Health TrialsbyHealthPanel

Mental Fatigue Effects on Posture and Spinal Reflexes

ConditionMental Fatigue
Trial statusNot yet recruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-35
SponsorIzmir Bakircay University

About this trial

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.

Eligibility criteria

This trial accepts healthy volunteers

Qualifiers

Healthy participants aged between 18 and 35 years

Recreational active

Disqualifiers

Previous major lower limb injury (last 6 months)

Present neurological or musculoskeletal disorders

Involvement in another concurrent physical or cognitive intervention study

Trial design

Design model

Crossover

Treatments tested in this trial

  • 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.

  • 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.

Treatment groups

26 Participants
are divided into 2 treatment groups
Group A: Control ConditionExperimental treatment 1 intervention
Group B: Mental Fatigue ConditionExperimental treatment 1 intervention

Trial outcomes

Primary outcomes

1

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.

Time frame
Pre-intervention and immediately post-intervention (each experimental session)
2

Subjective Mental Fatigue

Subjective mental fatigue will be assessed using a visual analog scale (VAS) ranging from 0 (no fatigue) to 100 (extreme fatigue).

Time frame
During intervention (every 15 minutes) and immediately post-intervention

Secondary outcomes

1

Spinal Reflex Excitability (H-reflex Modulation)

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.

Time frame
Pre-intervention and immediately post-intervention across sitting, bipedal stance, and unipedal stance conditions
2

Surface Electromyography (EMG) Activity of Postural Muscles

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).

Time frame
Continuous recording during postural tasks, pre-intervention and immediately post-intervention (each condition)
3

Hip / Leg Movement (IMU Angular Velocity)

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.

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

Other outcomes

Sponsors and contacts

Click on the lead sponsor to view all of their trials.

Izmir Bakircay University

Lead sponsor

Vrije Universiteit Brussel

Collaborator

University of Franche-Comté

Collaborator

Source ClinicalTrials.gov

This trial is not recruiting at the moment. You can still explore other options: