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

You might also read

Related Articles

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

Sort by
Same author

The Explosion of Life: Lessons from Live Imaging of Ovulation.

Reproduction (Cambridge, England)·2026
Same author

Characterizing individual differences in SCR responsivity: A hybrid mixture and single-trial modeling framework.

Biological psychology·2026
Same author

Integrated multiclass driver ctDNA profiling enables MPNST detection and monitoring in NF1 patients.

NPJ precision oncology·2026
Same author

Outcomes of Lung Transplantation for Pulmonary Sarcoidosis Across Multiple Eras: A 25-Year Experience from a US Center.

Sarcoidosis, vasculitis, and diffuse lung diseases : official journal of WASOG·2026
Same author

How Gun Violence Exposure Influences Racial Health Disparities among Adults in the United States.

Journal of racial and ethnic health disparities·2026
Same author

Update of the EORTC Health-related Quality of Life Modules for Bladder Cancer: Phase 1-2 of the Development Process.

European urology oncology·2026

Related Experiment Video

Updated: Mar 9, 2026

An Instrumented Pull Test to Characterize Postural Responses
12:18

An Instrumented Pull Test to Characterize Postural Responses

Published on: April 6, 2019

11.5K

Effect of Different Onset Thresholds on Isometric Midthigh Pull Force-Time Variables.

Thomas DosʼSantos1, Paul A Jones, Paul Comfort

  • 1Human Performance Laboratory, Directorate of Sport, Exercise, and Physiotherapy, University of Salford, Greater Manchester, United Kingdom.

Journal of Strength and Conditioning Research
|December 22, 2016
PubMed
Summary

The study recommends using a 5 standard deviations (SDs) of body weight (BW) onset threshold for accurate isometric midthigh pull (IMTP) force-time data. This threshold minimizes signal noise and ensures reliable measurement of force development, unlike relative BW thresholds.

More Related Videos

In Vivo Measurement of Hindlimb Dorsiflexor Isometric Torque from Pig
09:41

In Vivo Measurement of Hindlimb Dorsiflexor Isometric Torque from Pig

Published on: September 3, 2021

4.5K
Determining The Electromyographic Fatigue Threshold Following a Single Visit Exercise Test
06:00

Determining The Electromyographic Fatigue Threshold Following a Single Visit Exercise Test

Published on: July 27, 2015

13.2K

Related Experiment Videos

Last Updated: Mar 9, 2026

An Instrumented Pull Test to Characterize Postural Responses
12:18

An Instrumented Pull Test to Characterize Postural Responses

Published on: April 6, 2019

11.5K
In Vivo Measurement of Hindlimb Dorsiflexor Isometric Torque from Pig
09:41

In Vivo Measurement of Hindlimb Dorsiflexor Isometric Torque from Pig

Published on: September 3, 2021

4.5K
Determining The Electromyographic Fatigue Threshold Following a Single Visit Exercise Test
06:00

Determining The Electromyographic Fatigue Threshold Following a Single Visit Exercise Test

Published on: July 27, 2015

13.2K

Area of Science:

  • Biomechanics
  • Sports Science
  • Human Movement Analysis

Background:

  • The isometric midthigh pull (IMTP) is a common assessment in sports science.
  • Various onset thresholds are used to determine the start of muscle contraction during IMTP.
  • A lack of consensus on the optimal onset threshold complicates data interpretation and comparison.

Purpose of the Study:

  • To compare the effects of different relative body weight (BW) and arbitrary onset thresholds against a criterion threshold (5 SDs of BW).
  • To analyze the impact of these thresholds on key IMTP force-time variables.
  • To determine the most reliable onset threshold for accurate force-time data analysis.

Main Methods:

  • Nine academy rugby league players performed two IMTP trials each on a force platform.
  • Force-time data were analyzed using five different onset thresholds, including relative BW and SDs of BW.
  • Data were compared against a criterion threshold of 5 SDs of BW to assess variability in force-time variables.

Main Results:

  • The 5 SDs of BW threshold yielded significantly lower threshold force compared to 10% BW and 75 N thresholds.
  • Using lower thresholds (e.g., 10% BW) resulted in significantly higher time-specific force values and unacceptable limits of agreement.
  • No significant differences were found between 2.5% BW and 5 SDs of BW, or between 5% BW and 5 SDs of BW thresholds for most variables.

Conclusions:

  • The 5 SDs of BW onset threshold is recommended for accurate measurement of time-specific force values and rate of force development (RFD) in IMTP.
  • This threshold effectively accounts for signal noise during the initial weighing period, ensuring a more precise identification of muscle contraction onset.
  • Using the 5 SDs of BW threshold enhances the reliability and validity of IMTP data for scientists and practitioners.