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Acute Mental Fatigue and Muscle Strength

23. september 2026 opdateret af: Nicole Rendos, Florida Institute for Human and Machine Cognition

Influence of Acute Mental Fatigue on Muscle Strength and Limb Symmetry in Healthy Adults

This study will investigate the acute effects of mental fatigue on lower-extremity muscle strength and limb symmetry in healthy young adults. Participants will complete lower-extremity strength testing before and after a standardized computer-based mental fatigue protocol involving tasks of attention, reaction time, concentration, and working memory. Muscle strength and limb symmetry will be assessed using isokinetic dynamometry, with muscle activity measured using surface electromyography. Participants will also complete subjective measures of mental fatigue, sleepiness, mental effort, and perceived physical exertion. Heart rate will be monitored throughout the study, and brain activity may be assessed during cognitive tasks. The study will determine whether acute mental fatigue is associated with changes in muscle strength, limb symmetry, and neuromuscular performance.

Studieoversigt

Status

Rekruttering

Betingelser

Intervention / Behandling

Detaljeret beskrivelse

This study will investigate the acute effects of mental fatigue on lower-extremity muscle strength, interlimb symmetry, and neuromuscular performance in healthy young adults. The study will use a within-subject, repeated-measures design in which participants complete lower-extremity strength testing immediately before and after a standardized computer-based mental fatigue protocol. Each participant's pre-fatigue measurements will serve as the baseline comparison for their post-fatigue measurements.

Participants will complete one experimental session lasting up to approximately two hours at the Florida Institute for Human and Machine Cognition (IHMC) Healthspan, Resilience, and Performance Research Complex. Before testing, participants will undergo eligibility screening, provide written informed consent, and complete familiarization with the strength-testing procedures and computer-based cognitive tasks. Following familiarization, participants will complete a standardized rest period of at least five minutes before baseline measurements are collected.

Lower-extremity muscle strength will be assessed using a Biodex isokinetic dynamometer. Participants will perform knee extension and flexion with both lower extremities at three different movement speeds to assess strength across multiple testing conditions. Peak torque will be used as a primary measure of muscle strength. Testing of both limbs will also allow calculation of a Limb Symmetry Index (LSI) to quantify differences in strength between the lower extremities. Participants will rate their perceived physical exertion following each strength assessment.

Surface electromyography (EMG) will be used to record muscle activity from selected muscles of both thighs during strength testing. Participants may also perform maximal voluntary isometric contractions before the primary strength assessment to assist with normalization and interpretation of EMG signals. EMG measurements will be used to examine whether changes in strength following the mental fatigue protocol are accompanied by changes in muscle activity.

Following the baseline strength assessment, participants will complete approximately 30 minutes of standardized computer-based cognitive tasks designed to require sustained attention, concentration, reaction time, working memory, and mental effort and thereby induce acute mental fatigue. Tasks may include a psychomotor vigilance task, an incongruent Stroop task, and an n-back working-memory task. Reaction time and response accuracy may be recorded during the cognitive tasks.

Subjective mental fatigue and sleepiness will be assessed before and after the mental fatigue protocol. Following the cognitive tasks, participants will also rate the mental effort required to complete the tasks. These measures will be used to characterize the subjective response to the mental fatigue protocol and evaluate whether participants experienced increased mental fatigue following the intervention.

Heart rate and cardiac activity may be continuously monitored using a Polar H10 chest sensor during the experimental session to provide additional information regarding physiological responses during the strength-testing and cognitive-task portions of the protocol. Brain electrical activity may also be recorded using noninvasive electroencephalography (EEG) during the cognitive tasks in a subset of participants.

Immediately following completion of the mental fatigue protocol and post-task questionnaires, participants will repeat the same bilateral Biodex strength assessment performed at baseline. Testing procedures, positioning, movement speeds, instructions, and outcome measurements will be kept consistent between the pre- and post-fatigue assessments. Surface EMG will again be recorded during strength testing, and participants will rate their perceived physical exertion.

