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 Key load indicators and load variability in professional soccer players: a full season study
Reference: Res Sports Med. 2021 Jul 14;1-13. doi: 10.1080/15438627.2021.1954517. Online ahead of print.
Authors: José M Oliva-Lozano, Xavier Barbier, Víctor Fortes, José M Muyor
Summary: The aims of this study were to 1) determine the key load indicators in professional soccer through principal component analysis (PCA); and 2) analyse the load variability of each training and match day within the microcycle considering the principal components. Data from 111 load variables were collected using tracking systems in both training and match days (MD). The results showed that 7 variables, which belonged to the first two components of the PCA, explained 80.3% of total variance. Specifically, these variables were Metabolic power, total of steps, Fourier transform (FFT) duration, deceleration distance covered (2-3 m/s2), total of running actions (12-18 km/h; 21-24 km/h), and distance covered (6-12 km/h). Regarding the analysis of the load variability of each training and match day within the microcycle, the lowest load variability was observed in -1MD. Also, a great load variability in +1MD with significant differences compared to -5MD (p<0.001; d=0.49) and -4MD (p=0.01; d=0.26) was found. This study suggests the use of the PCA in the context of team sports to reduce the large number of variables, which are daily managed by strength and conditioning coaches, in addition to the analysis of load variability of each training and match day within the microcycle.
#2 Perceptual and Biochemical Responses in Relation to Different Match-Day +2 Training Interventions in Soccer Players
Reference: Front Physiol. 2021 Jun 24;12:685804. doi:10.3389/fphys.2021.685804. eCollection 2021.
Authors: Athos Trecroci, Enrico Perri, Giovanni Lombardi, Giuseppe Banfi, Riccardo Del Vescovo, Ermes M Rosa, Giampietro Alberti, F Marcello Iaia
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8264547/pdf/fphys-12-685804.pdf
Summary: The aim of this study was to examine the impact of two different post-match training interventions on the subsequent recovery of perceptual and biochemical parameters after the game. In a crossover design, eight sub-elite players underwent a soccer-specific training (SST) and an active recovery (AR) regimen on the second day after a match (+48 h). Muscle soreness as well as muscle damage (creatine kinase, CK), inflammatory (C-reactive protein and interleukin 6), immunological (e.g., lymphocytes, neutrophils, and monocytes), and endocrine (cortisol) markers were obtained at baseline (-72 h), immediately after (0 h), and 72 h post-match (+72 h). AR promoted a higher restoration of muscle soreness values (P = 0.004, η2 p = 0.49) together with a better restoration of CK within 72 h post-match compared with SST (P = 0.04, η2 p = 0.36). Conversely, no significant (P > 0.05, η2 p < 0.91) differences were observed in the recovery timeframe of inflammatory, immunological, and endocrine responses between SST and AR. Overall, AR elicited a quicker muscle soreness and CK restoration compared to SST intervention at 72 h post-match. Such information provides novel evidence-based findings on the appropriateness of different recovery strategies and may aid to improve the practitioners' decision-making process when two consecutive games are played within 3 days.
#3 Effects of respiratory muscle training in soccer players: a systematic review with a meta-analysis
Reference: Sportverletz Sportschaden. 2021 Jul 14. doi: 10.1055/a-1524-0021. Online ahead of print.
Authors: Felipe León-Morillas, Martha Cecilia León-Garzón, María Del Mar Martínez-García, Javier Reina-Abellán, María Victoria Palop-Montoro, Silvana Loana de Oliveira-Sousa
Summary: Respiratory muscle training can improve strength and reduce respiratory muscle fatigue during high-intensity exercise. Little is known about the existing evidence in soccer players. A systematic review with a meta-analysis was performed to analyse the existing evidence on the effects of respiratory muscle training in soccer players. Two independent researchers reviewed 17 databases until July 2019. Inclusion criteria were controlled clinical trials (randomised or not), soccer players (professional or recreational), females and/or males, and respiratory muscle training compared with simulated or regular training groups. The methodological quality and quality of evidence were evaluated with the Cochrane Collaboration Tool and GRADE score, respectively. Statistical analysis was performed using the integral meta-analysis 3.3.070. Nine studies met the eligibility criteria. The meta-analysis was performed for eight variables related to respiratory muscle function, lung function and sports performance. Respiratory muscle training provided a significant improvement compared with simulated or regular training in maximal inspiratory buccal pressure (6 studies, SDM = 0.89; 95 % CI = 0.42, 1.35) and maximum consumption of oxygen (3 studies, SDM = 0.92; 95 % CI = 0.24; 1.61). No significant improvements were observed for other variables. The quality of the evidence was rated as low or very low.
