Related Experiment Video
Updated: Jun 8, 2026

"Avatar", a Modified Ex vivo Work Loop Experiments Using In vivo Strain and Activation
Published on: August 18, 2023
Active response of skeletal muscle: in vivo experimental results and model formulation
1Group of Structural Mechanics and Materials Modelling, Aragón Institute of Engineering Research, University of Zaragoza, Spain.
Abstract:
The contractile properties of the tibial anterior (TA) of Wistar rats were measured by means of a multipurpose testing machine. The muscle was isolated from the connective tissues, preserving the proximal insertion. The distal tendon was transected and fixed to the machine actuator. The leg was inmobilised using a pin drilled through the femoral condyle. In this way the force response was studied in vivo at different constant lengths for some voltages and frequencies. Mathematical functions are proposed for adjusting the force-length, force-frequency and force-time relations. The model includes a novel formulation for the depression response during muscle tetanisation.
Related Concept Videos
Design Example: Frog Muscle Response
When the switch connecting the RL circuit is closed, a brief muscle contraction is observed. This is because, at a steady state, the inductor acts like a short circuit,...
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...
Generation of Action Potential in Skeletal Muscles
Like neurons, muscle cells are also regarded as excitable due to their capacity to change in response to stimuli, primarily due to voltage-gated ion channels embedded in their plasma membranes, which get activated by alterations in the cell's...
Excitation-Contraction Coupling in Skeletal Muscles
When an action potential...
Skeletal Muscle Anatomy
Muscle Contraction

