Can mental fatigue affect perception of barbell velocity in resistance training?

Perception of Velocity (PV) is the ability to estimate single repetition velocity during resistance training (RT) exercises. The main purpose of the study was to evaluate the effects of Mental Fatigue (MF) on the accuracy of barbell PV. The secondary aims were to evaluate whether MF affected RT performance and ratings of perceived exertion (RPE; OMNI-RES) in the back squat. Twenty-four (14 Females, 10 Males) resistance-trained participants underwent 2 familiarization sessions and 1RM test for the back squat. In two separate sessions, PV was tested for light, medium, and heavy loads in 2 conditions in random order: at rest (REST) and in MF condition (POST-MF) induced by previous incongruent Stroop color-word task. MF and Motivation were assessed through visual analog scales (VAS; 0-100) before and after the Stroop task. For each load subjects performed 2 repetitions and reported the RPE value. Mean propulsive velocity (Vr) of the barbell was recorded with a linear encoder, while the perceived velocity (Vp) of the subjects was self-reported using the Squat-PV scale. The PV accuracy was calculated through the delta score (ds: Vp-Vr). Following the Stroop task MF increased significantly (p < 0.001; F (1, 23) = 52.572), while motivation decreased (p < 0.05; F (1, 23) = 7.401). Ds, Vr, and RPE did not show significant differences between conditions (p > 0.05) for the three loads analyzed. MF induced by previous demanding cognitive task did not affect PV accuracy. Furthermore, subjects maintained unchanged both RT performance and RPE values associated with each load, even when mentally fatigued.

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.

Mental Fatigue Impairs Second Serve Accuracy in Tennis Players.

Purpose: The aim of this 2-week randomized, counterbalance and crossover study was to investigate the effect of acute mental fatigue (MF) on tennis serve performance and accuracy in tennis players. Methods: Ten male tennis players (18 ± 4 years, 1.80 ± 0.08 m; 71 ± 13 kg) were randomized to either the MF group (N = 5) that underwent an acute MF protocol or to a control (CON) group (N = 5). The MF condition consisted in a 30-min modified Stroop color word task performed before on-court serve speed test. A visual analogue scale (VAS) was used to assess the perceptions of MF and motivation toward the upcoming technical tests. Results: Reduction over baseline score of Stroop test was noted in accuracy (N < .001), but not in reaction time (N = .968) in the MF group. Increments in perceived workload were detected (N < .001) in MF group compared to CON. No differences for first and second serve speed from deuce and advantage side were observed. Increment of percentage of failed second serves from the deuce side (N = .043) in MF were detected. Conclusions: An acute MF protocol reduced tennis serve accuracy from deuce side in male tennis players. Players should avoid cognitive efforts before training sessions and matches to prevent negative effects of their technical performance.

The impact of sprint, middle-distance, and long-distance orienteering races on perceived mental fatigue in national level orienteers.

Experiencing mental fatigue (MF) before an orienteering race can lead to a slower completion time. This study aimed to explore the changes in perceived MF, mood and other psychological responses during an orienteering competition. Sixteen national level orienteering athletes (20.8 ± 4.9 years) provided informed consent and completed the online surveys, before and immediately after each race, and 24- and 48-hours post competition (48POST). This study measured MF, physical fatigue, stress, tiredness and motivation using 0-100 Visual Analogue Scale, and the mood was assessed using The Brunel Mood Scale (BRUMS). A moderate to large increase in MF (ES = 0.93 [0.54 to 1.31]), BRUMS fatigue (ES = 0.61 [0.3 to 0.92]), and PF (ES = 1.21 [0.81 to 1.61]) was reported following orienteering races. A small increase in tiredness and BRUMS confusion, and a small decrease in motivation, stress and BRUMS vigour was also reported. There was a delay in recovering from the MF elicited by competition, with a small increase in MF (ES = 0.54 [0.08 to 1.15]) at 48POST compared to the pre-competition value. This study found that orienteers experience MF during competition and have a delayed recovery that can last up to two days after the competition.

Mental fatigue and technical performance in elite rugby league.

