Mental Fatigue Effects on Posture and Spinal Reflexes

June 15, 2026 updated by: Gürsu Sayar, Izmir Bakircay University

Effects of Mental Fatigue on Posture and Spinal Reflexes Modulations

This randomized crossover study investigates the effects of mental fatigue on postural control and spinal reflex excitability in healthy physically active adults aged 18-35 years. Participants will complete two experimental conditions: a mentally fatiguing Stroop task and a control condition involving passive documentary watching, separated by at least 48 hours. Postural control will be assessed using force plate measures of center of pressure displacement during bipedal and unipedal stance, with and without concurrent cognitive dual-tasking. In parallel, spinal reflex excitability will be evaluated using H-reflex recordings from the triceps surae muscles across sitting and standing postures.

The primary aim is to determine whether mental fatigue increases postural sway, particularly in more challenging balance conditions such as single-leg stance. The secondary aim is to examine whether mental fatigue alters the normal modulation of spinal reflex excitability across progressively demanding postural tasks. Additional biomechanical and neuromuscular measures, including EMG activity and hip kinematics, will be recorded to provide insight into underlying control mechanisms.

The study will include approximately 26 participants, with each serving as their own control. Data will contribute to understanding how cognitive fatigue influences balance control and spinal-level neuromuscular regulation.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

26

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Healthy participants aged between 18 and 35 years
  • Recreational active

Exclusion Criteria:

  • Previous major lower limb injury (last 6 months)
  • Present neurological or musculoskeletal disorders
  • Involvement in another concurrent physical or cognitive intervention study

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Control Condition
Participants watch a 60-minute neutral documentary of their choice. This condition is designed to control for time, visual input, and arousal without inducing mental fatigue. Postural control and spinal reflex excitability are assessed immediately before and after the task.
Behavioral: Control Condition
Participants watch a 60-minute neutral documentary of their choice. This condition is designed to match the mental fatigue intervention in duration and general sensory engagement without inducing cognitive fatigue. No cognitive task performance is required. Subjective mental fatigue is assessed at equivalent time points using a visual analogue scale.
Experimental: Mental Fatigue Condition
Participants complete a 60-minute computerized Stroop task designed to induce mental fatigue. The task involves continuous performance of color-word interference trials adjusted to individual capacity. Postural control and spinal reflex excitability are assessed immediately before and after the task.
Behavioral: Mental Fatigue Induction
Participants complete a 60-minute computerized Stroop color-word task designed to induce mental fatigue. The task consists of repeated incongruent stimuli requiring rapid and accurate responses, with difficulty individualized based on a prior maximal Stroop performance test. Performance (reaction time and accuracy) is continuously recorded. Subjective mental fatigue is assessed intermittently during the task using a visual analogue scale.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Center of Pressure (CoP) Displacement (Postural Sway)
Time Frame: Pre-intervention and immediately post-intervention (each experimental session)
Postural sway will be assessed using center of pressure (CoP) displacement area and oscillation parameters measured during bipedal and unipedal stance on a force plate. Higher values indicate greater postural instability. Comparisons will be made between mental fatigue and control conditions, pre- and post-intervention.
Pre-intervention and immediately post-intervention (each experimental session)
Subjective Mental Fatigue
Time Frame: During intervention (every 15 minutes) and immediately post-intervention
Subjective mental fatigue will be assessed using a visual analog scale (VAS) ranging from 0 (no fatigue) to 100 (extreme fatigue).
During intervention (every 15 minutes) and immediately post-intervention

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Spinal Reflex Excitability (H-reflex Modulation)
Time Frame: Pre-intervention and immediately post-intervention across sitting, bipedal stance, and unipedal stance conditions
Spinal reflex excitability will be assessed using H-reflex amplitude (H50 and Hmax), normalized to maximal M-wave (Mmax), recorded from the triceps surae muscles (soleus, medial gastrocnemius, lateral gastrocnemius) during sitting, bipedal stance, and unipedal stance. Changes will be compared between mental fatigue and control conditions.
Pre-intervention and immediately post-intervention across sitting, bipedal stance, and unipedal stance conditions
Surface Electromyography (EMG) Activity of Postural Muscles
Time Frame: Continuous recording during postural tasks, pre-intervention and immediately post-intervention (each condition)
Muscle activation will be assessed using root mean square (RMS) electromyography (EMG) activity recorded from the soleus, medial gastrocnemius, lateral gastrocnemius, tibialis anterior, vastus medialis, and multifidus muscles, normalized to maximal M-wave (MMAX).
Continuous recording during postural tasks, pre-intervention and immediately post-intervention (each condition)
Hip / Leg Movement (IMU Angular Velocity)
Time Frame: Pre-intervention and immediately post-intervention during bipedal and unipedal stance
Hip and leg movements will be assessed using inertial measurement unit (IMU) sensors placed at the proximal femoral epicondyle. Outcome is the resultant angular velocity across movement axes during postural tasks.
Pre-intervention and immediately post-intervention during bipedal and unipedal stance

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Izmir Bakircay University

Collaborators

Vrije Universiteit Brussel
University of Franche-Comté

Investigators

  • Study Director: Bart Roelands, Professor, Vrije Universiteit Brussel

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

July 1, 2026

Primary Completion (Estimated)

September 1, 2026

Study Completion (Estimated)

December 1, 2026

Study Registration Dates

First Submitted

June 11, 2026

First Submitted That Met QC Criteria

June 15, 2026

First Posted (Actual)

June 16, 2026

Study Record Updates

Last Update Posted (Actual)

June 16, 2026

Last Update Submitted That Met QC Criteria

June 15, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • MFspinal

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be shared. Due to the sensitive nature of physiological and health-related data and GDPR restrictions, data access will be limited to the study investigators. De-identified aggregated results will be reported in publications.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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