Search Results (24)

Surface orientation can influence the aerodynamic response of modern soccer balls, particularly in the drag crisis regime. This study quantified the orientation-dependent aerodynamic characteristics of the FIFA World Cup match ball Trionda using a single specimen and examined how these differences affect simulated flight at sea level and 1500 m altitude. Two reproducible reference orientations were defined: a red-panel-centered orientation (Series A) and a seam-junction-centered orientation (Series B). Each reference orientation was rotated by 0°, 90°, and 180°, resulting in six fixed-orientation conditions. Wind tunnel measurements were repeated three times per condition to obtain drag, lift, and side-force coefficients, and two-dimensional non-spinning flight simulations were performed for representative long-kick and free-kick conditions. All six orientations exhibited drag crisis behavior, but the transition response magnitude, subcritical drag level, and supercritical drag state differed among conditions. The representative transition region occurred at approximately Re = 2.0 × 10⁵ to 2.5 × 10⁵. Among the tested conditions, B-90 showed the lowest full-range mean drag coefficient (0.231), whereas A-90 showed the highest (0.266). In the simulations, lower drag orientations consistently produced longer flight ranges, and the B-90 > A-90 ordering was preserved across representative launch conditions and the expanded parametric comparison. These findings indicate that the aerodynamic response of Trionda cannot be represented adequately by a single mean drag coefficient and that surface orientation should be considered in aerodynamic characterization and flight prediction. Full article

Wind-tunnel experiments were conducted on Trionda, the official match ball of the 2026 FIFA World Cup. Aerodynamic force coefficients derived from these measurements were incorporated into numerical trajectory simulations of kicked balls. The resulting aerodynamic characteristics and simulated flight behavior were compared with those of the four previous World Cup match balls: Al Rihla (2022), Telstar 18 (2018), Brazuca (2014), and Jabulani (2010). Relative to its predecessors, Trionda exhibits a drag crisis at lower flow speeds, consistent with an apparently rougher surface. Although its turbulent-regime drag coefficient is more stable than those of earlier designs, its magnitude is modestly larger. Trajectory simulations therefore indicate the potential for small but perceptible reductions in range for long kicks. This study therefore provides the first aerodynamic characterization of the 2026 FIFA World Cup match ball (Trionda) and places its drag-crisis behavior and flight characteristics in direct quantitative comparison with those of recent World Cup balls examined under identical experimental conditions. Full article

Increasing gender equality, United Nations Sustainable Development Goal Five (UN SDG 5), is one of many wicked problems that are difficult to solve in sport. Innovative policies may create a backdrop for improving women’s career outcomes in sport and beyond. This research aims to theorize and empirically demonstrate some of these contextual relationships. Using FIFA Women’s World Cup standings as outcomes, international analyses show that sustainability has real consequences for women and their countries’ success. Guided by wicked problems Literature explicitly recognizing complexities, this research considers the interconnectedness of the UN SDGs with a focus on sports. International empirical analyses demonstrate that leading countries’ more holistic sustainability policies help to address UN SDG 5. This study also compares sustainable development indicators in regression analyses to clarify how these composite measures relate to improved outcomes for women. Overall, future research should incorporate gender differences and thereby consider a broad set of sustainability factors. Full article

This article reports the findings of an ethnographic and historical study into an ultras group called Melbourne Croatia Fans (MCF), a group of mostly Croatian–Australian young men in their twenties who support Melbourne Knights (formerly known as Melbourne Croatia) in the second-tier Victorian Premier League competition. The aim is to explore identity formation and negotiation, and how identity formation informs relations with outsider groups. The interviews with the football club president, football club secretary, two MCF leaders, and the participant observation date back to the 2010–12 period. The supporters perceive that the club has fallen on hard times for reasons not of their own making. They participated in the former National Soccer League (NSL) (1977–2004) from 1984 to 2004, which was the first-ever national competition in Australia to involve club rather than state teams. However, the club was effectively banned from the new A-League (2005–present), which began based on a private-equity ownership model and a one-team-one-city concept. Despite this, the club can play in the annual knockout competition, the Australia Cup (formerly the FFA Cup), that features both A-League and lower-league teams. We observe here a group of young Croatian–Australian men, part of the Diaspora of Croatians that left the country, mostly in the communist era and afterwards, who aim to construct workable hybrid identities for themselves in an Anglo-majority nation on the other side of the world. They fight on two fronts—against an Anglo, corporate-style administration that effectively bans their club for reasons of ethnicity from the new national league, and against the Serbian youth who often live in the who live in adjacent or nearby suburbs and follow Serbian-origin clubs. Full article