The aims of this study were to determine the impact of elite rugby league competition on mental fatigue; and to investigate how mental fatigue influenced in-match technical performance. Twenty elite male rugby league players recorded their pre- and post-game subjective mental fatigue and had their technical performance analysed during matches across one competition season. Metrics were created to assess in-match technical performance and described the percentage of positive, neutral, and negative involvements for each player, while accounting for the context and difficulty of each involvement. Self-reported mental fatigue increased from pre-game to post-game (maximum a posteriori estimation [MAP] = 33.1, 95% high-density interval [HDI] = 26.9-39.8), with backs reporting higher changes in mental fatigue than forwards (MAP = 18.0, 95% HDI = 9.7-26.9). Larger increases in mental fatigue from pre-game to post-game were negatively associated with the adjusted percentage of positive involvements metric (MAP = -2.1, 95% HDI = -5.6 to 1.1). Elite rugby league players reported increased mental fatigue following competitive games, with backs reporting a greater increase than forwards. Mental fatigue impacted technical performance, whereby participants had a lower percentage of positive involvements when they reported being more mentally fatigued.

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.

International orienteering experts' consensus on the definition, development, cause, impact and methods to reduce mental fatigue in orienteering: A Delphi study.

Orienteering is an outdoor activity wherein participants use a map and compass to locate control points and choose the quickest path to the next control point in a natural environment. Attentional focus, rapid decision-making, and high aerobic fitness may influence orienteering performance. Therefore, this research aimed to seek international orienteering expert consensus regarding the definition, development, causes, influences and methods to reduce mental fatigue (MF) in orienteering based on practical experience. Following ethical approval, a three-round Delphi survey was conducted online with twenty-four orienteering coaches and athletes (or former athletes) from 10 different countries with international orienteering competition experience. The threshold of consensus was ≥ 70% agreement among respondents. The experts agreed that MF exists in daily life and orienteering with a substantial negative effect on their conscious decision-making performance and psychological responses. The experts disagreed that the form of MF that athletes experienced in orienteering training are similar to the competition. However, there was no agreement that MF would impact endurance and high-speed running performance during orienteering. This research refines the definition of MF and summarises the distinctions in what causes MF in orienteering training and competition, implying that MF should be addressed separately.

Proof-of-Concept and Test-Retest Reliability Study of Psychological and Physiological Variables of the Mental Fatigue Paradigm.

This study provided a proof-of-concept and test-retest reliability of measures frequently used to assess a mental fatigue paradigm. After familiarization, 28 healthy men performed (40-min) the Rapid Visual Information Processing (RVP) test in a test-retest design, having mental fatigue sensation, motivation, emotional arousal, total mood disturbance, and electroencephalography (EEG) in the prefrontal cortex measured before and after the test. EEG was recorded during a 3-min rest so that the power spectral density of theta (3-7 Hz) and alpha (8-13 Hz) bands was calculated. Pre-to-post RVP test changes in psychological and physiological domains were compared (paired-T tests), and absolute (standard error of measurement (SEM) and minimal difference (MD)) and relative reliability (intraclass correlation coefficient (ICC)) were calculated. The RVP test induced an increase (p < 0.05) in mental fatigue sensation (120.9% (109.4; 132.4)) and total mood disturbance (3.5% (-6.3; 13.3)), and a decrease in motivation (-7.1% (-9.2; -5.1)) and emotional arousal (-16.2% (-19.1; -13.2)). Likewise, EEG theta (59.1% (33.2; 85.0); p < 0.05), but not alpha band, increased due to RVP test. All psychophysiological responses showed poor-to-moderate relative reliability. Changes in mental fatigue sensation and motivation were higher than SEM and MD, but changes in EEG theta band were higher only than SEM. Mental fatigue sensation, motivation, and EEG theta band were sensitive to distinguish a mental fatigue paradigm despite true mental fatigue effects on theta activity may be trivial.

Investigating the Effects of Mental Fatigue on Resistance Exercise Performance.

