Mental Fatigue Effects on Posture and Spinal Reflexes

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

Interventions

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.

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.

Sponsors & Collaborators

• Vrije Universiteit Brussel

  collaborator OTHER

• University of Franche-Comté

  collaborator OTHER

• Izmir Bakircay University

  lead OTHER

Principal Investigators

• Bart Roelands, Professor · Vrije Universiteit Brussel

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

SINGLE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

35 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2026-07-01

Primary Completion

2026-09-01

Completion

2026-12-01

Countries

• Belgium

Study Locations