Date of Award

5-31-1993

Document Type

Thesis

Degree Name

Master of Science in Biomedical Engineering - (M.S.)

Department

Biomedical Engineering Committee

First Advisor

Stanley S. Reisman

Second Advisor

David S. Kristol

Third Advisor

Yun Q. Shi

Abstract

It has previously been determined that the power spectral density of an electromyogram shifts towards lower frequencies over time during an isometric contraction. In this study the power spectral density curve was examined to see if changes would occur over a period of time as a subject walked on a treadmill at various speeds. The shapes of the power spectral densities recorded from the soleus shifted to the lower frequencies over time. The parameters associated with the curves showed trends. One of the parameters, zero crossing, demonstrated adaptation and fatigue in all four patients, for the first portion of the study. The average frequency, median frequency, quarter area frequency and three quarter area frequency dropped when calculated over the entire frequency range of 0 to 500 Hz, thus confirming the fatiguing of fast twitch fibers and recruitment of slow twitch fibers to compensate. It was found that there were similarities for four of the subjects, in the shapes of the plots for area under the curve, such as a nadir after 175 seconds of walking and an acme at 250 seconds of walking. The variance another parameter also demonstrated fatigue.

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