#4 Evaluation of Lower Limb Arteriovenous Diameters in Indoor Soccer Athletes: Arterial Doppler Ultrasound Study
Reference: Front Physiol. 2021 Jun 28;12:687613. doi: 10.3389/fphys.2021.687613. eCollection 2021.
Authors: Sónia Mateus, Rui Paulo, Patrícia Coelho, Francisco Rodrigues, Vasco Marques, Henrique P Neiva, Pedro Duarte-Mendes
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8273383/pdf/fphys-12-687613.pdf
Summary: The purpose of this study was to analyze the arterial and venous diameters of lower limbs in indoor soccer athletes and non-athletes using Doppler ultrasound to identify the differences in the variation of arterial and venous diameters between groups. Additionally, we intended to verify the differences of arterial and venous diameters between the skilled member (right member) and the not skilled member in each group. 74 male volunteers, aged between 19 and 30 years old, were divided in a group of athletes (n = 37, 24 ± 2.7 years, soccer players from national championship), and a group of non-athletes (n = 37, 26 ± 2.83 years). Vascular lower limb was assessed using Doppler ultrasound (Philips HD7 echograph with linear transducer 7-12 MHz). The athletes showed higher diameters of right common femoral artery (p = 0.009; moderate), left common femoral artery (p = 0.005; moderate), right deep femoral artery (p = 0.013; moderate), right popliteal artery (p = 0.003; moderate), and left popliteal artery (p = 0.017; small) than non-athletes. Veins' diameters were also higher in athletes, specifically the right deep femoral vein (p ≤ 0.001; large), left deep femoral vein (p ≤ 0.001; large), right popliteal vein (p ≤ 0.001; large), and left popliteal vein (p ≤ 0.001; large). Differences were found between the skilled and non-skilled leg in athletes in the popliteal vein (7.68 ± 1.44 mm vs. 7.22 ± 1.09 mm, respectively, p < 0.003). It seems that futsal athletes have superior mean diameters of lower limbs arteries and veins of the deep venous system to non-athletes. Moreover, the veins presented greater dilation, namely of the leg of the skilled lower limb.
#5 Feasibility and Effectiveness of a Novel Smartphone Music Application on Anxiety and Sleep in Elite Soccer Coaches
Reference: J Sports Sci Med. 2021 Jul 1;20(3):546-547. doi: 10.52082/jssm.2021.546. eCollection 2021 Sep.
Authors: Christopher Carling, Chloé Leprince, Thomas Pavillon, Stéphane Guétin, Franck Thivilier
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8256527/pdf/jssm-20-546.pdf
#6 Isolated papillary muscle hypertrophy in a professional soccer player: the end of an athlete's career?
Reference: Kardiol Pol. 2021 Jul 16. doi: 10.33963/KP.a2021.0063. Online ahead of print.
Authors: Cyntia Zulema Machain Leyva, Cuitláhuac Arroyo-Rodríguez, José Roberto Victoria-Nandayapa, Sergio Ramón Figueroa-Sauceda
Download link: https://journals.viamedica.pl/kardiologia_polska/article/view/KP.a2021.0063/63491
#7 Relationships between Vitamin D and Selected Cytokines and Hemogram Parameters in Professional Football Players-Pilot Study
Reference: Int J Environ Res Public Health. 2021 Jul 2;18(13):7124. doi: 10.3390/ijerph18137124.
Authors: Anna Książek, Aleksandra Zagrodna, Anna Bohdanowicz-Pawlak, Felicja Lwow, Małgorzata Słowińska-Lisowska
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8297090/pdf/ijerph-18-07124.pdf
Summary: Vitamin D affects both innate and adaptive immunity. Most of the effects of vitamin D on innate immunity are anti-inflammatory. In monocytes/macrophages, vitamin D suppresses the production of the inflammatory cytokines TNF-alpha, IL-1beta, IL-6, and IL-8. Therefore, the aim of our study was to investigate the relationship between 25(OH)D concentration and selected cytokines-IL-6, TNF-α, and IL-1β, which are hemogram parameters for professional football players. We enrolled 41 Polish premier league soccer players. The mean age, career duration, and VO2max were, respectively: 22.7 ± 5.3 years, 14.7 ± 4.5 years, and 55.8 ± 4.0 mL/kg/min. Serum levels of 25(OH)D were measured by electrochemiluminescence (ECLIA) using the Elecsys system (Roche, Switzerland). Serum levels of IL-6, IL-1β, and TNF-α were measured by ELISA (R&D Systems, Minneapolis). Blood count with smear was measured on a Sysmex XT-4000i analyzer (Sysmex Corporation, Japan). Our study showed decreased serum 25(OH)D levels in 78% of the professional players. We found a significant negative correlation between 25(OH)D levels and TNF-α and LYMPH (%). The results also demonstrated a statistically significant positive correlation between vitamin D levels and NEUTH (%), NEUTH (tys/µL), and EOS (tys/µL). Based on the results of our study, we concluded that football players from Poland are not protected against vitamin D insufficiency in winter months. Moreover, vitamin D deficiency may be associated with an increased pro-inflammatory risk in well-trained athletes.
