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Mandarins are picked by hand with the use of shears. An average mandarin picker makes at least 20,000 cuts daily. This daily workload on the upper limbs is the cause of occupational cervicobrachial disorders (OCD). In order to improve their working conditions, we devised two types of shears, one with a soft grip wrapped around the handle and another with shock reducing cushions in between the handles. The following two experiments were conducted. First we tested and compared the Borg scale and pinch meter scores of each participant by having them cut sticks as the same radius as those of mandarin stems using both the improved and conventional shears. Next, we placed two pressure sensors on each shear, where the middle finger and thumb contact the handles, to measure and compare the impact pressure within the hand. The results of the first experiment suggested that the improved shears reduces workload to the hand and fingers when comparing results to those of the conventional shears. The second experiment indicates that the shock reducing cushions reduces impact pressure to the hand from the handles when cutting.

We have developed a new armrest (NA) with adequate width supporting forearms, inclining upper surface, an area for mouse, and fixers at the edge of a shallow desk. We compared the cervicobrachial load among NA, NA with a mouse-pad (NAM) and a conventional palmrest with a mouse-pad (PRM) during word processing work. Seventeen healthy subjects operated a word processor for 1-h, alternately using 3 devices. EMG and subjective pain scores (PS) were recorded mainly from the right-side upper limb. EMG of the trapezius in PRM was significantly lower than in NAM; EMG of the anterior deltoideus (DELTa) in NA lower than in NAM; EMG of the medial deltoideus (DELTm) in NA lower than in PRM. The shoulder PS in NA/NAM was significantly lower than in PRM; the upper arm PS in NAM lower than in PRM; the forearm PS in NA/NAM lower than in PRM. These results suggest that NA reduces the cervicobrachial load than PRM.

We have developed a new armrest (NA) with adequate width supporting forearms, inclining upper surface, an area for mouse, and fixers at the edge of a shallow desk. We compared the cervicobrachial load among NA, NA with a mouse-pad (NAM) and a conventional palmrest with a mouse-pad (PRM) during word processing work. Seventeen healthy subjects operated a word processor for 1-h, alternately using 3 devices. EMG and subjective pain scores (PS) were recorded mainly from the right-side upper limb. EMG of the trapezius in PRM was significantly lower than in NAM; EMG of the anterior deltoideus (DELTa) in NA lower than in NAM; EMG of the medial deltoideus (DELTm) in NA lower than in PRM. The shoulder PS in NA/NAM was significantly lower than in PRM; the upper arm PS in NAM lower than in PRM; the forearm PS in NA/NAM lower than in PRM. These results suggest that NA reduces the cervicobrachial load than PRM.