Influence of the time-task constraint on ocular metrics of semi-elite soccer players.

This study novelty aimed to investigate the influence of manipulating the available time to perform the training tasks on soccer players´ ocular metrics, following training. Specifically, pupillary response (pupil diameter) and saccadic features (latency, accuracy, velocity, and number) were measured with a portable eye tracker following training to reflect the mental load accumulated by players during the training sessions. Nine semi-elite soccer players performed two training sessions, based on large-sided games, on an artificial grass field. These two sessions were composed of the same tasks but varying the required time to complete the task goals (Session 1: No time limitations to perform the tasks; Session 2: Limited time to perform the tasks). The participants performed, before (pre-test) and after (post-test) each training session, a prosaccade task in a room near the playing field. Findings revealed a differentiated effect of the available time to complete the training tasks on ocular metrics because significant differences were found in all variables after training (p < .001 for pupil diameter; p < .01 for saccade accuracy and number of saccades; p < .05 for saccade velocity and latency). Ocular metrics could be a promising tool to evaluate mental load following practice because they were sensitive to the time-task constraint, providing researchers a valuable information for a better planning of the mental workload when designed training tasks.

Brain endurance training improves shot speed and accuracy in grassroots padel players.

OBJECTIVES: Evidence that mental fatigue impairs sport performance has created a demand for countermeasures. We examined the effects of brain endurance training, a form of fatigue-inoculation, on shot performance in grassroots padel players. DESIGN: A pre-, mid- and post-test design, with participants randomized to brain endurance training (n = 30) or control (n = 31) groups. METHODS: During testing, participants completed a Padel Stroke Performance Test, before and after a demanding 30-min cognitive task (Stroop). Training comprised 3 sessions/week for 6 weeks. In each training session, participants completed 10-min warm-up, 15-min technical drills, 15-min tactical drills, and 20-min simulated games. These physical activities were intermixed with short 4-min periods of Stroop (brain endurance training group) or rest (control group) totaling 20-min. Performance was measured by shot speed and accuracy of padel strokes. Mental fatigue indices were measured before and after the Stroop task using a visual analog scale rating, a psychomotor vigilance task, and a go/no-go task. RESULTS: During testing, the 30-min Stroop task elicited a state of mental fatigue, confirmed by higher subjective ratings, slower responses during the psychomotor vigilance task, and slower saccade latencies during the go/no go task. Compared to pre-testing, in mid- and post-testing, the brain endurance training group hit progressively faster and more accurate padel shots after the Stroop task compared to controls. CONCLUSIONS: Brain endurance training enhanced skill-based psychomotor performance when fatigued compared to standard padel training. Brain endurance training is a countermeasure that promotes mental fatigue durability.

An intervention program based on team building during tactical training tasks to improve team functioning.

The study aimed to analyze the effects of an intervention program based on team building developed in technical-tactical training tasks in football. Specifically, it examined the benefits of the intervention in variables related to the conceptual model of team building: role clarity, team identification, intra-team communication, cohesion, intra-group conflict, commitment to the team, inside sacrifice, transactive memory systems, collective efficacy, and perceived performance. The participants were 51 young elite footballers divided into an experimental group (n = 27) and a control group (n = 24). The methodological design was quasi-experimental with a duration of 8 weeks. The data were collected three times: pretest, posttest, and follow-up. The results showed differences favoring the experimental group compared to the control group after the implementation of the intervention program in the following variables: team identification (p < 0.001), role clarity (p < 0.001), intra-team communication (p < 0.001; except distinctiveness), group cohesion (p < 0.05), social conflict (p = 0.001), commitment to the team (p < 0.001), inside sacrifice (p < 0.001), transactive memory systems (p < 0.01; except coordination), collective efficacy (p = 0.02) and team performance (p = 0.001). Consequently, the application of team-building strategies incorporated into specific technical-tactical training tasks in football seems to improve group dynamics in sports teams.

Influence of Scoring Systems on Mental Fatigue, Physical Demands, and Tactical Behavior during Soccer Large-Sided Games.