#8 Football sports safety and the health risk assessment system
Reference: Work. 2021 Jul 14. doi: 10.3233/WOR-205348. Online ahead of print.
Authors: Ning Jin, Xiao Zhang, Zhitao Hou
Summary: Football has various educational functions that can strengthen the physique and cultivate students' patriotism and collectivist spirit. However, the characteristics of antagonism and competitiveness of football make it have certain risks. The study aims to effectively help students clarify the safety of football sports, solve the risks caused by confrontation and competition in football projects, and guide students to exercise healthily and safely. The risks of campus football are identified, evaluated, responded to, and monitored. Specific empirical data and Pareto analysis compile the risk investigation and risk assessment table of campus football, and the prevention measures are put forward. The older the person is, the higher the possibility of risk occurrence is. The sports risk of boys is significantly higher than that of girls. The human factors and sports environment have the most significant impact on the health risk of football sports. Human factors mainly involve students' lack of discipline, poor safety awareness, low professional level of teachers, and students' lack of enthusiasm. The study requires changing the concept, improving the students' sports risk awareness, strengthening the construction of system and policy, and changing the passive into the active. The study can provide research ideas for the safety and risk management of football sports and promote the popularity of football on the campus.
#9 Relationship between the hip range of motion and functional motor system movement patterns in football players
Reference: J Sports Med Phys Fitness. 2021 Jul 19. doi: 10.23736/S0022-4707.21.12679-9. Online ahead of print.
Authors: Gabriela Siwecka, Ewa Wodka-Natkaniec, Łukasz Niedźwiedzki, Anna Świtoń, Tadeusz Niedźwiedzki
Summary: The aim of this study was to determine the hip range of motion and the movement patterns of football players assessed with an aid of a Functional Motor Systems test, and to find an association between these parameters and the risk for hip joint injury. The study included 50 men aged between 16 and 20 years: 25 footballers and 25 age- and body mass index-matched controls. The hip ranges of motion (flexion, extension, internal and external rotation, adduction and abduction) were determined, and the movement patterns were evaluated with the tests from the Functional Motor Systems battery. Football players presented with significantly higher ranges of the hip flexion, extension, internal and external rotation than the controls. Moreover, footballers and controls differed significantly in terms of their mean overall Functional Motor Systems scores (15.77 points ± 2.44 vs. 13.79 ± 3.02 points, P = 0.019). Football players scored best on the shoulder mobility test for the right side and worst on the rotary stability test for the left side. The scores on the trunk stability test and rotary stability test for the left side were significantly higher in footballers than in the controls. Nevertheless, the overall Functional Motor Systems scores of 14 points or less were recorded in the case of as many as 10/25 footballers. Altogether, these findings suggest that some football players present with a strain which may predispose them to future injuries. Future research should center around the etiology of reduced hip ROM observed in footballers. Furthermore, football training seems to result in a considerable motor asymmetry of the trunk which also predisposes to injury.
#10 Epidemiology of Injuries in National Collegiate Athletic Association Women's Soccer: 2014-2015 Through 2018-2019
Reference: J Athl Train. 2021 Jul 1;56(7):651-658. doi: 10.4085/1062-6050-372-20.
