Soccer Match Research Articles

A multilayer network framework for soccer analysis

In this paper, we define a novel methodology for analyzing soccer matches and teams using spatial multilayer networks. Departing from a segmentation of the pitch into h×v regions, we create 2-layer networks that capture the exchange of ball possessions between teams throughout a match. To assess the significance of each node, we employed eigenvector centrality measures within the constructed multilayer network. Furthermore, we introduce three additional metrics, namely the leakage, recovery and switching factor, which quantify the possession transitions between layers. Finally, we apply our methodology to analyze the performance of Spanish soccer teams over an entire season, using the aforementioned multilayer parameters, and discuss the relation with the playing style and ranking of soccer teams.

Adequate Interval between Matches in Elite Female Soccer Players.

The present study compared four different intervals between three simulated soccer matches for changes in muscle damage and performance parameters. Thirteen well-trained female university soccer players performed three bouts of 90-min Loughborough Intermittent Shuttle Test (LIST) with four different intervals between bouts; one (1d), two (2d), three (3d) and four days (4d), with >12-weeks between conditions in a counterbalanced order. Heart rate, blood lactate, rating of perceived exertion and distance covered in each LIST were measured. Changes in several muscle damage markers (e.g., maximal voluntary isometric torque of the knee extensors: MVC-KE, muscle soreness), performance parameters (e.g., Yo-Yo intermittent recovery test level 1: Yo-Yo IR1), and blood measures (e.g., osmolality, high sensitivity cardiac troponin T) before the first LIST, 1 h after each LIST, and one to five days after the third LIST were compared among the conditions. The total distance covered during the first two LISTs was not different among the conditions, but that during the third LIST was shorter (P < 0.05) for the 1d (9,416 ± 885 m) and 2d conditions (9,737 ± 246 m) than the 3d (10,052 ± 490 m) and 4d conditions (10,432 ± 538 m). Changes in all measures were smaller (P < 0.05) in the 3d and 4d conditions (e.g., the decrease in MVC-KE at one day after the third LIST was -13 ± 4% and -10 ± 3%, respectively) when compared with the 1d and 2d conditions (-20 ± 7%, -18 ± 5%). Performance parameters showed smaller (P < 0.05) changes in the 4d (e.g., the decrease in Yo-Yo IR1 at one day after the third LIST was -9 ± 3%) and 3d (-13 ± 6%) conditions when compared with the 1d (-19 ± 4%) and 2d (-20 ± 8%) conditions. These results suggest that muscle damage and fatigue accumulate when soccer matches are performed three consecutive days or every other day, but if more than three days are inserted between matches, this could be minimized.

Team-Builder: Toward More Effective Lineup Selection in Soccer.

Lineup selection is an essential and important task in soccer matches. To win a match, coaches must consider various factors and select appropriate players for a planned formation. Computation-based tools have been proposed to help coaches on this complex task, but they are usually based on over-simplified models on player performances, do not support interactive analysis, and overlook the inputs by coaches. In this paper, we propose a method for visual analytics of soccer lineup selection by tackling two challenges: characterizing essential factors involved in generating optimal lineup, and supporting coach-driven visual analytics of lineup selection. We develop a lineup selection model that integrates such important factors, such as spatial regions of player actions and defensive interactions with opponent players. A visualization system, Team-Builder, is developed to help coaches control the process of lineup generation, explanation, and comparison through multiple coordinated views. The usefulness and effectiveness of our system are demonstrated by two case studies on a real-world soccer event dataset.

Fatigue Index Analysis in Student Soccer Clubs after 45 Minutes of Soccer Match

The purpose of this study was to determine and see the value of the fatigue index in student football athletes after playing a match for 45 minutes in the first halfs. This study used a quantitative descriptive method with 22 sample. The instrument used in this study is the Running-based Anaerobic Sprint Test (RAST), which is a test carried out by sprinting with a distance of 35 meters for 6 repetitions and a 10 second rest interval for each repetition performed by the athlete. The test results showed that from 22 students who played soccer for 45 minutes, 15 students (68.18%) had a high fatigue index value, while 7 students (31.82%) had a low fatigue index value. Based on the results of data analysis and discussion, it can be concluded that 15 out of 22 people (68.18%) of student soccer athletes after playing a soccer match for 45 minutes in the first half had a high fatigue index value.