Constraints are common in soccer training to develop physical, technical-tactical, and mental training concurrently. This study examined how different scoring systems influence physical, tactical, and mental demands during large-sided games in soccer. Eighteen youth-elite male (17.39 ± 1.04 y) soccer players completed three 8 vs. 8 large-sided games where the different score systems were i) official score system (OSS; i.e., 1 goal = 1 goal), ii) double the value of the goal-4 min (DVx4; i.e., 1 goal = 1 goal from 0.00 to 7.59 min, and 1 goal = 2 goals from 8.00 to 12.00 min), and iii) double the value of the goal-8 min (DVx8; i.e., 1 goal = 1 goal from 0.00 to 3.59 min, and 1 goal = 2 goals from 4.00 to 12.00 min). Physical demands and tactical behaviors were recorded during tasks using a global positioning system and video camera. Mental fatigue was recorded pre- and post-task using a visual analogue scale. Also, the ratio of perceived exertion and mental load were recorded after tasks were finished. Results reported the highest values of mental and physical demands in DVx4. Mental fatigue increased during all three large-sided games, although this increase was significantly higher in DVx4 compared with OSS (p = 0.006) and DVx8 (p = 0.027). Tactical behavior showed a trend towards more direct play during DVx4, which was less observed during DVx8, and not at all during OSS. In conclusion, changing the scoring system affects physical, tactical, and mental demands.

A Multiday Professional Padel Tournament Impairs Sleep, Mental Toughness, and Reaction Time: A World Padel Tour Field Study.

This study aimed to assess, for the first time, how self-reported sleep, mental toughness, and reaction time are impacted by a professional padel tournament. In addition, we evaluated whether sex, age, and/or ranking play a role in this possible effect of a tournament on these variables. Twenty-three professional players (15 men, Mage = 24 ± 6 years; eight women, Mage = 21 ± 5 years) were evaluated on two occasions: (a) baseline, in a noncompetitive week and (b) postmeasure, the morning after an individual was eliminated from the tournament. The Pittsburgh Sleep Quality Index, the Mental Toughness Questionnaire, and the psychomotor vigilance task were used to evaluate the dependent variables. Wilcoxon tests or paired samples t tests were employed to assess the effect of participating in the tournament. To test correlations between variables, Pearson correlation coefficients (quantitative variables) or chi-square distributions (qualitative variables) were employed. Results showed that self-reported sleep (p < .01), mental toughness (p = .01), and reaction time (p = .04) were significantly impaired by the tournament. Exploring moderating variables, results showed that mental toughness did not correlate with sleep impairments (p > .05). In contrast, a nearly significant correlation between sleep impairments and higher reaction times was found (p = .066). No significant effects of age, sex, and ranking were observed. In conclusion, participating in a padel competition impairs the self-reported sleep, mental toughness, and reaction time of professional padel players. A trend toward a significant correlation between the competition-related impairment in sleep and reaction time was observed, whereas age, ranking, and sex were not found to be moderators of any of these impairments.

Correction: Habay et al. Mental Fatigue-Associated Decrease in Table Tennis Performance: Is There an Electrophysiological Signature? Int. J. Environ. Res. Public Health 2021, 18, 12906.

In the published publication [...].

Effect of a Four-Week Soccer Training Program Using Stressful Constraints on Team Resilience and Precompetitive Anxiety.

The present study examined the effects of stressful constraints during soccer trainings on psychological skill development and internal load when compared with control (nonstressful) trainings. A total of 51 elite male youth soccer players (27 in the experimental group, M = 16.54 years; 24 in the control group, M = 15.44 years) participated in the study. In a 12-week longitudinal survey, team resilience, using the Spanish version of the Characteristics of Resilience in Sports Teams Inventory, and anxiety, using the Sport Anxiety Scale, were measured at baseline (after 4 weeks of regular trainings), postprotocol (after 4 weeks of control or experimental trainings), and follow-up (after 4 weeks of regular trainings). Results show that, when compared with the control group, a program with stressful constraints helped young soccer players to develop better psychological skills: specifically, increased ability to cope with impairments in resilience (both resilience characteristics and team vulnerability under pressure; p < 0.001). Increases in anxiety (p = 0.06) and decreases in preoccupation (p < 0.001) and lack of concentration (p < 0.001) were also observed. The adaptation of human behavior to specific trainings may explain these results. In conclusion, the regular exposure of young soccer players to stressful situations during trainings shows benefits for their psychological skill development in soccer. Then, benefits on internal load were also observed.

Mental fatigue changes from regular season to play-offs in semiprofessional soccer: A comparison by training days.