Authors: Avinash Chandran, Sarah N Morris, Adrian J Boltz, Hannah J Robison, Christy L Collins
Summary: The National Collegiate Athletic Association held the first women's soccer championship in 1982; sponsorship and participation have greatly increased since. Routine examinations of athlete injuries are important for identifying emerging temporal patterns. Exposure and injury data collected in the National Collegiate Athletic Association Injury Surveillance Program during the 2014-2015 through 2018-2019 seasons were analyzed. Injury counts, rates, and proportions were used to describe injury characteristics, and injury rate ratios were used to examine differential injury rates. The overall injury rate was 8.33 per 1000 athlete-exposures. Lateral ligament complex tears (ankle sprains) (8.6%), concussions (8.3%), and quadriceps tears (5.0%) were the most commonly reported injuries. Rates of lateral ligament complex tears followed an increasing trajectory during the study period, whereas quadriceps tear rates fluctuated during the early years, and concussion rates decreased then increased. The findings of this study were mostly consistent with existing evidence; notable temporal patterns were observed with regard to lateral ligament complex tears and concussions.
#11 Epidemiology of Injuries in National Collegiate Athletic Association Men's Soccer: 2014-2015 Through 2018-2019
Reference: J Athl Train. 2021 Jul 1;56(7):659-665. doi: 10.4085/1062-6050-370-20.
Authors: Avinash Chandran, Sarah N Morris, Adrian J Boltz, Hannah J Robison, Christy L Collins
Summary: The National Collegiate Athletic Association has sponsored men's soccer programs since 1959, and the popularity of the sport has grown over time. Routine examinations of athlete injuries are important for identifying emerging temporal patterns. Exposure and injury data collected in the National Collegiate Athletic Association Injury Surveillance Program from 2014-2015 through 2018-2019 were analyzed. Injury counts, rates, and proportions were used to describe injury characteristics, and injury rate ratios were used to examine differential injury rates. The overall injury rate was 8.51 per 1000 athlete exposures. Lateral ligament complex tears (ankle sprains) (9.2%), hamstring tears (7.0%), and concussions (5.2%) were the most commonly reported injuries. Rates of lateral ligament complex tears remained stable from 2014-2015 through 2018-2019, whereas hamstring tear rates decreased and concussion rates increased. The findings of this study were in line with the existing epidemiological evidence, although notable temporal patterns were observed. Incidence trajectories of commonly observed injuries warrant particular attention in the future.
#12 Correlation between Official and Common Field-Based Fitness Tests in Elite Soccer Referees
Reference: J Funct Morphol Kinesiol. 2021 Jul 1;6(3):59. doi: 10.3390/jfmk6030059.
Authors: Veronica Romano, Manuel Tuzi, Ada Di Gregorio, Anna Maria Sacco, Immacolata Belviso, Felice Sirico, Stefano Palermi, Daria Nurzynska, Franca Di Meglio, Clotilde Castaldo, Angelo Pizzi, Stefania Montagnani
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8293311/pdf/jfmk-06-00059.pdf
Summary: Official tests are used to assess the fitness status of soccer referees, and their results correlate with match performance. However, FIFA-approved tests expose the referees to high physical demands and are difficult to implement during the sportive year. The aim of our study was to evaluate the correlation between the 6 × 40-m sprint and Yo-Yo Intermittent Recovery Level 1 (IR1) official tests and other field-based tests that require no or little equipment, are not time-consuming, and impose low physical demands. All tests were performed by male referees from the Regional Section of the Italian Referee Association (n = 30). We observed a strong correlation between 6 × 40-m sprint and Illinois agility tests (r = 0.63, p = 0.001) and a moderate correlation between Yo-Yo IR1 and hand-grip strength in the dominant (r = 0.45, p = 0.014) and non-dominant hand (r = 0.41, p = 0.031). Interestingly, only a moderate correlation (r = -0.42, p = 0.025) was observed between the FIFA official tests, 6 × 40-m sprint and Yo-Yo IR1. These results suggest that Illinois agility and hand-grip tests could represent simple and low-physical-impact tools for repeated assessment and monitoring of referee fitness throughout the sportive season.
#13 Fatigue Induced by Repeated Changes of Direction in Élite Female Football (Soccer) Players: Impact on Lower Limb Biomechanics and Implications for ACL Injury Prevention
Reference: Front Bioeng Biotechnol. 2021 Jul 5;9:666841. doi: 10.3389/fbioe.2021.666841. eCollection 2021.
