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

Motor Unit Stimulation01:20

Motor Unit Stimulation

4.2K
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...
4.2K
Muscle Stimulation Frequency01:22

Muscle Stimulation Frequency

4.9K
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...
4.9K
Isotonic and Isometric Muscle Contractions01:22

Isotonic and Isometric Muscle Contractions

8.2K
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...
8.2K
Overview of Muscle Tissues01:25

Overview of Muscle Tissues

25.0K
The human body has three types of muscle tissue: skeletal, smooth, and cardiac. Each class has unique properties that enable them to perform specific functions. However, all muscle tissues share certain properties, including elasticity, contractility, and excitability. 
Elasticity
Elasticity is the ability of muscles to stretch and return to their original shape. This property is partly due to elastic fibers — macromolecules that run through the muscles. These fibers are firm and...
25.0K
Excitation-Contraction Coupling in Skeletal Muscles01:20

Excitation-Contraction Coupling in Skeletal Muscles

16.7K
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...
16.7K
Somatic Spinal Reflexes01:22

Somatic Spinal Reflexes

6.4K
Somatic spinal reflexes are rapid, involuntary muscular responses to external stimuli that involve the somatic musculature and the spinal cord.
One of the most well-known somatic spinal reflexes is the stretch reflex, which is activated by the sudden stretching of a muscle. This reflex involves the activation of specialized sensory receptors called muscle spindles, which are located in the muscle tissue and detect changes in the length and speed of muscle contractions. When a muscle is suddenly...
6.4K

You might also read

Related Articles

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

Sort by
Same author

Peripheral Neuromuscular Fatigue Responses of the Knee Extensors to Distinct Concurrent Training Protocols: A Preliminary Study.

Journal of functional morphology and kinesiology·2026
Same author

Strength and Conditioning Society (SCS) 8th Annual Meeting, Oslo, Norway, 2025.

Sports (Basel, Switzerland)·2026
Same author

Reduced physical activity during submarine deployment: health and performance consequences and feasible countermeasures-a narrative review.

Journal of occupational health·2026
Same author

What are the neurological, neurovascular, and psychological responses to stretching across the general population?

European journal of applied physiology·2026
Same author

Influence of Intended Slow and Fast Eccentric Back Squat Velocity on Subsequent Countermovement Jump Performance.

Journal of functional morphology and kinesiology·2026
Same author

Sex- and age-specific blood lactate recovery kinetics after high-intensity exercise in trained youth: a model-based analysis.

European journal of applied physiology·2026

Related Experiment Video

Updated: Mar 8, 2026

Evaluation of Muscle Function of the Extensor Digitorum Longus Muscle Ex vivo and Tibialis Anterior Muscle In situ in Mice
14:36

Evaluation of Muscle Function of the Extensor Digitorum Longus Muscle Ex vivo and Tibialis Anterior Muscle In situ in Mice

Published on: February 9, 2013

43.7K

Developmental differences in dynamic muscle-tendon behaviour: implications for movement efficiency.

Charlie M Waugh1,2, Thomas Korff3, Anthony J Blazevich1,4

  • 1Centre for Human Performance, Exercise and Rehabilitation, Brunel University, Uxbridge, Middlesex UB8 3PH, UK.

The Journal of Experimental Biology
|January 22, 2017
PubMed
Summary

Children use less elastic energy during hopping than adults, suggesting less efficient movement. However, both age groups select a hopping frequency that optimizes energy savings.

Keywords:
AchillesChildrenElastic energyHoppingStretch–shortening cycle

More Related Videos

Construction of Constant-Load (Isotonic) and Constant-Velocity (Isokinetic) Torque-Velocity-Power Profiles In vivo for the Rat Plantar Flexors
07:44

Construction of Constant-Load (Isotonic) and Constant-Velocity (Isokinetic) Torque-Velocity-Power Profiles In vivo for the Rat Plantar Flexors

Published on: October 3, 2025

767
In Vivo Canine Muscle Function Assay
09:34

In Vivo Canine Muscle Function Assay

Published on: April 5, 2011

17.6K

Related Experiment Videos

Last Updated: Mar 8, 2026

Evaluation of Muscle Function of the Extensor Digitorum Longus Muscle Ex vivo and Tibialis Anterior Muscle In situ in Mice
14:36

Evaluation of Muscle Function of the Extensor Digitorum Longus Muscle Ex vivo and Tibialis Anterior Muscle In situ in Mice

Published on: February 9, 2013

43.7K
Construction of Constant-Load (Isotonic) and Constant-Velocity (Isokinetic) Torque-Velocity-Power Profiles In vivo for the Rat Plantar Flexors
07:44

Construction of Constant-Load (Isotonic) and Constant-Velocity (Isokinetic) Torque-Velocity-Power Profiles In vivo for the Rat Plantar Flexors

Published on: October 3, 2025

767
In Vivo Canine Muscle Function Assay
09:34

In Vivo Canine Muscle Function Assay

Published on: April 5, 2011

17.6K

Area of Science:

  • Biomechanics
  • Human Movement Science
  • Pediatric Physiology

Background:

  • Children exhibit reduced efficiency in cyclic motor tasks compared to adults.
  • Underlying mechanisms for age-related differences in movement efficiency are not fully understood.
  • Differential muscle and tendon contributions to muscle-tendon unit (MTU) excursion may play a role.

Purpose of the Study:

  • Compare muscle and tendon excursion during vertical hopping in children and adults.
  • Investigate if children and adults select hopping frequencies that maximize movement efficiency via energy-saving mechanisms.

Main Methods:

  • 12 children (8.8 yrs) and 12 adults (26.0 yrs) performed hopping at various frequencies.
  • 3D motion capture and ultrasonography estimated gastrocnemius medialis MTU, muscle, and tendon excursions.
  • Optimum hopping frequency was defined by maximized elastic energy storage and minimized muscle excursion.

Main Results:

  • Adults demonstrated greater elastic energy storage potential and lower muscle excursion than children at self-selected frequencies.
  • Children appear less effective at utilizing energy-saving mechanisms during hopping compared to adults.
  • Both children and adults selected preferred hopping frequencies that maximized tendon elastic energy storage and minimized muscle excursion.

Conclusions:

  • Children's reduced efficiency in hopping may stem from less effective utilization of muscle-tendon unit energy-saving mechanisms.
  • Despite differences, children and adults appear to select preferred hopping frequencies based on similar criteria for optimizing movement efficiency.
  • Findings enhance understanding of age-related differences in movement energetics and task performance.