Force
Optimization of Skeletal Muscle (Grant # HD-41254)
Electrical
stimulation of skeletal muscle can be used to assist individuals paralyzed due
to central nervous system dysfunction to perform functional movements. Muscle fatigue, however, is a major
limitation in the practical use of this approach. Previous work has shown that patterns of
activation using variable-frequency trains (VFT’s)
that exploit the catch-like property of skeletal muscle produce greater forces
than traditionally used constant-frequency trains (CFT’s),
particularly in fatigued muscle. The
proposed studies will extend these previous findings and will provide
information that is needed to identify stimulation patterns that maximize force
and minimize fatigue under a variety of physiological conditions. The overall goal of this work is to enhance
our understanding of the factors that affect the force responses of skeletal
muscle to electrical stimulation using brief trains of pulses.
The long-term
goal of these studies is to contribute to the development of techniques and
hardware that improve the usefulness of FES.
The immediate goal of this study is to determine the stimulation
frequencies and patterns both within and across trains that maximize
performance during repetitive electrically elicited contractions of muscles
from subjects with spinal cord injuries.
A combination of experimental and modeling work is proposed to attack
this problem.
• Specific Aim 1 attempts to extend our understanding of variable-frequency train
stimulation to include its effect on the forces and fatigue produced from
muscles of subjects with spinal cord injuries (SCI).
• Specific Aim 2 continues the development and testing of mathematical models that
predict the force output and fatigue produced in response to a wide range of
stimulation frequencies and patterns.
These models
will allow us to identify the stimulation frequencies and patterns that
optimize any aspect(s) of the muscle’s response that we determine to be
important and will predict the “optimal activation pattern” for individual
subjects based on their responses to a brief period of testing. Both of these aims include the study of
isometric and non-isometric contractions.
Stuart
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Last Updated 1/14/2005