The main purpose was to compare by each training the mental load and fatigue reported by semiprofessional soccer players comparing between regular season phase and the play-offs. Fifty-three players (Mage  = 24.59 years) for two teams participated during the 2020/21 season. Mental load was measured with a Likert questionnaire. Mental fatigue was quantified with a Visual Analogue Scale. Four trainings were recorded each week (Monday = MD+1, Wednesday = MD-4, Thursday = MD-3 and Saturday = MD-1), with a competitive match on Sunday across 10 weeks (five dates of regular season - five dates of play-offs). A Linear Mixed Model was performed with R-studio, using the training days and the competitive phase as independent variables. The influence of time played as co-variable was also checked. Results showed MD+1 as the more mentally fatiguing day in both phases, although MD-4 were the training with higher mental load reported (p = 0.001). Comparing phases, mental fatigue was significantly higher during the play-offs (p = 0.037). With regard time played, players that did not usually play showed a decrease in mental load during the play-offs. Then, we recommend coaches to use recovery strategies for mental fatigue, avoid mentally fatiguing tasks close to competition and considerer the time played as a factor which may contribute to individual differences in player mental fatigue.

Do sport teams with greater team resilience perceive higher performance at the end of the season? A multilevel analysis.

A team's ability to respond positively to adversities, problems, and obstacles during their season is an essential part of success in collective sports. Grounded in team resilience theory and using a multilevel analytical approach, this study examined the relationship of the characteristics of resilience and vulnerability under pressure with perceived individual and team performance. Participants were 676 soccer players (530 males and 146 females) aged 15-42 years (M = 21.40, SD = 5.38), who played on 64 senior and under-18 soccer teams of several national leagues in Spain. In the final month of the season, factors related to team resilience and individual and team performance were analyzed. We estimated multilevel models by including perceived individual and team performance as dependent variables. Characteristics of resilience and vulnerability under pressure were considered as fixed and random effects (i.e., individual- and team-level intercepts and slopes). At the individual level, results showed that characteristics of resilience were positively associated with subjective individual and team performance, whereas vulnerability under pressure was negatively related to perceived team (but not individual) performance. At the team level, only characteristics of resilience positively predicted team performance. These findings suggest that more resilient teams report more successful performance from an individual and team perspective, whereas teams that are more vulnerable under pressure report poorer team performance. Taken together, the study underscores the importance of practitioners to develop strategies that improve their teams' resilience, given that team resilience helps to achieve positive subjective individual and team outcomes.

The impact of COVID-19 lockdown on soccer positional and physical demands in the Spanish La Liga.

The present study aimed to analyse the playing surface area, dispersion and distance covered of professional football teams comparing the pre-lockdown and post-lockdown periods. Positional and match physical demands data were collected from all matches played in the First Spanish Division (n = 760) during season 2019/2020. Pre-lockdown (1st-27th matchday) and post-lockdown periods (28th-38th matchday) were compared. Variables related to team-level spatial (i.e., convex hull, team width and team length) and physical performance (i.e., total distance and high-speed running distance) were analysed using an optical tracking system (i.e., ChyronHego). In addition, these variables were concerned with respect to the match location contextual variable. Linear mixed models were used to examine the difference between the pre-lockdown and post-lockdown periods following a hierarchical structure considering players, matches and teams. The results revealed that the pandemic lockdown affected the teams' performance when comparing the periods before and after lockdown, showing a general decrease in the average values of the spatial and physical variables measured. The current data could assist practitioners in making informed decisions in order to design and improve training plans for similar situations in which teams return to competition after an unusual period with no training.

Using the Conceptual Framework for Examining Sport Teams to Understand Group Dynamics in Professional Soccer.

(1) Background: The aim of this study is to propose a model of the interactions of group dynamics using the conceptual framework to examine sports teams; (2) Methods: The hypothesized model includes measures of group structure (authentic leadership, perceived justice, coaching competency, role clarity/ambiguity, and role conflict), group cohesion (cohesion and team conflict), and group processes (collective efficacy and transactive memory systems). Participants were 581 professional soccer players (M = 24.51, SD = 3.73; 356 males and 225 females) who completed a multisection questionnaire assessing group dynamics variables; (3) Results: The results show that coach leadership predicts coaching competency and perceived justice, and both competency and justice predict role ambiguity and role conflict. Furthermore, role ambiguity and role conflict predict group cohesion and team conflict, whereas group cohesion and team conflict both predict the transactive memory system. Finally, collective efficacy is predicted by the transactive memory system; (4) Conclusions: The results suggest the importance of coach behavior (leadership, justice, and competency) and group processes to improving team functioning in a professional sports context.

