Effects of mental fatigue on passing decision-making performance in professional soccer athletes

The relationship between match-play decision making and fatigue in elite women's water polo: A novel recurrent events approach

Fatigue is anecdotally associated with declines in decision-making performance. This study aimed to examine if the hazard of poor decisions increased over the course of an international water polo match and a tournament. Thirteen female water polo players played six games during the 2022 FINA World Championships, reporting their fatigue before and after each match. Offensive, on-ball actions were judged as either good or poor decisions. A linear mixed model revealed that fatigue was significantly higher post-match compared to pre-match, and on the days of match 5 and 6 compared to the day of match 2 (p < 0.05). A total of 4491 decisions were evaluated, and piece-wise exponential additive models applied for recurrent events analyses were used to model the hazard of poor decisions. There was great variation between matches and teams in how hazard for poor decisions evolved over time. A general increase in hazard throughout match play appeared negligible in scale. Within the tournament, the cumulative hazard of poor decisions did not increase with each match. Thus, despite the development of fatigue, there was no universal increase over time in poor offensive decisions, reinforcing the relevance of also considering other factors that may influence decision-making performance.

Effects of long-term mindfulness meditation training on attentional capacity in professional male fencer athletes

Attention is a crucial cognitive ability for sports performance. The current research aimed to investigate whether long-term mindfulness meditation (MM) intervention enhances male athletes' attentional function and alters the activity of brain regions related to attention. In this experiment, we recruited 47 professional male fencer athletes completed two main trials-an MM trial and a control trial. In MM trial, the participants were provided with 3 sessions/wk (20 min/session) of mindfulness meditation training for 20 weeks. In control trial, the participants were instead assigned a mind-wandering related audio to listen to at that time. In each main trial, the five facets of mindfulness questionnaire (FFMQ), cognitive function (i.e. attention span, attention concentrativeness, attention stability, attentional network, distractibility and attentional blink), salivary cortisol, blood lactate and mental fatigue were measured at baseline (pretest) and after the intervention (posttest). The cerebral oxygenation status was recorded using functional near-infrared spectroscopy(fNIRS) during the cognitive function test. In cognition test, participants' attention span, attention concentrativeness, attention stability, attentional networks on task-relevant information (targets) were better in the MM group, supported by eliciting increased oxygenated haemoglobin (HbO) concentration in the prefrontal cortex of the brain. Conversely, there are no remarkable different of distractibility and attentional blink on task-irrelevant information in the MM group than in the Con group (p > 0.05). Moreover, a lower mental fatigue level and lower salivary cortisol concentration were observed in the MM group than in the Con group after the intervention at posttest. Overall, 20-week MM training interventions after physical training improve attentive capacity and cerebral oxygenation concentration, decrease salivary cortisol concentrations and mental fatigue. The findings suggest that long-term MM training interventions after physical training facilitates focus during competition and improves athletic performance.

Anxiety and inhibitory control play a chain mediating role between compassion fatigue and Internet addiction disorder among nursing staff

Mental health problems among nurses are prevalent and harmful. Nurses worldwide have encountered serious mental health issues. Although fatigue has been proven to lead to substance abuse or addictive behaviors (such as internet addiction), there is a lack of sufficient data on whether there is a connection with compassion fatigue. Compassion fatigue is a common mental health problem in helping professions. Anxiety and inhibitory control have been demonstrated to be associated with internet addiction, but the mediating role between them in the state of compassion fatigue remains to be further explored. Therefore, this study aims to investigate the chain-mediating effect of anxiety and inhibitory control between compassion fatigue and internet addiction in the nurse population. From July to August 2024, a questionnaire survey was conducted using a convenience sampling method in 7 hospitals in Hunan Province, China. A total of 516 front-line clinical nurses were included, among whom 17 were male and 499 were female. Subjective data on compassion fatigue, internet addiction, anxiety, and inhibitory control were collected and analyzed. SPSS 26.0 and its PROCESS macro-plugin were used for data analysis. After controlling for age and gender, compassion fatigue was found to be a significant predictor of internet addiction (β = 0.40, P < 0.001). However, when anxiety and inhibitory control were added, the prediction of compassion fatigue on internet addiction in the nurse population remained significant (β = 0.18, P < 0.001). Eventually, the research results show that compassion fatigue can predict internet addiction through anxiety and inhibitory control. It is recommended that nursing managers provide appropriate emotional interventions for nurses with compassion fatigue or adjust the shift-scheduling and leave system to prevent the occurrence of internet addiction.

Mental fatigue increases perception of effort but does not compromise the inhibitory control of football referees during a match simulation physical task

Executive functioning (EF) in referees is associated with their decision-making during a match and can be affected by mental fatigue (MF), a psychobiological state induced by prolonged periods of cognitive activity or high cognitive demand within a short timeframe. Therefore, the aim of this study was to investigate the impact of MF on EF and the perception of effort during a physical task for football referees. Twelve male professional football referees were recruited (32 ± 7.3 years; 1.75 ± 0.06 cm; 85 ± 13.32 kg; 41.4 ± 5.92 mL kg-1 min-1 VO2max), visiting the laboratory on three occasions: one for characterization and familiarization and two experimental manipulations: high cognitive load (MF) and low cognitive load. After manipulations, they performed a physical task designed to replicate the physical demands of an official match. During the physical task, executive functioning was tested with a reaction time task and the ratings of perceived effort were assessed using subjective scales. The results revealed no effect of MF on response time performance (p = 0.395). However, higher perceptions of effort were observed in the high cognitive load condition (p = 0.018), which may impact physical performance. Despite the alteration in the perception of effort due to mental fatigue, executive function performance of football referees remained unimpaired.

Approaches to inducing mental fatigue: A systematic review and meta-analysis of (neuro)physiologic indices

Mental fatigue is a transient psychophysiological state characterized by impaired cognition and behavior across a range of dynamic contexts. Despite increasing interest in this phenomenon, its (neuro)physiologic representations remain unclear. This systematic review aimed to quantify the range of (neuro)physiologic outcomes and methodologies used to investigate mental fatigue in laboratory-based settings. Across the 72 studies meeting our inclusion criteria, we identified 30 unique physiologic, four visual outcomes, and the application of several neuroimaging techniques investigating neuronal function. Mental fatigue increased heart rate, systolic and diastolic blood pressure, mean arterial pressure, low frequency, and root mean square of successive differences (RMSSD), and reduced standard deviation of normal-to-normal intervals (SDNN) (all P ≤ 0.04) when compared with controls. Applying electroencephalography to investigate delta, theta, and alpha bandwidths may provide useful insights into this phenomenon, and functional near-infra-red spectroscopy to right-lateralized frontoparietal regions would be helpful to investigate cortical activity change in response to mental fatigue. More data are needed across a range of methodological contexts in order to further determine the (neuro)physiological manifestations of mental fatigue. However, this review provides direction to researchers and will assist them in navigating and considering the range of options available.

A, M. P. A narrative review on the role of cognition, nutrition and energy availability in athletes of competitive sports to combat RED-S

Background

In the present scenario, competitive sports require athletes to achieve a phenomenal balance between cognitive abilities, motor skills, nutritional intake, and energy deficiencies. Such stability would enable the athletes to excel in their sporting field. Evidence shows that athletes develop specific cognitive abilities based on their sporting field. Nutrition is vital in creating an athlete's cognitive ability and physical needs required to participate in competitive sports. The reduction in the intake of nutrients required before, after and during sports participation could result in relative energy deficiency in sports (RED-S), affecting the parts of the body.

Methods

The rationale behind the survey is to understand the role of nutrition and energy deficiency on the athletes' cognitive abilities. The review's research areas were identified as athletes' cognition and nutrition in the context of RED-S. Search keywords were found based on the research area, such as "cognitive", "nutrition", and "energy deficiency/availability" in athletes. The search keywords were combined to form search queries (SQs). SQs were used to carry out the search on the Web of Science and Scopus databases.

Results

Sports play an important role in athletes' cognitive abilities, such as decision-making, attention, memory, etc. Nutritional intakes, such as caffeinated, carbohydrate, alkaline, and protein-based supplements and diets, also significantly affect athletes' cognitive and motor abilities. Low energy availability (LEA) causes cognitive and physical health problems in both female and male athletes.

