Performance In Team Sports Research Articles

Testing decision-making skills in football using augmented reality

Decision-making skills are fundamental to successful performance in team sports. Current approaches to assess decision-making skills are incredibly resource intensive for both athletes and researchers. Athletes are required to travel to testing facilities and researchers invest time and effort to create representative experiments. A less resource intensive procedure is highly desired.
 In this study, the feasibility of an on-field decision-making task was assessed. The task was presented in augmented reality. The situations in the task were retrieved from open-source tracking data. Short sequences of build-up play were arranged into a testing battery based on a similarity score. For the similarity score, we harnessed the Kuhn-Munkres algorithm (Kuhn, 1955; Munkres, 1957) to select similar situations based on player positions and movement directions. The sampled situations preserve the natural variability experienced by football players in the performance environment. With the algorithmic approach, the need for selecting and creating situations manually was minimized.
 The display, which rendered the view of a regular 11v11 football situation was shown from the perspective of a midfield player. The content was displayed using a head mounted augmented reality device. The participant was free to move on a real football field onto which the other players were augmented as virtual avatars. The participant was presented with a freeze-frame of the situation and triggered the situation by moving into a visually designated area. Participants were instructed verbally to offer support to the ball-carrying team-mate. The situation ended with the participant receiving a virtual pass from the team-mate.
 Experienced football players were drawn from a pool of university students to participate in the study. During the experiment, the movement trajectory of the participant was recorded using IMU data retrieved from the head-mounted display. The movement patterns were analyzed using a timeseries-clustering approach to examine the characteristics of different movement solutions the participants deployed across the situations (Chow et al., 2008). Deviations from the original trajectories (i.e., the open-source data) were measured to gaze at the natural variability that occurs in build-up situations in football.
 In conclusion, the feasibility study attempted to facilitate the assessment of decision-making skills in team-sports. Two promising means were introduced: (1) The selection of the situations was automated to reduce efforts needed by the researcher. (2) The use of an augmented-reality device enabled testing directly on the field. The decision-making skills were assessed through the observed movement patterns which provided new insights on how players move when making decisions.
 References
 Chow, J. Y., Davids, K., Button, C., & Rein, R. (2008). Dynamics of movement patterning in learning a discrete multiarticular action. Motor Control, 12(3), 219-240. https://doi.org/10.1123/mcj.12.3.219
 Kuhn, H. W. (1955). The Hungarian method for the assignment problem. Naval Research Logistics Quarterly, 2(1‐2), 83-97. https://doi.org/10.1002/nav.3800020109
 Munkres, J. (1957). Algorithms for the assignment and transportation problems. Journal of the Society for Industrial and Applied Mathematics, 5(1), 32-38.

A commentary of factors related to player availability and its influence on performance in elite team sports.

A commentary of factors related to player availability and its influence on performance in elite team sports.

Microdosing Sprint Distribution as an Alternative to Achieve Better Sprint Performance in Field Hockey Players.

Introduction: The implementation of optimal sprint training volume is a relevant component of team sport performance. This study aimed to compare the efficiency and effectiveness of two different configurations of within-season training load distribution on sprint performance over 6 weeks. Methods: Twenty male professional FH players participated in the study. Players were conveniently assigned to two groups: the experimental group (MG; n = 11; applying the microdosing training methodology) and the control group (TG; n = 9; traditional training, with players being selected by the national team). Sprint performance was evaluated through 20 m sprint time (T20) m and horizontal force−velocity profile (HFVP) tests before (Pre) and after (Post) intervention. Both measurements were separated by a period of 6 weeks. The specific sprint training program was performed for each group (for vs. two weekly sessions for MG and TG, respectively) attempting to influence the full spectrum of the F-V relationship. Results: Conditional demands analysis (matches and training sessions) showed no significant differences between the groups during the intervention period (p > 0.05). No significant between-group differences were found at Pre or Post for any sprint-related performance (p > 0.05). Nevertheless, intra-group analysis revealed significant differences in F0, Pmax, RFmean at 10 m and every achieved time for distances ranging from 5 to 25 m for MG (p < 0.05). Such changes in mechanical capabilities and sprint performance were characterized by an increase in stride length and a decrease in stride frequency during the maximal velocity phase (p < 0.05). Conclusion: Implementing strategies such as microdosed training load distribution appears to be an effective and efficient alternative for sprint training in team sports such as hockey.