During the FIFA 2022 World Cup and the AFC 2023 Asian Cup in Qatar, podiatry was the second most requested service after radiology. Despite the growing role of podiatry in large sports events, there is limited documentation on the preparation and management of such services in a football (soccer) context. This study explores the delivery of podiatry services during the FIFA 2022 World Cup and AFC 2023 Asian Cup. Podiatry services were provided by four experienced podiatrists during FIFA 2022 and three during AFC 2023. Pre-event planning included team education, training, and resource preparation. Services were delivered centrally at the polyclinic, with additional basecamp visits for teams during FIFA 2022. Data on interventions, diagnoses, and consumables were collected and analyzed. During FIFA 2022, 22% of teams used podiatry services, with 48 requests primarily addressing skin and nail issues. In AFC 2023, 25% of teams requested services, with 32 consultations focused on chronic mechanical injuries. Adaptations in service delivery were made based on the scale of each event and regional needs. The findings highlight the importance of tailored podiatry services, multidisciplinary collaboration, and preparation for diverse clinical demands. Recommendations include improving communication, regional customization of services, addressing footwear needs, and providing pre-event training. Full article

In the present study, 96 teams’ performances across 48 matches in the group stage of the FIFA Club World Cup 2025 were analyzed. Teams scoring first won 62.5% of matches (p < 0.05), while goals were evenly distributed between halves (p > 0.05) and showed marginal variation across six 15 min intervals, peaking near the 30–45 and 75–90 min marks. Parametric analyses revealed a significant effect of match outcome on possession, with winning teams exhibiting higher average possession (53.3%) compared to losing and drawing teams. Non-parametric analyses identified significant differences between match outcomes for goals scored, attempts at goal, total and completed passes, pass completion rate, defensive line breaks, receptions in the final third, ball progressions, defensive pressures, and total distance covered. Winning teams scored more goals and registered more attempts on target than losing teams, although some metrics showed no significant difference between wins and draws. Logistic regression analysis identified attempts at goal on target, defensive pressures, total completed passes, total distance covered, and receptions in the final third as significant predictors of match success (AUC = 0.85), correctly classifying 80.2% of match outcomes. These results emphasized the crucial role of offensive accuracy and possession dominance in achieving success in elite football. Full article

This study explores how open-source pose estimation can be utilized to identify goalkeeper dive initiation during soccer penalty kicks. The purpose of this study is to provide an accessible, low-cost heuristic methodology for identifying goalkeeper dive initiation. This study uses single-camera broadcast footage (1080 p resolution, 50 frames per second) of all 41 penalty shootout kicks attempted during the 2022 FIFA Men’s World Cup. We isolated each penalty kick and recorded the frames of goalkeeper dive initiation and flight. We then identified goalposts to create a homography matrix to account for camera movement and identified the goalkeeper’s skeletal keypoints through pose estimation. From these keypoints, we derived frontal plane kinematics for the torso and legs. We identified local extrema for each kinematic variable and isolated the last observed extrema prior to goalkeeper flight for each variable. Using OLS regression, we found that the last local extremum of the goalkeeper centroid’s y-value was the strongest predictor of labeled commitment to the dive side, with an R2 of 0.998 and a p-value of 0.00. The results of this research are preliminary but demonstrate the promise of pose estimation in identifying sport-specific action timing during live game play using a single camera. Full article

Eight balls were manufactured with a 3D printer to resemble various types of 32-panel soccer balls. One ball was completely smooth, whereas the other seven possessed various dimple patterns on their surface panels. Seam width and seam depth were also varied. Wind-tunnel experiments were performed to extract aerodynamic coefficients, and also to determine the critical Reynolds number for each manufactured ball. A new surface roughness parameter is introduced, and a fitting formula is presented, which allows for the prediction of the critical Reynolds number if the new parameter is known. Full article

Changing the date of the FIFA World Cup Qatar 2022 may represent a factor to consider for the expected performance of participating players. This was due to fixture congestion at the start of the season and expected weather conditions during the competition. Thus, the main purpose of this brief report was to critically analyze the potential impact of changing the competition date and weather conditions on players’ performance. In addition, a brief description about the performance during the World Cup is also provided. For the research, the Web of Science, PubMed and SPORTDiscus databases were accessed using the primary keywords FIFA World Cup and World Soccer Cup associated with the secondary keywords match running performance, fixture congestion, fatigue and weather conditions. After applying inclusion and exclusion criteria, 52 articles were considered for analysis. The results seem to indicate that although changes were expected due to the modifications made (i.e., the competition date and scheduling congestion), the performance of the players seems not to have been affected in terms of the analyzed indicators. Furthermore, it seems possible to identify some patterns in the behavior of the teams that reached the most advanced stages of the competition. Full article

