TY - JOUR
T1 - Computation of continuous relative phase and modulation of frequency of human movement
AU - Varlet, Manuel
AU - Richardson, Michael J.
PY - 2011
Y1 - 2011
N2 - Continuous relative phase measures have been used to quantify the coordination between different body segments in several activities. Our aim in this study was to investigate how the methods traditionally used to compute the continuous phase of human rhythmic movement are affected by modulations of frequency. We compared the continuous phase computed method with the traditional method derived from the position-velocity phase plane and with the Hilbert Transform. The methods were tested using sinusoidal signals with a modulation of frequency between or within cycles. Our results showed that the continuous phase computed with the first method results in oscillations in the phase time-series not expected for a sinusoidal signal and that the continuous phase is overestimated with the Hilbert Transform. We proposed a new method that produces a correct estimation of continuous phase by using half-cycle estimations of frequency to normalize the phase planes prior to calculating phase angles. The findings of the current study have important implications for computing continuous relative phase when investigating human movement coordination.
AB - Continuous relative phase measures have been used to quantify the coordination between different body segments in several activities. Our aim in this study was to investigate how the methods traditionally used to compute the continuous phase of human rhythmic movement are affected by modulations of frequency. We compared the continuous phase computed method with the traditional method derived from the position-velocity phase plane and with the Hilbert Transform. The methods were tested using sinusoidal signals with a modulation of frequency between or within cycles. Our results showed that the continuous phase computed with the first method results in oscillations in the phase time-series not expected for a sinusoidal signal and that the continuous phase is overestimated with the Hilbert Transform. We proposed a new method that produces a correct estimation of continuous phase by using half-cycle estimations of frequency to normalize the phase planes prior to calculating phase angles. The findings of the current study have important implications for computing continuous relative phase when investigating human movement coordination.
UR - http://handle.uws.edu.au:8081/1959.7/535769
U2 - 10.1016/j.jbiomech.2011.02.001
DO - 10.1016/j.jbiomech.2011.02.001
M3 - Article
SN - 0021-9290
VL - 44
SP - 1200
EP - 1204
JO - Journal of Biomechanics
JF - Journal of Biomechanics
IS - 6
ER -