Effectiveness and Kinematic Analysis of Initial Step Patterns for Multidirectional Acceleration in Team and Racquet Sports.

The ability for quick multidirectional accelerations is crucial for athletic performance in team and racquet sports. So far, there has been little research dedicated to different initial step patterns usually applied by players. Therefore, the present study investigated the kinematic characteristics and effectiveness of the following step patterns: Jab Step (JS), Pivot Step (PS), Gravity Step (GS) and Counter Step (CS). Twenty-two male competitive team and racquet sport athletes completed maximum lateral accelerations utilizing the step patterns. Following familiarization with each step pattern, three 5 m sprints (5 m STs) into both directions (left & right) were completed. Sprint times, the translation of the center of mass (CoM) and joint angles were obtained using three-dimensional motion analysis. 5 m STs of the CS were faster compared to the GS and PS for both directions. A detailed distance-time analysis revealed that for shorter distances only the JS was faster than the GS. Regarding the sequence in which the maximum angular velocities (max. ) in the hip, the knee, and the ankle were reached during the push off, there was a proximal-to-distal sequence for the JS and the CS, but a distal-to proximal sequence for the GS and the PS. The results reveal that the JS and the CS are superior for accelerations towards the lateral direction. Specifically, they indicate that the JS is more suitable for covering very short distances and the CS is superior for covering further distances. In addition, the distal-to-proximal sequence of max. during the push-off in the GS and the PS might indicate lower kinematic efficiency.

The associations between physical-test performance and match performance in women's Rugby Sevens players.

Evaluating the relationships between physical-test and match performance in team sports could be useful for training prescription and athlete evaluation. Here we investigated these relationships in women's Rugby Sevens. Thirty provincial-representative players performed Bronco-fitness, countermovement-jump, acceleration, speed, and strength tests within two weeks before a two-day tournament. Match-running and match-action performance measures were provided by GPS units and video analysis. Generalised and general linear mixed models were employed to estimate the effect of a two standard-deviation difference in physical-test measures on match measures. Effect magnitudes were assessed via standardisation (using the between-player SD) and, for effects on tries scored, also via match winning (based on simulating matches). Evidence for substantial and trivial true magnitudes was provided by one-sided interval-hypothesis tests and Bayesian analysis. There was good evidence of positive effects of many physical-test measures on match high-intensity running, with large effects for jump height and acceleration. There was some evidence of small-moderate positive effects of speed and Bronco, and of small-moderate negative effects of maximal strength and jump height, on match total running and high intensity changes in speed. The evidence was generally inadequate for associations between physical-test measures and match actions, but there was good evidence of small-large positive effects of back squat and jump height on tries scored. Enhancing players' jump height and back-squat performance might therefore increase the likelihood of match success in women's Rugby Sevens.

Caffeine and Team ball performances: A Mini-Review

Background: Caffeine is the most consumed psychoactive substance globally, second only to water in beverage consumption. Its impact on athletic performance, particularly in team sports, has been a subject of growing research interest. This review focuses on recent studies investigating caffeine's influence on various aspects of team ball sports performance. Objectives: This mini-review aimed to (i) synthesize current research findings on caffeine supplementation in team sports, considering different doses, forms, and its effects across genders and (ii) to highlight key considerations for optimal caffeine use in these sports. Methods: THIS mini-review examined recent studies on caffeine's effects in team ball sports, analyzing variables such as supplementation strategies, habitual consumption, gender, washout periods, individual responses, and supplement forms (capsules or powders). The focus is on studies that have used caffeine doses ranging from 3 to 6 mg·kg -1, administered 60 minutes before competition. Results: Findings suggest beneficial effects of caffeine ingestion (3 to 6 mg·kg-1) in enhancing technical and physical aspects of team ball sports. However, results vary based on factors like the supplementation strategy, individual caffeine consumption habits, and gender. Most research has focused on single-dose effects, revealing a lack of comprehensive, gender-specific guidelines for caffeine's optimal use in team sports. Conclusion: While caffeine supplementation shows promise in enhancing team sports performance, there is a need for more comprehensive research, especially regarding gender-specific effects and optimal consumption strategies. Current evidence points to the potential benefits of caffeine in morning competitions or training sessions but indicates possible detrimental effects in afternoon or evening settings. Further research is needed to develop robust guidelines for caffeine use in team sports, considering dosage, timing, form, and differential gender effects.