Conclusion

The review identified that nutrition and LEA play crucial roles in athletes' cognitive performance. Deficits in nutritional intake and energy availability lead to RED-S. Hence, cognitive performance could be used as an early indication to identify the nutritional and energy deficits in advance, enabling athletes to combat RED-S.

High tackle headache: implications of referee agreement for tackle height law change

Objectives

Rugby Union has a relatively high risk of injury. Early evidence suggests a benefit of lowering tackle height to reduce head and neck injuries, although concerns persist among stakeholders regarding implementation challenges. This study aimed to understand whether referees can reach the same conclusion regarding tackle height in a controlled environment (ie, video) and whether priming influenced these decisions.

Methods

Forty-eight active referees completed a questionnaire based on high-tackle decision-making guidelines after watching tackles. Participants were randomly assigned one of two instructional videos containing a high or legal tackle to investigate the impact of priming on law interpretation.

Results

The percent agreement regarding tackle height was 78.1% between participants, 62.7% between participants and an experienced analyst, and 74.0% between participants and a gold-standard referee. Mean intra-rater reliability when determining whether a tackle was high was substantial (percent agreement: 91.2%). For high tackles, 83% of participants agreed on the danger level, 57% on the contact location and 71% on the presence of mitigating factors. No significant effects of priming were observed. Inter-rater agreement among participants and the gold-standard referee was moderate for all items except danger and height, which showed strong agreement.

Conclusion

These results suggest a need for improved referee training to support changes to the legal tackle height.

Age-specific effects of a sustained cognitive activity on perceived cognitive fatigue as well as single- and dual-task treadmill walking performance

During their daily lives humans are often confronted with sustained cognitive activities (SCA) leading to state fatigue, a psychobiological state characterized by a decrease in cognitive and/or motor performance and/or an increase in perception of fatigue. It was recently shown that performing SCA can impair overground dual-task gait performance in older adults, but it is currently unknown whether there is a task- and/or age-specific modulation in gait performance during treadmill walking. Therefore, the effect of a SCA on single- and dual-task treadmill walking performance was investigated in young and old adults. Using a crossover design, spatio-temporal gait parameters of 24 young and 23 older healthy participants were measured using motion capturing during single- and dual-task (including three cognitive interference tasks: word list generation, arithmetic, and Stroop-task) treadmill walking before and after SCA (30 min Stroop-task) and a control task (reading). Moreover, cognitive fatigue, wakefulness, mood, and arousal were assessed. Although the SCA induced age-specific perceptual responses, no difference was found for cognitive performance during the Stroop-task. The cognitive interference task performance (word list generation, arithmetic, and Stroop-task) during walking on the treadmill did not decrease after the SCA. Single- and dual-task gait performance (e. g., step width and step length) specifically changed after the SCA and after the reading control task in both groups. Data indicate that perceived cognitive fatigue has an impact on single- and dual-task treadmill walking performance, with task- and age-specific differences. Although no general age-specific changes in single- and dual task gait performance following SCA were identified, perceived cognitive fatigue should be considered as an intrinsic risk factor for falls.

Neuropsychophysiological Aspects of Soccer Performance: A Bibliometric Analysis and Narrative Review

In recent years, there has been growing scientific interest in the neuropsychophysiological aspects of soccer performance. The purpose of this study was to conduct a bibliometric analysis to identify and review key topics within the neuropsychophysiological dimensions of soccer performance and identify any research voids that warrant further attention. We retrieved 192 documents from the Scopus database and anayzed the extracted data using VOSviewer software to conduct a bibliometric analysis. We applied both performance analysis techniques (including the number of documents per year, top 20 authors by citations, and top 15 sources by documents) and science mapping analysis (co-authorship, bibliographic coupling, co-citation, and co-occurrence). The co-occurrence analysis identified three main clusters of research themes. The first cluster focused on the relationship between physical performance and cognitive factors, the second on technical-tactical performance, and the third on health and well-being. Our findings emphasize the significant role of neuropsychophysiological factors in all aspects of soccer performance. We highlight the importance of integrating cognitive and physical training to enhance player performance and underscore the need for further research to deepen our understanding of these relationships.

Mental Fatigue and Sports Performance of Athletes: Theoretical Explanation, Influencing Factors, and Intervention Methods

Mental fatigue is an important factor affecting athletes' performance. Explaining the effects of mental fatigue on sports performance from a theoretical point of view can help us deeply understand the interconnection between mental fatigue and sports performance and conduct effective interventions based on this. Combining the relevant literature in China and abroad reveals that the current academic theories on the mechanism of sports fatigue include motivational control theory, underload theory, neural waste disposal hypothesis, and resource depletion theory. The effects of mental fatigue on performance are reflected in aerobic endurance, sports decision-making, tactical performance, and technical performance. Current coping strategies for mental fatigue include physiological coping strategies based on nutrition (caffeine), odor, and noninvasive neuromodulation techniques and psychological and behavioral coping strategies based on music and positive thinking.

Mental Fatigue in Sport-From Impaired Performance to Increased Injury Risk

The literature describing the effects of mental fatigue (MF) has grown tremendously. This is accompanied by identification of a host of performance-determining parameters affected by MF. MF results from prolonged cognitive effort and predominantly affects physical, technical, tactical, and perceptual-cognitive dimensions of sport, while physiological parameters (eg, heart rate, lactate) and physical aspects of maximal and supramaximal efforts are predominantly unaffected. The aim of this paper was to provide an overview of the parameters described in the literature as influenced by MF. By identifying the different parameters, we not only see how they affect the performance of athletes but also raise concerns about the potentially increased injury risk due to MF. Preliminary evidence suggests that subsequent disturbances in balance, motor skills, and decision-making processes could potentially increase the vulnerability to injury. An abundance of lab-based studies looked into the effects of MF on performance; however, many questions remain about the mechanisms of origin and neurophysiological causes of MF, and only small steps have been taken to translate this knowledge into practice. Thus, there is a need for more research into the underlying mechanisms of MF and the role of the brain, as well as more applied research with a high ecological validity that also takes into account the potential increased risk of injury due to MF.

Caffeine Gum Improves Reaction Time but Reduces Composure Versus Placebo During the Extra-Time Period of Simulated Soccer Match-Play in Male Semiprofessional Players

This study aimed to determine whether caffeine gum influenced perceptual-cognitive and physical performance during the extra-time period of simulated soccer match-play. Semiprofessional male soccer players (n = 12, age: 22 ± 3 years, stature: 1.78 ± 0.06 m, mass: 75 ± 9 kg) performed 120-min soccer-specific exercise on two occasions. In a triple-blind, randomized, crossover design, players chewed caffeinated (200 mg; caffeine) or control (0 mg; placebo) gum for 5 min following 90 min of soccer-specific exercise. Perceptual-cognitive skills (i.e., passing accuracy, reaction time, composure, and adaptability) were assessed using a soccer-specific virtual reality simulator, collected pre- and posttrial. Neuromuscular performance (reactive-strength index, vertical jump height, absolute and relative peak power output, and negative vertical displacement) and sprint performance (15 and 30 m) were measured at pretrial, half-time, 90 min, and posttrial. Caffeine gum attenuated declines in reaction time (pre: 90.8 ± 0.8 AU to post: 90.7 ± 0.8 AU) by a further 4.2% than placebo (pre: 92.1 ± 0.8 AU to post: 88.2 ± 0.8 AU; p < .01). Caffeine gum reduced composure by 4.7% (pre: 69.1 ± 0.8 AU to post: 65.9 ± 0.8 AU) versus placebo (pre: 68.8 ± 0.8 AU to post: 68.3 ± 0.8 AU; p < .01). Caffeine gum did not influence any other variables (p > .05). Where caffeine gum is consumed by players prior to extra-time, reaction time increases but composure may be compromised, and neuromuscular and sprint performance remain unchanged. Future work should assess caffeine gum mixes with substances like L-theanine that promote a relaxed state under stressful conditions.

