Effects of Mental Fatigue on Inhibitory Control and Endurance Performance in Athletes With Different Levels of Dispositional Mindfulness: An Event-Related Potential Study
Phase: NA
Conditions: Mental Fatigue
Sponsor: National Taiwan Normal University

The Association between Trait Mindfulness and Mental Fatigue-Related Neurocognitive 
Function and Endurance Performance in Athletes 
 
NTC: NCT05466136 
Date: June 3, 2023 
 
Aim 
The present study aims to examine whether trait mindfulness in athletes is associated 
with impairments in neurocognitive function and endurance performance resulting from 
mental fatigue. It was hypothesized that following the mental fatigue manipulation, athletes 
with higher trait mindfulness would exhibit fewer impairments in neurocognitive function 
and endurance performance, report lower mental fatigue, higher task motivation and fewer 
mood disturbances. Furthermore, it was hypothesized that athletes with higher trait 
mindfulness would exhibit superior neurocognitive function and endurance performance 
across both experimental sessions. 
 
Methods 
Design and Sample 
The participants visited the lab on two counterbalanced order occasions to complete 
either an incongruent version Stroop task (mental fatigue condition, MF) or a congruent 
version Stroop task (control condition, CON) for 30 minutes to induce the mental fatigue 
state. Ninety athletes aged 18 to 25 years were recruited and categorized into higher trait 
mindfulness (HM, n = 27), intermediate trait mindfulness (IM, n = 35), and lower trait 
mindfulness (LM, n = 28).  
 
Procedure 
Participants completed the two sessions using a counterbalanced design, in which the 
Stroop task was administered for MF and a CON. Following Stroop task, behavioral and 
neuroelectric outcomes of neurocognitive function were measured using Flanker task with 
electroencephalography recording. Endurance performance outcomes were measured using 
the graded exercise test. Task motivation and mood states were assessed as secondary 
outcome. 
 
Statistical Analysis Plan 
The Statistical Package for the Social Sciences for mac version 26 (SPSS Inc., Chicago, 
IL, USA) was used to conduct all statistical analyses. All data are presented as means with 
standard errors of the mean (M ± SEM). No missing data were identified. Initial data screening 
identified eight univariate outliers exceeding ± 3.29 standard deviations from the mean. These 
outliers were adjusted by assigning a value one unit above or below the next most extreme 
value in the distribution. Data distribution was ascertained using Kolmogorov-Smirnov’s test, 
and Greenhouse-Geisser correction was applied when the assumption of sphericity was 
violated. To test for group differences in baseline characteristics, a one-way analysis of 
variance (ANOVA) was utilized for continuous variables, whereas a chi-square test was used 
for categorical variables.  
For the manipulation check, a mixed-design 3 (Mindfulness Level: HM vs. IM vs. LM) × 
2 (Manipulation: MF vs. CON) × 3 (Assessment Time: T0 vs. T1 vs. T2) ANOVA was used to 
examine changes in subjective mental fatigue (i.e., VAS-MF) among the three mindfulness 
levels following the experimental manipulation and Flanker task. Additionally, another mixed-
design 3 (Mindfulness Level: HM vs. IM vs. LM) × 2 (Manipulation: MF vs. CON) × 5 (Block: 
B1, B2, B3, B4, B5) ANOVA was conducted to compare changes in objective mental fatigue 

(i.e., SCWT accuracy) across Stroop blocks among the three mindfulness levels.  
For the neurocognitive function, multiple mixed-design 3 (Mindfulness Level: HM vs. IM 
vs. LM) × 2 (Manipulation: MF vs. CON) × 2 (Congruency: congruent vs. incongruent) 
ANOVAs were conducted separately to examine the difference in behavioral outcomes (i.e., 
reaction time and accuracy) and neuroelectric outcomes (i.e., the averaged mean amplitudes 
for N2 and P3) in Flanker task among the three mindfulness levels following the experimental 
manipulation.  
For the endurance performance, separate mixed-design 3 (Mindfulness Level: HM vs. IM 
vs. LM) × 2 (Manipulation: MF vs. CON) ANOVAs were conducted to examine the difference 
in TTE and VO2peak in GXT. Given that person-situation fit may influence the effects of 
mental fatigue, sport discipline was included as a covariate in the endurance performance 
analyses, dummy coded into six categories to contro NCT05466136 l for its potential impact. 
Finally, a mixed-design 3 (Mindfulness Level: HM vs. IM vs. LM) × 2 (Manipulation: MF vs. 
CON) ANOVA was conducted to examine the difference in task motivation (i.e., VAS-M) 
during Flanker task and GXT among the three mindfulness levels.  
For the mood state, a mixed 3 (Mindfulness Level: HM vs. IM vs. LM) × 2 (Manipulation: 
MF vs. CON) × 2 (Assessment Time: T0 vs. T1) ANOVAs were conducted to examine the 
changes in BRUMS subscales among the three mindfulness levels following the experimental 
manipulation. All statistical analyses were conducted with ⍺ = 0.05. The Bonferroni correction 
for multiple comparisons was applied when main effects and interactions were significant, and 
partial eta-squared (η2p) was reported as an estimate of effect size in all ANOVA analyses. 
 
Abbreviations: HM = higher trait mindfulness; IM = intermediate trait mindfulness; LM = 
lower trait mindfulness; MF = mental fatigue session; CON = control session; T0 = baseline; 
T1 = after manipulation; T2 = after Flanker task; VAS-MF = visual analogue scale for 
subjective mental fatigue; B1-B5 = block 1 to block 5; SCWT = Stroop Color and Word Test; 
VAS-M = visual analogue scale for motivation; GXT = graded exercise test; TTE = time to 
exhaustion.