Mental fatigue can impart negative effects on subsequent physical performance, although the mechanisms underlying these effects are not well understood. This study examined whether mental fatigue confers negative carryover effects on the performance of a set of biceps curls, while also investigating physiological and psychological mechanisms proposed to explain the predicted effect. A randomized, cross-over design was employed. On visit 1, participants (N = 10) performed a barbell biceps curl one-repetition maximum (1RM) test. On visits 2-3, participants performed 20 biceps curls at 50% of their 1RM, followed by their respective 10 min experimental manipulation (high vs. low cognitive exertion) and then a second set of biceps curls to exhaustion. Ratings of perceived exertion and electromyography of the biceps brachii, triceps brachii, upper trapezius, thoracic erector spinae and lumbar erector spinae were recorded during the physical task. The total number of repetitions completed was similar across the conditions. Results also failed to show between-condition differences for muscle activation and perceptions of exertion. Future research is needed to build an adequate knowledge base to determine whether there is an effect of mental fatigue on dynamic resistance-based task performance and, if so, identify the mechanisms explaining how and why.

Effects of mental fatigue on soccer-specific performance in young players.

OBJECTIVE: To investigate the effects of mental fatigue on soccer-specific physical and technical performance in young players. METHODS: Twelve under-14 (U14), twelve under-16 (U16) and twelve under-18 (U18) soccer players completed the two parts of the investigation. Part one assessed the soccer-specific physical performance using the Yo-Yo Intermittent Recovery Test, Level 1 (Yo-Yo IR1). Part two assessed the soccer-specific technical performance using the Loughborough Soccer Passing and Shooting Tests (LSPT, LSST). Each part was preceded by 30 min of Stroop task or 15 min of control task performed in a randomised and counterbalanced order. RESULTS: Subjective ratings of mental fatigue were higher after the Stroop task compared to the control in U14, U16 and U18 in both parts. Mental fatigue significantly reduced Yo-Yo IR1 distance, alongside an increase in heart rate and ratings of perceived exertion, and this effect was moderated by age as older players showed greater declines in performance. Soccer-specific technical performance was negatively affected by mental fatigue condition only in U18 in the LSPT..

Validation of the Multidimensional Fatigue Inventory with Coronary Artery Disease Patients.

BACKGROUND: Fatigue is a common distressing symptom in patients with coronary artery disease (CAD). The Multidimensional Fatigue Inventory (MFI) is used for measuring fatigue in various clinical settings. Nevertheless, its multidimensional structure has not been consistent across studies. Thus, we aimed to psychometrically evaluate the MFI in patients with CAD. METHODS: In sum, 1162 CAD patients completed questionnaires assessing their subjective fatigue level (MFI-20), mental distress symptoms (HADS, STAI), and health-related quality of life (SF-36). Participants also completed exercise capacity (EC) testing. RESULTS: Confirmatory factor analysis of the four-factor model, showed acceptable fit (CFI = 0.905; GFI = 0.895; NFI = 0.893, RMSEA = 0.077). After eliminating four items, confirmatory factor analysis testing showed improvement in the four-factor model of the MFI-16 (CFI = 0.910; GFI = 0.909; NFI = 0.898, RMSEA = 0.077). Internal consistency values were adequate for the total score and four MFI-16 subscales: General fatigue, physical fatigue, reduced activity, and mental fatigue with Cronbach's α range: 0.60-0.82. The inadequate value (Cronbach's α = 0.43) was received for the subscale of reduced motivation in both MFI-20 and MFI-16. Correlations between the MFI-16 and HADS, STAI, SF-36, and EC measures were statistically significant (all p's < 0.001). CONCLUSIONS: The Lithuanian version of the modified MFI of 16 items showed good factorial structure and satisfactory psychometric characteristics, except for reduced motivation subscale.

Mental Fatigue, But Not other Fatigue Characteristics, as a Candidate Feature of Obsessive Compulsive Personality Disorder in Patients with Anxiety and Mood Disorders-An Exploratory Study.