Authors: Matteo Zago, Sina David, Filippo Bertozzi, Claudia Brunetti, Alice Gatti, Francesca Salaorni, Marco Tarabini, Christel Galvani, Chiarella Sforza, Manuela Galli
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8287513/pdf/fbioe-09-666841.pdf
Summary: The etiology of Anterior Cruciate Ligament (ACL) injury in women football results from the interaction of several extrinsic and intrinsic risk factors. Extrinsic factors change dynamically, also due to fatigue. However, existing biomechanical findings concerning the impact of fatigue on the risk of ACL injuries remains inconsistent. We hypothesized that fatigue induced by acute workload in short and intense game periods, might in either of two ways: by pushing lower limbs mechanics toward a pattern close to injury mechanism, or alternatively by inducing opposed protective compensatory adjustments. In this study, we aimed at assessing the extent to which fatigue impact on joints kinematics and kinetics while performing repeated changes of direction (CoDs) in the light of the ACL risk factors. This was an observational, cross-sectional associative study. Twenty female players (age: 20-31 years, 1st-2nd Italian division) performed a continuous shuttle run test (5-m) involving repeated 180°-CoDs until exhaustion. During the whole test, 3D kinematics and ground reaction forces were used to compute lower limb joints angles and internal moments. Measures of exercise internal load were: peak post-exercise blood lactate concentration, heart rate (HR) and perceived exertion. Continuous linear correlations between kinematics/kinetics waveforms (during the ground contact phase of the pivoting limb) and the number of consecutive CoD were computed during the exercise using a Statistical Parametric Mapping (SPM) approach. The test lasted 153 ± 72 s, with a rate of 14 ± 2 CoDs/min. Participants reached 95% of maximum HR and a peak lactate concentration of 11.2 ± 2.8 mmol/L. Exercise duration was inversely related to lactate concentration (r = -0.517, p < 0.01), while neither%HR max nor [La-] b nor RPE were correlated with test duration before exhaustion (p > 0.05). Alterations in lower limb kinematics were found in 100%, and in lower limb kinetics in 85% of the players. The most common kinematic pattern was a concurrent progressive reduction in hip and knee flexion angle at initial contact (10 players); 5 of them also showed a significantly more adducted hip. Knee extension moment decreased in 8, knee valgus moment increased in 5 players. A subset of participants showed a drift of pivoting limb kinematics that matches the known ACL injury mechanism; other players displayed less definite or even opposed behaviors. Players exhibited different strategies to cope with repeated CoDs, ranging from protective to potentially dangerous behaviors. While the latter was not a univocal effect, it reinforces the importance of individual biomechanical assessment when coping with fatigue.
#14 Quantifying and Comparing the Match Demands of U18, U23, and 1ST Team English Professional Soccer Players
Reference: Front Physiol. 2021 Jul 2;12:706451. doi: 10.3389/fphys.2021.706451. eCollection 2021.
Authors: James Reynolds, Mark Connor, Mikael Jamil, Marco Beato
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8283180/pdf/fphys-12-706451.pdf
Summary: The aim of this study was to quantify and compare the match load demands of U18, U23, and 1ST team players during the official season. A total of 65 matches and 495 (U18 = 146, U23 = 146, and 1ST team = 203) individual player game observations were included in this analysis. A 10-Hz global navigation satellite systems (GNSS) and 100-Hz triaxial accelerometer (STATSports, Apex, Northern Ireland) were used to monitor the following metrics during official matches: total distance, high-speed running distance (HSR), sprint distance, high metabolic distance, explosive distance, high-intensity bursts distance, speed intensity, and dynamic stress load (DSL) were analyzed. A multivariate analysis of variance test reported significant (p < 0.001) differences among the groups. HSR during matches was lower (d = small) for U18 players than the U23 and 1ST team players. Sprint distance and high-intensity bursts distance were lower (small) in U18 compared with the U23 and 1ST team. DSL was greater in 1ST compared with U18 (small) and U23 (small). This study reported that the differences between groups were greater for HSR, sprint distance, high-intensity bursts distance, and DSL, while total distance, high metabolic load distance, explosive distance, and speed intensity did not differ between the groups. These findings could be used to design training programs in the academy players (i.e., U18) to achieve the required long-term physical adaptations that are needed to progress into the U23 and 1ST teams.
#15 How to improve technical and tactical actions of dominant and non-dominant players in children's football?
Reference: PLoS One. 2021 Jul 22;16(7):e0254900. doi: 10.1371/journal.pone.0254900. eCollection 2021.