¿Influye el liderazgo del entrenador sobre la resiliencia de equipo? Efecto mediador de los conflictos intragrupo y la cohesión grupal / Does coach leadership influence team resilience? Mediating effect of intra-group conflict and group cohesion

Resumen Introducción/objetivo: El presente estudio tiene como objetivo examinar la rela ción entre el liderazgo transformacional del entrenador y las características de resiliencia y la vulnerabilidad bajo presión, así como analizar si los factores del conflicto intragrupo (social y tarea) y de la cohesión grupal (social y tarea), pudieran mediar la relación entre dichas variables. Método: A través de un diseño longitudinal, se incluyó a un total de 301 depor tistas inscritos en los JUDEX, pertenecientes a 34 equipos de fútbol y voleibol, con edades comprendidas entre 13 y 18 años (M = 15.72; DT = 1.33). Resultados: Los resultados mostraron una relación positiva entre el liderazgo transformacional del entrenador y las características de resiliencia, y una asociación negativa respecto a la vulnerabilidad bajo presión. Además, el conflicto intragrupo (social y tarea) actuó como mediador entre la relación del liderazgo trans formacional del entrenador y la resiliencia de equipo. En cuanto al papel mediador de la cohe sión grupal, solo la cohesión tarea actuó como mediadora entre el liderazgo transformacional del entrenador y la resiliencia de equipo. Conclusiones: La presente investigación muestra la importancia del liderazgo del entrenador para mejorar la resiliencia del equipo en categorías de formación, y la influencia positiva que tiene la reducción de los conflictos intragrupo y el aumento de la cohesión tarea durante la temporada.

Abstract Introduction/objective: The present study aimed to examine the relationship be tween transformational coach leadership with the characteristics of resilience and vulnerability under pressure, as well as to analyze whether the factors of intra-group conflict (social and task) and group cohesion (social and task) could mediate the relationship between these variables. Method: Through a longitudinal design, a total of 301 athletes enrolled in the JUDEX, belong ing to 34 soccer and volleyball teams, and aged between 13 and 18 years (M = 15.72; SD = 1.33). Results: The results showed a positive relationship between transformational leadership of the coach and resilience characteristics, and a negative association with respect to vulnerability under pressure. In addition, intra-group conflict (social and task) acted as mediators between the relationship between transformational coach leadership and team resilience. Regarding the mediating role of group cohesion, only task cohesion acted as a mediator between trans formational coach leadership and team resilience. Conclusions: This research draws as main conclusion the importance of the coach's leadership to improve team resilience in youth cate gories, and the positive influence of the reduction of intragroup conflicts and the increase of task cohesion during the season.

Do Cognitive, Physical, and Combined Tasks Induce Similar Levels of Mental Fatigue? Testing the Effects of Different Moderating Variables.

Experts have highlighted the importance of coaches knowing the level of mental fatigue (MF) induced by different tasks. This study aimed to compare the mentally fatiguing nature of cognitive, physical, and combined tasks and, additionally, assess the effect of different moderating variables on MF. Twenty-three physically active (16 males: Mage = 24 years; seven females: Mage = 22.57 years) participants performed three experimental sessions: (a) physically fatiguing: 30 min of cycloergometer work (at 65%-75% of maximum heart rate), (b) mentally fatiguing: 30 min of an incongruent Stroop task, and (c) mixed fatiguing: 30 min of combining the physically and mentally fatiguing protocols. Subjective MF (visual analog scale), reaction time (psychomotor vigilance task), and cognitive performance (Stroop) were measured throughout the different protocols. Results showed significant increments in subjective MF after all tasks, with the mental and mixed protocols showing significantly higher increases. Only the mentally fatiguing protocol caused significant impairments in reaction time. No significant effects of sex, years of experience, or degree of mental toughness were observed. These results suggest that the use of all these tasks, and especially the mentally fatiguing exercises, should be avoided immediately prior to competitions due to the negative consequences of MF on performance. Moreover, this effect seems to be independent of the sex, years of experience, or mental toughness of athletes.