Using neural networks and hierarchical cluster analysis to study goal kicks in football

The objective of this study is to build a mathematical model that predicts the success of a goal kick in soccer. The model is based on an ensemble of neural networks whose inputs are five features extracted directly from the goal kick and one more that depends on the opposing team. This new variable is calculated using a hierarchical cluster analysis and divides the possible opponents by their defensive strategy. It is shown that it has a relevant importance in the result of a goal kick, which validates the idea of using the presented methodology that takes into account the opponent’s tactics when analyzing specific plays of a soccer match.

Examining the Link between Isokinetic Strength Metrics and Ball Speed in Women’s Soccer

The shot performance of female soccer players is one of the most critical factors in winning a soccer match. It is essential to thoroughly clarify the kinetic factors that can improve shot performance. This study explores the connections between ball velocity post-shooting and isokinetic knee extension (EXT) and flexion (FLX) strength performances among female soccer players. Thirteen voluntary players from professional leagues took part in the research study. The study analyzed the average and peak concentric (Con) and eccentric (Ecc) torques, isometric (Iso) strength performances at angular velocities of 60°/s, 180°/s and 300°/s, the time required to reach peak torque, and ball velocities during shooting. The relationships among these variables were investigated separately for the dominant (D) and non-dominant (ND) legs. The analysis unveiled significant correlations between ball velocities and D-EXT (Absolute) peak torque at an angular velocity of 60°/s (r = 0.597; p &lt; 0.05), D-%IPS (r = −0.580; p &lt; 0.05), and ND-FLX (Absolute) average torque (r = 0.559; p &lt; 0.05). Moreover, notable associations were observed between ball velocities and ND-EXT (Absolute) (r = 0.581; p &lt; 0.05), as well as ND-FLX (Absolute) (r = 0.602; p &lt; 0.05) average torques at an angular velocity of 180°/s. Additionally, significant relationships were found between ball velocities and peak (r = 0.664; p = 0.013) and average (r = 0.660; p = 0.014) torques generated during ND-EXT (Absolute) at an angular velocity of 300°/s. However, the connections between the time to reach peak torque, eccentric and isometric forces, and ball velocities were not statistically significant (p &gt; 0.05). The results of the study indicate that enhancing concentric isokinetic strength development at 60°/s, 180°/s, and 300°/s angular velocities, along with balanced strengthening of the ND extremity, holds paramount importance in elevating shot performance among female soccer players, particularly in the context of rapid shot strategies.

Continuous Monitoring of Interstitial Fluid Glucose Responses to Endurance Exercise with Different Levels of Carbohydrate Intake.

We compared the 24 h changes in interstitial fluid glucose concentration (IGC) following a simulated soccer match between subjects consuming a high-carbohydrate (HCHO; 8 g/kg BW/day) diet and those consuming a moderate-carbohydrate (MCHO; 4 g/kg BW/day) diet. Eight active healthy males participated in two different trials. The subjects were provided with the prescribed diets from days 1 to 3. On day 3, the subjects performed 90 min (2 bouts × 45 min) of exercise simulating a soccer match. The IGC of the upper arm was continuously monitored from days 1 to 4. No significant difference in the IGC was observed between trials during exercise. The total area under the curve (t-AUC) value during exercise did not significantly differ between the HCHO (9719 ± 305 mg/dL·90 min) and MCHO (9991 ± 140 mg/dL·90 min). Serum total ketone body and beta-hydroxybutyrate concentrations were significantly higher in the MCHO than in the HCHO after a second bout of exercise. No significant differences in the IGC were observed between trials at any time point during the night after exercise (0:00-7:00). In addition, t-AUC value during the night did not significantly differ between the HCHO (32,378 ± 873 mg/dL·420 min) and MCHO (31,749 ± 633 mg/dL·420 min). In conclusion, two days of consuming different carbohydrate intake levels did not significantly affect the IGC during a 90 min simulated soccer match. Moreover, the IGC during the night following the exercise did not significantly differ between the two trials despite the different carbohydrate intake levels (8 vs. 4 g/kg BW/day).