BACKGROUND: Obsessive compulsive personality disorder (OCPD) is commonly associated with anxiety and mood disorders (AMDs), in which fatigue and executive dysfunction represent key symptoms. Executive dysfunction has also been demonstrated in subjects with OCPD, and is additionally found to be a cardinal feature of fatigue. This study aimed to investigate the associations between fatigue, executive dysfunction, and OCPD in patients with AMDs. METHODS: In this cross-sectional study, 85 AMD patients (78% females, mean age 39 ± 11 years) were evaluated for OCPD traits by using the observer-rated Compulsive Personality Assessment Scale. The Multidimensional Fatigue Inventory-20 was used to measure different aspects of fatigue, and the Trail Making Test was employed to assess executive functioning. The Hamilton rating scales were used to evaluate anxiety and depression symptoms. RESULTS: Controlling for potential confounders, there was a significant link between OCPD and mental fatigue (OR, 1.27; 95% CI, 1.02 to 1.58; p = 0.033). No associations were found between the presence of OCPD and other relevant fatigue characteristics, including general fatigue, physical fatigue, reduced activity, and reduced motivation, as well as executive functions. CONCLUSIONS: To the best of our knowledge, this study is the first to report associations between OCPD and mental fatigue in patients with AMDs, suggesting mental fatigue as a clinically important symptom when considering particular personality pathologies.

The Acute Effect of Mental Fatigue on Badminton Performance in Elite Players.

PURPOSE: Several studies have examined the effect of MF on sport performance, but no studies have been conducted on badminton performance. The purpose of the present study was to examine the acute effect of mental fatigue (MF) on badminton performance in elite players. METHODS: In total, 19 elite Danish badminton players completed 2 test days in randomized order, separated by 48 h. On day 1, to elicit MF, a 60-min incongruent Stroop task was performed. On day 2, 60 min of an emotionally neutral documentary was used for the control condition. After either condition, subjects performed a badminton-specific test (BST) where performance time was measured, as well as countermovement-jump height, heart rate, rating of perceived exertion, and lactate. Psychological questionnaires were answered under both conditions. RESULTS: Subjects were significantly more mentally fatigued (P = .002) after the Stroop intervention than in the control. No differences between conditions were detected in the BST (control 32.43 [1.96] vs MF 32.43 [2.36] s; P = .99, Student t test). In addition, no effect of condition (P = .64), time (P = .14), or condition × time (P = .87) was found (2-way analysis of variance). Furthermore, no differences in heart rate, countermovement jump, or rating of perceived exertion were observed between conditions. Lactate showed no effect of condition (P = .46). CONCLUSION: Despite being more mentally fatigued after the Stroop test than in the control condition, performance was not negatively affected during a BST. In addition, no differences in physiological measures were observed.

Are Individuals Who Engage in More Frequent Self-Regulation Less Susceptible to Mental Fatigue?

The aim of this study was to investigate whether individuals who engage in more frequent self-regulation are less susceptible to mental fatigue. Occupational cognitive demand and participation in sports or exercise were quantified as activities requiring self-regulation. Cardiorespiratory fitness was also assessed. On separate occasions, participants either completed 90 min of an incongruent Stroop task (mental exertion condition) or watched a 90-min documentary (control condition). Participants then completed a cycling time-to-exhaustion (physical endurance) test. There was no difference in the mean time to exhaustion between conditions, although individual responses varied. Occupational cognitive demand, participation in sports or exercise, and cardiorespiratory fitness predicted the change in endurance performance (p = .026, adjusted R2 = .279). Only cognitive demand added significantly to the prediction (p = .024). Participants who reported higher levels of occupational cognitive demand better maintained endurance performance following mental exertion.

Associations between daily-on-the job hassles with perceived mental exertion and depression symptoms in taxi drivers.

INTRODUCTION: Taxi drivers experience frequent hassles that may contribute to mental exertion and depression symptoms. AIM: Mental exertion and depression symptoms in taxi drivers are explored in association with hassles, effort-reward imbalance, job strain, and iso-strain. METHODS: Personal interviews were conducted with 130 drivers in San Francisco. RESULTS: Mental exertion averaged 4.5 (±2.68) and physical exertion averaged 3.71 (±2.1) on 0 to 10 Borg scales. Based on the Center for Epidemiological Studies-Depression scale, 38% had depression symptoms. Mental exertion and depression symptoms correlated with job strain, iso-strain and effort-reward imbalance in anticipated directions, lending construct validity to the Borg mental exertion scale. Physical exertion, night shift, stressful personal events, and being uninsured for healthcare predicted mental exertion. Lack of respect by dispatchers and stressful personal events predicted depression symptoms. CONCLUSION: Selected hassles may be remedied by communication trainings, emphasizing mutual respect. Recognition and treatment of depression in taxi drivers are important.

