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

3.3K
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...
3.3K
Muscle Recovery and Fatigue01:24

Muscle Recovery and Fatigue

3.7K
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...
3.7K
Energy Supply for Muscle Contraction01:25

Energy Supply for Muscle Contraction

5.1K
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,...
5.1K
Muscle Stimulation Frequency01:22

Muscle Stimulation Frequency

4.1K
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...
4.1K
Impact Loading01:19

Impact Loading

553
Impact loading occurs when a moving object collides with a stationary structure, such as a rod with a uniform cross-sectional area fixed at one end. Under these conditions, the rod absorbs the kinetic energy from the striking object, leading to deformation and subsequent stress development. As the rod returns to its original position and reaches maximum stress, the absorbed energy, initially manifested as kinetic energy, transforms entirely into strain energy.
In cases of elastic deformation,...
553
Design Consideration01:22

Design Consideration

461
Designing a structure involves a series of considerations, primarily the material's ultimate strength, calculated through tests that measure changes under increased force until the material reaches its breaking point or limit. The ultimate load, where the material breaks, is divided by its original cross-sectional area, resulting in the ultimate normal stress or strength. The ultimate shearing stress is another significant factor taken into account.
The factor of safety is another key...
461

You might also read

Related Articles

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

Sort by
Same author

Novel measures of frontal plane knee wobbling predict anterior cruciate ligament injury in Japanese female basketball players: A prospective pilot study.

Clinical biomechanics (Bristol, Avon)·2026
Same author

Applying Differential Learning During Rehabilitation After Anterior Cruciate Ligament Injury: A Basketball Single-Case Study.

Healthcare (Basel, Switzerland)·2025
Same author

Perspectives on sports analytics to inform constraint manipulation, representative learning and functional variability in practice design.

Human movement science·2025
Same author

Comparison of Gluteus Medius Muscle Activation in Women With and Without Patellofemoral Pain.

Journal of athletic training·2025
Same author

The Role of Testing and Vaccination in Mediating Social Vulnerability and COVID-19 Prevalence in Southern Nevada.

International journal of environmental research and public health·2025
Same author

Individualized task difficulty promotes balance training outcomes and self-efficacy in individuals with lower limb loss.

Prosthetics and orthotics international·2025

Related Experiment Video

Updated: Dec 13, 2025

Measurement of Maximum Isometric Force Generated by Permeabilized Skeletal Muscle Fibers
11:30

Measurement of Maximum Isometric Force Generated by Permeabilized Skeletal Muscle Fibers

Published on: June 16, 2015

26.0K

Maximal force production requires OPTIMAL conditions.

Harjiv Singh1, Arthur Hockwald1, Nicholas Drake1

  • 1University of Nevada, Las Vegas, USA.

Human Movement Science
|August 4, 2020
PubMed
Summary
This summary is machine-generated.

Optimizing testing conditions with enhanced expectancies, autonomy support, and external focus boosts maximal strength performance. Standard assessments may underestimate true capabilities without these motivational and attentional factors.

Keywords:
Autonomy supportEnhanced expectanciesExternal focusHandgrip strengthOne-repetition maximum testsSquat lift

More Related Videos

Isometric and Eccentric Force Generation Assessment of Skeletal Muscles Isolated from Murine Models of Muscular Dystrophies
14:10

Isometric and Eccentric Force Generation Assessment of Skeletal Muscles Isolated from Murine Models of Muscular Dystrophies

Published on: January 31, 2013

33.6K
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

24.5K

Related Experiment Videos

Last Updated: Dec 13, 2025

Measurement of Maximum Isometric Force Generated by Permeabilized Skeletal Muscle Fibers
11:30

Measurement of Maximum Isometric Force Generated by Permeabilized Skeletal Muscle Fibers

Published on: June 16, 2015

26.0K
Isometric and Eccentric Force Generation Assessment of Skeletal Muscles Isolated from Murine Models of Muscular Dystrophies
14:10

Isometric and Eccentric Force Generation Assessment of Skeletal Muscles Isolated from Murine Models of Muscular Dystrophies

Published on: January 31, 2013

33.6K
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

24.5K

Area of Science:

  • Motor Learning and Performance
  • Sports Science
  • Psychology of Sport

Background:

  • The OPTIMAL theory highlights motivational and attentional factors influencing motor learning.
  • Standardized assessments may not capture maximal performance due to suboptimal testing conditions.
  • Key OPTIMAL theory factors include enhanced expectancies (EE), autonomy support (AS), and external focus (EF).

Purpose of the Study:

  • To investigate the impact of optimized testing conditions on maximum force production.
  • To determine if enhanced expectancies, autonomy support, and external focus improve strength assessments.
  • To challenge the validity of standard testing protocols in reflecting true maximal capabilities.

Main Methods:

  • Experiment 1: Handgrip strength task with optimized (EE, AS, EF) vs. control (neutral) conditions.
  • Experiment 2: One-repetition maximum (1-RM) squat lift tests under optimized vs. control conditions.
  • Counterbalanced order of conditions and baseline measurements were employed.

Main Results:

  • The optimized group significantly outperformed the control group in handgrip strength after baseline.
  • Optimized conditions led to increased 1-RM squat lift performance, while control conditions showed no change.
  • Standard testing conditions appear insufficient for eliciting maximal strength output.

Conclusions:

  • Motivational and attentional factors are crucial for accurate strength performance assessment.
  • Implementing optimized testing conditions, as per the OPTIMAL theory, is essential for revealing true maximal capabilities.
  • Findings support revising standard assessment protocols to include factors that enhance performance.