The effect of COVID-19 lockdown on ball possession performance in Spanish professional soccer leagues

ABSTRACT This research analysed the influence of lockdown and interruption of competitions due to COVID-19 on different ball possession-related variables. Also, match location and the differences between divisions were considering between the pre- and post-lockdown. A total of 144,689 records from 842 soccer matches during the 2019/20 season of the First (n = 380) and Second Spanish Division (n = 462) were collected. Match data were collected using the ChryonHego video-tracking system. Pre-lockdown (1st–27th matchday in First Division and 1st–31st matchday in Second Spanish Division) and post-lockdown periods (28th–38th matchday in First Division and 32nd–42nd matchday in Second Spanish Division) were compared. The match location contextual-related variable was also considered for the analysis. Linear mixed models showed that the number of outplayed players by ball possession (3.1%), successful passes (17.5%) and total passes (18.9%) increased during the post-lockdown period (p < .001). In addition, match location and league significantly influenced the successful and total passes in all situations (p < .001), increasing in the post-lockdown period. In conclusion, the lockdown period has led changes in the ball possession of the soccer teams. These results help to understand the impact that a particular and unusual situation as the interruption of the league due to COVID-19 lockdown had on the performance of professional soccer teams.

Case manipulation of football match score by the referee in the framework of fulfilling sports purposes

The manipulation of football match scores in Indonesia is familiar and continues to increase. The settlement of the case in the judge's decision was based on two criminal acts, namely the crime of fraud (Article 378 of the Criminal Code) and bribery (UU No. 11 of 1980). It is stated in several judge's decisions, including in Judge's Decision No.31/Pid.Sus/2020/PN.Smd and Judge's Decision No.48/Pid.Sus/2019/PN BNR. Manipulation of match scores as an attempt to violate the goals of the sport of football. This research aims to verify cases of match score manipulation by referees in realizing sports goals. The results of the discussion prove that the two judges' decisions that classify match score manipulation In the two judges' decisions that classify match score manipulation cases as fraud and bribery, there is the fulfillment of the elements in both of these crimes. In contrast, the subject of the violation is the referee who leads the match, which requires Integrity and leadership character. Then the goal of a soccer match is to support the embodiment of the formation of national values and character. Then when a referee is involved in a match score manipulation case, it means he has generally failed the goals of the sport.

Analisis Standar Operasional Prosedur Dalam Pengamanan Pertandingan Sepak Bola

Supporters are people who provide active support. These supporters are different from ordinary football spectators who only see the football match because supporters are football spectators who support a certain team, and are ready to give up all their energy in motivating their favorite club. These football fans are very active and have excessive fanaticism for the team they support. It is this fanaticism that usually causes chaos and riots at every football match in Indonesia. Because riots and riots in soccer matches often occur, the police, in this case the police, tighten security at every soccer match. However, the tight security often leads to repressive actions that lead to violence against supporters by the police in securing football matches. The violence perpetrated by the security forces against the fans clearly violated the provisions of the applicable law. And this is a violation of the law for which there must be criminal accountability for the perpetrators of the violence so that there is no more violence experienced by fans in football matches.

Exploring the interplay between metabolic power and equivalent distance in training games and official matches in soccer: a machine learning approach.