Relación entre los conflictos intra-grupo y el rendimiento en deportes colectivos: efecto mediador de la eficacia colectiva / Relação entre conflitos intra-grupo e desempenho em esportes coletivos: efeito mediador da eficácia coletiva / Relationship between intra-group conflicts and performance in collective sports: mediator effect of collective efficacy

El presente estudio tuvo como objetivo analizar la relación entre el conflicto intra-grupo y el rendimiento percibido a final de temporada, y examinar como actúa la eficacia colectiva como variable mediadora en esta asociación. Participaron 420 jugadores semi-profesionales y amateurs (M = 22,40; DT = 4,71) de baloncesto, balonmano, fútbol y voleibol. Los resultados mostraron que el conflicto intra-grupo (tarea y social) se relacionó negativamente con el rendimiento percibido del equipo, y que la eficacia colectiva mostró resultados significativos actuando como mediadora entre la relación de el conflicto intra-grupo (tarea y social) y el rendimiento percibido del equipo. Por lo tanto, es importante destacar que los conflictos intra-grupo parecen empeorar las percepciones sobre el rendimiento grupal y que la eficacia colectiva puede suavizar esta relación negativa, consiguiendo un aumento en el la percepción de los jugadores sobre el rendimiento del equipo a final de temporada. (AU)

The present study aimed to analyze the relationship between intra-group conflict and team perceived performance at the end of the season, and to examine the mediating effect of collective efficacy on this relationship. 420 semi-professional and amateur players (M = 22,40; SD = 4,71) of basketball, handball, soccer and volleyball participated. The results showed that intra-group conflict (task and social) was negatively related to team performance and collective efficacy showed significant results acting as a mediator between the relationship of intra-group conflict (task and social) and team perceived performance. Therefore, it is important to highlight that intra-group conflict seems to worsen the collective functioning and that collective efficacy can soften this negative relationship, achieving an increase in team performance at the end of the season. (AU)

O presente estudo teve como objetivo analisar a relação entre conflito intra-grupo e desempenho percebido no final da temporada, e examinar como a eficácia coletiva atua como uma variável mediadora nesta associação. Participaram 420 jogadores semiprofissionais e amadores (M = 22,40; DT = 4,71) de basquete, handebol, futebol e voleibol. Os resultados mostraram que o conflito intra-grupo (trabalho de casa e social) estava negativamente relacionado ao desempenho percebido da equipe e que a eficácia coletiva apresentou resultados significativos atuando como mediador entre a relação do conflito intra-grupo (trabalho de casa e social) e o desempenho percebido da equipe. Portanto, é importante destacar que o conflito intra-grupo parece agravar o funcionamento coletivo da equipe e que a eficácia coletiva pode amenizar essa relação negativa, conseguindo um aumento na percepção do desempenho da equipe no final da temporada. (AU)

Mental Fatigue-Associated Decrease in Table Tennis Performance: Is There an Electrophysiological Signature?

Mental fatigue (MF) is a psychobiological state negatively impacting both cognitive and physical performance. Although recent research implies that some table tennis (TT) performance outcomes are impaired by MF, open skill sports such as TT require a more detailed overview of MF-related performance decrements. Moreover, research into MF and sport-specific psychomotor performance lacks the inclusion of brain-related measurements to identify MF mechanisms. Eleven experienced TT players participated in this randomized counterbalanced crossover trial. Participants were either required to perform an individualized Stroop task (MF condition) or watch a documentary (control condition). The primary outcomes were reaction time on a sport-specific visuomotor task and EEG activity throughout the trial. The subjective feeling of MF was significantly different between both conditions and confirmed that the MF condition induced the mentally fatigue state of participants (p < 0.001), though no behavioral indicators (i.e., decrease in performance on Stroop and flanker task) of MF. MF worsened reaction time on the visuomotor task, while other secondary measurements remained largely ambiguous. Spectral power (i.e., decreases in upper α band and θ band) was influenced by MF, while ERPs measured during the visuomotor task remained unaltered. The present study confirms that MF negatively impacts table tennis performance, specifically inhibitory stimuli during the visuomotor task. These findings also further augment our understanding of the effects of MF on human performance.

Prefrontal Cortex Oxygenation During Endurance Performance: A Systematic Review of Functional Near-Infrared Spectroscopy Studies.