The Effect of Mental Fatigue on Cognitive and Aerobic Performance in Adolescent Active Endurance Athletes: Insights from a Randomized Counterbalanced, Cross-Over Trial.

The aim of this randomized counterbalanced, 2 × 2 cross-over study was to investigate the effects of mental fatigue on cognitive and aerobic performance in adolescent active endurance athletes. Ten active male endurance athletes (age = 16 ± 1.05 years, height = 1.62 ± 0.54 m, body mass = 55.5 ± 4.2 kg) were familiarized to all experimental procedures on day 1. On days 2 and 3, participants provided a rating of mental fatigue before and after completing a 30 min Stroop test that measures selective attention capacity and skills and their processing speed ability (mentally fatigued condition), or a 30 min control condition in a randomized counterbalanced order. They then performed d2 test and a 20 m multistage fitness test (MSFT), which was used to measure selective and sustained attention and visual scanning speed (i.e., concentration performance (CP) and total number of errors (E)) and aerobic fitness (i.e., maximum oxygen uptake (VO2max) and velocity at which VO2max occurs (vVO2max)), respectively. Rating of perceived exertion (RPE) was assessed after a MSFT. Subjective ratings of mental fatigue were higher after the Stroop task (p < 0.001). CP (p = 0.0.1), E (p < 0.001), vVO2max (p = 0.020), and estimated VO2max (p = 0.021) values were negatively affected by mental fatigue. RPE were significantly higher in the mentally fatigued than in the control conditions (p = 0.02) post-MSFT. Mental fatigue impairs aerobic and cognitive performance in active male endurance athletes.

Mental fatigue does not alter performance or neuromuscular fatigue development during self-paced exercise in recreationally trained cyclists.

PURPOSE: The purpose of this study was to investigate the effects of mental fatigue, characterized by a subjective feeling of tiredness, on the development of neuromuscular fatigue during a 4-km cycling time trial (4-km TT). METHODS: Eight recreationally trained male cyclists performed a 4-km TT after either performing a prolonged cognitive task (mental fatigue) or after viewing emotionally neutral documentaries (control). The neuromuscular function of the knee extensors was assessed using electrical nerve stimulation at baseline, before (pre-TT), and after (post-TT) the 4-km TT. Rating of perceived exertion (RPE) and physiological variables were periodically measured during 4-km TT. RESULTS: Subjective ratings of fatigue increased significantly only after a prolonged cognitive task (P = 0.022). Neuromuscular function at baseline was similar between conditions and remained unchanged at pre-TT. Time to complete the 4-km TT was similar between control (376 ± 27 s) and mental fatigue (376 ± 26 s). There was no significant difference between conditions for RPE, [Formula: see text], [Formula: see text], and HR throughout the exercise. The 4-km TT-induced similar decrease (from baseline to post-TT) in maximal voluntary contraction (mental fatigue - 11 ± 10%, control - 16 ± 12%), twitch force (mental fatigue - 26 ± 16%, control - 24 ± 17%), and voluntary activation (mental fatigue - 5 ± 7%, control - 3 ± 2%) for both conditions. CONCLUSION: Mental fatigue induced by prolonged cognitive task does not impair performance nor alter the degree of central and peripheral fatigue development during self-paced exercise in recreationally trained cyclists.

Psychosocial work factors and low back pain in taxi drivers.

