Design of Stool Height for Ground Level Farming Activities
In industrial context, many Indian workers do their jobs in squatting postures for longer duration to manipulate jobs on the ground in various jobs such as shoe making, glass manufacturing, farming activities etc. Musculoskeletal problems have been reported by workers assuming squatting postures in their daily activities.In this work we focus on squatting postures during farming activities. The stool height is used as an independent variable. A psychophysical approach is also used to verify the results. Psychophysical approach involved experiments for measuring perceived comfort level for different stool heights. Three different squatting postures are defined depending upon the stool height, which included a squatting posture without a stool and two squatting posture with different stool height, 10 cm and 15 cm. Six healthy subjects participated in this study. In order to estimate the proper height of squatting stool according to working position, a simple wooden stool is designed and used. This study concluded that the production rate for given agricultural task is higher with a stool height of 10 cm. In other words, the average time taken to complete a task is the lowest with 10 cm stool height as compared to 15 cm stool height and zero cm stool height i.e. without stool. This shows that the workers are comfortable with stool height of 10 cm because they were able to complete their tasks in lesser time with this stool height. ANOVA results show that mean time to complete given tasks is significantly different for three stool heights.Psychophysical method is also used to find out perceived comfort level for different stool heights. Results of this method also show that workers are most comfortable with stool height of 10 cm.
Keywords- Farming activities, Stool height, Perceived level of Comfort, Psychophysical response.