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Measurement of Maximum Isometric Force Generated by Permeabilized Skeletal Muscle Fibers
Published on: June 16, 2015
The passive properties of muscle fibers are velocity dependent
Michael R Rehorn1, Alison K Schroer1, Silvia S Blemker2
1Biomedical Engineering, University of Virginia, PO Box 800759, Health system, Charlottesville, VA 22908, United States.
Abstract:
The passive properties of skeletal muscle play an important role in muscle function. While the passive quasi-static elastic properties of muscle fibers have been well characterized, the dynamic visco-elastic passive behavior of fibers has garnered less attention. In particular, it is unclear how the visco-elastic properties are influenced by lengthening velocity, in particular for the range of physiologically relevant velocities. The goals of this work were to: (i) measure the effects of lengthening velocity on the peak stresses within single muscle fibers to determine how passive behavior changes over a range of physiologically relevant lengthening rates (0.1-10Lo/s), and (ii) develop a mathematical model of fiber viscoelasticity based on these measurements. We found that passive properties depend on strain rate, in particular at the low loading rates (0.1-3Lo/s), and that the measured behavior can be predicted across a range of loading rates and time histories with a quasi-linear viscoelastic model. In the future, these results can be used to determine the impact of viscoelastic behavior on intramuscular stresses and forces during a variety of dynamic movements.
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