Impacts and Mechanisms of Age and Muscle Fatigue on Postural Control and Force Control

Muscle fatigue is one of the clinical symptoms in elderly people and demonstrates task dependency and muscle dependency. Muscle fatigue has been shown to negatively impact postural control, physical activity, and quality of life. However, the evidence for the influence of muscle fatigue on postural control is limited and inconsistent in elderly people. Therefore, this study aims to investigate the impacts of aging and muscle fatigue on postural control and gait performance with fatiguing exercises of upper and lower extremities.

Study Overview

• Status: Recruiting
• Conditions: Aging; Muscle Fatigue
• Intervention / Treatment: Other: Age; Other: Muscle fatigue

Detailed Description

This study aims to investigate the effects of muscle fatigue on postural control and gait performance in healthy older adults (≥65 years) and young adults (20-40 years). Neuromuscular fatigue has been associated with postural instability, but its influence on gait and potential age-related differences remain unclear. Therefore, this study will compare fatigue-induced changes in motor performance between age groups and examine whether fatigue of the upper and lower extremities produces similar functional effects.

Healthy older adults and young adults will be recruited from the community. Eligible participants must be in good health, able to walk independently, demonstrate normal cognitive function, and provide informed consent. Individuals with neurological, cardiovascular, musculoskeletal, or other conditions that may affect motor performance will be excluded.

A repeated-measures design will be used. The study will involve two laboratory sessions separated by at least one week. Participants will undergo pre-test assessments, a fatiguing exercise protocol, and post-test assessments. Motor outcomes-including maximal voluntary isometric contraction, postural control, and gait performance-will be measured before and after the fatiguing exercises. Fatiguing exercises will consist of repeated cycles of maximal contractions with rest periods, while heart rate and perceived exertion are monitored to ensure safety. The protocol will terminate if exertion reaches a predefined threshold or heart rate exceeds the age-predicted maximum.

Surface electromyography and electrical stimulation will be used to assess neuromuscular function. Postural control will be evaluated using a force plate under multiple standing conditions, and gait parameters will be measured while participants walk at comfortable and fast speeds. Statistical analyses will use repeated-measures mixed-model ANOVAs to examine the effects of age group and fatigue on motor outcomes.

• Study Type: Observational
• Enrollment (Estimated): 140

Contacts and Locations

• Study Contact: Name: Chu-Ling Yen; Phone Number: 3059 886-3-2118800; Email: clyen@mail.cgu.edu.tw

Study Locations

• Taiwan
  • Taoyuan District, Taiwan
    • Recruiting
    • Chang Gung Memorial Hospital
  • Taoyuan District, Taiwan
    • Recruiting
    • Chang Gung University

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Probability Sample

Study Population

This study recruits healthy elderly individuals and healthy young individuals

Description

Inclusion Criteria:

• 20 to 40 years (young), and 60-85 years (old)
• walk independently
• able to follow commands (Mini Mental Status Exam (MMSE) scores greater than 21
• able and willing to provide informed consent.

Exclusion Criteria:

• pregnancy
• neurologic, psychiatric, cardiac, vascular, pulmonary, musculoskeletal, immune, integumentary disease or disorder which might influence this study
• any current loss of sensation in the arms, wrists, hands, fingers, hips, knees, ankles or toes
• any pain at the time of testing
• any restriction in range of motion of lower extremity.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Healthy people; General healthy people aged 20-40 and 60-85 years.	Other: Age; We compare the young and the old groups; Other: Muscle fatigue; We compare the results before and after muscle fatigue

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maximal force	The maximal force of upper and lower extremity muscles	Baseline (pre-fatigue protocol) and immediately after the fatigue protocol
Walking speed	The time taken by participants to walk a standardized distance	Baseline (pre-fatigue protocol) and immediately after the fatigue protocol
Step Length	The linear distance between the two ankles, typically expressed in centimeter(cm).	Baseline (pre-fatigue protocol) and immediately after the fatigue protocol
Cadence	The number of steps taken per minute (SPM)	Baseline (pre-fatigue protocol) and immediately after the fatigue protocol
Single Support Time	The duration within the gait cycle when only one foot is in contact with the ground, typically measured in seconds or as a percentage of the total gait cycle.	Baseline (pre-fatigue protocol) and immediately after the fatigue protocol
Double Support Time	The portion of the gait cycle where both feet are in contact with the ground, indicating the transition phase between steps, expressed as a percentage of the gait cycle or in seconds.	Baseline (pre-fatigue protocol) and immediately after the fatigue protocol
Swing Time	The portion of the gait cycle where the foot is not in contact with the ground, moving forward to the next step. It is usually expressed as a percentage of the total gait cycle or in seconds.	Baseline (pre-fatigue protocol) and immediately after the fatigue protocol
COP Velocity in Balance Tasks	The speed at which the COP moves, calculated over the duration of the balance task. Higher velocities may reflect more dynamic balance adjustments or instability. Unit：millimeter per second(mm/s)	Baseline (pre-fatigue protocol) and immediately after the fatigue protocol
COP Area in Balance Tasks	The area covered by the COP trajectory during the balance task, providing an estimate of the sway envelope. A larger area might indicate poorer balance control. Unit：square millimeter(mm^2)	Baseline (pre-fatigue protocol) and immediately after the fatigue protocol

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Oxygenated hemoglobin	Oxygenated hemoglobin is the amount of hemoglobin bound to oxygen, reflecting tissue oxygen availability. It's expressed as the percentage.	Baseline (pre-fatigue protocol), during the fatigue protocol, and immediately after the fatigue protocol.
Total hemoglobin	Total hemoglobin is the combined amount of oxygenated and deoxygenated hemoglobin, reflecting overall blood volume in the tissue.	Baseline (pre-fatigue protocol), during the fatigue protocol, and immediately after the fatigue protocol.
Deoxygenated hemoglobin	Deoxygenated hemoglobin is the amount of hemoglobin not bound to oxygen, reflecting oxygen extraction by tissues. It's expressed as the percentage.	Baseline (pre-fatigue protocol), during the fatigue protocol, and immediately after the fatigue protocol.

Collaborators and Investigators

• Sponsor: Chang Gung Memorial Hospital
• Collaborators: Chang Gung University
• Investigators: Principal Investigator: Chu-Ling Yen, Chang Gung University

Study record dates

Study Major Dates

• Study Start (Actual): August 1, 2022
• Primary Completion (Estimated): July 31, 2028
• Study Completion (Estimated): July 31, 2028

Study Registration Dates

• First Submitted: January 23, 2026
• First Submitted That Met QC Criteria: February 9, 2026
• First Posted (Actual): February 12, 2026

Study Record Updates

• Last Update Posted (Actual): February 12, 2026
• Last Update Submitted That Met QC Criteria: February 9, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: balance; old; muscle force; fatigability; gait performance
• Additional Relevant MeSH Terms: Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena; Physiological Phenomena; Growth and Development; Aging; Muscle Fatigue
• Other Study ID Numbers: 202200723A3

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No