Journal of Applied Physiology, Vol 38, Issue 1 101-107, Copyright © 1975 by American Physiological Society
Acceleration time series resulting from repetitive extension-flexion of the hand
R. N. Stiles
Power, or variance, spectra of acceleration records obtained from normal
subjects during extension-flexion oscillations of a hand at frequencies
between 0.5-5.0 Hz generally contained two or three frequency bands.
Partial separation of these oscillations in the time domain was obtained
using the method of digital filtering (smoothing). In general, the peak
frequency of the lowest frequency band occurred at, or nearly at, the
frequency that the subject attempted to maintain during a 16-s digitization
period. Consideration of absolute frequencies and the effect of mass on
frequency indicated that one of the higher frequency bands was the result
of normal hand tremor. For low frequencies of voluntary oscillation
(0.5-1.25 Hz), a second, higher frequency band occurred with a peak
frequency (3.0-4.25 Hz) within the range (3-6 Hz) usually reported for
abnormal hand tremor. For voluntary oscillation frequencies above about 1.5
Hz, this second, higher frequency oscillation generally occurred at twice
the frequency of the voluntary oscillation.
