Related Experiment Video
Updated: Jun 10, 2026

In Vivo Measurement of Hindlimb Dorsiflexor Isometric Torque from Pig
Published on: September 3, 2021
Time-dependent effects of pre-conditioning activation on muscle fiber conduction velocity and twitch torque
Ernest Nlandu Kamavuako1, Dario Farina
1Center for Sensory-Motor Interaction, Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7 D-3, DK-9220 Aalborg, Denmark.
Abstract:
In this study we investigate the range of interstimulus intervals influencing the recovery functions for conduction velocity (velocity recovery function, or VRF) and twitch torque (twitch torque recovery function, or TRF) of muscle fibers. We studied the tibialis anterior muscle of 8 healthy men by varying the time interval between a pair of stimuli in the range of 4-1000 ms, with (triplet) and without (doublet) a preconditioning stimulus. For triplet stimulations, the interval between the first and second stimulus or between the second and third stimulus was fixed, and the other interval was varied. VRF and TRF were influenced by a preconditioning stimulus only when it was delivered within 125 ms and 30 ms, respectively, before the doublet stimulation. The results provide evidence of the range of preconditioning intervals influencing the VRF and TRF; this is relevant for understanding the mechanisms of force generation and for standardizing compound action potential measurements.
Related Concept Videos
Motor Unit Stimulation
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...
Muscle Stimulation Frequency
Wave summation
At low firing rates, motor neurons induce individual twitch contractions in muscle fibers. These twitches...
Relaxation of Skeletal Muscles
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open.
Excitation-Contraction Coupling in Skeletal Muscles
When an action potential...
Muscle Contraction
Muscle Contraction

