Mental Fatigue Effects on Posture and Spinal Reflexes

NCT07650903 | Not Yet Recruiting

• 1 other identifier: MFspinal
• Study Type: interventional
• Target: 26
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Mental Fatigue

Keywords

Postural control; Center of pressure; Spinal reflex excitability; H-reflex; Stroop task; Electromyography

Outcome Measures

Primary Outcomes (2)

• Center of Pressure (CoP) Displacement (Postural Sway)

  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

  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 Outcomes (3)

• Spinal Reflex Excitability (H-reflex Modulation)

  Pre-intervention and immediately post-intervention across sitting, bipedal stance, and unipedal stance conditions

• Surface Electromyography (EMG) Activity of Postural Muscles

  Continuous recording during postural tasks, pre-intervention and immediately post-intervention (each condition)

• Hip / Leg Movement (IMU Angular Velocity)

  Pre-intervention and immediately post-intervention during bipedal and unipedal stance

Study Arms (2)

Control Condition

EXPERIMENTAL

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

Mental Fatigue Condition

EXPERIMENTAL

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

Interventions

Mental Fatigue Induction BEHAVIORAL

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.

Mental Fatigue Condition

Control Condition BEHAVIORAL

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.

Control Condition

Eligibility Criteria

• Age: 18 Years - 35 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

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

You may not qualify if:

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

Sponsors & Collaborators

• Izmir Bakircay University: lead
• Vrije Universiteit Brussel: collaborator
• University of Franche-Comté: collaborator

Study Sites (1)

Vrije Universiteit Brussel

Brussels, Pleinlaan 2, 1050, Belgium

Location

MeSH Terms

Conditions

Mental Fatigue

Condition Hierarchy (Ancestors)

Fatigue; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Behavioral Symptoms; Behavior

Study Officials

• Bart Roelands, Professor

  Vrije Universiteit Brussel

  STUDY DIRECTOR

Central Study Contacts

Sidney Grosprêtre, PhD

CONTACT

+32 (0)2 629 22 22; sidney.grospretre@univ-fcomte.fr

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: MSc. PT

Model Details: Randomized crossover design in which each participant completes both a mental fatigue condition and a control condition in counterbalanced order, separated by a washout period of at least 48 hours. Participants serve as their own control, and outcomes are measured pre- and post-intervention under identical testing conditions.

Study Record Dates

• First Submitted: June 11, 2026
• First Posted: June 16, 2026
• Study Start: July 1, 2026
• Primary Completion (Estimated): September 1, 2026
• Study Completion (Estimated): December 1, 2026
• Last Updated: June 16, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share

Locations

BE (1)