Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Motor Unit Stimulation

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...

Specialized Characteristics of Cardiac Muscles

Specialized Characteristics of Cardiac Muscles

The primary role of cardiac muscles is to propel blood throughout the cardiovascular system. The cardiac muscle cells, or cardiomyocytes, exhibit specialized characteristics that allow them to perform this function.
Cardiac muscle cells are smaller than skeletal muscles, averaging 10–20 mm in diameter and 50–100 mm in length. However, they have large energy demands for continuous contraction and relaxation. This energy is almost exclusively derived from aerobic metabolism of energy reserves in...

Muscle Stimulation Frequency

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...

Motor Units

Motor Units

The motor unit is a fundamental component of the neuromuscular system and plays a crucial role in coordinating muscle contractions. It consists of a somatic motor neuron, which connects and controls multiple skeletal muscle fibers, forming a single functional segment. The axon of the motor neuron branches out and establishes synaptic connections known as neuromuscular junctions with individual muscle fibers within the motor unit.
Motor units come in different sizes, with smaller units...

Motor Units

Motor Units

A motor unit consists of two main components: a single efferent motor neuron (i.e., a neuron that carries impulses away from the central nervous system) and all of the muscle fibers it innervates. The motor neuron may innervate multiple muscle fibers, which are single cells, but only one motor neuron innervates a single muscle fiber.

Smooth Muscle Contraction

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...

You might also read

Related Articles

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

Sort by

Same author

Adaptation of Muscles With Different Physiological Properties to Resistance Training With and Without Bloodflow Restriction.

Sports health·2026

Same author

Association between adherence to the Mediterranean diet and metabolic syndrome in children and adolescents: a systematic review and meta-analysis.

BMJ nutrition, prevention & health·2026

Same author

Age-related differences in force steadiness and motor unit behavior during dynamic ankle dorsiflexions.

Journal of neurophysiology·2026

Same author

Field Position-Related Variations in Body Mass, Postural Control, and Isokinetic Strength in Portuguese Professional Football.

Journal of functional morphology and kinesiology·2025

Same author

Muscle Strength and Fatness on Falls and Fear of Falling Among Older Adults.

Journal of aging and physical activity·2025

Same author

Effects of Global Postural Re-Education Versus Specific Therapeutic Exercises on Pain, Head Posture, and Pain-Related Psychosocial Factors in Women with Chronic Nonspecific Neck Pain: A Randomized Clinical Trial.

Journal of clinical medicine·2025

Search research articles

Related Experiment Video

Updated: Jun 20, 2026

Functional Isolation of Single Motor Units of Rat Medial Gastrocnemius Muscle

Functional Isolation of Single Motor Units of Rat Medial Gastrocnemius Muscle

Published on: December 26, 2020

Motor unit conduction velocity during sustained contraction after eccentric exercise.

Nosratollah Hedayatpour¹, Deborah Falla, Lars Arendt-Nielsen

¹Centre for Sensory-Motor Interaction, Department of Health Science and Technology, Aalborg University, Denmark.

Medicine and Science in Sports and Exercise

|September 4, 2009

Summary

This summary is machine-generated.

Eccentric exercise damages muscle fibers, reducing force and slowing action potential propagation velocity. This study quantifies these changes in motor units after exercise.

More Related Videos

Muscle Velocity Recovery Cycles to Examine Muscle Membrane Properties

Muscle Velocity Recovery Cycles to Examine Muscle Membrane Properties

Published on: February 19, 2020

Simultaneous Intracellular Recording of a Lumbar Motoneuron and the Force Produced by its Motor Unit in the Adult Mouse In vivo

Simultaneous Intracellular Recording of a Lumbar Motoneuron and the Force Produced by its Motor Unit in the Adult Mouse In vivo

Published on: December 5, 2012

Related Experiment Videos

Last Updated: Jun 20, 2026

Functional Isolation of Single Motor Units of Rat Medial Gastrocnemius Muscle

Functional Isolation of Single Motor Units of Rat Medial Gastrocnemius Muscle

Published on: December 26, 2020

Muscle Velocity Recovery Cycles to Examine Muscle Membrane Properties

Muscle Velocity Recovery Cycles to Examine Muscle Membrane Properties

Published on: February 19, 2020

Simultaneous Intracellular Recording of a Lumbar Motoneuron and the Force Produced by its Motor Unit in the Adult Mouse In vivo

Simultaneous Intracellular Recording of a Lumbar Motoneuron and the Force Produced by its Motor Unit in the Adult Mouse In vivo

Published on: December 5, 2012

Area of Science:

Exercise Physiology
Muscle Electrophysiology
Neuromuscular Function

Background:

Eccentric contractions cause muscle fiber damage, leading to reduced force generation and increased membrane permeability.
Altered membrane permeability affects muscle fiber depolarization and action potential propagation velocity.

Purpose of the Study:

To investigate changes in action potential propagation velocity in individual motor units.
Assess these changes at 24 and 48 hours post-eccentric exercise.

Main Methods:

Recorded multichannel surface and intramuscular EMG from the vastus medialis muscle in 10 healthy men.
Subjects performed isometric contractions at 10% and 30% of maximal voluntary contraction (MVC).

Main Results:

Maximal voluntary contraction (MVC) force decreased significantly post-exercise (23-26%).
Motor unit conduction velocity decreased by 6-8% across different contraction intensities and muscle locations.
Conduction velocity showed a time-dependent decrease during sustained contractions post-exercise.

Conclusions:

Exercise-induced muscle damage alters the electrophysiological membrane properties of muscle fibers.
These alterations impact the speed of action potential propagation within motor units.