure to RSHI among former footballers although some further external validation is still warranted.



#2 Repeated stroboscopic vision training improves anticipation skill without changing perceptual-cognitive skills in soccer players

Reference: Appl Neuropsychol Adult. 2023 Aug 8;1-15. doi: 10.1080/23279095.2023.2243358.

Authors: Leonardo S Fortes, Heloiana Faro, Jocelyn Faubert, Carlos G Freitas-Júnior, Dalton de Lima-Junior, Sebastião S Almeida

Summary: In this study we aimed to analyze the repeated effect of stroboscopic vision training on perceptual-cognitive skills in soccer players. A total of 28 male soccer players participated in this experimental and randomized study with parallel groups. The soccer players were pair-matched according to perceptual-cognitive skills and randomized into two groups: Stroboscopic vision training and Control. Multiple object tracking, anticipation, and decision-making skills were measured before and after the 8-week intervention. An increase in multiple object tracking (p < 0.05) and decision-making skills (p < 0.05) from baseline to post-experiment was found in both groups without main group effect (p > 0.05). The findings showed an increase in anticipation skill from baseline to post-experiment in both groups (p < 0.05), with higher anticipation skill for the stroboscopic group than in the control group post-experiment (p < 0.05). Thus, we conclude that repeated stroboscopic vision training could improve anticipation skill in soccer athletes.



#3 Position Comparison of sport-related Concussions in female youth soccer players

Reference: Phys Sportsmed. 2023 Aug 11. doi: 10.1080/00913847.2023.2246869. Online ahead of print.

Authors: Hannah Worrall, Caroline Podvin, Claire Althoff, Jane Chung, Dai Sugimoto, Mathew Stokes, Luke C Radel, Munro Cullum, Shane Miller, Jacob Jones

Summary: Youth soccer participation, particularly among females, continues to grow worldwide. With the high incidence of sport-related concussion (SRC) in soccer, it is important to investigate if SRC occurs disproportionally by positions. Our hypothesis was to see no positional differences of SRCs, SRC-related characteristics, and outcomes among in female youth soccer athletes. Data were prospectively collected from participants at a single sports medicine institution between August 2015-April 2021. Female participants aged 8-18 diagnosed with SRC sustained during an organized soccer practice, scrimmage, or game were separated into 4 groups based on position: Forward, Midfielder, Defender, and Goalkeeper. Demographics, medical history, injury-related details, and outcomes were reviewed. A chi square test or Fisher's exact test were used for categorical variables. Continuous variables were compared with Mann-Whitney or Kruskal-Wallis test. Two hundred fourteen participants were included: 52 Forwards, 65 Midfielders, 63 Defenders, and 34 Goalkeepers. No significant differences between the groups in age, race, ethnicity, or previous concussion history. Differences in mechanism existed with Goalkeepers most commonly reporting Head to Body Part. Goalkeepers, which make up 1/11 of the total positions on the field, had a significantly higher proportion of SRCs compared to Field Positions. (9.1% vs 15.9%)At 3-month post-enrollment, there were no significant differences in reported symptoms or return-to-play between the different positions. In youth female soccer players, goalkeepers sustained a higher proportion of sport-related concussions compared to field players based upon the composition of a soccer team. The mechanism of injury also differed among the different soccer positions. However, no differences in concussion characteristics, outcomes, or RTP were seen across the different soccer positions.



#4 The effect of three different pre-match warm-up structures on male professional soccer players' physical fitness

Reference: PeerJ. 2023 Aug 3;11:e15803. doi: 10.7717/peerj.15803. eCollection 2023.

Authors: Mehdi Ben Brahim, Alejandro Sal-de-Rellán, Adrián García-Valverde, Hussain Yasin, Javier Raya-González

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Summary: Optimizing the soccer players' match preparation is one of the most relevant concerns of coaches for strength and conditioning training. Thus, the aim of this study was to analyze the effects of three pre-match warm-up structures on the physical condition of male professional soccer players. Seventeen male professional soccer players (age: 20.9 ± 2.4 years) of one Tunisian Professional Soccer League team participated in this study. Players performed three times a typical pre-match warm-up (WU) [aerobic phase (AE); neuromuscular phase (NM); velocity phase (VL); and ball-specific phase (BS) variating the order of the included phases/exercises: WU1 (AE + BS + NM + VL); WU2 (AE + NM + VL + BS); and WU3 (AE + VL + BS + NM). After each warm-up phase, players completed the following physical fitness tests: linear sprint test, countermovement jump test, 15-m ball dribbling agility test and ball shooting test. Additionally, the rate of perceived exertion (RPE) was registered after each warm-up. The results indicated significant differences between WU1 and WU3, with better results in the ball shooting test and RPE in WU3. In addition, there were no significant differences in the other variables and between other warm-up structures. These findings could be of great interest for coaches to the strength and conditioning coaches for professional soccer teams in order to improve the players physical performance and perceived exertion.