The keys of pressing to gain the ball – Characteristics of defensive pressure in elite soccer using tracking data

ABSTRACT Recently, the availability of big amounts of data enables analysts to dive deeper into the constraints of performance in various team sports. While offensive analyses in football have been extensively conducted, the evaluation of defensive performance is underrepresented in this sport. Hence, the aim of this study was to analyze successful defensive playing phases by investigating the space and time characteristics of defensive pressure. Therefore, tracking and event data of 153 games of the German Bundesliga (second half of 2020/21 season) were assessed. Defensive pressure was measured in the last 10 seconds of a defensive playing sequence (time characteristic) and it was distinguished between pressure on the ball-carrier, pressure on the group (5 attackers closest to the ball), and pressure on the whole team (space characteristic). A linear mixed model was applied to evaluate the effect of success of a defensive play (ball gain), space characteristic, and time characteristic on defensive pressure. Defensive pressure is higher in successful defensive plays (14.47 ± 16.82[%]) compared to unsuccessful defensive plays (12.87 ± 15.31[%]). The characteristics show that defensive pressure is higher in areas closer to the ball (space characteristic) and the closer the measurement is to the end of a defensive play (time characteristic), which is especially true for successful defensive plays. Defensive pressure is a valuable key performance indicator for defensive play. Further, this study shows that there is an association between the pressing of the ball-carrier and areas close to the ball with the success of defensive play.

Evaluating the influence of a constraint manipulation on technical, tactical and physical athlete behaviour.

Evaluating practice design is an important component of supporting skill acquisition and improving team-sport performance. Constraint manipulations, including creating a numerical advantage or disadvantage during training, may be implemented by coaches to influence aspects of player or team behaviour. This study presents methods to evaluate the interaction between technical, tactical and physical behaviours of professional Australian Football players during numerical advantage and disadvantage conditions within a small-sided game. During each repetition of the game, team behaviour was manually annotated to determine: repetition duration, disposal speed, total disposals, efficiency, and disposal type. Global Positioning System devices were used to quantify tactical (surface area) and physical (velocity and high intensity running) variables. A rule association and classification tree analysis were undertaken. The top five rules for each constraint manipulation had confidence levels between 73.3% and 100%, which identified the most frequent behaviour interactions. Specifically, four advantage rules involved high surface area and medium high intensity running indicating the attacking team's frequent movement solution within this constraint. The classification tree included three behaviour metrics: surface area, velocity 1SD and repetition duration, and identified two unique movement solutions for each constraint manipulation. These results may inform if player behaviour is achieving the desired outcomes of a constraint manipulation, which could help practitioners determine the efficacy of a training task. Further, critical constraint values provided by the models may guide practitioners in their ongoing constraint manipulations to facilitate skill acquisition. Sport practitioners can adapt these methods to evaluate constraint manipulations and inform practice design.