INTRODUCTION: Taxi drivers are at high risk for low back pain (LBP). AIM: Identify the association between psychosocial-work factors (Job strain, Iso-strain, effort-reward imbalance [ERI], unfairness, and mental exertion) and LBP in taxi drivers. METHODS: A cross-sectional study was done with 129 taxi drivers. RESULTS: Approximately 63% reported LBP in the prior 12 months. Chi square or t-test analyses identified the associations between demographic, work, health, and psychosocial work factors, and self-report of LBP in the prior 12 months. Depression, perceived physical exertion, dispatcher and manager support, unfair treatment at work, and unfair treatment due to nationality were significantly associated with LBP in bivariate analyses. Multivariate logistic regression was done to identify the predictors of LBP. High dispatcher support remained the sole significant predictor for lower prevalence of LBP (OR = 0.66, P = 0.017). CONCLUSION: Greater understanding of psychosocial work factors may aid in developing interventions to prevent LBP in taxi drivers.

Monitoring Alpha Oscillations and Pupil Dilation across a Performance-Intensity Function.

Listening to degraded speech can be challenging and requires a continuous investment of cognitive resources, which is more challenging for those with hearing loss. However, while alpha power (8-12 Hz) and pupil dilation have been suggested as objective correlates of listening effort, it is not clear whether they assess the same cognitive processes involved, or other sensory and/or neurophysiological mechanisms that are associated with the task. Therefore, the aim of this study is to compare alpha power and pupil dilation during a sentence recognition task in 15 randomized levels of noise (-7 to +7 dB SNR) using highly intelligible (16 channel vocoded) and moderately intelligible (6 channel vocoded) speech. Twenty young normal-hearing adults participated in the study, however, due to extraneous noise, data from only 16 (10 females, 6 males; aged 19-28 years) was used in the Electroencephalography (EEG) analysis and 10 in the pupil analysis. Behavioral testing of perceived effort and speech performance was assessed at 3 fixed SNRs per participant and was comparable to sentence recognition performance assessed in the physiological test session for both 16- and 6-channel vocoded sentences. Results showed a significant interaction between channel vocoding for both the alpha power and the pupil size changes. While both measures significantly decreased with more positive SNRs for the 16-channel vocoding, this was not observed with the 6-channel vocoding. The results of this study suggest that these measures may encode different processes involved in speech perception, which show similar trends for highly intelligible speech, but diverge for more spectrally degraded speech. The results to date suggest that these objective correlates of listening effort, and the cognitive processes involved in listening effort, are not yet sufficiently well understood to be used within a clinical setting.

Mental fatigue induced by prolonged self-regulation does not exacerbate central fatigue during subsequent whole-body endurance exercise.

It has been shown that the mental fatigue induced by prolonged self-regulation increases perception of effort and reduces performance during subsequent endurance exercise. However, the physiological mechanisms underlying these negative effects of mental fatigue are unclear. The primary aim of this study was to test the hypothesis that mental fatigue exacerbates central fatigue induced by whole-body endurance exercise. Twelve subjects performed 30 min of either an incongruent Stroop task to induce a condition of mental fatigue or a congruent Stroop task (control condition) in a random and counterbalanced order. Both cognitive tasks (CTs) were followed by a whole-body endurance task (ET) consisting of 6 min of cycling exercise at 80% of peak power output measured during a preliminary incremental test. Neuromuscular function of the knee extensors was assessed before and after CT, and after ET. Rating of perceived exertion (RPE) was measured during ET. Both CTs did not induce any decrease in maximal voluntary contraction (MVC) torque (p = 0.194). During ET, mentally fatigued subjects reported higher RPE (mental fatigue 13.9 ± 3.0, control 13.3 ± 3.2, p = 0.044). ET induced a similar decrease in MVC torque (mental fatigue -17 ± 15%, control -15 ± 11%, p = 0.001), maximal voluntary activation level (mental fatigue -6 ± 9%, control -6 ± 7%, p = 0.013) and resting twitch (mental fatigue -30 ± 14%, control -32 ± 10%, p < 0.001) in both conditions. These findings reject our hypothesis and confirm previous findings that mental fatigue does not reduce the capacity of the central nervous system to recruit the working muscles. The negative effect of mental fatigue on perception of effort does not reflect a greater development of either central or peripheral fatigue. Consequently, mentally fatigued subjects are still able to perform maximal exercise, but they are experiencing an altered performance during submaximal exercise due to higher-than-normal perception of effort.