Journal of Biomechanics
Volume 18, Number 1 (1985), Pages 39-47.
We address amplification of noise in double differentiation of position
histories for dynamic analysis of gait. Measurements of the frequency
domain characteristics of signal and noise are required to quantitatively
assess errors in raw, filtered, and dynamic gait data. The results of
a simple technique to determine the frequency content of gait using
a population of 12 subjects and a total of 30 gait records is presented.