Comparing semi-professional and amateur game contexts via Football Competence (Procedural Tactical Knowledge)

This study aimed to analyze the game context of the same task (a reduced game P+4 vs. 4+P) in two groups (8 semi-professionals and 8 amateurs), comparing the procedural tactical knowledge of the players. 1377 tactical behaviors were analyzed through the Football Competition Observation System (FOCOS), evaluating the volume and efficiency of 67 variables. Student's t-test for independent samples and Cohen's d effect size were calculated. Using the Bonferroni correction to control for the family error rate in each criterion of the observation tool, significant differences were found in 13 variables (volume, n = 1; efficiency, n = 12), with the following sizes of effect (very large = 4; large = 9). The results revealed that game contexts differ mainly in the efficiency of tactical behaviors that take place outside the game center. Based on this finding, variables focused on the relationship with the ball, widely used to assess performance in team sports, must be carefully judged when comparing players from different divisions and categories; and coaches must prioritize their attention on what happens away from the ball, instead of focusing feedback on those tactical behaviors that occur in the heat of the action.Keywords: performance, decision making, comparative analysis, observational methodology, reduced games

Effects of New Zealand Blackcurrant Extract on Sequential Performance Testing in Male Rugby Union Players.

Previous studies on performance effects by New Zealand blackcurrant (NZBC) extract used mainly a single exercise task. We examined the effects of NZBC extract in a battery of rugby union–specific tests including speed, agility and strength testing. University male rugby union players (n = 13, age: 21 ± 2 years, height: 182 ± 6 cm, body mass: 87 ± 13 kg) completed two full familiarisations and two experimental visits in an indoor facility. The study had a double blind, placebo-controlled, randomised, crossover design. For the experimental visits, participants consumed NZBC extract (210 mg/day of anthocyanins for 7 days) or placebo with a 7-day wash-out. Testing order was the running-based anaerobic sprint test, the Illinois agility test, seated medicine ball (3 kg) throw, and handgrip strength. With NZBC extract, there may have been an effect for average sprint time to be faster by 1.7% (placebo: 5.947 ± 0.538 s, NZBC extract: 5.846 ± 0.571 s, d = −0.18 (trivial), p = 0.06). However, with NZBC extract there may have been reduced slowing of sprint 2 (d = −0.59 (moderate), p = 0.06) and reduced slowing for sprint 6 (d = −0.56 (moderate), p = 0.03). In the Illinois agility test, there may have also been an effect for the mean time to be faster by 1.6% (placebo: 18.46 ± 1.44 s, NZBC extract: 18.15 ± 1.22 s, d = −0.24 (small), p = 0.07). The correlation between the %change in average sprint time and %change in mean agility time was not significant (Pearson R2 = 0.0698, p = 0.383). There were no differences for the seated medicine ball throw distance (p = 0.106) and handgrip strength (p = 0.709). Intake of NZBC extract in rugby union players seems to improve tasks that require maximal speed and agility but not muscle strength. NZBC blackcurrant extract may be able to enhance exercise performance in team sports that require repeated movements with high intensity and horizontal change of body position without affecting muscle strength.

A Perception-Action Assessment of the Functionality of Peripheral Vision in Expert and Novice Australian Footballers.

While widely acknowledged as being important for team-sport performance, the contribution of peripheral vision is poorly understood. This study aimed to better understand the role of far peripheral vision in team sport by exploring how domain experts and novices used far peripheral vision to support decision making and action control. Expert (n = 25) and novice (n = 23) Australian football players completed a perception-only task to assess the extent of their peripheral field. Next, they completed two sport-specific variations (response and recognition) of a "no-look" pass task that required passing a ball to a teammate who appeared in their far peripheral field. In the perception-only task, novices outperformed experts. However, in the sport-specific action response and recognition tasks, experts demonstrated superior performance as they responded to the stimulus farther from central vision and more accurately. Results demonstrate expertise effects for the use of far peripheral vision in sport.