#5 Using Bar Velocity to Assess Post-match Neuromuscular Fatigue in Young Soccer Players

Reference: Int J Sports Med. 2023 Aug 7. doi: 10.1055/a-2150-0960. Online ahead of print.

Authors: João Barreira, Petrus Gantois, Jorge Castro, Xavier Mesquita, Rafael Peixoto, Miguel Ferreira Cid, Irineu Loturco, Ana Sousa, Fábio Yuzo Nakamura

Summary: This study aimed to investigate the recovery of neuromuscular performance using mechanical parameters collected during jump (vertical and horizontal) and strength-power exercises in youth soccer players after official soccer matches. Twenty-one outfield highly trained youth male soccer athletes (age: 18.23 ± 0.73 years; weight: 72.12 ± 6.99 kg; height: 1.78 ± 0.08 m) from two teams competing in the 1st division of U-19 Portuguese National Championship participated in this study. Players completed a battery of physical tests at -2h, +30 min, +24h, and +48h in relation to the match. Countermovement jump height, horizontal jump distance, and bar velocity during the half-squat, bench press, and hip-thrust exercises, at fixed loads, were recorded. Countermovement jump was impaired until 24h post-match (-1.7% from pre to 24h post, p=0.050; ES=-0.82). Half-squat bar velocity was reduced immediately following the match (-6.8 % from pre- p=0.004; ES=-0.64) but recovered at +24h (+2.9%, p=1.00; ES=0.02). Hip-thrust bar velocity was reduced for up to 48h post-match (-7.4% from pre to 48h post, p<0.001; ES=-0.80). No impairments were found in the horizontal jump and bench press at any moment. Our findings show prolonged decrements in strength of the posterior chain following a soccer match, measured in the hip-thrust exercise, while the other exercises displayed faster recovery dynamics.



#6 Two-Dimensional and Three-Dimensional Biomechanical Factors During 90° Change of Direction are Associated to Non-Contact ACL injury in Female Soccer Players

Reference: Int J Sports Phys Ther. 2023 Aug 1;18(4):887-897.  doi: 10.26603/001c.84308. eCollection 2023.

Authors: Stefano Di Paolo, Alberto Grassi, Filippo Tosarelli, Matteo Crepaldi, Laura Bragonzoni, Stefano Zaffagnini, Francesco Della Villa

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Summary: The two-dimensional (2D) video-analysis of the change of direction (COD) technique has never been used to attempt to predict the risk of ACL injury in female football players. The purpose of the present pilot study was to prospectively investigate the biomechanical predictors of ACL injury during a COD task in female football players using both gold standard 3D motion capture and a qualitative scoring system based on 2D video-analysis. Sixteen competitive female football (soccer) players (age 21.4 ± 4.3) performed a series of pre-planned 90° COD tasks. 3D motion data was recorded through 10 stereophotogrammetric cameras and a force platform. 2D frontal and transverse plane joint kinematics were computed through video-analysis from three high-speed cameras. A scoring system based on five criteria was adopted: limb stability, pelvis stability, trunk stability, shock absorption, and movement strategy. The players were prospectively followed for the next two consecutive football seasons and the occurrence of severe knee injuries was registered. Four players (25%) experienced an ACL injury. In 3D analysis, ACL-injured players showed greater knee valgus, knee internal rotation, and lower knee flexion (p= 0.017 - 0.029). Lower hip flexion coupled with greater external rotation (p= 0.003 - 0.042), ankle eversion, and contralateral pelvic drop (p<0.001) were also noted. In 2D analysis, ACL-injured players showed greater internal foot rotation, contralateral pelvic drop, lower knee flexion, and contralateral trunk tilt (moderate-to-large effect size). Pelvis stability and trunk stability showed the highest predictive value towards ACL injury. Total score was significantly lower in ACL-injured players with a moderate effect size (d=0.45). Both 3D and 2D methodologies depicted biomechanical risk factors and offered predictive insights towards the ACL injury risk. Awareness should rise in women's football regarding the high risk of ACL injury and the strategies to assess and mitigate it.