The primary analyses will compare pre- and post-fatigue measures of lower-extremity muscle strength and limb symmetry to determine whether acute mental fatigue is associated with changes in peak torque or LSI. Additional analyses will examine subjective mental fatigue, sleepiness, mental effort, perceived physical exertion, muscle activity, cognitive-task performance, and physiological responses. The findings will help determine whether acute mental fatigue should be considered when measuring and interpreting lower-extremity strength and limb symmetry in research, rehabilitation, and human performance settings.

Undersøgelsestype

Interventionel

Tilmelding (Anslået)

50

Fase

  • Ikke anvendelig

Kontakter og lokationer

Dette afsnit indeholder kontaktoplysninger for dem, der udfører undersøgelsen, og oplysninger om, hvor denne undersøgelse udføres.

Studiekontakt

  • Navn: Nicole K Rendos, PhD
  • Telefonnummer: 850-202-4442
  • E-mail: nrendos@ihmc.org

Studiesteder

    • Florida
      • Pensacola, Florida, Forenede Stater, 32502
        • Rekruttering
        • Florida Institute for Human and Machine Cognition
        • Kontakt:

Deltagelseskriterier

Forskere leder efter personer, der passer til en bestemt beskrivelse, kaldet berettigelseskriterier. Nogle eksempler på disse kriterier er en persons generelle helbredstilstand eller tidligere behandlinger.

Berettigelseskriterier

Aldre berettiget til at studere

18 år til 39 år (Voksen)

Tager imod sunde frivillige

Ja

Køn, der er berettiget til at studere

Alle

Beskrivelse

Inclusion Criteria:

  1. Age 18-39 years
  2. Able to produce maximal force against Biodex protocol
  3. Able to perform required lower extremity movements through range of motion necessary for Biodex protocol
  4. No known cognitive impairment
  5. Sufficient musculoskeletal health to complete the tasks

Exclusion Criteria:

  1. History of a neurological disorder, disease, or cognitive impairment that may affect cognition, motor control, reaction time, or force production
  2. History of musculoskeletal injury affecting the lower extremities within the past 6 months
  3. History of lower extremity surgery affecting force production of the hip, knee, or ankle
  4. Color-vision impairment
  5. Significant visual or hearing impairment
  6. History of migraine headaches
  7. Current significant sleep disturbances or sleep deprivation
  8. Head injury that may affect cognitive function
  9. Medical condition affecting ability to produce maximal force safely
  10. Allergy to adhesive tape, parabens, or propylene glycol
  11. Scalp lacerations, open wounds, or sutures on the scalp
  12. Cranial surgery or skull defects
  13. History of unexplained dizziness or fainting in the past 6 months
  14. Individuals who are pregnant, prisoners, or not yet adults
  15. Inability to communicate with investigators
  16. Inability to provide written informed consent

Studieplan

Dette afsnit indeholder detaljer om studieplanen, herunder hvordan undersøgelsen er designet, og hvad undersøgelsen måler.

Hvordan er undersøgelsen tilrettelagt?

Design detaljer

  • Primært formål: Grundvidenskab
  • Tildeling: N/A
  • Interventionel model: Enkelt gruppeopgave
  • Maskning: Ingen (Åben etiket)

Våben og indgreb

Deltagergruppe / Arm
Intervention / Behandling
Eksperimentel: Mental Fatigue Intervention

Participants will complete baseline lower-extremity muscle strength testing followed by approximately 30 minutes of standardized computer-based cognitive tasks designed to induce acute mental fatigue. Lower-extremity muscle strength testing will then be repeated immediately following the mental fatigue intervention.