Dual-Tasks in Soccer: Effects of Players' Experience and Task Condition on Physical Performance

In this study, we examined whether experience level and various dual motor and cognitive or single tasks influenced young soccer players' physical performance during small-sided games. Participants were 72 players from U-13 (n = 36) and U-17 (n = 36) groups who participated in 3-to-a-side small-sided games under four experimental conditions: control, a secondary motor task, an additional related secondary cognitive task, and an additional secondary non-specific task. We used GPS devices to measure physical performance in terms of distances covered and accelerations at different thresholds. We found no significant interaction effect between player experience and task condition (p = .540), meaning that dual tasks had comparable effects on players of different experience levels. There were significant main effects of both experience level (p < .001) and condition (p < .001) on most physically related variables. Older players outperformed younger ones, particularly in high-intensity actions. While secondary motor tasks decreased physical performance, secondary cognitive tasks, irrespective of specificity, did not impair players' performances. In conclusion, experience level did not influence the players' physical response to dual tasks, and a secondary motor task was more disruptive to physical performance than either of two types of secondary cognitive tasks. Cognitive tasks can be incorporated into soccer training without compromising physical performance.

The Influence of the Playing Surface on Workload Response in Spanish Professional Male Soccer Players

This study aimed to quantify the influence of the playing surface on workload-related variables (i.e., external load, Rate of perceived exertion (RPE), and mental load) in training sessions with a Spanish professional soccer team. Twenty professional male players from the same soccer team were involved. A total of thirty training sessions related to the preseason period were included. All the players completed training sessions on three playing surfaces: natural turf of poor quality, natural turf of high quality, and third-generation artificial turf. Monitoring during sessions involved assessing internal load (i.e., RPE and mental load) via self-reported questionnaires, and external load using Global Positioning System devices. Linear mixed models showed that RPE was significantly higher on natural turf of high quality than on natural turf of poor quality (p < 0.001). Total distance, relative total distance, the number of accelerations, decelerations, and high metabolic load distance were significantly lower on third-generation artificial turf compared to natural turf of poor quality (p < 0.001) and high quality (p < 0.001). In addition, high-speed running, sprint running distances, and the number of sprints reached higher values on third-generation artificial turf compared to the other two playing surfaces. These findings highlight the need for coaches to consider the type of training surface in soccer to optimize training load planning and prevent injuries.

Comment on: influence of the time-task constraint on ocular metrics of semi-elite soccer

This letter offers a constructive review of the article 'Influence of the time-task constraint on ocular metrics of semi-elite soccer' by Luis-del Campo et al. (2023), focusing on methodological considerations and avenues for future research enhancement. The study investigates the impact of task constraints on eye-tracking metrics among semi-elite soccer players, aiming to gauge mental workload during training sessions. While the study presents valuable insights, there are opportunities for methodological refinement. Suggestions include emphasizing sample size determination, randomization of the experimental conditions, and employing robust statistical analyses to mitigate potential biases. Moreover, future studies could benefit from integrating external load measures alongside heart rate monitoring to comprehensively assess training task variations. Despite these considerations, the study underscores the promising application of eye-tracking techniques in evaluating mental workload during soccer training, paving the way for further exploration and refinement of methodologies to enhance player performance assessment and training optimization in the field.

The Role of Virtual Reality in the Management of Football Injuries

Injuries represent a serious concern for football players, with a significant loss in terms of sport participation and long periods of rehabilitation. According to the 2019/20 UEFA Élite Club Injury Report, the average incidence of injuries during training is 2.8 per 1000 h of training, with an average absence from training of 20 days. In addition, injured athletes are 4 to 7 times more likely to relapse than uninjured athletes. High workloads and reduced recovery periods represent two of the most important modifiable risk factors. In this context, prevention and an adequate rehabilitation protocol are vital in managing injuries, reducing their incidence, and improving the return to competition. In recent years, technological development has provided new tools in rehabilitation, and Virtual reality (VR) has shown interesting results in treating neurologic and orthopedic pathologies. Virtual Reality (VR) technology finds application in the sports industry as a tool to examine athletes' technical movements. The primary objective is to detect the biomechanical risk factors associated with anterior cruciate ligament injury. Additionally, VR can be used to train athletes in field-specific techniques and create safe and controlled therapeutic environments for post-injury recovery. Moreover, VR offers a customizable approach to treatment based on individual player data. It can be employed for both prevention and rehabilitation, tailoring the rehabilitation and training protocols according to the athletes' specific needs.

The effects of mobile phone dependence on athletic performance and its mechanisms

Mobile phone dependence (also known as internet dependence, MPD), defined as a problematic behavior characterized by excessive use or intermittent craving to use a mobile phone, results in various social, behavioral, and affective problems in daily life. In sports, MPD is directly related to the physical and mental health and sports performance of athletes. The individual and environmental factors, neurobiological mechanisms and theoretical models of MPD affecting athletic performance were analyzed by reviewing previous studies, aiming to construct effective training and development protocols to prevent and control the occurrence of MPD in athletes. At present, athletic performance can be affected by MPD through individual factors and environmental factors. The neurobiological mechanisms between the two are based on the brain reward system and microwave radiation from mobile phones, with athletic performance being restricted by alterations in the corresponding brain regions. Relevant theoretical models mainly include the social cognitive model of self-regulation and the integrative model of self-control, which explain the interrelationship between MPD and athletic performance from the perspectives of athletes' self-regulation and self-control, respectively. As an emerging phenomenon, the influence pathways and mechanisms by which MPD affects athletic performance need to be further investigated. A longitudinal perspective should be adopted to trace the dynamic impact relationship between the two, and developing relevant theoretical frameworks from an interdisciplinary research perspective should be valuable for providing theoretical support for coaches and sports administrators to formulate scientific training protocols and thus improve the mental health of athletes.

Effect of mental fatigue on mean propulsive velocity, countermovement jump, and 100-m and 200-m dash performance in male college sprinters

The objective of this study was to analyze the effect of mental fatigue on mean propulsive velocity (MPV), countermovement jump (CMJ), 100, and 200-m dash performance in college sprinters. A total of 16 male athletes of sprint events (100 and 200-m dash) participated in this study. Each participant underwent two baseline visits and then running under the three experimental conditions. Assessments (MPV and CMJ) occurred both before and after either smartphone use (SMA) or Stroop task (ST), or watching a documentary TV show about the Olympic Games (CON). Then, the athletes ran the simulated race (i.e. the 100 and 200-m dash). There was no condition (p > 0.05) or time effect (p > 0.05) for MPV, CMJ, 100-m, or 200-m dash performance. In conclusion, the present study results revealed no mental fatigue effect induced by SMA or ST on neuromuscular, 100-m or 200-m dash performance in male college sprinters.

Visual perceptual processing is unaffected by cognitive fatigue

Cognitive fatigue (CF) can lead to an increase in the latency of simple reaction time, although the processes involved in this delay are unknown. One potential explanation is that a longer time may be required for sensory processing of relevant stimuli. To investigate this possibility, the current study used a visual inspection time task to measure perceptual processing speed before and after a CF (math and memory) or non-fatiguing (documentary film) intervention. Subjective fatigue and simple reaction time significantly increased following the CF, but not the non-fatiguing intervention, confirming that CF was induced. Conversely, there was no effect of CF on inspection time task performance. It was therefore concluded that the speed of perceptual processing is not significantly impacted by CF, and thus is unlikely to underlie CF-related reaction time increases. Instead, increases in simple reaction time latency in CF may be due to delays in response preparation or initiation.

The effects of mental fatigue on fine motor performance in humans and its neural network connectivity mechanism: a dart throwing study

While it is well known that mental fatigue impairs fine motor performance, the investigation into its neural basis remains scant. Here, we investigate the impact of mental fatigue on fine motor performance and explore its underlying neural network connectivity mechanisms. A total of 24 healthy male university students were recruited and randomly divided into two groups: a mental fatigue group (MF) and a control group (Control). Both groups completed 50 dart throws, while electroencephalography (EEG) data were collected. Following the Stroop intervention, participants in the MF group exhibited a decrease in Stroop task accuracy and throwing performance, and an increase in reaction time along with VAS and NASA scores. The EEG data during dart-throwing revealed that the network connectivity strength of theta oscillations in the frontal and left central regions was significantly higher in the MF group compared with the Control group, while the network connectivity strength of alpha oscillations in the left parietal region was significantly enhanced. The interregional connectivity within the theta and alpha rhythm bands, particularly in the frontal-central-parietal network connections, also showed a significant increase in the MF group. Mental fatigue impairs dart throwing performance and is accompanied by increased connectivity in alpha and theta.