#7 Clinical, Biomechanical, and Self-reported Health Status After ACL Reconstruction With Meniscal Repair in Soccer Players: Results at Minimum 1-Year Follow-up

Reference: Orthop J Sports Med. 2023 Aug 2;11(8):23259671231177309. doi: 10.1177/23259671231177309. eCollection 2023 Aug.

Authors: Lorenzo Moretti, Ilaria Bortone, Michelangelo Delmedico, Danilo Giuseppe Cassano, Nuccio Caringella, Davide Bizzoca, Biagio Moretti

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Summary: Performing meniscal repair with anterior cruciate ligament reconstruction (ACLR) has been shown to contribute to the long-term preservation of knee health and gait biomechanics. The purpose was to evaluate the role of meniscal repair in the performance of semiprofessional soccer players who returned to sport after ACLR. This study included 51 male soccer players (mean ± SD age, 28.82 ± 5.33 years) who underwent ACLR at a single institution between July 2018 and July 2019. The players were divided into 3 groups according to surgery type: ACLR only (n = 30), ACLR with lateral meniscal repair (n = 9), and ACLR with medial meniscal repair (n = 12). Outcomes were evaluated through clinical examination, self-reported health questionnaires (Cincinnati Knee Rating System, Tegner activity score, Tegner Lysholm Knee Scoring Scale, Tampa Scale of Kinesiophobia, and ACL-Return to Sport After Injury), and biomechanical performance evaluations (balance, strength, coordination, and symmetry tests). Parametric and nonparametric tests were carried out for multiple comparisons. The mean ± SD follow-up time was 20.75 ± 9.38 months. Although no significant differences emerged in clinical and self-reported health status, almost all the physical parameters tested resulted in lower performance in players treated with ACLR and meniscal repair. Moreover, patients with ACLR with lateral meniscal repair reported higher pain and fear of reinjury, with lower outcomes in terms of strength, symmetry, and coordination as compared with the other 2 groups. Balance abilities were significantly affected in players who underwent meniscal repair as compared with those who underwent ACLR only. The findings showed that biomechanical performance measures and fear of reinjury were significantly worse in soccer players with associated meniscal repair at a minimum 1-year follow-up, especially in those with a lateral meniscal tear.



#8 Resultant equations for training load monitoring during a standard microcycle in sub-elite youth football: a principal components approach

Reference: PeerJ. 2023 Aug 4;11:e15806. doi: 10.7717/peerj.15806. eCollection 2023.

Authors: José Eduardo Teixeira, Pedro Forte, Ricardo Ferraz, Luís Branquinho, Ryland Morgans, António José Silva, António Miguel Monteiro, Tiago M Barbosa

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Summary: Applying data-reduction techniques to extract meaningful information from electronic performance and tracking systems (EPTS) has become a hot topic in football training load (TL) monitoring. The aim of this study was to reduce the dimensionality of the internal and external load measures, by a principal component approach, to describe and explain the resultant equations for TL monitoring during a standard in-season microcycle in sub-elite youth football. Additionally, it is intended to identify the most representative measure for each principal component. A principal component analysis (PCA) was conducted with a Monte Carlo parallel analysis and VariMax rotation to extract baseline characteristics, external TL, heart rate (HR)-based measures and perceived exertion. Training data were collected from sixty sub-elite young football players during a 6-week training period using 18 Hz global positioning system (GPS) with inertial sensors, 1 Hz short-range telemetry system, total quality recovery (TQR) and rating of perceived exertion (RPE). Five principal components accounted for 68.7% of the total variance explained in the training data. Resultant equations from PCA was subdivided into: (1) explosiveness, accelerations and impacts (27.4%); (2) high-speed running (16.2%); (3) HR-based measures (10.0%); (4) baseline characteristics (8.3%); and (5) average running velocity (6.7%). Considering the highest factor in each principal component, decelerations (PCA 1), sprint distance (PCA 2), average HR (PCA 3), chronological age (PCA 4) and maximal speed (PCA 5) are the conditional dimension to be considered in TL monitoring during a standard microcycle in sub-elite youth football players. Current research provides the first composite equations to extract the most representative components during a standard in-season microcycle in sub-elite youth football players. Futures research should expand the resultant equations within training days, by considering other well-being measures, technical-tactical skills and match-related contextual factors.