Participants will complete approximately 30 minutes of standardized computer-based cognitive tasks designed to induce acute mental fatigue. The tasks require sustained attention, concentration, reaction time, working memory, and mental effort and may include the Psychomotor Vigilance Task (PVT), incongruent Stroop task, and n-back task. Participants will complete the mental fatigue protocol after baseline strength testing and before the post-intervention strength assessment. Subjective mental fatigue and sleepiness will be assessed before and after the intervention, and perceived mental effort will be assessed following the intervention.

Hvad måler undersøgelsen?

Primære resultatmål

Resultatmål
Foranstaltningsbeskrivelse
Tidsramme
Lower-Extremity Muscle Strength
Tidsramme: Baseline and immediately following the approximately 30-minute mental fatigue intervention, during a single study visit lasting up to 2 hours.

Lower-extremity muscle strength will be assessed using a Biodex isokinetic dynamometer during bilateral knee extension and flexion at three different movement speeds. Peak torque will be recorded as the primary measure of muscle strength. Changes in peak torque from baseline to immediately following the computer-based mental fatigue intervention will be evaluated.

Baseline and immediately following the approximately 30-minute mental fatigue intervention, during a single study visit lasting up to 2 hours.
Lower-Extremity Limb Symmetry
Tidsramme: Baseline and immediately following the approximately 30-minute mental fatigue intervention, during a single study visit lasting up to 2 hours.

Limb symmetry will be assessed using peak torque measurements obtained from both lower extremities during isokinetic knee extension and flexion testing. A Limb Symmetry Index (LSI) will be calculated to quantify the similarity in muscle strength between the two lower extremities. Changes in LSI from baseline to immediately following the computer-based mental fatigue intervention will be evaluated.

Baseline and immediately following the approximately 30-minute mental fatigue intervention, during a single study visit lasting up to 2 hours.

Samarbejdspartnere og efterforskere

Det er her, du vil finde personer og organisationer, der er involveret i denne undersøgelse.

Sponsor

Efterforskere

  • Ledende efterforsker: Nicole K Rendos, PhD, Florida Institute for Human and Machine Cognition

Datoer for undersøgelser

Disse datoer sporer fremskridtene for indsendelser af undersøgelsesrekord og resumeresultater til ClinicalTrials.gov. Studieregistreringer og rapporterede resultater gennemgås af National Library of Medicine (NLM) for at sikre, at de opfylder specifikke kvalitetskontrolstandarder, før de offentliggøres på den offentlige hjemmeside.

Studer store datoer

Studiestart (Faktiske)

23. september 2026

Primær færdiggørelse (Anslået)

31. december 2027

Studieafslutning (Anslået)

31. december 2027

Datoer for studieregistrering

Først indsendt

23. september 2026

Først indsendt, der opfyldte QC-kriterier

23. september 2026

Først opslået (Faktiske)

29. september 2026

Opdateringer af undersøgelsesjournaler

Sidste opdatering sendt (Faktiske)

29. september 2026

Sidste opdatering indsendt, der opfyldte kvalitetskontrolkriterier

23. september 2026

Sidst verificeret

1. september 2026

Mere information

Begreber relateret til denne undersøgelse

Andre undersøgelses-id-numre

  • IRB-2026-0026

Plan for individuelle deltagerdata (IPD)

Planlægger du at dele individuelle deltagerdata (IPD)?

JA

IPD-planbeskrivelse

De-identified individual participant data that underlie the results reported in publications from this study may be made available to other researchers for scientific research purposes. Data will be shared without information that directly identifies participants.

IPD-delingstidsramme

Data will be available beginning 12 months and ending 36 months following publication of the primary findings from this study.

IPD-delingsadgangskriterier

De-identified data may be shared with scientific and clinical researchers for research purposes, including individual participant data meta-analyses. Requests for data should be directed to Dr. Nicole Rendos at nrendos@ihmc.org and may be submitted up to 36 months following publication of the primary findings from this study. Researchers requesting access will be required to provide an appropriate scientific rationale for the request and sign a data access agreement before receiving the data.

IPD-deling Understøttende informationstype

  • STUDY_PROTOCOL

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