Fukui Tsutomu, Ueda Yasuhisa, Chiyomaru Masashi, Ohkawa Takahiro, Fuse Yoko
Health Science Technology, Bunkyo Gakuin University, Japan.
Health Care Science, Graduate School, Bunkyo Gakuin University: 1-19-1 Mukogaoka, Bunkyo-ku, Tokyo 113-8668, Japan.
J Phys Ther Sci. 2023 Sep;35(9):638-644. doi: 10.1589/jpts.35.638. Epub 2023 Sep 2.
[Purpose] This study aimed to develop a clinical observation method to evaluate the position of the mass center. From the human visual capability, we considered it would be practical to divide the body into two parts: the upper and the lower body mass. If we could identify their optimal position, we could observe the middle point in between as the center of mass. [Participants and Methods] Twenty healthy males performed forward bending, backward bending, squatting, and walking. The three-dimensional coordinates were analyzed using a conventional model. In addition, five "virtual" markers were assigned as upper and lower mass, respectively. The midpoints of each five virtual marker combinations defined the mass centers, providing 25 coordinates. We calculated the difference in the coordinates between mass centers from virtual markers and mass centers using a conventional model. The combination with the slightest error was evaluated to determine the 95% confidence interval of the observed points and whether the value was clinically beneficial. [Results] The optimal combination of the upper and lower mass was Th8 and in the middle of both hip and knee centers. [Conclusion] The overall magnitude of error was about 30 mm and enough to evaluate the center of mass with macroscopy.
[目的] 本研究旨在开发一种临床观察方法以评估质心位置。从人类视觉能力出发，我们认为将身体分为上半身和下半身两部分是可行的。如果我们能够确定它们的最佳位置，就可以将两者之间的中点视为质心。[参与者与方法] 20名健康男性进行前屈、后伸、下蹲和行走动作。使用传统模型分析三维坐标。此外，分别指定五个“虚拟”标记作为上半身和下半身的质量标记。每五个虚拟标记组合的中点定义了质心，从而得到25个坐标。我们计算了虚拟标记质心与传统模型质心之间坐标的差异。评估误差最小的组合，以确定观察点的95%置信区间以及该值在临床上是否有益。[结果] 上半身和下半身质量的最佳组合是胸8以及髋部和膝部中心的中点。[结论] 误差的总体大小约为30毫米，足以通过肉眼评估质心。
