Abstract
Horizontal oscillation of the center of pressure is useful for clinical diagnoses.But the vertical oscillation of the center of gravity is left unclear. The vertical oscillation was studied in physiological condition. METHOD: The vertical oscillation was measured from 8 healthy volunteers, aged from 36 to 55 years, with a force plate (G-5500, ANIMA Corp. Japan). Summed signals from 3 load cells were measured in a standing posture with eyes open for 1 min, and in a posture with knee flexion at 45 degree with eyes open for 1 min. The signal was sampled at 100Hz, and digitalized as 16 bits. Every 5 s-signal was analyzed with a Hanning window with the fast Fourier transform and the mean of the power spectra were used for discussion. RESULTS: An oscillation was noted for the knee flexed posture around 2-7 Hz. CONCLUSION: The vertical oscillation was reported to be responsive to the heart pulsations. However, the oscillation was suspected to be increased in physiological tremor. [Jpn J Physiol 54 Suppl:S186 (2004)]