The Application of a Team-Building Program for Team Match in the National Archery Team

PURPOSE This study aimed to apply a team-building program for preparing the national archery team for competition in the Olympics. METHODS To achieve the purpose of this study, six national archers (three men and three women) were included. The team-building program was applied for a total 6 sessions (one session per week). Group cohesion and efficacy were measured three times before, after, and at a later application of the program. The collected data were analyzed with the Friedman and Wilcoxon signed-rank tests, which are nonparametric statistical techniques for data analysis. In addition, an in-depth interview for qualitative data was conducted for each archer to explore the effects and changes resulting from participation in the program. RESULTS The results of the study are as follows: first, the levels of team cohesion and efficacy in the national archery team increased after the implementation of the program compared to those in the pre-implementation state. Furthermore, high levels of team cohesion and efficacy were maintained at the follow-up measurement. Second, the archers recognized that closeness and faith in one another increased more between team members. Furthermore, there were positive changes in team communication, atmosphere, cohesion, and efficacy during team matches. CONCLUSIONS The team-building program applied in this study was found to have a positive effect on various factors related to team cohesion, such as team communication and team atmosphere. Therefore, future studies should consider developing a team-building program that can contribute to improving team sport performance for different sports and the effects of the program should be examined using various methods.

Effects of Eight-Week Circuit Training with Core Exercises on Performance in Adult Male Soccer Players.

Core exercises have been widely promoted in the last 25 years. However, the scientific debate about its efficacy for improving individual and team sports performance is still open. Thus, the present study aims to investigate the effects of circuit training with a core exercise program on physical performance in competitive amateur soccer players. The training was conducted during the off-season period, two times per week for 8 weeks. Pre- and post-evaluations were conducted using the following tests: Y-Balance Test (YB), standing long jump (SLJ), medicine ball chest press (MBC), curl-up (CU), and Illinois Agility Test (IAT). A total of 19 adults were divided into an experimental group (EG, n = 11, age 22 years, weight 71.2 ± 4.8 kg, height 174 ± 5.8 cm) and a control group (CG, n = 8, age 22 years, weight 73.2 ± 4.1 Kg, height 176 ± 6.3 cm). The EG showed significant improvements in lower and upper body strength, core endurance and balance, whereas the CG did not report significant changes in the pre- and post-test comparison. Despite study limitations, our positive results show that circuit training with core exercises appears to be a good strategy for performance improvement in adult soccer players.

Ketone Monoester Ingestion Alters Metabolism and Simulated Rugby Performance in Professional Players

Ketone ingestion can alter metabolism but effects on exercise performance are unclear, particularly with regard to the impact on intermittent-intensity exercise and team-sport performance. Nine professional male rugby union players each completed two trials in a double-blind, randomized, crossover design. Participants ingested either 90 ± 9g carbohydrate (CHO; 9% solution) or an energy matched solution containing 20 ± 2g CHO (3% solution) and 590mg/kg body mass β-hydroxybutyrate monoester (CHO + BHB-ME) before and during a simulated rugby union-specific match-play protocol, including repeated high-intensity, sprint and power-based performance tests. Mean time to complete the sustained high-intensity performance tests was reduced by 0.33 ± 0.41s (2.1%) with CHO + BHB-ME (15.53 ± 0.52s) compared with CHO (15.86 ± 0.80s) placebo (p = .04). Mean time to complete the sprint and power-based performance tests were not different between trials. CHO + BHB-ME resulted in blood BHB concentrations that remained >2mmol/L during exercise (p < .001). Serum lactate and glycerol concentrations were lower after CHO + BHB-ME than CHO (p < .05). Coingestion of a BHB-ME with CHO can alter fuel metabolism (attenuate circulating lactate and glycerol concentrations) and may improve high-intensity running performance during a simulated rugby match-play protocol, without improving shorter duration sprint and power-based efforts.