Counteracting mental fatigue for athletes: a systematic review of the interventions

The deleterious effects of mental fatigue (MF) on athletes have been carefully studied in various sports, such as soccer, badminton, and swimming. Even though many researchers have sought ways to ameliorate the negative impact of MF, there is still a lack of studies that review the interventions used to counteract MF among athletes. This review aims to report the current evidence exploring the effects of interventions on MF and sport-specific performance, including sport-specific motor performance and perceptual-cognitive skills. Web of Science, Scopus, PubMed, and SPORTDicus (EBSCOhost) were combed through to find relevant publications. Additionally, the references and Google Scholar were searched for any grey literature. For the current review, we included only randomized controlled trials that involved athletes, a primary task to induce MF, interventions to counter MF with comparable protocols, and the outcomes of sport-specific motor performance and perceptual-cognitive skill. The selection criteria resulted in the inclusion of 10 articles. The manipulations of autonomous self-control exertion, person-fit, nature exposure, mindfulness, and transactional direct current stimulation showed that positive interventions counteract MF and improve sport-specific performance in different domains, including strength, speed, skill, stamina, and perceptual-cognitive skills. The selected interventions could significantly counteract MF and improve subsequent sport-specific performance. Moreover, self-regulation and attention resources showed the importance of the potential mechanisms behind the relevant interventions.

The influence of the perceived requirements of the next match and motivation on the mental fatigue of soccer players

The high cognitive and/or emotional demands of competition can lead to a state of mental fatigue which has shown to be detrimental to soccer performance. However, there is a need to further understand the true mental demands of soccer players. The aim of the present study was to analyze the influence of motivation and the perceived requirements of the next match on mental fatigue perceived by soccer players over the passing of a season. The combined effect of both variables on the perception of mental fatigue, as well as the influence of the time of the season on perceived mental fatigue, were also analyzed. Twenty-six semi-professional Spanish male players (M = 26.31 ± 5.18 years) participated in the present study, conducted during the 2020-2021 season. Perceived mental fatigue and motivation were measured at each training session. The perceived requirements of the next match were also measured in each of the competitive weeks. Linear mixed models were run with R Studio to examine the influence of motivation and the perceived difficulty of the next match on perceived mental fatigue, the combined effect of both variables on perceived mental fatigue, and the influence of the passing of the season on perceived mental fatigue. The results showed a negative and significant influence of motivation on perceived mental fatigue (p < 0.001) and a positive and significant influence of the perceived requirements of the next match on perceived mental fatigue (p < 0.001). Regarding the combined effect, there was a positive and significant effect (p < 0.01) of the perceived difficulty of the next match on the relation between motivation and perceived mental fatigue. A negative influence of season passage on perceived mental fatigue levels was found (p < 0.001). We recommended coaches to consider using the most motivating training tasks when higher next-match requirements are perceived and to be careful with avoidance strategies for mental fatigue, especially at the beginning of the season.

Effects of smartphone use before resistance exercise on inhibitory control, heart rate variability, and countermovement jump

BACKGROUND

The effect of MF induced by exposure time to social media smartphone apps on inhibitory control, heart rate variability (HRV), and high-intensity physical effort following a resistance exercise session might indicate whether strength and conditioning professionals should suggest avoiding smartphone usage before a resistance exercise session.

AIM

The objective of this study was to analyze the effect of mental fatigue on inhibitory control, HRV, and countermovement jump (CMJ) in trained adults after resistance exercise.

METHODS

A total of 16 trained males (21.4 ± 3.3 years) volunteered in this study. The participants performed resistance exercises with and without mental fatigue. The Stroop Task, countermovement jump, and heart rate variability were evaluated before and after the resistance exercise. The participants used smartphones in the mental fatigue condition, whereas the participants watched TV in the control condition.

RESULTS

No condition × time interaction was found for the Stroop accuracy (p = 0.87), CMJ (p = 0.68), SDNN (p = 0.15), or pNN50 (p = 0.15) in the heart rate variability. An interaction was found for Stroop response time (p = 0.01) with a higher response time for the mental fatigue condition (p = 0.01).

CONCLUSIONS

Mental fatigue impaired the inhibitory control performance after a resistance exercise session in trained adults.

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

BACKGROUND

Throughout 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.

PURPOSE

We 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.

METHODS

Twenty 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.

RESULTS

There 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).

CONCLUSION

We 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.

Neuromuscular and perceptual-cognitive response to 4v4 small-sided game in youth soccer players

The physical and psychological load of small-sided games (SSGs) can affect players' neuromuscular and cognitive functions. Yet, little is known about the acute performance changes after such a specific exercise in young soccer players and their association with exercise load applied. This study investigates i) the neuromuscular and perceptual-cognitive response to the SSG exercise load, and ii) the relationship between pre- and post-SSG changes in variables of performance and the respective exercise load in youth soccer players. Sixteen participants (13.6 ± 0.5 years) underwent a 30-min SSG 4v4 + GK protocol. Prior to and after the SSG they performed countermovement jump (CMJ), planned and reactive Y-shaped agility tests (PA, RA), and go/no-go task (GNG). Their subjective perception of fatigue was evaluated by visual analog scale. Fatigue induced by SSG (perception of fatigue increased by 41.56%, p = .001, g = 4.15) increased PA time (4.04%, p = .002, g = .97), RA time (6.45%, p = .003, g = 1.16), and number of errors in the response inhibition task (87.1%, p = .023, rc = .57), whilst decreased CMJ height (-6.65%, p = .014, g = .56). These performance deteriorations were not significantly associated with neither internal nor external load variables. However, a less pronounced drop in performance was related to external load variables, i.e., ∆CMJ height and ∆RA time correlated with very high-speed running (rs = .66, p = .006; rs = -.50, p = .022; respectively) and maximal speed (r = .54, p = .032; r = -.52, p = .037; respectively), whilst ∆PA time was associated with high-intensity accelerations (rs = -.76, p = .002). These findings indicate that fatigue induced by SSG affects both planned and reactive agility, decision-making in response inhibition task, and explosive strength in youth soccer players regardless of significant contribution of any robust internal or external load variables. Nonetheless, high-intensity actions within SSG partially compensate for the decrements in their agility performance and explosive strength. The load variables encountered during SSG do not fully reflect youth players' neuromuscular and perceptual-cognitive responses to sport-specific exercise.

The use of heart rate variability in esports: A systematic review

Heart rate variability (HRV) is a psychophysiological measure of particular interest in esports due to its potential to monitor player self-regulation. This study aimed to systematically review the utilisation of HRV in esports. Consideration was given to the methodological and theoretical underpinnings of previous works to provide recommendations for future research. The protocol was made available on the Open Science Framework. Inclusion criteria were empirical studies, examining HRV in esports, using esports players, published in English. Exclusion criteria were non-peer-reviewed studies, populations with pre-existing clinical illness other than Internet Gaming Disorder (IGD), opinion pieces or review papers. In November 2022 a search of Web of Science, PubMed, and EBSCOHost identified seven studies using HRV in esports. Risk of bias was assessed using the Mixed Methods Appraisal Tool. Narrative review identified two primary uses of HRV in esports; stress response and IGD. A lack of theoretical and methodological underpinning was identified as a major limitation of current literature. Further investigation is necessary before making recommendations regarding the use of HRV in esports. Future research should employ sound theoretical underpinning such as the use of vagally mediated HRV and the robust application of supporting methodological guidelines when investigating HRV in esports.

