Mindfulness Training, Mental Fatigue, Neurocognitive Functions and Sport Performance

Effect of Mindfulness Training on Inhibitory Control and Endurance Performance in Mentally Fatigued Athletes: An Event-Related Potential Study

Mental fatigue has been suggested that would impair neurocognitive functions and sports performance. On the other hand, mindfulness training (MT) seems to as a promising approach to attenuate mental fatigue and counteract its detrimental effect on cognitive functions and sports performance. The purpose of the present study is to examine the effect of MT on behavioral and neuroelectric indices of inhibitory control, and endurance performance in mentally fatigued athletes.

Accumulating research indicates that mental fatigue induced by prolonged cognitive tasks would impair neurocognitive functions and sports performance. Additionally, recent studies demonstrate that inhibitory control and endurance performance are significantly susceptible to detrimental effects of mental fatigue. On the other hand, mindfulness training (MT) has been widely been used to enhance cognitive functions and sports performance in neurocognitive and sports research, which has been considered a promising approach for attenuating mental fatigue and counteracting the detrimental effect of mental fatigue. However, the effect of MT on inhibitory control, endurance performance, and underlying mechanisms in mentally fatigued athletes remain unclear. Therefore, the purpose of the present study is to examine the effect of MT on behavioral and neuroelectric indices of inhibitory control, and endurance performance in mentally fatigued athletes. Specifically, the targeted primary outcomes are neurocognitive functions (i.e., reaction time, accuracy and ERPs in Flanker task) and endurance performance (i.e., VO2max & time to exhaustion); The secondary outcomes are changes in dispositional mindfulness, subjective (i.e., scores in visual analog scale)/objective (i.e., reaction time, accuracy in Stroop task) mental fatigue, motivation in tasks, and changes in mood state (i.e., BRUMS-C).

Participants in the mindfulness training (MT) group will engage in a 60-min session of mindfulness program per week for 8 weeks.

Participants in the waitlist control group will be required to maintain regular life and routine training. Once the participants in control group finished the whole experiment, they will be invited to participate in the MBPP program for eight weeks.

The mindfulness program called "Mindfulness-based peak performance (MBPP)" will be used in this study. MBPP is a program that consists of eight 60-min training, and a 60-min session weekly for 8-weeks. The MBPP program will include (1) 5 minutes of will start with a brief recap of the preceding session and homework discussion, (2) after which the 5 minutes of a brief story about performance aimed at inducing the learning motivation of the participants; (3) Followed by 20 minutes of a theoretical lecture introducing a new topic and then (4) 25 minutes of mindfulness exercise. (5) Finally, how to apply the mindfulness skills to sports context will be discussed at the end of each session for 5 minutes.

Followed by the manipulation conditions, inhibitory control will be evaluated by a Flanker task (i.e., either mental fatigue condition or control condition). In the Flanker task, participants will be presented with five arrows and will be instructed to respond as quickly and accurately as possible to the direction where the middle arrow is pointing (i.e., left or right). Types of trials are the congruent (i.e., > > > > >) and incongruent (i.e., < < > < <). The reaction time and accuracy in Flanker task will be calculated as inhibitory control performance.

The graded exercise test (GXT) on treadmill (h/p/cosmos pulsar 3p, Germany) will be used to assess participant's endurance performance (i.e., VO2max and exhaustion time). Bruce protocol will be adopted in the test. The initial speed and grade of the GXT will be set at 2.74 km/hr with grade of 10% and increases speed and grade every 3 min until participants are voluntarily exhausted. Maximum oxygen consumption (VO2max) and time to exhaustion (TTE) will be recorded from test results.

The neuroelectrical activities during the cognitive tasks (i.e., Stroop task, Flanker task) will be recorded and analyzed using the Neuroscan system. Changes in the neuroelectrical activities from baseline to end of the intervention (i.e., week 8) will be examined in each conditions (i.e., mental fatigue condition & control condition).

Both in the baseline and post-intervention, the visual analog scale for mental fatigue (VAS-MF) will be used to assess changes in subjective mental fatigue before and after two separate experimental conditions, including mental fatigue condition (i.e., 30-min of incongruent version Stroop task) and control condition (i.e., 30-min of congruent version Stroop task).

Both in the baseline and post-intervention, participants will complete either a 30-min incongruent version Stroop task or 30-min congruent version Stroop task, the reaction time and accuracy in both Stroop tasks will be calculated as an index of objective mental fatigue.

The changes in dispositional mindfulness will be assessed using the 16-items (5-Likert scale) athlete mindfulness questionnaire (AMQ). Higher mean scores indicates a higher levels of dispositional mindfulness. Changes in mindfulness scores from baseline to end of intervention will be examined.

The change in mood state before and after manipulation conditions will be assessed using the Brunel mood scale-Chinese (BRUMS-C), which contains 23 items and divided into six respective sub-scales such as anger, confusion, depression, fatigue, tension, and vigour.

During the graded exercise test, the perception of effort will be asked at beginning and every 2.5-min using Borg 6 to 20 scale, until the participant comes to voluntary exhaustion.

Inclusion Criteria: Regular sports training at least 4 hours weekly Normal or corrected-to-normal vision Right-handed Exclusion Criteria: Physical limitation or injury in lower limbs before and during the study Diagnosed or self-reported neurological disorders (e.g., epilepsy) Diagnosed or self-reported major psychiatric illness (e.g., major depression, schizophrenia) Major previous experience with mindfulness training