Authors: Mirjam Hintermann, Dennis-Peter Born, Jörg Fuchslocher, Raphael Kern, Michael Romann
Download link: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0254900
Summary: As young football players develop important technical and tactical skills during competitive matches, this study investigated quantity and quality of technical and tactical actions in real game conditions in a 4v4 compared to the traditional 7v7 match format. In total, three matches of each format were played by 103 young football players (10.3±0.6 years) and video monitored for subsequent manual tagging of technical and tactical events. Based on the number of technical and tactical actions in the 7v7 matches, players were classified as dominant or non-dominant and changes in these subgroups were assessed during the 4v4 match format. The 4v4 match format significantly (P<0.001) increased total number of actions per player per minute compared to the 7v7 matches (5.59±1.44 and 2.78±0.73, respectively) and the number of successful (2.88±0.92 and 1.15±0.49, respectively) and unsuccessful (1.05±0.42 and 0.67±0.23, respectively) actions. Both dominant and non-dominant players increased their number of actions during the 4v4 compared to 7v7 match format. Despite a missing significant interaction effect, there was a larger percentage increase in number of actions for the non-dominant players (143%) compared to dominant players (72%) in 4v4. The 4v4 match format shows twice as many technical and tactical actions in real game conditions and, therefore, may improve players' skill development.
#16 How the COVID-19 Pandemic has Changed the Game of Soccer
Reference: Int J Sports Med. 2021 Aug 3. doi: 10.1055/a-1518-7778. Online ahead of print.
Authors: Daniel Link, Gabriel Anzer
Download link: https://www.thieme-connect.com/products/ejournals/pdf/10.1055/a-1518-7778.pdf
Summary: This study explores the influence of corona-specific training and playing conditions - especially empty stadiums - on match performance, contact behavior, and home advantage in the Bundesliga (BL) and Bundesliga 2 (BL2). We analyzed the 2017/18, 2018/19, and 2019/20 seasons and compared matches in rounds 26-34 before shutdown with "ghost" matches after restart. Results show increased running activity for high intensity distance: (+ 6.1%) and total distance covered (+ 4.3%). In BL2 in particular there were also changes in tactical aspects of the game (time in last third: -6.3%, pressure on pass receiver: -8.6%, success of attacking duels: -7.9%, share of long passes completed: + 15.6%, outplayed opponents per pass: -14.7%). Contact time to other players (< 2 m distance) was 15:35 mins per match. After restart, contact was reduced, especially when the ball was not in the last third (-11.2%). Away wins increased by +44.2% in BL and the home-away difference in yellow cards changed in favor of the away team (+31.2%) in BL2. We conclude that empty stadiums have reduced home advantage and decreased referee bias when awarding yellow cards. Player behavior might have been affected by tactical demands and/or conscious or unconscious self-protection.
#17 Towards soccer pass feasibility maps: the role of players' orientation
Reference: J Sports Sci. 2021 Aug 6;1-14. doi: 10.1080/02640414.2021.1959176. Online ahead of print.
Authors: Adrià Arbués-Sangüesa, Adrián Martín, Javier Fernández, Gloria Haro, Coloma Ballester
Summary: Once player tracking has been established as one of the main data sources in soccer, many challenges have emerged for data scientists, who attempt to recognize patterns from 2D trajectories in order to build tools that might help coaches to improve the performance of their teams. For instance, pass models predict where the ball should go next during pass events. However, existing models are mainly fed with players' location and prior data, hence omitting critical pieces of information such as players' body orientation. This paper presents a computational model to obtain pass feasibility maps, where player orientation is exploited and analysed. As a matter of fact, orientation proves to be crucial when modelling field-of-view and correct positioning of players, since it limits the potential receiving area of all candidates. Different proposals are given to evaluate the proposed pass feasibility map, reaching 0.46 and 0.79 in Top1 and Top3 accuracy, respectively, with a + 0.2 boost obtained after merging positional data with orientation.
#18 Explaining the difference between men's and women's football
Reference: PLoS One. 2021 Aug 4;16(8):e0255407. doi: 10.1371/journal.pone.0255407. eCollection 2021.
Authors: Luca Pappalardo, Alessio Rossi, Michela Natilli, Paolo Cintia
Download link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8336886/pdf/pone.0255407.pdf
Summary: Women's football is gaining supporters and practitioners worldwide, raising questions about what the differences are with men's football. While the two sports are often compared based on the players' physical attributes, we analyze the spatio-temporal events during matches in the last World Cups to compare male and female teams based on their technical performance. We train an artificial intelligence model to recognize if a team is male or female based on variables that describe a match's playing intensity, accuracy, and performance quality. Our model accurately distinguishes between men's and women's football, revealing crucial technical differences, which we investigate through the extraction of explanations from the classifier's decisions. The differences between men's and women's football are rooted in play accuracy, the recovery time of ball possession, and the players' performance quality. Our methodology may help journalists and fans understand what makes women's football a distinct sport and coaches design tactics tailored to female teams.