差尺の違いに影響される模擬食事中の動作筋電学および運動学的分析

The influence of above-the-seat table height on simulated food intake through kinematic and electromyographic analysis

要旨：机の高さが模擬食事動作中の重心動揺と上肢筋活動に及ぼす影響について検討した．被験者の身体に適した高さの机，これから±10cmの高さの机を使用し実験した．また別の被験者を対象に一般的な机（高さ70cm），車椅子対応の机（高さ75cm）および身体に適した机で実験した．＋10cmの机では脊柱起立筋，僧帽筋上部の筋活動が有意に大きく，主観的疲労度も大きかった．-10cmの机では作業量が有意に少なかった．身体に適した机での食事動作は，高さ70cm，75cmの机と比較し重心総軌跡長が有意に短く，75cmの机では，僧帽筋上部の筋活動が有意に増大した．身体に合わせて机の高さを設定することの重要性が示唆された．

　Body sway and activities of the shoulder girdle muscles during simulated food intake were investigated in healthy subjects at different table heights. The experiment was conducted with the subjects sitting on a chair 42 cm in height. The height of the table above the seat was set to three heights: one-third of the sitting height of each individual minus 3 cm (the adjusted height), adding 10 cm to the adjusted height and subtracting 10 cm from the adjusted height. The myoelectric activities of the cervical erector spinae and the upper trapezius during simulated food intake and the degree of subjective fatigue were significantly higher when the adjusted height was increased by 10 cm (p＜0.05，p＜0.01). The amount of effort during simulated food intake was significantly less when 10 cm was subtracted from the adjusted height. The same experiment was conducted on different subjects. The height of the table above the seat was set to 28 cm, 33 cm, and the adjusted height. The total length of body sway during simulated food intake was significantly lower at the adjusted height than at 28 cm and 33 cm (p＜0.01). The myoelectric activity of the upper trapezius during simulated food intake was significantly higher at the height difference of 33 cm than at the adjusted height difference (p＜0.05). The result suggests the importance of adjusting the height of the table above the chair to achieve an ideal individual sitting height.