Introduction: This study aimed to explore the interplay between metabolic power (MP) and equivalent distance (ED) and their respective roles in training games (TGs) and official soccer matches. Furthermore, the secondary objective was to investigate the connection between external training load (ETL), determined by the interplay of metabolic power and equivalent distance, and internal training load (ITL) assessed through HR-based methods, serving as a measure of criterion validity. Methods: Twenty-one elite professional male soccer players participated in the study. Players were monitored during 11months of full training and overall official matches. The study used a dataset of 4269 training games and 380 official matches split into training and test sets. In terms of machine learning methods, the study applied several techniques, including K-Nearest Neighbors, Decision Tree, Random Forest, and Support-Vector Machine classifiers. The dataset was divided into two subsets: a training set used for model training and a test set used for evaluation. Results: Based on metabolic power and equivalent distance, the study successfully employed four machine learning methods to accurately distinguish between the two types of soccer activities: TGs and official matches. The area under the curve (AUC) values ranged from 0.90 to 0.96, demonstrating high discriminatory power, with accuracy levels ranging from 0.89 to 0.98. Furthermore, the significant correlations observed between Edwards' training load (TL) and TL calculated from metabolic power metrics confirm the validity of these variables in assessing external training load in soccer. The correlation coefficients (r values) ranged from 0.59 to 0.87, all reaching statistical significance at p < 0.001. Discussion: These results underscore the critical importance of investigating the interaction between metabolic power and equivalent distance in soccer. While the overall intensity may appear similar between TGs and official matches, it is evident that underlying factors contributing to this intensity differ significantly. This highlights the necessity for more comprehensive analyses of the specific elements influencing physical effort during these activities. By addressing this fundamental aspect, this study contributes valuable insights to the field of sports science, aiding in the development of tailored training programs and strategies that can optimize player performance and reduce the risk of injuries in elite soccer.

Research on soccer prediction model based on machine learning combined with domain knowledge

With the global popularity of soccer and the increasing collection of data, more and more research focuses on using machine learning (ML) algorithms to predict match outcomes. However, accurately predicting soccer match results is a complex task that requires considering multiple factors such as team strength and player status. This paper aims to predict soccer match results using ML techniques in Python. To achieve this goal, a series of methods are employed to collect, analyze, and utilize historical match data, combined with knowledge and experience from the soccer domain, to identify factors relevant to predicting soccer match outcomes. By establishing appropriate feature extraction and selection methods, this paper is able to capture information closely related to match results. Based on this foundation, the paper proceeds with model development and enhances its performance through training and parameter tuning. Specifically, ML algorithms such as Support Vector Machines (SVM) and various techniques are applied to optimize the models and improve their predictive accuracy. Emphasis is placed on model stability and generalization, taking into account issues of overfitting and underfitting during the training process, with appropriate regularization and cross-validation techniques. Finally, a comprehensive performance evaluation is conducted on the established models, and a comparative analysis of different algorithms is performed. The experimental results demonstrate the excellent performance of the models proposed in this paper in predicting soccer match results, showcasing the significant potential of ML in this domain.

Average demands and most demanding passages of national-level female soccer matches: do small- and large-sided games replicate match demands?

This study aims to (1) determine the average and most demanding passage (MDP) load of national-level female soccer matches and (2) evaluate the relationship between average and MDP load during small-sided games (SSGs), large-sided games (LSGs), and matches. A total of 37 national-level female soccer players from a single club senior team and the U18 team participated. The average and 1-, 3-, and 5-min MDP external (total, high-speed, and very-high-speed running distances, acceleration and deceleration distances, average metabolic power, and high-metabolic load distance) and internal loads (average heart rate, rate of perceived exertion) of the 29 league matches, ten 4 vs. 4 + goalkeepers SSGs, and six 8 vs. 8 + goalkeepers LSGs were analyzed by the Polar Team Pro player tracking system. In matches, the external load variables during 1-, 3-, and 5-min MDPs were 167%-1,165%, 135%-504%, and 126%-359%, of match average values, respectively. In LSGs, all external load variables reached higher average values compared with those during matches, except for the very-high-speed running distance; however, no variable reached higher values of 1-min MDP compared with those during the matches. In SSGs, the average acceleration and deceleration distances were higher compared with those during the matches. The findings from the present study suggest that LSGs and SSGs can be used to overload the average values of the selected external load variables compared with those during the matches; however, other training options must be explored to overload 1-min match MDPs.

Using Microtechnology and the Fourier Transform for the Analysis of Effective Activity Time in Professional Soccer.