Head-to-head opponent mitigates mental fatigue effects during a 20-km time trial in well-trained cyclists

We aimed to analyze the effect of a head-to-head virtual race on 20-km time trial performance in well-trained mentally fatigued cyclists. A total of 24 male professional cyclists participated in the present study, which was conducted in a within-factors design [four experimental conditions × four times (throughout 20-km time trial cycling)]. An avatar representing the participant on the racecourse was visible during the time trials. Then, a second virtual avatar representing the opponent was projected onto the screen in the mental fatigue head-to-head and control head-to-head experimental conditions. Measurements [rating of perceived exertion, heart rate, and eye-tracking measures (i.e., pupil diameter)] were performed every 5-km throughout the 20-km time trial. As a result, impaired total time, power output, and cadence throughout the 20-km cycling time trial were found for mental fatigue compared to mental fatigue head-to-head, control head-to-head, and control conditions (p < 0.05). Also, impaired 20-km time trial performance (total time, power output, and cadence) was found for mental fatigue head-to-head compared to control head-to-head (p < 0.05). Moreover, lower RPE was found for the control and control head-to-head conditions than mental fatigue head-to-head and mental fatigue experimental conditions (p < 0.05). Higher pupil diameter was also found for mental fatigue head-to-head, control head-to-head, and control than the mental fatigue experimental condition (p < 0.05). In summary, the overall performance throughout the 20-km cycling time trial was improved by the presence of a virtual opponent for the mentally fatigued cyclists.

Understanding mental fatigue and its detection: a comparative analysis of assessments and tools

Mental fatigue has shown to be one of the root causes of decreased productivity and overall cognitive performance, by decreasing an individual's ability to inhibit responses, process information and concentrate. The effects of mental fatigue have led to occupational errors and motorway accidents. Early detection of mental fatigue can prevent the escalation of symptoms that may lead to chronic fatigue syndrome and other disorders. To date, in clinical settings, the assessment of mental fatigue and stress is done through self-reported questionnaires. The validity of these questionnaires is questionable, as they are highly subjective measurement tools and are not immune to response biases. This review examines the wider presence of mental fatigue in the general population and critically compares its various detection techniques (i.e., self-reporting questionnaires, heart rate variability, salivary cortisol levels, electroencephalogram, and saccadic eye movements). The ability of these detection tools to assess inhibition responses (which are sensitive enough to be manifested in a fatigue state) is specifically evaluated for a reliable marker in identifying mentally fatigued individuals. In laboratory settings, antisaccade tasks have been long used to assess inhibitory control and this technique can potentially serve as the most promising assessment tool to objectively detect mental fatigue. However, more studies need to be conducted in the future to validate and correlate this assessment with other existing measures of mental fatigue detection. This review is intended for, but not limited to, mental health professionals, digital health scientists, vision researchers, and behavioral scientists.

The seven phases of match status differentiate the running performance of soccer players in UEFA Champions League

The purpose of this research was to investigate the running performance of professional soccer players in relation to seven phases which resulted in the changing or maintaining the match status in the UEFA Champion League games during season 2020/2021. Moreover, we aimed to define which match status phases occur at the earliest stage of regular game time. This study involved professional soccer players from 24 teams participating in the group stage of UEFA Champions League in season 2020/21. The match status was divided into seven phases that result in changing or maintaining the match outcome: DW (Drawing to Winning); LD (Losing to Drawing); WW (Winning to Winning); DD (Drawing to Drawing); LL (Losing to Losing); DL (Drawing to Losing); WD (Winning to Drawing). Such running performance variables as: total distance covered (TDC) and distance covered in high-intensity running (HIR) were analyzed. Players participating in the UEFA Champions League matches cover the longest TDC in DW, DL and DD phases. TDC in these stages was between 111 and 123 m min^-1. The highest HIR was recorded during phases: DW, DL and LL (range between 9.91 and 10.82 m min^-1). In contrast, the lowest total distance and distance in HIR is covered during WD phase (only 105.57 ± 1.89 m min^-1 and 7.34 m min^-1 respectively). On average, phases resulting in the change of the match status occur during the first half, while all phases maintaining the result in the second half. Coaching staffs should consider registering and analysing the physical match performance in relation to described seven match status phases. Such information allows to prepare team-specific training drills, that players should perform more often in order to change or maintain the status of the game.

The effects of mental fatigue on sport-specific motor performance among team sport athletes: A systematic scoping review

Background

The psychobiological state known as mental fatigue (MF) is by engaging in mentally taxing activities for an extended period, which is typically found in team sports, of the high cognitive demand and unpredictable environment. It increases the perception of effort and influences executive functions, impairing sport-specific performance in athletes. However, the consequences of MF on sport-specific motor performance (SSMP) among athletes in team sports remain unclear.

Objective

This scoping review seeks to find and map research publications that investigate the effect of MF on SSMP in team sports.

Methods

Web of Science, Scopus, and PubMed were searched as the main databases, and CENTRAL, Psychology, and Behavioral Sciences Collection, SPORTDicus obtained from EBSCOhost, as well as gray literature was searched for relevant literature and Google Scholar. Cognitive tasks before the SSMP exam are the focus of the selected literature on mental exhaustion. Only experiments testing mental and non-mental exhaustion were chosen.

Results

Twelve studies fulfill the requirement of selection criteria. SSMP in team sports, including soccer, basketball, cricket, and Australian football mainly is examined as physical and technical performance. More specifically, MF significantly influenced physical performance measured as intermittent endurance and total distance (P < 0.05), while data was inclusive when assess in an ecological setting (e.g., small-sided game) (P > 0.05). Technical performance was mainly measured as ball loss, errors in passing and shooting, interception, and successful tackle and showed a dramatic impairment (P < 0.05). The decline of physical activity is relevant with higher level PRE, while decreased technical performance is related to impaired attention resources shown as visual perceptual.

Conclusion

MF adversely influences SSMP in team sports. The most relevant theory for future study to examine the impacts of MF on team-sport athletes could be the psychological model of exercise and its potential extension on attention resources, rather than the traditional "catastrophe" theory.

Daytime Napping Benefits Passing Performance and Scanning Activity in Elite Soccer Players

The present study explored the effect of a daytime napping opportunity on scanning activity, which is an essential component of successful soccer performance. Fourteen male elite collegiate soccer players performed the Trail Making Test (TMT), which was used to assess complex visual attention. In addition, a soccer passing test, modified with reference to the Loughborough Soccer Passing Test, was used to evaluate passing performance as well as scanning activity. A cross-over design was applied to examine nap and no-nap interventions. Participants (N = 14, mean age: 21.6 SD = 0.5 years, height: 1.73 ± 0.06 m, body mass: 67.1 ± 4.5 kg) were randomly allocated to a midday nap (40 minutes) or no-nap group. Subjective sleepiness was measured using the Karolinska Sleepiness Scale, and perceptive fatigue was evaluated by the visual analog scale. There were no significant differences in subjective measurements or TMT between the nap and no-nap groups. However, the performance time for the passing test and scanning activity was significantly shorter (p < 0.001) and scanning activity was significantly more frequent in the nap condition than in the no-nap condition (p < 0.00005). These results suggest that daytime napping is beneficial for soccer-related cognitive function, represented by visuospatial processing and decision-making, and particularly as a potential countermeasure to mental fatigue. Considering that inadequate sleep and residual fatigue are commonly observed in elite soccer, this finding may have practical implications for the preparation of players.

Playing videogames or using social media applications on smartphones causes mental fatigue and impairs decision-making performance in amateur boxers

This study aimed to analyze the effect of playing videogames and using social media applications on smartphones on decision-making and countermovement jump (CMJ) performance in amateur boxers. Twenty one boxers were enrolled in the study and were randomly assigned to all three experimental conditions [smartphone (30SMA), videogame (30VID), and control (CON)]. CMJ was measured before and 30-min after each experimental condition. The athletes ran simulated combat recorded for decision-making analysis. The boxers watched coaching videos (CON), used social media applications on smartphones (30SMA), and played video games (30VID) for 30 min just before the combat simulation. Both attack and defense decision-making performance were worse in both 30SMA and 30VID conditions compared to the CON condition (p = 0.001). Regarding CMJ, despite no condition effect (p = 0.96) been obtained, a time effect (p = 0.001) was observed; So, it was found a decrease in CMJ performance after all experimental conditions (p = 0.001), with no difference between them. Using social media applications on smartphones and playing video game impairs decision-making performance in amateur boxers, with no harms for CMJ performance.

Bibliometric analysis of the effects of mental fatigue on athletic performance from 2001 to 2021

Aims

To explore the research hot topics and main contents in the field of the influence of mental fatigue on athletic performance, and to provide new ideas and directions for future research in this field.

Methods

Using CiteSpace and VOSviewer visualization tool software core collection of Web of Science database to TS = ("mental fatigue" OR "mental exertion" OR "cognitive fatigue" OR "Cognitive exertion" OR "mental exhaustion" OR "mental tiredness") AND ("athletic performance" OR "technical skill*" OR "Skill*" OR "technique" OR "decision making" OR "performance") AND ("Humans") searched for the influence of mental fatigue on athletic performance from 2001 to 2021 to conduct visual analysis. Research hot topics were analyzed from the aspects of high-impact countries/regions, institutions, authors, high-frequency keywords, and mutation terms.

Results

A total of 658 publications were identified finally, and there has been an increasing trend in the annual number of publications, with the United States ranking first in the number of publications and influence. Future research will focus on promoting the application of EEG technology as an objective indicator for assessing mental fatigue, exploring effective methods and measures for pharmacological or non-pharmacological interventions against fatigue, and focusing on the effects of mental fatigue on endurance performance, technical skills, and sports-related decision-making.

Conclusion

The results of the present study help us understand the status of the mental fatigue and athletic performance field and its recent developments.

Effects of mentally induced fatigue on balance control: a systematic review

The relationship between cognitive demands and postural control is controversial. Mental fatigue paradigms investigate the attentional requirements of postural control by assessing balance after a prolonged cognitive task. However, a majority of mental fatigue research has focused on cognition and sports performance, leaving balance relatively underexamined. The purpose of this paper was to systematically review the existing literature on mental fatigue and balance control. We conducted a comprehensive search on PubMed and Web of Science databases for studies comparing balance performance pre- to post-mental fatigue or between a mental fatigue and control group. The literature search resulted in ten relevant studies including both volitional (n = 7) and reactive (n = 3) balance measures. Mental fatigue was induced by various cognitive tasks which were completed for 20-90 min prior to balance assessment. Mental fatigue affected both volitional and reactive balance, resulting in increased postural sway, decreased accuracy on volitional tasks, delayed responses to perturbations, and less effective balance recovery responses. These effects could have been mediated by the depletion of attentional resources or impaired sensorimotor perception which delayed appropriate balance-correcting responses. However, the current literature is limited by the number of studies and heterogeneous mental fatigue induction methods. Future studies are needed to confirm these postulations and examine the effects of mental fatigue on different populations and postural tasks. This line of research could be clinically relevant to improve safety in occupational settings where individuals complete extremely long durations of cognitive tasks and for the development of effective fall-assessment and fall-prevention paradigms.

Executive function during exercise is diminished by prolonged cognitive effort in men

The speed and accuracy of decision-making (i.e., executive function (EF) domains) is an integral factor in many sports. At rest, prolonged cognitive load (pCL) impairs reaction time (RT). In contrast, exercise improves RT and EF. We hypothesized that RT and EF during exercise would be diminished by prolonged 'dual tasking' as a consequence of pCL. To test the hypothesis, twenty healthy male participants performed four conditions [resting control (Rest), pCL only (pCL_Rest), exercise only (EX), and pCL + exercise (pCL_EX)] in a randomized-crossover design. Both exercise conditions utilized a 50-min cycling exercise protocol (60% VO₂ peak) and the pCL was achieved via a 50-min colour-word Stroop task (CWST). Compared with Rest, pCL_Rest caused a slowed CWST RT (P < 0.05) and a large SD (i.e., intraindividual variability) of CWST RT (P < 0.01). Similarly, compared with EX, the slowed CWST RT (P < 0.05) and large SD of CWST RT (P < 0.01) were also observed in pCL_EX. Whereas the reverse-Stroop interference was not affected in pCL_Rest (P = 0.46), it was larger (i.e., declined EF) in pCL_EX than EX condition (P < 0.05). These observations provide evidence that the effort of pCL impairs RT and EF even during exercise.

Do executive function performance, gaze behavior, and pupil size change during incremental acute physical exercise?

Several studies have investigated the interaction between acute physical exercise and cognitive performance. However, few studies have investigated this issue during acute high-intensity exercise. In the present study, we evaluated executive functions (EFs) during incremental exercise in three different intensities [below lactate threshold (LT), at LT, and above LT], measuring EFs performance, gaze behavior, and pupil diameter. Twenty subjects were familiarized with the EFs test and participated in a graded maximal exercise test on a cycle ergometer on the first visit. On the second visit, they performed the EFs task at rest and while exercising at three different intensities using mobile eye-tracking glasses. Our results showed that the psychophysiological measures differed between the conditions. Regarding EFs performance, during exercise above LT, the subjects showed worse accuracy when compared with rest (p < .001) and below LT (p < .001). In addition, the response time (RT) at LT and above LT was shorter than in the rest condition (p < .050). Further, RT was faster (p = .002) in the above LT than in the below LT condition. In addition, the gaze behavior measures indicated that exercise, independently of the intensity, improves the number of fixations with shorter fixation durations compared to the rest condition (p < .050). Additionally, we found no significant differences in average and peak pupil diameter between conditions. In conclusion, exercise at LT improves the EFs performance while exercising above LT worsens EFs performance. However, there were no significant differences in average and peak pupil diameter between conditions.

National vs. Non-National Soccer Referee: Physiological, Physical, and Psychological Characteristics

Purpose: The objectives of the present study were to analyze the relationship between psychological variables (self-esteem, anxiety and self-confidence) assessed before the competition and physical and physiological responses demonstrated during the competition in soccer referees and to compare these psychophysical and physiological responses by category (CAT; national and non-national). Method: A total of 153 soccer referees participated (age Mage = 23.2; SD = 4.8 years; experience Mage = 6.0; SD = 4.5 years) in the study. The CSAI-2 and Rosenberg questionnaires were conducted before the match, and match performance data were collected using GPS devices. Results: The results showed significant differences in self-esteem and self-confidence across CATs (p < .001; d > .84). The national referees had higher psychological and physical-physiological responses (mean and maximum heart rate) Some correlations were observed among the psychophysical and physiological responses, CAT and age, demonstrating that the age could explain up to 48.4% of the variance the referee CAT (p < .001) and this CAT could explain self-esteem, anxiety and self-confidence by up to 20% of the variance. Conclusions: national referees presented better psychological responses prior to the competition, and also obtained greater physical and physiological records, which could be translated into a better position on the pitch in conflicting plays in order to make a right and just decision.

A plausible link between the time-on-task effect and the sequential task effect

Mental fatigue can be studied by using either the time-on-task protocol or the sequential task protocol. In the time-on-task protocol, participants perform a long and effortful task and a decrease in performance in this task is generally observed over time. In the sequential task protocol, a first effortful or control task is followed by a second effortful task. The performance in the second task is generally worse after the effortful task than after the control task. The principal aim of the present experiment is to examine the relationship between these two decrements in performance while concomitantly using a sequential task protocol and assessing the performance of the first effortful task as a function of time-on-task. We expect a positive correlation between these two decrements in performance. A total of 83 participants performed a 30-min fatiguing mental task (i.e., a modified Stroop task) or a control task followed by a time-to-exhaustion handgrip task. As expected, this protocol combining the time-on-task and sequential task protocols allowed us to observe (1) a decrease in performance over time during the Stroop task, (2) a worst performance in the handgrip task after the Stroop task by comparison to the control task, (3) a positive correlation between these two effects. The decrease in performance during the Stroop task also correlated with the subjective measures of boredom and fatigue, whereas the detrimental effect observed in the handgrip task did not. Our findings suggest that the two fatigue-related phenomena share a common mechanism but are not completely equivalent.

Nature exposure might be the intervention to improve the self-regulation and skilled performance in mentally fatigue athletes: A narrative review and conceptual framework

Background

Due to causing inability of self-regulation (ego depletion) and executive functions such as directed attention and visual searching for relevant information (e.g., the ball location and the position of teammates), mental fatigue impairs skilled performance in various sports. On the other hand, natural scenes could improve directed attention, which may considerably benefit visual searching ability and self-regulation. However, nature exposure as a potential intervention to improve skilled performance among mentally fatigued athletes has not been discussed thoroughly.

