リンゴ栽培における脚立作業の人間工学的研究

第3報, 脚立上各種体勢時の下肢抗重力筋の筋電図について

抄録

The author studied the effect of surface EMG of the antigravity muscles of the lower limbs in the most common body posture and foot position on commercially available ladders. The following results were obtained.
1. The activity of M. gastrocnemius increases in the frontfacing position when the arms are raised. The activity of the flexor and extensor muscles of the thigh increases in the frontfacing or backward-facing position if the lower leg touches the ladder.
2. The antigravity muscles of the lower limbs are more strenuously in the backward-facing position than in the front-facing position.
3. The side-ways position and front-facing position result in more or less the same muscular activity, but the activity of the extensor and flexor muscles of the thigh increases in the splitlevel or straddled position.
4. The activity of M. gastrocnemius increases when the arch of the transverse axis rests on the rungs, and the activity of the flexor and extensor muscles of the thigh increases when the heel supports the body. There are significant differences between the front and backward-facing positions when the body rests on the arch area; in other words, the activity of M. gastrocnemius increases in the front-facing position and the activity of the thigh muscles increases in the backward-facing position.