Abstract:Kneeling seat is an ergonomic chair that can help the human body’s spine in a sitting posture to be closer to the natural state. In this study, we used non-contact camera method to measure visual distance. Using surface electromyography (sEMG) combined with subjective evaluation, we studied the obvious effects of seat angle and leg support angle in kneeling sitting posture on the ride comfort of healthy female school-age children without myopia. Using three experiment seat angles (10◦, 20◦ and 30◦), we found that as the sitting angle increased, the absolute value of the slope of the erector spinae linearity curve, MPF-t, gradually decreased. At 30◦, the slope of MPF-t was −0.26, the descent speed was the slowest, the activity of erector spinae was relatively lowest, and the comfort of children’s waist was also improved, while the comfort of calf gastrocnemius decreased, just the opposite. At the same time, leg support angles of 20◦, 30◦ and 40◦ were used. And in the study we found that the elevation of the leg support angle had no significant effect on the erector spinae muscle, but had a significant effect on the gastrocnemius muscle. When the leg support angle was 30◦, the slope of MPF-t was −0.42, and the gastrocnemius comfort reached its peak.

Key words:kneeling chair, sitting comfort, school-age children

摘要：跪式坐姿椅是一种能够促使脊柱在坐姿状态下自然直立的人体工学椅。本研究采用非接触式摄像法测量视距，利用表面肌电信号（sEMG）和主观评价结合的方法评估舒适度，探究跪坐姿势中座椅座面角度和腿部支撑角度对无近视的健康学龄期女童人体舒适度的影响。设置三个座面实验角度（10°，20°，30°），随着座面倾斜角度的增大，竖脊肌拟合曲线斜率的绝对值 MPF-t 逐渐减小。在座面角度为30°时，MPF-t 的斜率为−0.26，且下降速度最慢；此时竖脊肌的活动相对最低，儿童腰部的舒适度得以提升；相反地，小腿腓肠肌的舒适度呈下降趋势。同时，实验设置了20°、30°和40°的腿部支撑角度。实验发现：加大腿部支撑角度对竖脊肌无显著影响，但对腓肠肌有显著影响；当腿部支撑角度为30°时，MPF-t 的斜率为−0.42，且腓肠肌的舒适度达到峰值。

关键词:跪式坐姿椅，坐姿舒适度，学龄儿童