Effects of Physical and Cognitive Fatigue on Reaction Time and Depth Perception in Adolescents

September 28, 2026 updated by: Ahmet Kaan Aslan, AslanAhmetKaan

Differential Effects of Physical, Cognitive, and Combined Fatigue on Reaction Time and Depth Perception in Adolescents

This study investigates how physical fatigue, cognitive fatigue, and a combination of both affect reaction time and depth perception in adolescents.

Sixty healthy adolescents will participate in four experimental conditions: a control condition, a physical fatigue condition, a cognitive fatigue condition, and a combined fatigue condition. Physical fatigue will be induced using a modified shuttle run protocol, while cognitive fatigue will be induced using computerized Stroop and mental arithmetic tasks.

Reaction time will be assessed using the BlazePod system, and depth perception will be evaluated using the Titmus Fly Stereotest before and after each condition. Heart rate, perceived exertion, and mental fatigue will also be measured to verify the effectiveness of the fatigue protocols.

The findings may improve understanding of how different types of fatigue influence perceptual and motor performance in adolescents and may contribute to the development of safer and more effective training and sport participation strategies.

Study Overview

Detailed Description

Fatigue is a multifactorial phenomenon that can impair cognitive, perceptual, and motor performance. While the independent effects of physical fatigue and cognitive fatigue have been widely investigated, limited evidence exists regarding their comparative and combined effects on reaction time and depth perception during adolescence. Because perceptual and motor functions play a critical role in sports performance, injury prevention, and daily activities, understanding the effects of different fatigue states in adolescents is of practical and scientific importance.

The purpose of this study is to examine the differential effects of physical fatigue, cognitive fatigue, and combined fatigue on reaction time and depth perception in healthy adolescents. A within-subject crossover design will be employed, in which each participant completes four experimental conditions: control, physical fatigue, cognitive fatigue, and combined fatigue. Physical fatigue will be induced using a modified 20-meter shuttle run protocol. Cognitive fatigue will be induced through computerized Stroop and mental arithmetic tasks designed to impose sustained demands on attention, inhibitory control, working memory, and information processing. The combined fatigue condition will include both physical and cognitive fatigue protocols within the same session.

Reaction time will be measured using the BlazePod wireless light-based system, and depth perception will be assessed using the Titmus Fly Stereotest. Measurements will be obtained immediately before and after each experimental condition. Heart rate, rating of perceived exertion, and mental fatigue scores will be collected as manipulation checks to confirm the effectiveness of the fatigue protocols.

The results of this study are expected to improve understanding of the mechanisms through which different types of fatigue influence perceptual and motor performance in adolescents and may provide practical implications for youth sports training, performance monitoring, and injury prevention strategies.

Study Type

Interventional

Enrollment (Actual)

60

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 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

14 years to 18 years (Child, Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Adolescents aged 14 to 18 years.
  • Male or female participants.
  • Normal or corrected-to-normal vision.
  • Ability to understand and follow study procedures.
  • Written informed consent from both the participant and a parent/legal guardian.

Exclusion Criteria:

  • History of neurological disorders.
  • Visual disorders affecting depth perception.
  • Orthopedic injuries or musculoskeletal conditions limiting physical activity.
  • Any medical condition that would contraindicate participation in physical exercise.
  • Failure to complete all experimental sessions.

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: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Control Condition

Participants completed the testing procedures without exposure to any physical or cognitive fatigue protocol. Reaction time and depth perception were assessed before and after the control condition.

Participants completed the testing procedures without exposure to any physical or cognitive fatigue protocol.

Experimental: Physical Fatigue Condition

Participants completed a 16-minute modified 20-meter shuttle run protocol designed to induce physical fatigue. Reaction time and depth perception were assessed before and after the protocol.

A 16-minute modified 20-meter shuttle run protocol designed to induce physical fatigue through progressively increasing running intensity.

Experimental: Cognitive Fatigue Condition

Participants completed a 16-minute cognitive fatigue protocol consisting of an 8-minute Stroop task and an 8-minute mental arithmetic task. Reaction time and depth perception were assessed before and after the protocol.

A 16-minute computerized protocol consisting of Stroop and mental arithmetic tasks designed to induce cognitive fatigue.

Experimental: Combined Fatigue Condition

Participants completed a combined fatigue protocol consisting of 8 minutes of a modified shuttle run followed by 4 minutes of a Stroop task and 4 minutes of a mental arithmetic task. Reaction time and depth perception were assessed before and after the protocol.

A protocol combining physical and cognitive fatigue tasks, including a modified shuttle run, Stroop task, and mental arithmetic task.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Reaction Time
Time Frame: Immediately before and immediately after each experimental condition.

Reaction time will be assessed using the BlazePod wireless light-based system. Reaction time will be recorded in milliseconds as the latency between stimulus presentation and participant response. Two trials will be performed, and the best performance will be used for analysis.

Immediately before and immediately after each experimental condition.
Depth Perception
Time Frame: Immediately before and immediately after each experimental condition.

Depth perception will be assessed using the Titmus Fly Stereotest. Stereopsis will be expressed in arc seconds, with lower values indicating better depth perception performance. Two trials will be conducted at each measurement point, and the lowest value will be used for analysis.

Immediately before and immediately after each experimental condition.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Heart Rate
Time Frame: Immediately before and immediately after each experimental condition.

Heart rate will be measured before and after each experimental condition using photoplethysmography (PPG)-based smartwatches to verify the effectiveness of fatigue induction.

Immediately before and immediately after each experimental condition.
Rating of Perceived Exertion (RPE)
Time Frame: Perceived exertion will be assessed using the Borg CR-20 Scale before and after each experimental condition to evaluate subjective fatigue levels.

Perceived exertion will be assessed using the Borg CR-20 Scale before and after each experimental condition to evaluate subjective fatigue levels.

Perceived exertion will be assessed using the Borg CR-20 Scale before and after each experimental condition to evaluate subjective fatigue levels.
Mental Fatigue Scale Score
Time Frame: Immediately before and immediately after each experimental condition.

Mental fatigue will be assessed using the Mental Fatigue Scale (MFS), a 15-item self-report questionnaire measuring cognitive, emotional, and sensory aspects of fatigue.

Immediately before and immediately after each experimental condition.

Collaborators and Investigators

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

Sponsor

Investigators

  • Principal Investigator: Ahmet Kaan ASLAN, PhD, Gazi University

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 (Actual)

April 1, 2026

Primary Completion (Actual)

May 21, 2026

Study Completion (Actual)

May 31, 2026

Study Registration Dates

First Submitted

September 28, 2026

First Submitted That Met QC Criteria

September 28, 2026

First Posted (Actual)

October 2, 2026

Study Record Updates

Last Update Posted (Actual)

October 2, 2026

Last Update Submitted That Met QC Criteria

September 28, 2026

Last Verified

September 1, 2026

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be made publicly available. Data contain information collected from adolescent participants, and sharing is restricted to protect participant confidentiality and privacy.

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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