Purpose

To propose the potential intervention for the impairment of skilled performance among mentally fatigued athletes and generate a framework for future studies.

Methods

A narrative review was applied to search broadly across disciplines, retrieving literature from several databases (PubMed, Web of Science, Scopus, and EBSCOhost).

Results

Thirty-three works of literature including 39 experiments (mental fatigue 15; ego depletion 5; and nature exposure 19) were obtained. Finally, a conceptual framework was built regarding the effect of nature exposure intervention on skilled performance in athletes for future studies.

Conclusion

Three theories (the psychobiological model of exercise performance, the strength model of self-regulation, and attention restoration theory) could be potentially integrated to be a conceptual framework and explain the mechanism of preventing prior mental exertion (e.g., mental fatigue and ego depletion). Future studies could examine more on the duration of the intervention.

Gender differences in professional drivers’ fatigue level measured with BAlert mobile app: A psychophysiological, time efficient, accessible, and innovative approach to fatigue management

Addressing fatigue is useful in a variety of scenarios and activities. Fatigue has recently been studied from a psychophysiological standpoint. As a result, the expression and impact of peripheral and central fatigue has been evaluated. Driving is one occupation where tiredness has disastrous consequences. BAlert is a smartphone app that approaches exhaustion with psychophysiological measures. More specifically, it evaluates the level of fatigue via heart rate variability (HRV) data and the cognitive compromise via Stroop effect. The goal of this study is to determine if there are gender differences in fatigue levels among professional drivers using the BAlert app. Statistically significant differences were found in the number of hours awake, in different parameters of HRV (AVNN, PNN50, RMSSD, and SDNN), in the level of stress, as well as in the cognitive response evaluated through the app. The results are discussed and their implications for the management of work fatigue are presented.

Brain Stimulation Over the Motion-Sensitive Midtemporal Area Reduces Deleterious Effects of Mental Fatigue on Perceptual-Cognitive Skills in Basketball Players

The objective of this study was to analyze the effect of anodal transcranial direct current stimulation (a-tDCS) over the motion-sensitive midtemporal area on perceptual-cognitive skills (visuomotor and basketball decision-making skills) in mentally fatigued basketball players. A total of 20 male basketball players were recruited. This was a randomized, double-blinded, and counterbalanced crossover study with two experimental conditions: a-tDCS and Sham. The participants completed the basketball decision-making task and visuomotor skill after performing a 60-min sport-based videogame task with anodal (i.e., a-tDCS) or placebo (Sham) stimulation over the motion-sensitive middle temporal area. Worse response time was observed in visuomotor skill for Sham than a-tDCS postexperiment (p < .05). There was no main condition effect for accuracy of visuomotor skill (p > .05). There was more impairment in accuracy and response time in basketball decision-making skills for the Sham condition than a-tDCS (p < .05). Notably, a-tDCS over the motion-sensitive middle temporal area removed the negative effects of mental fatigue on perceptual-cognitive skills.

Effects of mental fatigue on technical performance in soccer players: A systematic review with a meta-analysis

Background

Mental fatigue largely influences technical performance in soccer, including offensive and defensive skills. However, these effects on technical performance among the soccer players have not yet been aggregated to be assessed systematically.

Objective

The purpose of the review was to evaluate the impact of mental fatigue on soccer players' overall technical skills.

Methods

Drawing on Web of Science, PubMed, Scopus, and EBSCOhost (CENTRAL and SPORTDicus), an in-depth search was conducted. PICOS established the eligibility criteria to select the studies as follows: (i) population-healthy soccer players; (ii) intervention-involving any mental-fatigue-prompted protocol; (iii) comparison-control conditions (active or passive without inducing mental fatigue); (iv) outcomes-technical performance (offensive and defensive skill); and (v) study design-randomized controlled trials.

Results

A total of eight studies were qualified for inclusion in the systematic literature review. Overall, the results indicate that mental fatigue had significant effects on technical skills, including offensive and defensive skills. Specifically, there were significant effects on errors (ES = 0.977; p < 0.001), number of tackles (ES = -0.739; p = 0.005), and the percentage of successful tackles (ES = -0.628; p = 0.022), while there were no significant effects on the number of passes (ES = 0.240; p = 0.328), the percentage of accurate passing (ES = -0.008; p = 0.985), and the number of successful passes (ES = -0.322; p = 0.217).

Conclusion

Overall, a significant effect of mental fatigue on the technical performance (e.g., tackles and errors) of soccer players was detected, while no significant effects on passing skills were detected. Future studies may consider investigating technical performance together with other important results (e.g., decision-making skills or internal load).

Systematic Review Registration

https://inplasy.com/inplasy-2022-2-0008/, Inplasy protocol 202220008.

The Counteractive Effect of Self-Regulation-Based Interventions on Prior Mental Exertion: A Systematic Review of Randomised Controlled Trials

BACKGROUND

Many investigations have been performed on the effects of mental exertion that consumes self-regulatory resources and then affects physical and/or cognitive performance later on. However, the effect of manipulating self-regulation and interventions to attenuate this negative effect remains unclear. Moreover, there is continuous controversy regarding the resource model of self-regulation.

OBJECTIVE

We conducted a systematic review to assess the literature on manipulating self-regulation based on four ingredients (standard, monitoring, strength, and motivation) in order to counter mental exertion and improve physical and/or cognitive performance. The results provide more insight into the resource model.

METHOD

A thorough search was conducted to extract the relevant literature from several databases, as well as Google Scholar, and the sources from the references were included as grey literature. A self-regulation intervention compared to a control condition, a physical and/or cognitive task, and a randomised controlled trial were selected.

RESULT

A total of 39 publications were included. Regarding the four components of self-regulation, the interventions could mainly be divided into the following: (i) standard: implementation intervention; (ii) monitoring: biofeedback and time monitoring; (iii) strength: repeated exercise, mindfulness, nature exposure, and recovery strategies; (iv) motivation: autonomy-supportive and monetary incentives. The majority of the interventions led to significant improvement in subsequent self-regulatory performance. In addition, the resource model of self-regulation and attention-restoration theory were the most frequently used theories and supported relevant interventions.

CONCLUSION

In line with the resource model, manipulating the four components of self-regulation can effectively attenuate the negative influence of mental exertion. The conservation proposed in the strength model of self-regulation was supported in the current findings to explain the role of motivation in the self-regulation process. Future studies can focus on attention as the centre of the metaphorical resource in the model.

Can Self-Regulatory Strength Training Counter Prior Mental Exertion? A Systematic Review of Randomized Controlled Trials

Background

Prior mental exertion consumes self-regulation and influences any subsequent physical or cognitive performance according to the strength model of self-regulation. However, the counteractive effect of self-regulatory strength training remains unclear.

Objective

This study aims to report a comprehensive systematic review investigating self-regulatory strength training programmes on physical or cognitive performance.

Methods

To select relevant studies from the available literature, a thorough search was conducted on PubMed, Web of Science, EBSCOhost (CENTRAL, Psychology and Behavioral Sciences Collection, SPORTDicus), Scopus, and Google Scholar, as well as the sources of reference for gray literature. Only randomized controlled trials involving healthy humans, strength-based self-regulation training programmes with comparable protocols, and a physical or cognitive task associated with the study were selected for the current review. The Grading of Recommendations Assessment Development and Evaluation (GRADE) framework was used to develop the summary of findings.

Results

Twelve articles were included based on the selection criteria. Evidence certainty for outcomes was graded as either low or very low level. The majority of the studies reported that self-regulatory strength training programmes can significantly counter prior mental exertion and decrement of performance, while only one study did not find such improvement. According to the strength model, a period of training increased the ‘self-regulatory muscle.'

Conclusion

Strength is an important ingredient in the resource model of self-regulation and can be trained to counter prior mental exertion and improve subsequent physical and cognitive performance. The training effects are cross-domain (e.g., emotional and cognitive domains; higher and lower levels of executive functions). However, motivation plays a key role to mobilize this resource. Future studies should examine the mechanism that underlies the strength.

