Matsuda Tadamitsu, Koyama Takayuki, Kurihara Yasushi, Tagami Miki, Kusumoto Yasuaki, Nitta Osamu
Department of Physical Therapy, Faculty of Social Work Studies, Josai International University: 1 Gumyo, Togane, Chiba 283-8555, Japan.
Department of Physical Education, Nihon University, Japan.
J Phys Ther Sci. 2017 Sep;29(9):1649-1652. doi: 10.1589/jpts.29.1649. Epub 2017 Sep 15.
[Purpose] This study investigated lumbar muscle fatigue before and after maintaining a seated position for one hour, lumbar and pelvic inclination angle change, in subjects with and without active lumber support. [Subjects and Methods] Fourteen healthy subjects randomized into two groups sat on a floor chair, placed on an office chair, that cyclically changed its lumbar supporting shape to provide active lumbar support (ALS) or no ALS for one hour. Before and after, we measured the frequency of muscle waveforms of the trunk extensor muscles when the subjects lifted an object weighing 10% of their body weight, using both hands while seated. In addition, ROMt (Range of motion test) of trunk rotation, degree of fatigue and muscle stiffness were analyzed. [Results] Muscle frequency while lifting the weight decreased significantly without ALS compared to with ALS. Mean muscle stiffness increased, ROMt decreased in desk work task significantly without ALS compared to with ALS. [Conclusion] These results suggest that the lumbar muscles became fatigued, because low frequencies, increased muscle stiffness, and decreased ROMt without ALS. We suggest lumbar muscle fatigue was maintained low for subjects seated in a chair with ALS.
[目的] 本研究调查了有或没有主动腰部支撑的情况下，受试者保持坐姿一小时前后的腰肌疲劳情况、腰椎和骨盆倾斜角度变化。[对象与方法] 14名健康受试者随机分为两组，坐在放置在办公椅上的地板椅上，该办公椅可循环改变其腰部支撑形状，以提供主动腰部支撑（ALS）或不提供ALS，持续一小时。在前后两个时间段，当受试者坐着用双手提起相当于其体重10%的物体时，我们测量了躯干伸肌的肌肉波形频率。此外，还分析了躯干旋转的活动度测试（ROMt）、疲劳程度和肌肉僵硬程度。[结果] 与有ALS相比，没有ALS时举重时的肌肉频率显著降低。与有ALS相比，在伏案工作任务中，没有ALS时平均肌肉僵硬程度增加，ROMt显著降低。[结论] 这些结果表明，没有ALS时，低频、肌肉僵硬程度增加和ROMt降低会导致腰肌疲劳。我们认为，对于坐在有ALS的椅子上的受试者，腰肌疲劳程度保持较低。