Oliva-Lozano, JM, Chmura, P, Granero-Gil, P, and Muyor, JM. Using microtechnology and the Fourier Transform for the analysis of effective activity time in professional soccer. J Strength Cond Res 37(12): 2491-2495, 2023-This study aimed to investigate the use of the fast Fourier transform (FFT) for the analysis of effective activity time in professional soccer by (a) exploring the relationship between this variable and standard external load parameters and (b) analyzing the effective activity time during official professional soccer matches. Twenty-six male players participated in the study. Each player was categorized as midfielder, central defender, full-back, wide-midfielder, or forward. Tracking systems based on inertial sensors (4 3D accelerometers, 3 3D gyroscopes, and 1 magnetometer), and global positioning systems technology were used to collect external load measures for 35 matches. Each match was analyzed considering 15-minute periods to explore the evolution of effective activity time during the matches. The extra time from each match was also included. Fast Fourier transform duration may be a representative variable of effective activity time, given the strong positive correlation with the external load variables ( p < 0.001). The linear regression analysis showed that the variables that significantly contributed to the model ( R2 = 0.97) were the total of steps and the distance covered. The mean effective activity time in soccer match play was ∼48.69 minutes. This time significantly changed depending on factors such as the period of the match ( F = 239.05; p < 0.001; ηp 2 = 0.60) or playing position ( F = 16.99; p < 0.001; ηp 2 = 0.06). The greatest effective activity time was observed for all playing positions in the 0'-15' period. However, the 60'-75' period showed the lowest effective activity times compared with the rest of the 15-minute periods for all positions except for forwards (75'-90'). From a practical standpoint, sports performance practitioners may consider these results to improve the individualization of training and match demands. Also, a more accurate indicator of exercise intensity may be obtained (e.g., multiplying the rating of perceived exertion by the effective activity time).

Normative reference and cut-offs values of maximal aerobic speed-20 m shuttle run test and maximal oxygen uptake for Tunisian adolescent (elite) soccer players

This study aimed to develop reference curves of aerobic parameters of 20 m shuttle run test for Tunisian soccer players. The study was conducted in the 2022/2023 pre-season. The reference curves of the maximal aerobic speed (MAS) and the maximal oxygen uptake (VO2max) were developed according to the Lambda, Mu and Sigma (LMS) method, using data from 742 Tunisian premier league soccer players aged 11–18 years. Measured variables included: weight, height, body mass index and maximal heart rate (HRmax). HRmax was measured when the participants completed the maximal aerobic speed. VO2max was estimated using the 20 m shuttle run test protocol (speed increment every minute). Our results presented the smoothed percentiles (3rd, 10th, 25th, 50th, 75th, 90th and 97th) of MAS (km/h) and VO2max (ml/kg•min⁻1) according to age. In addition, raw data showed that VO2 max was positively correlated with age (r = 0.333; P < 0.001), height (cm) (r = 0.279; P < 0.001), weight (kg) (r = 0.266; P < 0.001), practice period (years) (r = 0.324; P < 0.001) and BMI (kg/m2) (r = 0.10; P < 0.05). However, it was negatively correlated to HRmax (bpm) (r = −0.247; P < 0.001). Only the measurements within the age group [12–12.99] are significantly higher (p < 0.001; ES = 0.63) compared with the previous age group [11–11.99]. Finally, regarding prevalence, our findings showed that 15.5 % of the players in our sample had VO2max values above the 87.7th percentile cut-off, while only 0.3 % exceeded the 99.18th percentile. The development of normative curves could help coaches and physical trainers to more accurately detect weaknesses in the aerobic performance of their players in order to sustain high-intensity repetitive actions during a soccer match.