Improving identity leadership through a novel targeted reflective practice intervention

The purpose of this study was to investigate the effectiveness of a novel identity leadership-framed reflective practice intervention for developing sport coach leadership skills. We adopted an eight-week randomized control intervention design, including five experimental group coaches and their associated athletes (n = 47) and four control group coaches and their athletes (n = 32). Athletes’ perceptions of their coach engaging in identity leadership behaviors were measured at Weeks 0 and 8 for both groups. The experimental group coaches completed three specifically designed social identity-framed reflective practice tasks in Weeks 1, 3, and 5. Results showed that when controlling for baseline scores and compared to the control condition, the experimental condition reported significantly greater advancement, entrepreneurship, and impresarioship, but not prototypicality at post-intervention. The results provide support for the use of tailored reflective practice interventions to elicit desirable identity leadership behaviors as perceived by athletes. Lay summary: Leadership is a key aspect of team sport performance. Reflective practice is a core component of coach development. The present study shows the potential to develop leadership through social identity-framed reflective practice activities. Implications for practice Investigation of new ways for developing leadership In-direct development of Identity Leadership Multi-faceted and innovative approach to reflective practice

Reliability of a Medicine Ball Explosive Power Test in Young Volleyball Players

The purpose of the study was to evaluate the reproducibility of the medicine ball explosive power test to assess explosive power in young volleyball players. Materials and methods. Data were collected using twelve volleyball players (age = 16.5 ± 0.52 years; body mass = 72.05 ± 7.9 kg; height = 182 ± 0.06 cm and body mass index = 21.63 ± 1.85) volunteered for this study. They completed a test and retest of the medicine ball explosive power test on two separate days. The medicine ball explosive power test was conducted using a 3 kg medicine ball. Testing was carried out in two separated testing session preceded by a standardized warming up protocol. The paired-sample t-test was conducted to determine the differences signification observed between the test and the retest of the medicine-ball explosive power test. The intraclass correlation coefficient (ICC1,1) aims to assess relative reliability of the test. The coefficient of variation between test and retest performance was used to check the absolute reproducibility. The Bland and Altman method was used to evaluate the relative and absolute reproducibility of the medicine ball explosive power test. Results and discussion. Explosive power is often considered as one of the main determinants of a successful high-level performance in many team sports including volleyball. It is frequently measured in different occasion during competitive season using field‐based tests. Thus, it is mandatory that strength and conditioning coaches have to use valid and reliable tests to evaluate the power for their athletes. However, contestation regarding test selection still exists grounded upon the particularity of the explosive power evaluation tests in volleyball. There was no significant difference between medicine ball explosive power test (11.08 ± 0.72 meter) and retest (11.27 ± 0.93 meter) performance. The T-paired Sample test did not show any statistically significant difference (t= 1.035; p =0.393), while the intraclass correlation coefficient aimed to assess relative reliability of the test was of 0.83. The coefficient of variation between test and retest performance was of 5.7% which is near to the 5% confidence interval level. The intraclass correlation coefficient was situated between 0.9 and 0.8 (ICC1,1 = 0.83) Thus this study suggests that the medicine ball explosive power test has moderate relative reliability level. Conclusion. The medicine ball explosive power test is reliable regardless to the age. The Bland and Altman method confirmed our finding suggesting the medicine ball explosive power test is a reliable test

Multiple Players Tracking in Virtual Reality: Influence of Soccer Specific Trajectories and Relationship With Gaze Activity.

The perceptual-cognitive ability to track multiple moving objects and its contribution to team sports performance has traditionally been studied in the laboratory under non-sports specific conditions. It is thus questionable whether the measured visual tracking performance and the underlying gaze activity reflected the actual ability of team sports players to track teammates and opponents on a real field. Using a Virtual Reality-based visual tracking task, the ability of participants to track multiple moving virtual players as they would do on a soccer field was observed to pursue two objectives. (i) See the influence of different scenario types (soccer-specific trajectories versus pseudo-random trajectories) on the visual tracking performance of soccer (n = 15) compared to non-soccer players (n = 16). (ii) Observe the influence of spatial features of the simulated situations on gaze activity between soccer players and non-soccer players. (i) The linear mixed model regression revealed a significant main effect of the group but no interaction effect between group and the type of trajectories, suggesting that the visual tracking ability of soccer players did not benefit from their specific knowledge when they faced scenarios with real game trajectories. (ii) Virtual players’ spatial dispersion and crowding affected the participants’ gaze activity and their visual tracking performance. Furthermore, the gaze activity of soccer players differed in some aspects from the gaze activity of non-soccer players. Assumptions are formulated as to the implication of these results in the difference in visual tracking performance between soccer players and non-soccer players. Overall, using soccer-specific trajectories might not be enough to replicate the representativeness of the field conditions in the study of visual tracking performance. Multitasking constraints should be considered along with motor-cognitive dual-tasks in future research to develop the representativeness of visual exploration conditions.

