Muscular Fatigue vs. Mental Fatigue on Balance, Proprioception and Reaction Time

Comparison of the Effects of Extremity Fatigue and Mental Fatigue on Balance, Proprioception and Reaction Time

This study aims to understand how different types of fatigue affect balance and reaction time, proprioception, and fine motor in healthy young adults. Fatigue is a common experience in daily life and can arise from physical activity or prolonged mental effort. The study seeks to determine whether fatigue of the upper body, lower body, or mental fatigue from cognitively demanding tasks can negatively affect balance and reaction time, proprioception, and fine motor abilities.

To examine this, participants will undergo controlled fatigue protocols designed to tire specific parts of the body or the mind. the Upper body fatigue will be induced through repeated maximal push-up sets performed until the participant can no longer maintain proper form. Lower body fatigue will be created through repeated maximal 1-minute squat jump sets, with participants touching a low box to ensure standardized depth and proper movement. Mental fatigue will be induced using a 20-minute computer-based cognitive task that alternates between the 2-back working memory task and the numerical Stroop task. These tasks are designed to require continuous attention, mental effort, and inhibitory control. Each type of fatigue will be induced independently, and participants' performance will be measured before and after each fatigue protocol.

Following fatigue induction, participants will complete a series of tests designed to assess balance and reaction time, proprioception, and fine motor abilities. This includes both static and dynamic postural tasks, as well as reaction time and proprioceptive accuracy assessments. By evaluating these measures before and after fatigue, the study will determine how different forms of physical and mental fatigue impact postural stability, sensory processing, and precise motor control.

The study addresses the question: "Do upper body fatigue, lower body fatigue, or mental fatigue reduce balance and reaction time, proprioception, and fine motor performance in healthy young adults?" The hypothesis is that each form of fatigue upper body, lower body, or mental-will meaningfully impair balance and reaction time, proprioception, and fine motor performance compared to non-fatigued conditions.

Study Overview

• Status: Recruiting
• Conditions: Mental Fatigue; Muscular Fatigue
• Intervention / Treatment: Other: Upper Extremity Fatigue Protocol; Other: Lower Extremity Fatigue Protocol; Other: Mental Fatigue Protocol

• Study Type: Interventional
• Enrollment (Estimated): 66
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Çiçek Günday, PhD; Phone Number: 0850 283 6000; Email: cicek.gunday@istinye.edu.tr
• Study Contact Backup: Name: Alaa Aldeen Hamwi, PT; Phone Number: 0850 283 6000; Email: alaa.hamwi@stu.istinye.edu.tr

Study Locations

• Turkey (Türkiye)
  • Istanbul, Turkey (Türkiye)
    • Recruiting
    • Istinye University Research and Application Center (ISUFIZYOTEM)
    • Contact: Nurgül Dürüstkan Elbaşı, PhD; Phone Number: 0850 283 6000; Email: nelbasi@istinye.edu.tr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Being between 18 and 35 years of age
• Self-reporting good general health status
• Not having any physician-diagnosed medical condition
• Not using any assistive device or orthotic insoles

Exclusion Criteria:

• History of neurological disorders affecting balance (e.g., stroke, Parkinson's disease, multiple sclerosis, vestibular disorders)
• Current or recent (within the past 6 months) lower extremity or spinal injury
• Current lower extremity pain
• Uncontrolled cardiovascular disease
• Uncorrected visual impairment affecting balance
• Current pregnancy