#9 Evaluation of electrocardiographic parameters in amputee football players

Reference: Front Psychol. 2023 Jul 24;14:1189712. doi: 10.3389/fpsyg.2023.1189712. eCollection 2023.

Authors: Ahmet Kurtoğlu, Ertuğrul Kurtoğlu, Alkame Akgümüş, Bekir Çar, Özgür Eken, Ioan Sârbu, Carmen Iulia Ciongradi, Dan Iulian Alexe, Iuliana Laura Candussi

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Summary: The present study aimed to compare electrocardiographic (ECG) parameters of amputee football players (AF) with football players without disability (FP) and sedentary individuals without disability (SI). A total of 32 participants (AF = 9, FP = 11, SI = 12) were included in the study. ECG parameters including P-wave amplitude, P-wave duration, PR interval, QRS duration, RR interval, QT interval, corrected-QT interval (QTc), ST segment duration, Tp-e duration, Tp-e/QT and Tp-e/QTc ratios were assessed in all the study participants by using a 12-lead ECG device. OneWay ANOVA Test was used for statistical analysis. Of all ECG parameters, P-wave amplitude and QTc were significantly higher in the AF group in comparison to FP and SI groups. QRS duration was found to be lower in the AF group when compared to FP and SI groups. Myocardial repolarization parameters including Tp-e duration, Tp-e/QT and Tp-e/QTc ratios were similar between groups, as were other parameters such as P-wave duration, PR interval, RR interval, QRS duration and QT interval. It was found that some ECG parameters of amputee football players differ from those with non-disabled players and non-disabled sedentary individuals. These different parameters were within normal limits.



#10 Health status of university football athletes through multidimensional screening

Reference: Phys Sportsmed. 2023 Aug 10;1-8. doi: 10.1080/00913847.2023.2246178. Online ahead of print.

Authors: Naruto Yoshida, Shogo Miyazaki, Hideaki Waki, Yoichi Minakawa, Masaaki Koido, Sonoko Mashimo

Summary: Adequate conditioning results from various physical, environmental, and psychological factors in sports activities. In this study, we aimed to clarify the concurrence and relevance of injuries, psychological problems, and sleep disturbance in university football (soccer) players. Biomechanical characteristics and risk factors for those injuries were also investigated. Overall, 1,084 university football players participated in this cross-sectional study using a web-based health history questionnaire. Assessments were made via the presence of injuries for physical problems, the Athlete Psychological Strain Questionnaire (APSQ) for psychologicalproblems, and the Athlete Sleep Screening Questionnaire (ASSQ) for sleep difficulties. There were 200 (19%) athletes with injuries; 413 (38%) of these were APSQ-positive, 246 (23%) were ASSQ-positive, and 468 (43%) athletes had no physical, psychological, or sleep problems. APSQ-positive respondents were significantly more likely to have a current injury than those who were APSQ-negative. No significant difference was observed between the number of ASSQ-positive and -negative respondents and current injuries. Those with sleep problems were significantly more likely to have psychological problems. More than 60% of university football players had one or more physical, psychological, or sleep problems. Players may have co-occurring problems, and it is important to address them for these athletes to reach peak performance.



#11 Creatine kinase concentration on the second post-match day is not associated with risk of subsequent muscle injury in professional football players: a four-season cohort study

Reference: Phys Sportsmed. 2023 Aug 10;1-6. doi: 10.1080/00913847.2023.2246175. Online ahead of print.

Authors: Augusto Camillo Tamujo, Hebert Nunes Flores, Tiago Cetolin, João Breno Ribeiro-Alvares, Alessandro Haupenthal, Bruno Manfredini Baroni

Summary: The objective of this study was to examine the relationship between creatine kinase (CK) concentration following official matches and the risk of subsequent muscle injury in professional male football (soccer) players. Blood samples were collected on the second post-match day for CK analysis over four consecutive seasons in a professional football club. Players were then followed for five days to observe any occurrence of indirect muscle injury (structural or functional in nature). Players exposed to at least 45 minutes in two consecutive matches within seven days were considered valid cases for analysis. Eighty players participated in the study, generating 1,656 cases eligible for analysis, of which 229 resulted in muscle injuries. The hamstrings were the most frequently injured muscle group (54%), followed by the adductor (21%), triceps surae (19%), quadriceps (5%), and psoas (1%). While CK concentration was higher in muscle injury cases [783 ± 507 U/L (95%CI, 717 to 849; min-max, 105-2,800)] compared with uninjured cases [688 ± 446 U/L (95%CI, 665 to 711; min-max, 100-2,950)], it was not an accurate predictor of subsequent muscle injury risk in professional football players (sensitivity = 56%; specificity = 55%; odds ratio = 1.00; area under curve = 0.557). CK concentration on the second post-match day cannot be used to effectively screen subsequent muscle injury risk in professional male football players.