Physical Demands during the Game and Compensatory Training Session (MD + 1) in Elite Football Players Using Global Positioning System Device.

The aims of this study were to analyze the differences of physical demands of non-starter players regarding the playing time during the competition and to evaluate the physical demands of the compensatory training (MD + 1C) for substitute players in elite football. The match statistics and MD + 1C of substitute players from a professional Spanish LaLiga football club were analyzed using a 10-Hz global positioning system (GPS) Apex GPS system device, which has been validated as a reliable and valid method to analyze performance in team sports, during all games of the 2016/2017, 2017/2018 and 2018/2019 seasons. The starting players showed both lower total distances covered and high-intensity actions compared to the substitutes. Regarding the minutes played by the substitutes, greater physical performance was found for the players with fewer minutes (5–15 min). Furthermore, no differences were found between first and second divisions regarding physical performance of substitutes (p > 0.05). This study highlights the importance of individualizing the workload of training sessions for substitutes and starters. Furthermore, the complementary session should be individualized according to the minutes played by the substitutes. These players are potentially under-loaded compared to starters, especially in terms of high-intensity actions, therefore additional session-specific training for each substitute would be useful to reach the optimal training load according to the minutes played during the game.

A case study on altitude training and its effects of volly ball players

Altitude training is to enhance training performance. The fundamental theory behind altitude training in that, by exposing an athlete to an environmental that is low in oxygen, (Hypoxic), the body will eventually adapt and improve its efficiency (acclimatized). In volley ball it is necessary to clarify the effect of altitude training on hematological variables, increased oxygen intake, fitness factor, molecular adaptations, and genetic adaptations acclimatization. The main objective of altitude training and team sport is to present cutting –edge research on the basic &amp; applied aspects of altitude training to enhance match related performance in team sport. Exercise and training in hypoxic environment includes neuromuscular metabolic and cardiac vascular adaption. Despite the limited research on the effects of altitude (or hypoxic) training interventions on team-sport performance, players from all around the world engaged in these sports are now using altitude training more than ever before. In March 2013, an Altitude Training and Team Sports conference was held in Doha, Qatar, to establish a forum of research and practical insights into this rapidly growing field.

Acute caffeine supplementation and live match-play performance in team-sports: A systematic review (2000–2021)

ABSTRACT Caffeine is a psycho-active stimulant that can improve physical and cognitive performance. We systematically reviewed the evidence on the effects of acute caffeine ingestion on physiological parameters, physical and technical-skill performance during high-performance team-sport match-play. Following PRISMA guidelines, studies were identified using scientific databases (PubMed, Web-of-Science, Scopus, and SPORTDiscus) in February 2021. Of 281 results, 13 studies met inclusion, totalling 213 participants. Included studies adopted the randomised double-blinded cross-over design, involving caffeine and control conditions. In studies reporting physiological variables, responses to caffeine included higher peak (n=6/ 8 [n/ total studies measuring the variable]) and mean (n=7/ 9) heart rates, increased blood glucose (n=2/ 2) and lactate (n=2/ 2) concentrations. Improvements in physical performance were widely documented with caffeine, including greater distance coverage (n=7/ 7), high-speed distance coverage (n=5/ 7) and impact frequencies (n=6/ 8). From three studies that assessed technical-skills, it appears caffeine may benefit gross-skill performance, but have no effect, or negatively confound finer technical-skill outcomes. There is compelling evidence that ingesting moderate caffeine doses (~3 to 6 mg·kg−1) ~60 minutes before exercise may improve physical performance in team-sports, whereas evidence is presently too scarce to draw confident conclusions regarding sport-specific skill performance.