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Upper Extremity Fatigue	Other: Upper Extremity Fatigue Protocol; The upper extremity fatigue will be created by requiring participants to perform consecutive sets of push-ups until task failure. Push-ups will be executed according to standardized ACSM guidelines, and repetitions will be recorded. Participants will first complete one maximal set to exhaustion, followed by a 1-minute rest period and a second maximal set. If performance in the second set exceeds 60% of the initial repetition count, additional sets will be performed after 1-minute recovery intervals. This sequence will continue until the participant's performance declines below 60% of the previous set, at which point neuromuscular fatigue will be considered achieved.
Experimental: Lower Extremity Fatigue	Other: Lower Extremity Fatigue Protocol; The lower extremity fatigue will be created by requiring participants to perform repeated 1-minute sets of maximal squat jumps until exhaustion. During each jump, participants will execute countermovement jumps and touch a low box with their hips to ensure standardized depth, under researcher supervision for proper technique. After completing an initial 1-minute maximal set, total jump count will be recorded. Following a 1-minute recovery period, a second 1-minute maximal set will be performed. If performance in the second set exceeds 60% of the first set's total repetitions, additional 1-minute sets will be completed after 1-minute rest intervals. This procedure will continue until jump performance declines below 60% of the previous set, at which point neuromuscular fatigue will be considered achieved.
Experimental: Mental Fatigue	Other: Mental Fatigue Protocol; Mental Fatigue will be created by administering a continuous 20-minute computerized cognitive protocol composed of four consecutive 5-minute blocks without rest. The 2-back task (5 minutes) and the numerical Stroop task (5 minutes) will each be performed twice in alternating order. The sustained and repeated working memory and inhibitory control demands are intended to induce progressive cognitive load and mental fatigue.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Y Balance Test (YBT)	The assessment will be performed using a standard YBT kit, which includes a central stance platform and three measurement tapes extending in the anterior (ANT), posteromedial (PM), and posterolateral (PL) directions. Participants will stand barefoot on their dominant leg on the central platform. While maintaining balance and keeping the stance foot stationary, they will reach as far as possible in each of the three directions with the contralateral leg to push a reach indicator. To ensure maximum performance, three trials will be conducted for each direction, and the best score (maximum reach distance) will be recorded for analysis.	Day 1
BlazePod Reaction System for Lower Extremity	Four pods will be arranged in a square configuration at a distance equal to the participant's leg length. Participants stand barefoot in the center on one leg for 30 seconds. They must tap the illuminated pods with their raised foot as quickly as possible without the raised foot touching the ground more than once.	Day 1
BlazePod Reaction System for Upper Extremity	Four pods will be arranged in a rectangular layout (91 cm long and 30 cm wide), with two pods on each side. The protocol follows the same principles as the lower extremity test. Performance is measured by the total number of "hits" and the average RT between responses.	Day 1

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Ruler Drop Reaction Test	The Ruler Drop Reaction Test will be performed using a standard 30-centimeter ruler to assess simple visual reaction time. The protocol requires the participant to sit parallel to a table with the elbow flexed at 90° and resting on the surface. The dominant hand will be extended, with the thumb and index finger positioned at the 0 cm mark without touching the ruler. The researcher will hold the ruler vertically, aligning the zero point with the top of the participant's thumb and index finger, and release it without warning. The participant will attempt to catch the ruler as quickly as possible. The distance the ruler falls (in centimeters) will be measured from the 0 cm mark to the top of the participant's thumb. Three trials will be conducted for both the dominant and non-dominant hands, and the best performance (shortest distance) will be used for data analysis.	Day 1
Purdue Pegboard Test (PPT)	The Purdue Pegboard Test (PPT) will be utilized to evaluate fine motor skills and the coordinated movement of the hands, fingers, and arms. Participants will sit comfortably in front of the pegboard to perform four distinct batteries, where the score for each section is determined by the number of items successfully placed or assembled within the allotted time. The first and second sections involve individual pin placement for 30 seconds using the dominant and non-dominant hands respectively; the third section requires simultaneous bimanual pin placement for 30 seconds; and the final section tests the ability to assemble pins, collars, and washers using both hands over a 60-second duration.	Day 1
Joint Position Sense Test (JPS Test)	To ensure measurement precision, fixed anatomical landmarks-the greater trochanter, the lateral knee joint space, and the lateral malleolus-will be marked. At the start of the test, the participant will be positioned with the knee and hip joints at 90°. The researcher will passively move the participant's leg to a target angle of 45° flexion. After holding this position briefly, the leg will be returned to the starting position. Participants will be blindfolded to eliminate visual feedback. They will then be asked to actively reproduce the target angle. The absolute difference between the target angle and the actively reproduced angle will be recorded as the test score.	Day 1

Collaborators and Investigators

• Sponsor: Istinye University

Study record dates

Study Major Dates

• Study Start (Actual): November 11, 2025
• Primary Completion (Estimated): July 30, 2026
• Study Completion (Estimated): July 30, 2026

Study Registration Dates

• First Submitted: March 31, 2026
• First Submitted That Met QC Criteria: June 1, 2026
• First Posted (Actual): June 2, 2026

Study Record Updates

• Last Update Posted (Actual): June 2, 2026
• Last Update Submitted That Met QC Criteria: June 1, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: fatigue; balance; cognitive; reaction time
• Additional Relevant MeSH Terms: Behavioral Symptoms; Pathological Conditions, Signs and Symptoms; Behavior; Signs and Symptoms; Fatigue; Mental Fatigue
• Other Study ID Numbers: ISU-25-099

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No