Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Experiment Videos

Changes in the surface electromyogram during increasing isometric shoulder forward flexions.

B Gerdle1, N E Eriksson, C Hagberg

  • 1National Institute of Occupational Health, Work Physiology Unit, Umeå, Sweden.

European Journal of Applied Physiology and Occupational Physiology
|January 1, 1988
PubMed
Summary
This summary is machine-generated.

Related Concept Videos

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Procedural sedation: a flawed definition for a problematic term.

Anaesthesia·2021
Same author

Pain intensity and pressure pain thresholds after a light dynamic physical load in patients with chronic neck-shoulder pain.

BMC musculoskeletal disorders·2020
Same author

Plasma Cytokine Levels in Fibromyalgia and Their Response to 15 Weeks of Progressive Resistance Exercise or Relaxation Therapy.

Mediators of inflammation·2018
Same author

Association of insomnia severity with well-being, quality of life and health care costs: A cross-sectional study in older adults with chronic pain (PainS65+).

European journal of pain (London, England)·2017
Same author

Illness beliefs among patients with chronic widespread pain - associations with self-reported health status, anxiety and depressive symptoms and impact of pain.

BMC psychology·2017
Same author

Does psychotherapy work? An umbrella review of meta-analyses of randomized controlled trials.

Acta psychiatrica Scandinavica·2017
Same journal

Reply to the letter by morton

European journal of applied physiology and occupational physiology·1999
Same journal

Effects of caffeine, ephedrine and their combination on time to exhaustion during high-intensity exercise.

European journal of applied physiology and occupational physiology·1999
Same journal

The effect of strength training on estimates of mitochondrial density and distribution throughout muscle fibres.

European journal of applied physiology and occupational physiology·1999
Same journal

Latency to CNS oxygen toxicity in rats as a function of PCO(2) and PO(2).

European journal of applied physiology and occupational physiology·1999
Same journal

Diurnal variations in ventilatory and cardiorespiratory responses to submaximal treadmill exercise in females.

European journal of applied physiology and occupational physiology·1999
Same journal

Comparison of cardiopulmonary responses to two types of dry-land upper-body exercise testing modes in competitive swimmers.

European journal of applied physiology and occupational physiology·1999
See all related articles

Muscle load evaluation using electromyography (EMG) revealed that the relationship between torque and EMG amplitude changes during sustained contractions. A decrease in the power spectral density function was observed, impacting the EMG-force relationship at higher exertion levels.

Area of Science:

  • Biomechanics
  • Neuroscience
  • Human Physiology

Background:

  • Accurate assessment of muscular load via electromyography (EMG) requires understanding the torque-EMG amplitude relationship.
  • Previous studies suggest non-linear increases in EMG amplitude (RMS) with force, but spectral changes are less understood.

Purpose of the Study:

  • To investigate changes in the power spectral density function during gradually increasing isometric contractions.
  • To determine if spectral shifts correlate with torque and EMG amplitude during sustained exertion.

Main Methods:

  • Twenty-two healthy females performed a 10-second isometric shoulder flexion to 100% MVC.
  • Surface EMG was recorded from trapezius, deltoid, infraspinatus, and biceps brachii.
  • Torque, mean power frequency (MPF), and RMS were analyzed in 256 ms intervals.

Related Experiment Videos

Main Results:

  • RMS-torque regressions showed higher coefficients from 6-9 seconds compared to 0-5 seconds.
  • No significant correlation was found between MPF and torque for the four muscles.
  • A general decrease in MPF was observed starting around the 6th second of contraction.

Conclusions:

  • The decrease in power spectral density function (MPF) during the latter half of the contraction may explain the increased RMS-torque regression coefficient.
  • These findings highlight dynamic spectral changes in EMG during increasing isometric contractions, impacting load assessment.