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 Concept Videos

Isotonic and Isometric Muscle Contractions01:22

Isotonic and Isometric Muscle Contractions

Two primary types of muscle contractions are isotonic and isometric, each serving unique functions and involving distinct mechanisms. Both isotonic and isometric contractions are integral to the body's complex system of movement and stability. Isotonic exercises contribute significantly to functional strength and movement, while isometric contractions are crucial for maintaining posture and joint stability.
Isotonic contractions
Isotonic contractions occur when a muscle changes length while the...
Smooth Muscle Contraction01:25

Smooth Muscle Contraction

Smooth muscle contraction is a complex process vital for various bodily functions, from maintaining blood vessel tension to facilitating the movement of food through the digestive tract. Unlike striated muscles, smooth muscle contraction begins more slowly and lasts longer.
The onset of contraction is triggered by an increase in calcium ions within the sarcoplasm, similar to the process in striated muscle. However, smooth muscles have a relatively smaller reservoir of the sarcoplasmic...
Motor Unit Stimulation01:20

Motor Unit Stimulation

When the neuron of a motor unit fires an action potential, it triggers a series of events, leading to a twitch contraction in the muscle fibers. The process of excitation-contraction coupling is crucial in relaying the action potential to the muscle fibers.
The latent period of contraction marks the onset of excitation-contraction coupling, when the action potential propagates across the sarcolemma, preparing the muscle fibers for contraction. As the fibers enter the contraction phase, the...
Alterations in Muscle Tone lll01:11

Alterations in Muscle Tone lll

Rigidity and myotonia are distinct abnormalities of muscle tone that affect resistance and relaxation during movement. Although both involve altered muscle contraction, they arise from different neurological and muscular mechanisms.CharacteristicsRigidity is characterized by uniform resistance to passive movement across the entire range, independent of speed, affecting flexors and extensors equally. It may appear as lead-pipe rigidity (smooth, constant resistance) or cogwheel rigidity...
Muscle Stimulation Frequency01:22

Muscle Stimulation Frequency

The contraction strength of muscles is regulated by motor neurons, which modulate the frequency of action potentials dispatched to the motor units based on the body's requirements. This process of varying the muscle stimulation frequency allows muscles to contract with a force that is precisely tailored to the needs of the moment, whether lifting a feather or a heavy box.
Wave summation
At low firing rates, motor neurons induce individual twitch contractions in muscle fibers. These twitches...
Relaxation of Skeletal Muscles01:29

Relaxation of Skeletal Muscles

The period of muscle contraction primarily influences the duration of stimulation at the neuromuscular junction (NMJ), the presence of free calcium ions in the sarcoplasm, and the availability of energy or ATP to support contractions.
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open.

You might also read

Related Articles

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

Sort by
Same author

Distinguishing Muscle Oxygen Saturation from Tissue Oxygen Saturation: Accuracy, Limitations, and Practical Utility in Muscle Oximetry.

Sports medicine - open·2026
Same author

Heat Acclimation with Blood Flow Restriction Improves Cognitive-Motor Dual-Task Ability and Neuromuscular Fatigue.

Scandinavian journal of medicine & science in sports·2026
Same author

Blood flow restriction induces similar peripheral stress but greater central drive impairments than systemic hypoxia during repeated cycling sprints.

European journal of applied physiology·2026
Same author

Comparison between soldiers and fitness-matched civilians on sustained attention, neuromuscular fatigue and perceived responses during an exhaustive cognitive-motor dual-task.

European journal of applied physiology·2026
Same author

Reassessing combined exercise-tDCS strategies in chronic pain.

Lancet regional health. Americas·2026
Same author

Investigating interbrain synchrony under teamwork disruption: an fNIRS hyperscanning study.

Behavioral and brain functions : BBF·2026

Related Experiment Video

Updated: Jun 22, 2026

Ex Vivo Assessment of Contractility, Fatigability and Alternans in Isolated Skeletal Muscles
14:02

Ex Vivo Assessment of Contractility, Fatigability and Alternans in Isolated Skeletal Muscles

Published on: November 1, 2012

Altitude-induced changes in muscle contractile properties.

Stéphane Perrey1, Thomas Rupp

  • 1EA 2991 Motor Efficiency and Deficiency Laboratory, Faculty of Sport Sciences, University of Montpellier, 700 Avenue du Pic Saint Loup, 34090 Montpellier, France. stephane.perrey@univ-montpl.fr

High Altitude Medicine & Biology
|June 13, 2009
PubMed
Summary

Hypoxia has minimal impact on human skeletal muscle maximal force generation, even at high altitudes. Chronic hypoxia exposure appears to protect against skeletal muscle dysfunction during exercise.

More Related Videos

Contractility Measurements on Isolated Papillary Muscles for the Investigation of Cardiac Inotropy in Mice
06:22

Contractility Measurements on Isolated Papillary Muscles for the Investigation of Cardiac Inotropy in Mice

Published on: September 17, 2015

Application of Chronic Stimulation to Study Contractile Activity-induced Rat Skeletal Muscle Phenotypic Adaptations
09:50

Application of Chronic Stimulation to Study Contractile Activity-induced Rat Skeletal Muscle Phenotypic Adaptations

Published on: January 25, 2018

Related Experiment Videos

Last Updated: Jun 22, 2026

Ex Vivo Assessment of Contractility, Fatigability and Alternans in Isolated Skeletal Muscles
14:02

Ex Vivo Assessment of Contractility, Fatigability and Alternans in Isolated Skeletal Muscles

Published on: November 1, 2012

Contractility Measurements on Isolated Papillary Muscles for the Investigation of Cardiac Inotropy in Mice
06:22

Contractility Measurements on Isolated Papillary Muscles for the Investigation of Cardiac Inotropy in Mice

Published on: September 17, 2015

Application of Chronic Stimulation to Study Contractile Activity-induced Rat Skeletal Muscle Phenotypic Adaptations
09:50

Application of Chronic Stimulation to Study Contractile Activity-induced Rat Skeletal Muscle Phenotypic Adaptations

Published on: January 25, 2018

Area of Science:

  • Exercise Physiology
  • Environmental Physiology
  • Skeletal Muscle Biology

Background:

  • Skeletal muscle's high energy demand makes it sensitive to oxygen levels.
  • Previous research primarily focused on voluntary contractions under hypoxia.
  • Skeletal muscle function encompasses both voluntary and evoked contractions, including force-frequency properties.

Purpose of the Study:

  • To review the effects of acute and prolonged hypoxia on human skeletal muscle performance.
  • To examine the impact of hypoxia on skeletal muscle contractile properties.
  • To understand how excitation-contraction coupling is affected by varying oxygen availability.

Main Methods:

  • Review of existing human studies on skeletal muscle function during hypoxia.
  • Analysis of data from simulated altitude exposures and brief hypoxic events.
  • Consideration of physiological conditions, including extreme environments like Mt. Everest.

Main Results:

  • Hypoxia causes only modest changes in muscle action potential propagation during voluntary contractions.
  • Maximal force-generating capacity in humans remains largely unchanged under physiological hypoxic conditions.
  • Adaptations to chronic hypoxia mitigate skeletal muscle dysfunction seen in acute hypoxia for certain exercises.

Conclusions:

  • Human skeletal muscle exhibits remarkable resilience to acute hypoxia regarding maximal force output.
  • Chronic hypoxia adaptations offer protection against skeletal muscle impairments.
  • Sustained isometric exercise above 30% MVC causing ischemia is unaffected by acute hypoxia.