(1) Objetive: Compare the internal load (ILO), external load (ELO) and wellness (WS) between official preparation friendly matches (FM) and France 2019 women world cup (WWC) matches in female soccer players. (2) Methods: Ten field players of the Chilean national football team (age 27 ± 3.4 years, height 162.8 ± 4.32 cm, weight 60.5 ± 4.6 kg, fat percentage 24.7 ± 1.62% and muscle percentage 49.2 ± 1.63%) participated in the study. Participants were compared across three FM before the world cup and three matches of the group stages in the WWC in June 2019. Both, ELO and ILO were recorded using GPS (Catapult Sports^®, 10 Hz) and rating of perceived exertion (RPE), respectively. In addition, wellness was analyzed via personal questionnaire at 24 and 48 h after match. The intra subject difference was analyzed with a Student’s t-test for related samples. (3) Results: Moderate differences were observed between WWC and FM for total and relative total distance covered [TD and TDr, respectively] (p = 0.025, ES = −0.74 and p = 0.017, ES = −0.6). In addition, a non-significant (p = 0.088; ES = −0.43) larger high-intensity distance (HSR) was also found for WWC. Likewise, greater RPE was observed in WWC (p = 0.001; ES = −1.50) when compared to FM. Finally, significantly better wellness scores were shown for FM at stress ST24h, fatigue FT48h, and muscle pain MS48h (p = 0.038; ES = 0.72, p = 0.066; ES = 0.71; and p = 0.63; ES = 0.77) when compared to WWC matches. (4) Conclusion: It was concluded that ELO and ILO were greater at WWC soccer matches, whereas WS scores were better for FM. Moreover, ILO measures (i.e., TD, HSR and TDr) were greater in WWC, which could be at least in part, be the reason behind the differences in the values reported in the wellness questionnaires at 24 and 48 h after the match. Full article

The study aimed at finding relationships between lactate threshold and psychomotor fatigue threshold during incremental exercise in thermo-neutral climate conditions and conditions for the 2022 FIFA World Cup in Qatar simulated in an environmental test chamber. The study included 24 soccer players aged 21.02 ± 3.22 years old. The following procedures were performed: The incremental exercise test to mark lactate concentration—LA (mmol·l⁻¹); Psychomotor test to determine choice reaction time; Designation of the lactate threshold (T_LA) and psychomotor fatigue threshold (T_PF). Climate conditions: The procedure was performed twice in the climatic chamber: (1) in thermo-neutral conditions—TNC (ambient temperature 20.5 °C and relative air humidity 58.7%), (2) after 7 days—in Qatar conditions—QC (28.5 ± 1.92 °C) and (58.7 ± 8.64%). It was confirmed that the T_PF, which reflects the highest efficiency of CNS functioning, occurs at a higher running speed than the T_LA. The temperature of 28.5 °C with 58.7% humidity, which is the lower limit of heat stress, causes the psychomotor fatigue threshold to appear at a lower running speed than in thermoneutral conditions. The data recorded in this work may help to understand the specificity of physiological and psychomotor reactions to various climatic conditions. Full article

The term knuckleball in sporting jargon is used to describe a ball that has been launched with minimal spin, resulting in a trajectory that is erratic and unpredictable. This phenomenon was first observed in baseball (where the term originated) and has since been observed in other sports. While knuckleball has long fascinated the scientific community, the bulk of research has primarily focused on knuckleball as it occurs in baseball. Following the changes in the design of the soccer ball after the 2006 World Cup, knuckleball and ball aerodynamics were exploited by soccer players. This research examined the properties of a knuckleball in the sport of soccer. We designed and evaluated a system that could reproduce the knuckleball effect on soccer balls based on previous theories and characteristics outlined in our literature review. Our system is comprised of the Adidas miCoach Smart Ball, a companion smart phone app for data collection, a ball-launching machine with programmable functions, and a video-based tracking system and Tracker motion analysis software. The results from the testing showed that our system was successfully able to produce knuckleball behaviour on the football in a highly consistent manner. This verified the dynamic models of knuckleball that we outline. While a small portion of the data showed some lateral deviations (zig-zag trajectory), this erratic and unpredictable trajectory was much smaller in magnitude when compared to examples seen in professional games. The sensor data from the miCoach app and trajectory data from the Tracker motion analysis software, showed that the knuckleballs were consistently reproduced in-line with theoretical dynamics. Full article