#12 Do non-contact injuries occur during high-speed running in elite football? Preliminary results from a novel GPS and video-based method

Reference: J Sci Med Sport. 2023 Jul 22;S1440-2440(23)00180-9. doi: 10.1016/j.jsams.2023.07.007.

Authors: Francesco Aiello, Christian Di Claudio, Maurizio Fanchini, Franco M Impellizzeri, Alan McCall, Carwyn Sharp, Susan J Brown

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Summary: Understanding how injuries occur (inciting circumstances) is useful for developing etiological hypotheses and prevention strategies. The aims of this study were 1) to evaluate the feasibility of a method combining video and Global Positioning System data to estimate the speed and acceleration of activities leading to injuries and 2) to use this method to analyse the inciting circumstances leading to non-contact injuries. Injury inciting circumstances from 46 elite players over three seasons were analysed from video recordings and from external load measures collected through Catapult Vector S7 Global Positioning System. In total 34 non-contact injuries were analysed. Sixteen out of the seventeen hamstring injuries occurred when players were running for (median and interquartile range) 16.75 m (8.42-26.65 m) and achieved a peak speed of 29.28 km·h-1 (26.61-31.13 km·h-1) which corresponded to 87.55 % of players' maximal speed (78.5 %-89.75 %). Of the three adductor injuries, one occurred whilst the player was decelerating without the ball, one occurred whilst the player was accelerating and controlling the ball at knee level, and one occurred whilst the player was performing an instep kick. Two quadriceps injuries occurred whilst the players were kicking either whilst walking or running. From the preliminary results reported in this study most hamstring injuries occurred when players ran >25 km·h-1 and above 80 % of their maximal speed. This study suggests that this novel approach can allow a detailed and standardised analysis of injury inciting circumstances.



#13 Higher age and present injury at the start of the season are risk factors for in-season injury in amateur male and female football players-a prospective cohort study

Reference: Knee Surg Sports Traumatol Arthrosc. 2023 Aug 5. doi: 10.1007/s00167-023-07517-6.

Authors: Sofi Sonesson, Hanna Lindblom, Martin Hägglund

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Summary: The aim was to describe the injury prevalence, injury pattern, and potential baseline risk factors for injuries in male and female adolescent and adult amateur football players. This prospective study followed adolescent and adult amateur football players over one season March-October 2020. The study was completed by 462 players (130 men, age 20.0 ± 5.7, 14-46 years) who answered a baseline survey and a weekly web survey during the season. A total of 1456 weekly surveys were registered from males and 5041 from females. Injuries were recorded with the Oslo Sports Trauma Research Center Overuse Injury Questionnaire (OSTRC-O2). Potential baseline risk factors (age, performance of strength/conditioning training, participation in other sports, perceived importance of sporting success, self-rated training and match load, perceived balance between training/match load and recovery, previous/present injury at start of season, and injury beliefs) and their association with injury were analysed with Poisson regressions within each sex. Males reported 95 injuries (262 injury weeks, weekly prevalence 18.0% (95% CI 16.1-20.1)) and females 350 injuries (1206 injury weeks, weekly prevalence 23.9% (95% CI 22.8-25.1)). Gradual-onset injuries accounted for 57% of the injuries in males and 66% in females. For males, substantial injuries were most common in the hip/groin (weekly prevalence 3.8%), ankle (2.1%), posterior thigh (2.0%), and knee (2.0%); and for females, in the knee (4.3%), ankle (2.5%), and lower leg/Achilles tendon (2.0%). Significant risk factors for injury were higher age (rate ratio males 1.05 per year increase (95% CI 1.02-1.08), females 1.03 (95% CI 1.01-1.05)), and present injury at baseline (males 1.92 (95% CI 1.27-2.89), females 1.58 (95% CI 1.19-2.09)). At any given week, almost one in five male and one in four female amateur football players reported new or ongoing injuries. Hip/groin injuries were more frequent in males, while female players had a higher prevalence of knee injuries. Older players and those with an existing injury at the start of the season were more prone to new injury during the season. Rehabilitation of pre-season injury and complaints are key to reduce the injury burden in amateur football.



