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ISSO Y2005 Annual Report | Contents Voluntary Muscle Contractions in Advance of Mechanical Foot
Stimulation To Enhance Neuromuscular Reflex Responses • 109-114 Abstract--Researchers seek to determine the modulating effect of background muscle activity on enhanced neuromuscular responses to mechanical foot stimulation. A small solenoid embedded within a platform provided non-noxious stimulation to the lateral portion of the sole for 100 ms at 3 mm protrusion. Stimulation was applied during different contraction levels of the homonymous muscle and of remote, Jendrassik-like contractions. Root mean square electromyography was measured from the soleus and lateral gastrocnemius. Homonymous muscle contraction linearly increased the neuromuscular response to foot stimulation, although no effect was exhibited from remote contractions. The levels of response to stimulation in all conditions were 80-100 percent of maximal contraction levels. Mechanical foot stimulation can be used to elicit and enhance neuromuscular activity of the triceps surae muscles, particularly when combined with preexisting "background" voluntary contractions. This activity could be used to attenuate neuromuscular degradation experienced during prolonged bedrest and during extended stays in microgravity. |
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