Introduction: A myriad of factors underlie pacing-/exhaustion-decisions that are made during whole-body endurance performance. The prefrontal cortex (PFC) is a brain region that is crucial for decision-making, planning, and attention. PFC oxygenation seems to be a mediating factor of performance decisions during endurance performance. Nowadays, there is no general overview summarizing the current knowledge on how PFC oxygenation evolves during whole-body endurance performance and whether this is a determining factor. Methods: Three electronic databases were searched for studies related to the assessment of PFC oxygenation, through near-IR spectroscopy (NIRS), during endurance exercise. To express PFC oxygenation, oxygenated (HbO2) and deoxygenated hemoglobin (HHb) concentrations were the primary outcome measures. Results: Twenty-eight articles were included. Ten articles focused on assessing prefrontal oxygenation through a maximal incremental test (MIT) and 18 focused on using endurance tasks at workloads ranging from low intensity to supramaximal intensity. In four MIT studies measuring HbO2, an increase of HbO2 was noticed at the respiratory compensation point (RCP), after which it decreased. HbO2 reached a steady state in the four studies and increased in one study until exhaustion. All studies found a decrease or steady state in HHb from the start until RCP and an increase to exhaustion. In regard to (non-incremental) endurance tasks, a general increase in PFC oxygenation was found while achieving a steady state at vigorous intensities. PCF deoxygenation was evident for near-to-maximal intensities at which an increase in oxygenation and the maintenance of a steady state could not be retained. Discussion/Conclusion: MIT studies show the presence of a cerebral oxygenation threshold (ThCox) at RCP. PFC oxygenation increases until the RCP threshold, thereafter, a steady state is reached and HbO2 declines. This study shows that the results obtained from MIT are transferable to non-incremental endurance exercise. HbO2 increases during low-intensity and moderate-intensity until vigorous-intensity exercise, and it reaches a steady state in vigorous-intensity exercise. Furthermore, ThCox can be found between vigorous and near-maximal intensities. During endurance exercise at near-maximal intensities, PFC oxygenation increases until the value exceeding this threshold, resulting in a decrease in PFC oxygenation. Future research should aim at maintaining and improving PFC oxygenation to help in improving endurance performance and to examine whether PFC oxygenation has a role in other performance-limiting factors.

The Influence of Time Winning and Time Losing on Position-Specific Match Physical Demands in the Top One Spanish Soccer League.

The aim of the present study was to analyze the influence of time winning and time losing on position-specific match physical demands with and without ball possession in the top Spanish professional soccer league. All matches played in the First Spanish soccer league over four consecutive seasons (from 2015/16 to 2018/19) were recorded using an optical tracking system (i.e., ChyronHego), and the data were analyzed via Mediacoach®. Total distance (TD), and TD > 21 km·h-1 covered with and without ball possession were analyzed using a Linear Mixed Model, taking into account the contextual variables time winning and losing. Results showed that TD and TD > 21 km·h-1 covered by central midfielders (0.01 and 0.005 m/min, respectively), wide midfielders (0.02 and 0.01 m/min, respectively), and forwards (0.03 and 0.02 m/min, respectively) significantly increased while winning (p < 0.05). By contrast, TD and TD > 21 km·h-1 covered by central defenders (0.01 and 0.008 m/min, respectively) and wide defenders (0.06 and 0.008 m/min, respectively) significantly increased while losing (p < 0.05). In addition, for each minute that teams were winning, total distance with ball possession (TDWP) decreased, while, for each minute that teams were losing, TDWP increased. Instead, TDWP > 21 km·h-1 obtained opposite results. Total distance without ball possession increased when teams were winning, and decreased when teams were losing. Therefore, the evolution of scoreline significantly influences tactical-technical and physical demands on soccer matches.

How Mentally Fatiguing Are Consecutive World Padel Tour Matches?

