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

Classification of Skeletal Muscle Fibers01:48

Classification of Skeletal Muscle Fibers

58.5K
Skeletal muscles continuously produce ATP to provide the energy that enables muscle contractions. Skeletal muscle fibers can be categorized into three types based on differences in their contraction speed and how they produce ATP, as well as physical differences related to these factors. Most human muscles contain all three muscle fiber types, albeit in varying proportions.
Slow-Twitch Muscle Fibers
Slow oxidative, muscle fibers appear red due to large numbers of capillaries and high levels of...
58.5K
Muscle Recovery and Fatigue01:24

Muscle Recovery and Fatigue

3.5K
Muscle fatigue refers to the decline in a muscle's ability to maintain the force of contraction after prolonged activity. It primarily stems from changes within muscle fibers. Even before experiencing muscle fatigue, one may feel tired and have the urge to stop the activity. This response, known as central fatigue, occurs due to changes in the central nervous system, namely the brain and spinal cord. While there is no single mechanism that induces fatigue, it may serve as a protective...
3.5K
Types of Skeletal Muscle Fibers01:32

Types of Skeletal Muscle Fibers

3.5K
Skeletal muscles comprise various fibers, each with distinct characteristics and roles in movement and stability. They are mainly categorized into three types — fast-twitch, slow-twitch, and intermediate.
Fast-twitch fibers
Fast-twitch fibers, or Type II fibers, are designed for quick, powerful bursts of speed and strength. They reach peak tension within approximately 0.01 seconds following stimulation. Characterized by a large diameter and densely packed myofibrils, these fibers contain...
3.5K
Exercise and Muscle Performance01:27

Exercise and Muscle Performance

2.0K
Exercise induces a range of adaptations in muscle tissue, depending on the type and duration of activity. Such physical training can be broadly categorized into two types: endurance exercises and resistance exercises.
Endurance exercises
Endurance exercises involve running, swimming, or cycling, which require repetitive movements with low force output. When a person engages in endurance exercise, a few noticeable changes occur in their skeletal muscles. For instance, the number of capillaries...
2.0K
Energy Supply for Muscle Contraction01:25

Energy Supply for Muscle Contraction

4.8K
Skeletal muscle fibers have the unique ability to switch between rest and contraction states, using different sources of ATP for energy. The contraction cycle and Ca2+ transport back into the sarcoplasmic reticulum for relaxation require significant ATP. However, the ATP reserves in muscle fibers are limited and can only sustain contractions for a few seconds. Additional ATP production becomes necessary for prolonged contractions. As a result, muscle fibers generate ATP through various sources,...
4.8K
Pathophysiology of Cardiac Performance01:29

Pathophysiology of Cardiac Performance

1.0K
Typical heart performance is influenced by heart rate, rhythm, myocardial contraction, and metabolism or blood flow. The cardiac muscle exhibits distinct electrophysiological features, including pacemaker activity and calcium channel control, which play a vital role in the heart's response to various drugs. The autonomic nervous system, comprising the sympathetic and parasympathetic branches, regulates heart rate. Sympathetic activation increases heart rate, while parasympathetic activation...
1.0K

You might also read

Related Articles

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

Sort by
Same author

Effects of acute resistance exercise on prefrontal oxygenation and task-switching performance: Considerations of loading strategies and blood flow restriction.

Behavioural brain research·2026
Same author

Fatiguing, Unilateral, Maximal Intended Velocity Leg Extensions Do Not Affect the Performance of the Contralateral Limb.

Journal of strength and conditioning research·2026
Same author

Passive Blood Flow Restriction Accelerates Muscle Recovery After Exercise-Induced Muscle Damage in Healthy, Recreationally Active Females.

Journal of strength and conditioning research·2026
Same author

Early-Phase and Cross-Education Adaptations Following Very Short-Term Unilateral Isokinetic Forearm Extension and Flexion Training in Untrained Women.

Muscles (Basel, Switzerland)·2026
Same author

Submaximal running with blood flow restriction induces similar muscle oxygenation responses relative to maximal unrestricted running.

