Bio-mechanical Analysis of the Grapevine Cluster Thinning Task using Working Chair

Abstract

Objective: This study examined the effects of working chair that was developed for farmers who work in grapevine's cluster thinning. Background: Agricultural work involves some of the nation's highest occupational risk exposures. Fruit cultivation has been recognized as one of the most hazardous crops in which to work. Grapevine cluster thinning task involve activities related to the main risk factors associated with upper limb work-related musculoskeletal disorders. Method: An experiment was designed to test the working chair. Six healthy male(25.8±4.9years) were selected as the subjects for this study. Electromyography(EMG) was used to monitor the muscles activity, and Electro-goniometer was used to measure the ranges of motions of the elbow, trunk and knee. Subjective test was also carried out to examine discomfort body parts and their pain intensity. A grapevine's working space was built for the experiment and working chair was installed on it. In order to examine the muscle activity and range of motion, subjects used to the working chair for 30 minutes for each experimental condition. Another test without working chair was also performed for comparison. %MVC was used to quantify the level of muscle activity. Results: Decreases of muscle activity was found in all leg muscles and significant decrease of muscle activity was found in left Gastrocnemius. The range of motion of the trunk and knee also decreased when working chair used. Discomfort in lower back, thigh and shank region were reduced significantly. However, in upper limbs muscle activity tended to increase in working chair compared with conventional task. Conclusion: Improvement for cushion in seat back and pan required to reduce discomfort in buttocks. Application: Overall findings verified that the working chair might help to prevent upper limb and lower back MSDs based on the current study. These results can be practically used for work improvement for the grapevine growers to prevent MSDs.

Guidelines for Working Heights of the Lower-Limb Exoskeleton (CEX) Based on Ergonomic Evaluations

“…Most previous research on lower-limb exoskeleton systems [ 13 , 25 , 33 ] was conducted at work heights of 100–140 cm, considering the reach of the arms, etc. Additionally, the typical work height, including the height of hydroponic cultivation, is reported to be 40 to 140 cm [ 9 , 10 , 11 , 12 , 13 , 14 ]; this presents a burden on the musculoskeletal system during harvesting of red pepper, lettuce, strawberry, and grape crops. Thus, in this study, the working heights were set to 40 to 140 cm.…”

“…The ball was attached at six different levels, ranging from 40 to 140 cm, at intervals of 20 cm; these distances were chosen considering the height of the harvesting work that causes physical stress and the height that can be reached when wearing the lower extremity exoskeleton (Figure 2). Most previous research on lower-limb exoskeleton systems [13,25,33] was conducted at work heights of 100-140 cm, considering the reach of the arms, etc. Additionally, the typical work height, including the height of hydroponic cultivation, is reported to be 40 to 140 cm [9][10][11][12][13][14]; this presents a burden on the musculoskeletal system during harvesting of red pepper, lettuce, strawberry, and grape crops.…”

“…When growing lettuce or strawberries, which exerts a high body burden, guidelines for appropriate heights to minimize body loads are needed because there are no clear standards for bed height [ 10 , 11 , 12 ]. The harvesting work is the most intense in grape fields, and the work is performed in a standing position for a long time at a working height of about 90–140 cm [ 13 , 14 ].…”