It is currently unknown whether mental fatigue occurs throughout a WPT competition and whether consecutive matches affect how mentally fatiguing a match is perceived to be. The objective was to quantify the effects of successive professional matches on mental fatigue. A total of 14 professional players (9 males, Mage = 25, 5 females, Mage = 21) participated during qualified rounds of a WPT with three eliminatory matches: Match 1 (morning) and 2 (afternoon) on day 1 (n = 14), Match 3 (morning) on day 2 (n = 6). Mental fatigue and motivation, with scales, and reaction time, with a 3-min Psychomotor Vigilance Test, were measured at two time intervals (pre and post matches (<30 min)). To analyze the evolution of these variables, a two-way repeated measures MANOVA was performed. An increase in mental fatigue from pre- to post-matches was observed (p < 0.01), with an accumulation of mental fatigue between matches played on day 1 (p < 0.01), maximizing the mental fatigue perceived during Match 2. Padel matches impair motivation and reaction time (p = 0.04), without effects between successive matches, which reinforced the idea that mental fatigue may impair padel performance (i.e., reaction time). Coaches should use training interventions and recovery strategies to counteract/avoid the accumulation of mental fatigue during professional tournaments.

Integrating video tracking and GPS to quantify accelerations and decelerations in elite soccer.

The aim of this study was to analyze the degree of agreement comparing number and distance covered in different acceleration and deceleration sections registered by a video tracking system (MEDIACOACH) and a GPS device (WIMU PRO) during official competition. Data from a Spanish professional club were registered over the course of a season. First, the descriptive statistics presented more bursts of accelerations and decelerations in WIMU PRO than in MEDIACOACH, whereas the distances covered recorded by both systems were similar. Second, negative relationships were found (i.e., negative bias) comparing WIMU PRO to MEDIACOACH in the number of accelerations and decelerations between 0/1 m/s2 and ½ m/s2 (p < 0.05), and in the distances covered in accelerations and decelerations (p < 0.05) between 0/1 m/s2 and in accelerations and decelerations registered between 2/3 m/s2 and more than 3 m/s2. Moreover, the differences in means (i.e., standardized mean bias) across the two devices were trivial (> 0.19) and small (0.2-0.59) for most variables. The standardized typical errors in the estimate (TEE) were moderate (0.3-0.59) and small to moderate (0.1-0.29 to 0.3-0.59), respectively. Also, the Intra class Correlation Coefficients (ICCs) for agreement and consistency between systems showed good and excellent values (> 0.90). The magnitude of change in means (%) between systems, defined as the percentage change between the numbers or values, was below 14% and 7% for number and distances covered, respectively. All scores in the smallest worthwhile change were lower than 9% and in the coefficients of variation were lower than 95% and 15%, respectively. Thus, both systems demonstrated an acceptable degree of agreement and could be useful in analyzing players' acceleration demands in professional soccer. However, caution is required when interpreting the results and a comparison with a gold standard is required in order to validate both systems.

The Relationship between Students' Physical Self-Concept and Their Physical Activity Levels and Sedentary Behavior: The Role of Students' Motivation.

This study aimed to analyze the association between specific dimension (i.e., fitness, appearance, physical competence, physical strength, and self-esteem) of students' physical self-concept (PSC) and their physical activity (PA) levels (i.e., intentions to be physically active and out-of-school PA levels perceived by students) and sedentary behavior (SB) (i.e., total sitting and screen time perceived by students). We also tested the role of students' motivation (i.e., intrinsic motivation and amotivation) towards PA in these relationships. A total of 1998 Spanish male (n = 1003) and female (n = 995) secondary students, aged between 13 and 17 years (M = 14.92, SD = 0.87) from 22 schools, enrolled in third grade (n = 1081) and fourth grade (n = 917), completed the self-reported questionnaires. Five independent structural equation modeling (SEM) adjusted by students' sex was used to examine the association between specific dimension of students' PSC (i.e., fitness, appearance, physical competence, physical strength, and self-esteem) and self-reported PA and SB variables, and to test the role of students' motivation in these relationships. Overall, most of students' PSC dimension positively predicted students' PA outcomes, and were negatively associated with SB. In addition, most of students' PSC dimension were positively associated with intrinsic motivation, and negatively predicted amotivation. In turn, intrinsic motivation was a positive predictor of PA outcomes, and a negative predictor of SB, whereas amotivation was a negative predictor of PA outcomes and sitting time, and a positive predictor of screen time. Finally, from PSC dimensions, sex as a covariate was a positive predictor of intrinsic motivation and PA outcomes, and was a negative predictor of amotivation and sitting time. These findings suggest the importance of the specific dimensions of PSC perceived by adolescents on their motivational processes, and in turn, on their PA and SB outcomes.