MENTAL FATIGUE DOES NOT AFFECT HEART RATE RECOVERY BUT IMPAIRS PERFORMANCE IN HANDBALL PLAYERS

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.

Interindividual Variability in Mental Fatigue-Related Impairments in Endurance Performance: A Systematic Review and Multiple Meta-regression

BACKGROUND

The negative effect of mental fatigue (MF) on physical performance has recently been questioned. One reason behind this could lie in the interindividual differences in MF-susceptibility and the individual features influencing them. However, the range of individual differences in mental fatigue-susceptibility is not known, and there is no clear consensus on which individual features could be responsible for these differences.

OBJECTIVE

To give an overview of interindividual differences in the effects of MF on whole-body endurance performance, and individual features influencing this effect.

METHODS

The review was registered on the PROSPERO database (CRD42022293242). PubMed, Web of Science, SPORTDiscus and PsycINFO were searched until the 16th of June 2022 for studies detailing the effect of MF on dynamic maximal whole-body endurance performance. Studies needed to include healthy participants, describe at least one individual feature in participant characteristics, and apply at least one manipulation check. The Cochrane crossover risk of bias tool was used to assess risk of bias. The meta-analysis and regression were conducted in R.

RESULTS

Twenty-eight studies were included, with 23 added to the meta-analysis. Overall risk of bias of the included studies was high, with only three presenting an unclear or low rating. The meta-analysis shows the effect of MF on endurance performance was on average slightly negative (g = - 0.32, [95% CI - 0.46; - 0.18], p < 0.001). The multiple meta-regression showed no significant influences of the included features (i.e. age, sex, body mass index and physical fitness level) on MF-susceptibility.

CONCLUSIONS

The present review confirmed the negative impact of MF on endurance performance. However, no individual features influencing MF-susceptibility were identified. This can partially be explained by the multiple methodological limitations such as underreporting of participant characteristics, lack of standardization across studies, and the restricted inclusion of potentially relevant variables. Future research should include a rigorous description of multiple different individual features (e.g., performance level, diet, etc.) to further elucidate MF mechanisms.

Burnout Syndrome in Selectable Athletes for the Brazilian Handball Team-Children Category

To investigate the presence of burnout syndrome in child athlete tryouts for the Brazilian Handball Team, before and after the National Development and Technical Improvement Camp is of great interest. A correlational study, with longitudinal design of the before-and-after type, carried out with 64 male athletes in the children's category, immersed in the National Camp for Development and Improvement of Handball Technique, in the municipality of São Bernardo do Campo, São Paulo, Brazil, in December 2018. To evaluate burnout syndrome, we used the Athlete Burnout Questionnaire (ABQ). There was a statistically significant increase of the mean scores for burnout and dimensions (Physical and Emotional Exhaustion = 1.5 to 1.6; p-value < 0.001; Reduced Sense of Accomplishment = 2.7 to 2.9; p-value < 0.001; Sports Devaluation = 1.4 to 1.6; p-value < 0.001; and General Burnout = 1.9 to 2.0; p-value < 0.001). The athletes selected for the national team had lower mean scores for general burnout and dimensions (Physical and Emotional Exhaustion = 1.5; Reduced Sense of Accomplishment = 2.7; Sports Devaluation = 1.5; General Burnout = 1.9). The National Camp for Development and Technical Improvement can have a negative impact on the mental health of athletes. This event is important to select the competitors with greater ability to face the pressure and adversities present in the sport environment.

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.

Mindfulness-Based Interventions for the Recovery of Mental Fatigue: A Systematic Review

Background: There is evidence that mindfulness-based interventions (MBI) can help one to recover from mental fatigue (MF). Although the strength model of self-control explains the processes underlying MF and the model of mindfulness and de-automatization explains how mindfulness training promotes adaptive self-regulation leading to the recovery of MF, a systematic overview detailing the effects of MBI on the recovery of MF is still lacking. Thus, this systematic review aims to discuss the influences of MBI on the recovery of MF. Methods: We used five databases, namely, PubMed, Web of Science, EBSCOhost, Scopus, and China National Knowledge Infrastructure (CNKI) for articles published up to 24 September 2021, using a combination of keywords related to MBI and MF. Results: Eight articles fulfilled all the eligibility criteria and were included in this review. The MBI directly attenuated MF and positively affected the recovery of psychology (attention, aggression and mind-wandering) and sports performance (handgrip, plank exercise and basketball free throw) under MF. However, the interaction did not reach statistical significance for the plank exercise. Therefore, the experience and duration of mindfulness are necessary factors for the success of MBI. Conclusions: mindfulness appears to be most related to a reduction in MF. Future research should focus on improving the methodological rigor of MBI to confirm these results and on identifying facets of mindfulness that are most effective for attenuating MF.