Physiological Profile and Correlations between VO2max and Match Distance Running Performance of Soccer Players with Visual Impairment

Aerobic capacity is crucial for the performance of soccer players; however, the relationship between VO2max and the running performance of soccer players with visual impairment is not known. Possibly finding relationships would help in the training process, as training would be more targeted. Additionally, both bodyweight and relative VO2max are factors that affect people’s health and wellness. From the literature, it appears that there are no studies that present the normal profile of soccer players with visual impairment. The aims of this study were to (a) determine the differences in VO2max between soccer players and sedentary men with visual impairment; (b) to assess the relationship between the VO2max of players with visual impairment and the distance covered in a soccer match and (c) to describe a profile of physiological parameters and distance running during a soccer match. Six male soccer players with VI and six male sedentary people with VI participated in this study. Anthropometric characteristics (age, height, bodyweight, body fat (BF), body mass index (BMI), cardiorespiratory markers (VO2max, maximum heart rate (HRmax), respiratory exchange ratio (RER)) and the running performance of soccer players during matches were measured, and the VO2max of all the participants was measured in a laboratory. Mann–Whitney U test was used to evaluate differences between sedentary and soccer players’ anthropometric characteristics and performance. A correlation analysis by Spearman’s’ method was used to examine relationships between VO2max and the rest of the physical values during the match. The level of statistical significance was set at p &lt; 0.05. The soccer players’ weight was 33% lower, and their BMI was 23% lower than that of sedentary men (p = 0.023, η2 = 0.457 and p = 0.048, η2 = 0.394, respectively). The relative body mass VO2max of the athletes was 42.9% higher in comparison with sedentary men with VI (p = 0.002, η2 = 0.755). No correlations were found between VO2max and match running performance (p = 0.957, r = −0.029) or other parameters during the match in soccer players with VI. In conclusion, relative VO2max is not related to the match running performance of soccer players. The tactics applied by the team, the style of play and the position of the player may affect the distances covered. Also, as expected, the soccer players showed lower bodyweight and higher relative VO2max. However, this is the first study to observe the level of these differences.

Synchronization of passes in event and spatiotemporal soccer data

The majority of soccer analysis studies investigates specific scenarios through the implementation of computational techniques, which involve the examination of either spatiotemporal position data (movement of players and the ball on the pitch) or event data (relating to significant situations during a match). Yet, only a few applications perform a joint analysis of both data sources despite the various involved advantages emerging from such an approach. One possible reason for this is a non-systematic error in the event data, causing a temporal misalignment of the two data sources. To address this problem, we propose a solution that combines the SwiftEvent online algorithm (Gensler and Sick in Pattern Anal Appl 21:543–562, 2018) with a subsequent refinement step that corrects pass timestamps by exploiting the statistical properties of passes in the position data. We evaluate our proposed algorithm on ground-truth pass labels of four top-flight soccer matches from the 2014/15 season. Results show that the percentage of passes within half a second to ground truth increases from 14 to 70%, while our algorithm also detects localization errors (noise) in the position data. A comparison with other models shows that our algorithm is superior to baseline models and comparable to a deep learning pass detection method (while requiring significantly less data). Hence, our proposed lightweight framework offers a viable solution that enables groups facing limited access to (recent) data sources to effectively synchronize passes in the event and position data.

Prolonged cognitive effort impairs inhibitory control and causes significant mental fatigue after an endurance session with an auditive distractor in professional soccer players