#14 Case Report: Indirect Traumatic Optic Neuropathy from Sub-Concussive Soccer Headers in a 62-year-old Athlete

Reference: Optom Vis Sci. 2023 Aug 14. doi: 10.1097/OPX.0000000000002051. Online ahead of print.

Authors: Radha P Pandya, Shruti Pandya, Kelly H Thomann

Summary: Traumatic optic neuropathy (TON) is an uncommon but devastating cause of vision loss following injury to the head. Soccer players may have a heightened risk due to the game's emphasis on heading the ball, a technique in which a player hits the soccer ball with their head. This paper reviews the case of an avid soccer player with traumatic optic neuropathy that occurred after numerous soccer ball headings during a game. This paper also (1) provides a summary of the pathophysiology and epidemiology of traumatic optic neuropathy, (2) reviews the current literature on head and eye injuries in soccer, and (3) discusses biomechanical differences in orbital structure throughout aging, which may predispose older patients to traumatic optic neuropathy. We present the case of a 62-year-old male patient who reported to the clinic, following repeated sub-concussive soccer ball headers the previous day, with symptoms of blurred vision and "seeing stars" in the right eye and a right inferior visual field impairment. Physical examination, subsequent lab work, and neurologic consults implicated TON as the primary diagnosis, and halting soccer playing resulted in symptom improvement. Though not commonly encountered in soccer players, the potential for TON exists. Older athletes may be predisposed due to morphological changes of the orbit. Future direction may look to further investigate hazards promoting traumatic optic neuropathy in older athletes and determine possible protections against injury.



#15 Measuring the popularity of football players with Google Trends

Reference: PLoS One. 2023 Aug 16;18(8):e0289213. doi: 10.1371/journal.pone.0289213. eCollection 2023.

Authors: Pilar Malagón-Selma, Ana Debón, Josep Domenech

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Summary: Google Trends is a valuable tool for measuring popularity since it collects a large amount of information related to Google searches. However, Google Trends has been underused by sports analysts. This research proposes a novel method to calculate several popularity indicators for predicting players' market value. Google Trends was used to calculate six popularity indicators by requesting information about two football players simultaneously and creating popularity layers to compare players of unequal popularity. In addition, as the main idea is to obtain the popularity indicators of all players on the same scale, a cumulative conversion factor was used to rescale these indicators. The results show that the proposed popularity indicators are essential to predicting a player's market value. In addition, using the proposed popularity indicators decreases the transfer fee prediction error for three different models that are fitted to the data using the multiple linear regression, random forest, and gradient boosting machine methods. The popularity indicator Min, which is a robust reflection of the popularity that represents a player's popularity during the periods when they are less popular, is the most important popularity indicator, with a significant effect on the market value. This research provides practical guidance for developing and incorporating the proposed indicators, which could be applied in sports analytics and in any study in which popularity is relevant.



#16 Acute Effects of Different Conditioning Activities on Amateur Soccer Players

Reference: Int J Sports Med. 2023 Aug 18. doi: 10.1055/a-2126-5972. Online ahead of print.

Authors: Manoel E Silva-Neto, Saulo F M Oliveira, José Igor V Oliveira, Willemax S Gomes, Hugo A A S Lira, Leonardo S Fortes

Summary: Several warm-up activities are used to prepare soccer players for training and games. However, few studies have focused on comparing different activities (strength vs. stretching) in young and amateur athletes, especially for performance improvement in explosive actions. Thus, in order to compare the effect of four conditioning activities on jump and sprint performances, 12 soccer athletes (age: 19±0.8; weight (kg): 72.8±8.0; height (cm): 180±6.7) performed four warm-up activities: strength exercise (cluster system), combined exercise, plyometric exercise, and static stretching (control). The countermovement jump (CMJ) and 30-meter run (30-m Sprint) were performed 10 min after each experimental condition. A ONE-WAY ANOVA test of repeated measures was conducted with a Tukey's post-hoc test to compare the conditions. The strength conditioning activity protocol (33.68±2.87) showed a significant difference for the CMJ from static stretching (30.96±3.16) (p>0.05). There were significant differences regarding the 30-m Sprint test between strength conditioning (4.72±0.19) and combined activities (4.71±0.21) compared to static stretching (4.84±0.21) (p>0.05). In conclusion, the combined conditioning activity and strength protocols can be chosen in warm-up activities instead of static stretching (control condition) for improved immediate sprint and jump abilities in amateur soccer players.


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