Physiology international·2026
Same author

The effect of muscle oxygenation on neuromuscular efficiency and force complexity.

European journal of applied physiology·2025

Related Experiment Video

Updated: Nov 8, 2025

Skeletal Muscle Neurovascular Coupling, Oxidative Capacity, and Microvascular Function with 'One Stop Shop' Near-infrared Spectroscopy
09:04

Skeletal Muscle Neurovascular Coupling, Oxidative Capacity, and Microvascular Function with 'One Stop Shop' Near-infrared Spectroscopy

Published on: February 20, 2018

12.7K

Are mode-specific differences in performance fatigability attributable to muscle oxygenation?

John Paul V Anders1, Tyler J Neltner2, Joshua L Keller3

  • 1Department of Nutrition and Human Sciences, University of Nebraska-Lincoln, Lincoln, NE, 68510, USA. janders@huskers.unl.edu.

European Journal of Applied Physiology
|April 24, 2021
PubMed
Summary

Unilateral leg extensions fatigue faster than bilateral ones, but muscle oxygenation differences do not explain this. Individual responses in muscle oxygenation vary significantly during fatigue.

Keywords:
DynamicIsokineticNear-infrared spectroscopy

More Related Videos

Using Near-Infrared Spectroscopy Wearable Devices to Identify Central Versus Peripheral Limitations During Exercise
09:33

Using Near-Infrared Spectroscopy Wearable Devices to Identify Central Versus Peripheral Limitations During Exercise

Published on: December 19, 2024

1.1K
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

24.2K

Related Experiment Videos

Last Updated: Nov 8, 2025

Skeletal Muscle Neurovascular Coupling, Oxidative Capacity, and Microvascular Function with 'One Stop Shop' Near-infrared Spectroscopy
09:04

Skeletal Muscle Neurovascular Coupling, Oxidative Capacity, and Microvascular Function with 'One Stop Shop' Near-infrared Spectroscopy

Published on: February 20, 2018

12.7K
Using Near-Infrared Spectroscopy Wearable Devices to Identify Central Versus Peripheral Limitations During Exercise
09:33

Using Near-Infrared Spectroscopy Wearable Devices to Identify Central Versus Peripheral Limitations During Exercise

Published on: December 19, 2024

1.1K
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

24.2K

Area of Science:

  • Exercise physiology
  • Muscle physiology
  • Biomedical engineering

Background:

  • Muscle oxygenation, including deoxygenated hemoglobin and myoglobin (deoxy[heme]), oxygenated hemoglobin and myoglobin (oxy[heme]), and total hemoglobin and myoglobin (total[heme]), is crucial for understanding muscle fatigue.
  • Tissue saturation index (StO2%) provides insights into muscle oxygen availability during exercise.

Purpose of the Study:

  • To investigate composite, intra-individual, and inter-individual response patterns of muscle oxygenation parameters during fatiguing, maximal, isokinetic leg extensions.
  • To compare these patterns between unilateral and bilateral leg extension conditions.

Main Methods:

  • Nine healthy men performed unilateral and bilateral maximal, concentric, isokinetic leg extensions at 180°/s.
  • Muscle oxygenation (deoxy[heme], oxy[heme], total[heme], StO2%) and isokinetic torque were measured using near-infrared spectroscopy and an isokinetic dynamometer.
  • Repeated measures ANOVAs and polynomial regression analyses examined differences in fatigue-induced responses.

Main Results:

  • Unilateral leg extensions showed greater performance fatigability compared to bilateral extensions.
  • Across conditions, deoxy[heme] increased and StO2% decreased significantly with fatigue.
  • The bilateral condition exhibited a more sustained decline in oxy[heme] than the unilateral condition.
  • Deoxy[heme], oxy[heme], and total[heme] demonstrated significant intra- and inter-individual variability in fatigue responses.

Conclusions:

  • Greater fatigability in unilateral versus bilateral leg extensions is not explained by differences in muscle oxygenation.
  • Future research on muscle oxygenation during fatigue should report both individual and composite response patterns due to significant variability.