BackgroundThroughout official soccer matches, the presence of cheer by the crowd could be considered a critical auditive distraction that could further impair the cognitive interference control system, multiple object tracking (MOT) skill, heart rate variability (HRV), and increase mental fatigue. As the resource is not immediately replenished, the impairment of the cognitive interference control system may be delayed following a soccer game. Then, evaluating the recovery time course of the cognitive interference control system, MOT skill, HRV, and mental fatigue after prolonged tasks combining physical, endurance, and cognitive effort are essential. PurposeWe aimed to analyze the acute effect of cognitive effort and auditive distractor with 24-h follow-up throughout a prolonged endurance session on inhibitory control, subjective mental fatigue, MOT skill, and HRV in professional soccer players. MethodsTwenty professional male soccer players were recruited (23.56 ± 3.8 years, 78.1 ± 6.9 kg, 1.77 ± 0.06 m, and 12.5 ± 5.3% body fat). The sessions were performed in a randomized and counterbalanced crossover design, divided into four experimental conditions: endurance, endurance + MOT, endurance + MOT + AD, and endurance + AD. The soccer players completed the incongruent Stroop task utilizing an eye-tracker to assess cognitive effort. MOT task, subjective mental fatigue, and HRV were evaluated before the endurance training (60%Δ of maximal aerobic velocity during 40-min) and after 30-min and 24-h of recovery. These sessions were designed to investigate the acute effect of prolonged cognitive effort (repeated MOT throughout the endurance task) and AD (constant crowd noise and coach's voice each 15–40 s, totalizing = 80 voices) on inhibitory control, MOT skills, HRV, and subjective mental fatigue after a fixed endurance training session. ResultsThere was no condition × time interaction for accuracy of inhibitory control (p > 0.05, ηp2 = 0.001). There was a significant condition × time interaction for inhibitory control response time (p < 0.05, ηp2 = 0.16). A higher response time of inhibitory control was found for the endurance + MOT + AD and endurance + MOT experimental sessions (p < 0.05). There was a significant condition × time interaction for subjective mental fatigue (p < 0.05, ηp2 = 0.46). A higher subjective mental fatigue was found for the endurance + MOT + AD and endurance + MOT experimental sessions (p < 0.05). There was no condition × time interaction for HRV (p > 0.05, ηp2 = 0.02). ConclusionWe concluded that cognitive effort throughout a prolonged endurance session impaired inhibitory control and increased mental fatigue without promoting greater MOT skill and HRV changes in professional soccer players.

The effects of high-intensity interval training at the anaerobic and psychomotor fatigue thresholds on physiological parameters in young soccer players: a prospective study.

This study aimed to investigate the effects of a 4-week specific high-intensity interval training (HIIT) program performed between the anaerobic threshold (ANT) and the psychomotor fatigue threshold (PFT) on physiological parameters in 14 professional soccer players at the under-17 level. The first and second stages of the research protocol included a treadmill running exercise with increasing load and six 3-min four-versus-four games of soccer with a 3-min break between games. Players then participated in a training microcycle involving three specific HIIT exercises twice per week for 4 weeks, after which they repeated stages one and two, followed by an assessment of changes. The measurement of lactate (LA) determined ANT, whereas the choice reaction time (CRT) indicated PFT among other selected physiological parameters. The repeated-measure analysis of variance (ANOVA) compared mean values for the examined variables using Bonferroni post hoc test. It demonstrated significantly increased maximal oxygen consumption (VO2 max) from 45.9 ± 3.0 to 48.7 ± 2.6at the ANT and from 49.1 ± 3.4 to 52.0 ± 3.6 on the PFT after 4 weeks of training. A significant increase in the running speed (RS) at both thresholds and heart rate (HR) at the ANT (p ≤ 0.05) was also recorded. Moreover, the players exceeded their intensity of effort during ANT while playing four-versus-four soccer matches, but they did not reach intensity during PFT. In conclusion, the findings of the study demonstrated that both thresholds shifted toward higher loads and the proposed specific HIIT effectively increased the exercise capacity of soccer players.

Lessons Learned on a High-Altitude Expedition to Mount Kilimanjaro.

High-altitude expeditions expose teams to particular medical, environmental, and social challenges that can have unintended and severe consequences for crew members. In June 2017, the 9-d Equal Playing Field (EPF) expedition to Mount Kilimanjaro to set a world record for the highest-altitude soccer match ever played demonstrated the variety of challenges that may arise during these types of trips. This trip included a full-length soccer match at 5714 m (18,746 ft), leading to additional challenges for expedition members participating in the athletic event. The EPF medical team identified the challenges that occurred during the expedition and documented the methods used to resolve these challenges in real time. From the challenges faced during the expedition, we describe the lessons learned for future expeditions to Mount Kilimanjaro and other high-altitude environments. Challenges arose with medical tent visibility, medical disqualification, underreporting of medical events, and acute pain management, while anticipated challenges with interpersonal conflict did not occur. The rigorous preparation and anticipation by the EPF medical team prior to expedition departure may have helped mitigate this conflict as well as prevented unintended severe medical events from occurring.