Systematic Review Registration

https://inplasy.com/inplasy-2022-1-0060/, identifier: INPLASY202210060.

Non-invasive brain stimulation over the orbital prefrontal cortex maintains endurance performance in mentally fatigued swimmers

BACKGROUND

Using anodal transcranial direct current stimulation (a-tDCS) on frontal brain areas might be a promising strategy to mitigates mental fatigue and maintain endurance performance swimmers.

OBJECTIVE

The objective was to analyze the effect of a-tDCS over the orbital prefrontal cortex (oPFC) on endurance performance of mentally fatigued female amateur swimmer.

METHODS

Nineteen female amateur swimmers participated in this study. In two experimental visits, the swimmers completed the 3-min all-out tethered swimming after performing a 30-min Stroop test with a-tDCS or placebo (Sham) stimulation over the left-oPFC. The brain stimulation conditions (i.e., a-tDCS and Sham) were performed in a double-blinded and counterbalanced order.

RESULTS

It was found lower critical force, mean force, force minimum, fatigue index, and aerobic impulse for Sham than a-tDCS (p < 0.05). There was no main effect of condition for peak force (p >  0.05).

CONCLUSION

We concluded that a-tDCS applied over the left-oPFC in female amateur swimmers mentally fatigued maintained endurance performance. From a practical point of view, the use of a-tDCS should be considered to counteract harmful cognitive effects and maintain endurance performance during competitive race events.

How to Tackle Mental Fatigue: A Systematic Review of Potential Countermeasures and Their Underlying Mechanisms

INTRODUCTION

Mental fatigue (MF) is a psychobiological state that impairs cognitive as well as physical performance in different settings. Recently, numerous studies have sought ways to counteract these negative effects of MF. An overview of the explored countermeasures for MF is, however, lacking.

OBJECTIVES

The objective of this review is to provide an overview of the different MF countermeasures currently explored in literature. Countermeasures were classified by the timing of application (before, during or after the moment of MF) and type of intervention (behavioural, physiological and psychological).

METHODS

The databases of PubMed (MEDLINE), Web of Science and PsycINFO were searched until March 7, 2022. Studies were eligible when MF was induced using a task with a duration of at least 30 min, when they assessed MF markers in at least two out of the three areas wherein MF markers have been defined (i.e., behavioural, subjective and/or [neuro]physiological) and used a placebo or control group for the countermeasure.

RESULTS

A total of 33 studies investigated one or more countermeasures against MF. Of these, eight studies assessed a behavioural countermeasure, 22 a physiological one, one a psychological countermeasure and two a combination of a behavioural and psychological countermeasure. The general finding was that a vast majority of the countermeasures induced a positive effect on behavioural (e.g., task or sport performance) and/or subjective MF markers (e.g., visual analogue scale for MF or alertness). No definitive conclusion could be drawn regarding the effect of the employed countermeasures on (neuro)physiological markers of MF as only 19 of the included studies investigated these measures, and within these a large heterogeneity in the evaluated (neuro)physiological markers was present.

DISCUSSION

Within the physiological countermeasures it seems that the use of odours during a MF task or caffeine before the MF task are the most promising interventions in combating MF. Promising behavioural (e.g., listening to music) and psychological (e.g., extrinsic motivation) countermeasures of MF have also been reported. The most assumed mechanism through which these countermeasures operate is the dopaminergic system. However, this mechanism remains speculative as (neuro)physiological markers of MF have been scarcely evaluated to date.

CONCLUSION

The present systematic review reveals that a wide range of countermeasures have been found to successfully counteract MF on a subjective, (neuro)physiological and/or behavioural level. Of these, caffeine, odours, music and extrinsic motivation are the most evidenced for countering MF. To provide in-detail practical guidelines for the real-life application of MF countermeasures, more research must be performed into the underlying mechanisms and into the optimal dosage and time of application/intake.

Nature Scenes Counter Mental Fatigue-Induced Performance Decrements in Soccer Decision-Making

Background

It has been well investigated that nature exposure intervention can restore directed attention and improve subsequent cognitive performance. The impairment of decision-making skills in mentally fatigued soccer players was attributed to the inability of attention allocation. However, nature exposure as the potential intervention to counter mental fatigue and improve the subsequent decision-making skill in soccer players has never been investigated.

Objects

This study aimed to evaluate the effects of nature exposure intervention on decision-making skills among mentally fatigued university soccer players. Moreover, different durations of nature exposure were also evaluated.

Methods

A random control between-subject design was adopted. Players were randomly assigned into six groups with three different durations of the experimental group compared with the corresponding control group (4.17 min: Exp 1 vs. Con 1; 8.33 min: Exp 2 vs. Con 2; and 12.50 min: Exp 3 vs. Con 3). All players were first mentally fatigued by performing a 45-min Stroop task; then, they viewed virtual photos of natural or urban scenes; and finally, they performed a soccer decision-making task.

Results

The subjective ratings of mental fatigue were significantly higher following the Stroop task. Only Exp 3 (12.50 min viewing natural scenes) significantly improved decision-making reaction time compared with Con 3 (p = 0.09). Moreover, the accuracy slightly increased in Exp 3 after the intervention.

Conclusion

In line with attention restoration theory, nature exposure significantly improved decision-making skills in mentally fatigue university players. However, the duration must be 12.50 min for each stimulus to stay longer to attract involuntary attention.

Training Monitoring in Sports: It Is Time to Embrace Cognitive Demand

Appropriate training burden monitoring is still a challenge for the support staff, athletes, and coaches. Extensive research has been done in recent years that proposes several external and internal indicators. Among all measurements, the importance of cognitive factors has been indicated but has never been really considered in the training monitoring process. While there is strong evidence supporting the use of cognitive demand indicators in cognitive neuroscience, their importance in training monitoring for multiple sports settings must be better emphasized. The aims of this scoping review are to (1) provide an overview of the cognitive demand concept beside the physical demand in training; (2) highlight the current methods for assessing cognitive demand in an applied setting to sports in part through a neuroergonomics approach; (3) show how cognitive demand metrics can be exploited and applied to our better understanding of fatigue, sport injury, overtraining and individual performance capabilities. This review highlights also the potential new ways of brain imaging approaches for monitoring in situ. While assessment of cognitive demand is still in its infancy in sport, it may represent a very fruitful approach if applied with rigorous protocols and deep knowledge of both the neurobehavioral and cognitive aspects. It is time now to consider the cognitive demand to avoid underestimating the total training burden and its management.

The Effect of Acute Caffeine Ingestion on Tactical Performance of Professional Soccer Players

In soccer, physical, tactical, and decision-making processes are highly important facets of successful performance. Caffeine has well established effects for promoting both physical and cognitive performance, but the translation of such benefits specifically for soccer match play is not well established. This study examined the effects of acute caffeine ingestion on tactical performance during small-sided games (SSG) in professional soccer players. Nineteen soccer players (22 ± 4 years) underwent a randomized, counterbalanced, crossover, double-blind placebo-controlled trial. The protocol consisted of 5 bouts of 5-min SSG with 3 players plus a goalkeeper in each team (3 + GK × 3 + GK) with each SSG separated by 1 min rest intervals. Tactical performance was assessed using the system of tactical assessment in soccer (FUT-SAT). Prior to each experimental trial, participants ingested caffeine (5 mg·kg⁻¹) or a placebo 60 min before the protocol. Overall, caffeine ingestion resulted in an increased ball possession time when compared to the placebo. When the offensive and defensive core principles were analyzed, the results were equivocal. Caffeine resulted in positive effects on some tactical decisions during the protocol, but it was deleterious or promoted no observed effect on other of the core tactical principles. Caffeine ingestion resulted in less offensive (during SSG3) and defensive (SSG 2, SSG3, and SSG4) errors. Caffeine ingestion also resulted in higher total offensive success during SSG 1 and SSG2, but it was detrimental during SSG3. Additionally, total defensive success was lower for the caffeine conditions during SSG 2 and SSG5 when compared to the placebo. In conclusion, caffeine influenced aspects of tactical decisions in soccer, resulting in fewer offensive and defensive errors, although it may be deleterious considering other tactical parameters. Future studies may clarify the effects of caffeine ingestion on specific decision-making parameters in soccer.