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

Muscle Stimulation Frequency01:22

Muscle Stimulation Frequency

3.8K
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...
3.8K
Muscle Contraction01:15

Muscle Contraction

94.3K
 
94.3K
Muscle Contraction01:10

Muscle Contraction

8.1K
In skeletal muscles, acetylcholine is released by nerve terminals at the motor endplate—the point of synaptic communication between motor neurons and muscle fibers. The binding of acetylcholine to its receptors on the sarcolemma allows entry of sodium ions into the cell and triggers an action potential in the muscle cell. Thus, electrical signals from the brain are transmitted to the muscle. Subsequently, the enzyme acetylcholinesterase breaks down acetylcholine to prevent excessive...
8.1K
Excitation-Contraction Coupling in Skeletal Muscles01:20

Excitation-Contraction Coupling in Skeletal Muscles

12.1K
Excitation-contraction coupling is a series of events that occur between generating an action potential and initiating a muscle contraction. It occurs at the triad, a structure found in skeletal muscle fibers that comprise a T-tubule and terminal cisternae of the sarcoplasmic reticulum on each side. These triads are visible in longitudinally sectioned muscle fibers. They are typically located at the A-I junction — the junction between the A and I bands of the sarcomere.
When an action...
12.1K
Motor Unit Stimulation01:20

Motor Unit Stimulation

3.0K
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...
3.0K
Generation of Action Potential in Skeletal Muscles01:24

Generation of Action Potential in Skeletal Muscles

7.2K
Every cell in the body maintains a membrane potential due to an uneven distribution of positive and negative charges across its plasma membrane. The membrane potential is measured in millivolts and quantifies the difference in charge across the membrane.
Like neurons, muscle cells are also regarded as excitable due to their capacity to change in response to stimuli, primarily due to voltage-gated ion channels embedded in their plasma membranes, which get activated by alterations in the...
7.2K

You might also read

Related Articles

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

Sort by
Same author

Early rehabilitation after total hip or knee joint replacement: a narrative review.

European journal of translational myology·2026
Same author

Isometric single-joint rate of force development shows trivial to small associations with jumping rate of force development, jump height, and propulsive duration.

JSAMS plus·2026
Same author

Vibration Perception Threshold as a Method for Detecting Diabetic Peripheral Neuropathy: A Systematic Review of Measurement Characteristics.

Diagnostics (Basel, Switzerland)·2026
Same author

Do Flywheel Exercises Provide Eccentric-Overload Training?

Sports medicine - open·2026
Same author

Joint torque and electromyographic activity during eccentric exercise for hip adductors at different hip flexion angles.

PloS one·2025
Same author

Curvilinear sprint acceleration-speed profile in youth soccer players is constrained by tighter radii and sprinting side dominance.

Journal of biomechanics·2025

Related Experiment Video

Updated: Nov 10, 2025

Author Spotlight: Bridging the Gap Between In Vivo and Ex Vivo Studies with the "Avatar" Technique to Advance Muscle Mechanics Research
07:03

Author Spotlight: Bridging the Gap Between In Vivo and Ex Vivo Studies with the "Avatar" Technique to Advance Muscle Mechanics Research

Published on: August 18, 2023

1.1K

Muscle Activation Sequence in Flywheel Squats.

Darjan Spudić1, Darjan Smajla2,3, Michael David Burnard3

  • 1Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia.

International Journal of Environmental Research and Public Health
|April 3, 2021
PubMed
Summary
This summary is machine-generated.

Muscle coordination during flywheel (FW) squats is load-dependent. Lower loads follow a proximal-to-distal activation pattern, while higher loads require a distinct, stable coordination strategy for effective exercise.

Keywords:
EMGeccentric exerciseisoinertial trainingmuscle coordinationoverload

More Related Videos

Quantifying Arms and Legs Contributions during Repetitive Electrically-Assisted Sit-To-Stand Exercise in Paraplegics: A Pilot Study
08:40

Quantifying Arms and Legs Contributions during Repetitive Electrically-Assisted Sit-To-Stand Exercise in Paraplegics: A Pilot Study

Published on: November 11, 2022

1.3K
Muscle Function Obtained with Motion Mode Ultrasound and Surface Electromyography during Core Endurance Exercise
09:21

Muscle Function Obtained with Motion Mode Ultrasound and Surface Electromyography during Core Endurance Exercise

Published on: August 25, 2022

3.5K

Related Experiment Videos

Last Updated: Nov 10, 2025

Author Spotlight: Bridging the Gap Between In Vivo and Ex Vivo Studies with the "Avatar" Technique to Advance Muscle Mechanics Research
07:03

Author Spotlight: Bridging the Gap Between In Vivo and Ex Vivo Studies with the "Avatar" Technique to Advance Muscle Mechanics Research

Published on: August 18, 2023

1.1K
Quantifying Arms and Legs Contributions during Repetitive Electrically-Assisted Sit-To-Stand Exercise in Paraplegics: A Pilot Study
08:40

Quantifying Arms and Legs Contributions during Repetitive Electrically-Assisted Sit-To-Stand Exercise in Paraplegics: A Pilot Study

Published on: November 11, 2022

1.3K
Muscle Function Obtained with Motion Mode Ultrasound and Surface Electromyography during Core Endurance Exercise
09:21

Muscle Function Obtained with Motion Mode Ultrasound and Surface Electromyography during Core Endurance Exercise

Published on: August 25, 2022

3.5K

Area of Science:

  • Biomechanics and Kinesiology
  • Exercise Physiology
  • Neuromuscular Control

Background:

  • Muscle coordination is crucial for designing effective therapeutic and exercise interventions.
  • Flywheel (FW) training utilizes equipment mimicking functional movements.
  • This study is the first to investigate muscle coordination during FW squats.

Purpose of the Study:

  • To assess the muscle activation order during flywheel squats.
  • To determine how different flywheel loads influence muscle coordination patterns.
  • To compare observed muscle activation with the expected proximal-to-distal principle.

Main Methods:

  • Electromyography (EMG) was used to measure the time-of-peak activation for leg muscles.
  • Four different flywheel loads (0.025, 0.05, 0.075, 0.1 kg·m²) were analyzed.
  • Sequential Rank Agreement (SRA) and Kendall's tau tests were employed to analyze activation order and concordance.

Main Results:

  • A latent muscle activation order was identified at higher flywheel loads (0.05-0.1 kg·m²).
  • The proximal-to-distal muscle activation principle was observed only at the lowest load (0.025 kg·m²).
  • Muscle activation order showed high concordance across higher loads and moderate-to-strong concordance with the expected order at the lowest load.

Conclusions:

  • Muscle activation patterns during FW squats are load-dependent.
  • Higher flywheel loads necessitate a specific, stable muscle coordination strategy beyond the proximal-to-distal principle.
  • Understanding these load-specific coordination patterns can optimize FW training interventions.