The current case study aimed to quantify within-subjects correlations between training load and well-being in elite male beach soccer players. Data were obtained over three consecutive days during the preparation camp for the FIFA Beach Soccer World Cup Russia 2021. The session rating of perceived exertion (s-RPE) and external training load metrics using global positioning system (GPS) were recorded. Eleven players reported perceived well-being (sleep quality, fatigue, muscle soreness and stress) using a Likert scale (Hooper Index) before breakfast. Within-subjects correlation coefficients between workload and well-being were calculated. Workload metrics and perceived well-being indices were significantly lower on day three than on days one and two. The Hooper Index presented a very large positive correlation with s-RPE (r = 0.86 [0.67, 0.94], 95% confidence interval, CI), exposure time (r = 0.88 [0.71, 0.95]), total distance (r = 0.83 [0.60, 0.93]), high-speed distance (r = 0.77 [0.50, 0.91]), and number of sprints (r = 0.75 [0.47, 0.90]). Sleep quality presented a moderate to large positive correlation with s-RPE (r = 0.51 [0.11, 0.77]), exposure time (r = 0.50 [0.10, 0.76]), high-speed distance (r = 0.53 [0.15, 0.78]), number of sprints (r = 0.62 [0.28, 0.83]) and total distance (r = 0.41 [0.18, 0.78]). Fatigue presented a large to very large positive correlation with s-RPE (r = 0.85 [0.66, 0.94]), exposure time (r = 0.90 [0.78, 0.96]), total distance (r = 0.86 [0.68, 0.94]), high-speed distance (r = 0.65 [0.31, 0.84]) and number of sprints (r = 0.56 [0.18, 0.79]). Muscle soreness presented a large to very large positive correlation with s-RPE (r = 0.79 [0.56, 0.91]), exposure time (r = 0.83 [0.62, 0.93]), total distance (r = 0.81 [0.59, 0.92]), high-speed distance (r = 0.75 [0.47, 0.89]) and number of sprints (r = 0.59 [0.22, 0.81]). Overall, workload presented a meaningful correlation with perceived well-being indices in elite male beach soccer players during a training camp. These findings suggest that workload metrics and perceived well-being indices can be implemented into the daily routine of an elite beach soccer team, which may assist coaches, sports scientists, and practitioners in better preparing players for beach soccer competitions. Full article

I investigate the paradoxes associated with the Fédération Internationale de Football Association (FIFA) point-based ranking of national soccer teams. The ranking has been plagued with paradoxes that incentivize teams to avoid playing friendly matches, i.e., matches that are not part of any official FIFA tournament or preliminaries, and applying other counterintuitive strategies. The most spectacular paradox was the dramatic underrating of the hosts of major tournaments. For a long time, host teams, which were absent from preliminary matches, would play only friendly matches that awarded few points. Here, I present three models that estimate the magnitude of the resulting “host effect” at 14.2–16 positions. Such an estimate counteracts the intuition that a large investment in hosting a tournament should result in an improvement in the host team’s standing. However, as discussed here, a given host’s low ranking could decrease interest in the tournament, and likely result in a major loss of advertisement revenue. Full article

In 2019, numerous championships of youth categories soccer national teams were held. In the present study, we analyzed the existence of the Relative Age Effect (RAE) in four major male championships that, due to their importance and participating teams, most likely brought together the great bulk of the players who will dominate professional soccer in the next decade. Participants were professional and amateur youth male soccer players who participated in the last international championships: UEFA European Under-21 Championship (2017–2019); UEFA European Under-19 Championship (2019); South American Youth Football Championship (also known as Conmebol U-20) (2019); and FIFA U-20 World Cup (2019), with 823 players (20.25 ± 0.84 years). In the four championships analyzed, the existence of RAE was found for all players (p < 0.001). Analyzing the players when considering their position on the pitch and their championship, RAE was found, statistically significant, in 10 of the 16 classifications. New generations of elite soccer players arrive with a clear bias in the selection of talent; an unfair bias, based on unequal opportunities in early categories, which should be reviewed by sports authorities. Full article