重心移動として求めた身体動揺度の指標化に関する研究
1981 年 35 巻 6 号 p. 821-830
詳細
1981 年 35 巻 6 号 p. 821-830
Human body sway is measured as the movement of the center of gravity. In this paper, parameters to express sway and the time required for such measurements were examined.
Twenty-one healthy normal subjects, aged 19 to 51, were measured twice with their eyes open using a strain gauge-platform system (San-ei Instrument Co., 1G02 type, Tokyo). Five parameters to evaluate changes in the center of gravity were developed. Parameters A, B, C, and D gave the amplitude of sway as frequency-bands. The standard deviation was calculated on the X and Y axes and their sum expressed in parametric values. It was expected that parameters A, B, C, and D would locate in the wide, the low, the middle, and the high frequency-band, respectively. Parameter E gave the length of the movement of the center of gravity.
The following results were obtained.
1) In the case when subjects stood still for 13 minutes, no signficant changes were observed in parameters A, B, and D during this period. But, after subjects stood for 8 and 13 minutes respectively the values of parameter C increased significantly and all values of parameter E increased significantly after subjects stood for only 3 minutes.
2) Factor analysis method was applied on the correlation matrix among the five parameters based on each of the one-minute values in the case when subjects stood for 13 minutes. Two factors, F 1 and F 2, were extracted by this method. Parameters A and B were similarly loaded mainly with F 1. In contrast, the load of F 1 decreased and that of F 2 increased in parameters C, D, and E.
3) The values of each of the parameters were calculated after an initial three minutes' stand. These values were found to be reproducible. But the individual difference were found for all parameters.
4) Two factors, F 1 and F 2, were extracted as the result of factor analysis method on the correlation matrix among the five parameters based on the three minute values. In every case, the residue after extracting these two factors were less than 0.04. Parameter A was similar to B in its factor load pattern, mainly occupied by F 1. F 1 decreased and F 2 increased in parameters C, D, and E. But, the loading pattern of F 1 and F 2 was differed among parameters C, D, and E.
From the above results, the following conclusion is drawn: The values found after 3 minutes of standing do not influence continuous standing. Parameters B and E were essential to indicate body sway.