Negative Effects of Mental Fatigue on Performance in the Yo-Yo Test, Loughborough Soccer Passing and Shooting Tests: A Meta-Analysis

We aimed to examine the effects of mental fatigue on the Yo-Yo test and Loughborough soccer passing and shooting tests performance using a meta-analysis. The search for studies was performed through eight bibliographic databases (Academic Search Elite, AUSPORT, Cochrane Library, PsycInfo, PubMed/MEDLINE, Scopus, SPORTDiscus, and Web of Science). The methodological quality of the included studies was assessed using the PEDro checklist. A random-effects meta-analysis was performed for data analysis. After reviewing 599 search results, seven studies with a total of ten groups were included in the review. All studies were classified as being of good methodological quality. Mental fatigue reduced the distance covered in the Yo-Yo test (Cohen's d: -0.49; 95% confidence interval [CI]: -0.66, -0.32). In the Loughborough soccer passing test, mental fatigue increased the original time needed to complete the test (Cohen's d: -0.24; 95% CI: -0.46, -0.03), increased penalty time (Cohen's d: -0.39; 95% CI: -0.46, -0.31), and decreased performance time (Cohen's d: -0.52; 95% CI: -0.80, -0.24). In the Loughborough soccer shooting test, mental fatigue decreased points per shot (Cohen's d: -0.37; 95% CI: -0.70, -0.04) and shot speed (Cohen's d: -0.35; 95% CI: -0.64, -0.06). Overall, the findings presented in this review demonstrated that mental fatigue negatively impacts endurance-based running performance as well as soccer passing and shooting skills.

No Effects of Mental Fatigue and Cerebral Stimulation on Physical Performance of Master Swimmers

Background: Mental fatigue is a psychobiological state caused by extended periods of cognitive effort, and evidence suggests that mentally fatigued athletes present impaired physical performance. Different ergogenic aids have been proposed to counteract the deleterious effects of mental fatigue, but whether brain stimulation can counteract mental fatigue is still unknown. This scenario is even more obscure considering the effects of these interventions (mental fatigue induction and brain stimulation) in a very experienced population consisting of master athletes.

Method: Ten master swimmers (30 ± 6 years old and 14 ± 8 years of experience) participated in the study. They underwent four experimental conditions before an 800-m freestyle test: mental fatigue with brain stimulation; mental fatigue without brain stimulation; absence of mental fatigue with brain stimulation; and absence of mental fatigue and no brain stimulation. Mental fatigue was induced by a cognitively demanding Stroop Color Test, whereas stimulation was applied on the temporal cortex. After that, the athletes swan 800 m as fast as possible and provided their ratings of perceived exertion (RPE) every 200 m.

Results: Mental fatigue was effectively induced, as evidenced by a greater fatigue perception and more errors in the last blocks of the cognitive task. Mental fatigue induction did not influence performance (time to complete the swimming trial) and RPE. Similarly, brain stimulation failed to change these two parameters, regardless of mental fatigue induction.

Conclusion: The prolonged physical performance of experienced master athletes is not influenced, under the present conditions, by mental fatigue induction, cerebral stimulation, and their association.

Effect of mental fatigue on performance, perceptual and physiological responses in orienteering athletes

BACKGROUND

Mental fatigue seems to impair the athletes' performance; however, in sports with high cognitive demand, such as orienteering, this negative effect could be attenuated during the race. Therefore, this study investigated mental fatigue effect on performance, perceptual, and physiological responses in orienteers.

METHODS

Fifteen male orienteers (30±8 years) participated in the study. Two conditions of cognitive tasks preceded the orienteering performance, performed randomly: 30 minutes of mental exertion (experimental condition [EXP]) by Stroop task, or 30 min without mental exertion (control condition [CON]). Orienteering performance was determined by the time required to perform the Orienteering race. The perceived recovery and motivation were evaluated in each condition, pre-cognitive task, and heart rate during the task. Perceived exertion (RPE) was measured pre- and post-orienteering race. Orienteering performance and perceived performance were measured immediately after the race.

RESULTS

Orienteering performance and remain variables showed no significant differences between conditions (EXP versus CON) (P>0.05). Although a slight increase in performance-time was found in EXP (40.8±11.4 min) versus CON (38.4±13 min) (P=0.4; ES=0.20). RPE increase post-EXP (P<0.05; ES=0.96) but not post-orienteering race (P>0.05).

CONCLUSIONS

Thirty minutes of the cognitive task did not significantly affect the perceptual and physiological responses but demonstrates the addition of 2.4 minutes to orienteering performance. Orienteers may cope with mental effort due to the cognitive demands and physical conditions required in orienteering.

MENTAL FATIGUE IN SOCCER: A SYSTEMATIC REVIEW

ABSTRACT Fatigue in soccer players is traditionally investigated based on neuromuscular and metabolic factors. However, given that soccer is one of the sports that has the highest cognitive demand, it is believed that players' performance might also be influenced by the high levels of attention, and frequent decision-making required in soccer. This systematic review aimed to verify the effects of mental fatigue on physical, technical, tactical and cognitive performance of soccer players. We searched in the electronic databases Pubmed, Web of Science and Scopus, for articles published up to 30 April 2018. We included articles that used a protocol of mental fatigue through cognitive tasks performed prior to a physical or cognitive task related to soccer. Only studies that presented an experimental design with the control condition (without mental fatigue) and the experimental condition (with mental fatigue) were selected. A total of six articles met the inclusion criteria, one study by backward reference search and other through the authors' indication. The results showed smaller distances covered in physical tests, while the effects of mental fatigue on physical performance in small-sided games were not clear. In technical tests, there were more penalties in passes and less accuracy and speed when kicking the ball when players were in conditions of mental fatigue. Regarding the tactical variables, it was found that mental fatigue had a detrimental effect on the synchronization between team players and on individual tactical performance in defensive actions. In cognitive tests, based on video recordings of game play, negative effects on the players' speed and accuracy of decision-making were observed. According to the results of the literature search, it can be inferred that mental fatigue is a factor that has a negative influence on soccer performance. Level of evidence II; Systematic review.