Prabir Mukhopadhyay

Upper limb discomfort profile due to intermittent isometric pronation torque at different postural combinations of the shoulder-arm system

Twenty-seven right-handed male university students participated in this study, which comprised a full factorial model consisting of three forearm rotation angles (60% prone and supine and neutral range of motion), three elbow angles (45°, 90° and 135°), three upper arm angles (45° flexion/extension and neutral), one exertion frequency (15 per min) and one level of pronation torque (20% maximum voluntary contraction (MVC) relative to MVC at each articulation). Discomfort rating after the end of each 5 min treatment was recorded on a visual analogue scale. Results of a repeated measures analysis of covariance on discomfort score, with torque endurance time as covariate, indicated that none of the factors was significant including torque endurance time (p = 0.153). An initial data collection phase preceded the main experiment in order to ensure that participants exerted exactly 20% MVC of the particular articulation. In this phase MVC pronation torque was measured at each articulation. The data revealed a significant forearm rotation angle effect (p = 0.001) and participant effect (p = 0.001). Of the two-way interactions, elbow*participant (p = 0.004), forearm*participant (p = 0.001) and upper arm*participant (p = 0.005) were the significant factors. Electromyographic activity of the pronator teres and biceps brachii muscles revealed no significant change in muscle activity in most of the articulations. Industrial jobs involving deviated upper arm postures are typical in industry but have a strong association with injury. Data from this study will enable better understanding of the effects of deviated upper arm postures on musculoskeletal disorders and can also be used to identify and control high-risk tasks in industry.

Evaluating ergonomic risk factors in non-regulated stone carving units of Jaipur.

BACKGROUND Stone carving at Jaipur in Rajasthan state of India, is a traditional craft employing a large number of local youths. As an unorganized sector problems are many ranging from lack of benefits to occupational ergonomic issues of Work Related Musculoskeletal Disorders(WMSDs) and injury to body parts. STUDY DESIGN Twenty five male workers were selected in each of the three sections of a stone carving unit. The focus was to identify different ergonomic risk factors associated in this profession from the field. METHODS Still photography and video photography was used to record different activities. Different types of non invasive tools like Rapid Entire Body Assessment (REBA), Rapid Upper Limb Assessment (RULA), Occupational Repetitive Action Index (OCRA) were used. Psychophysical measures were investigated by Body part discomfort map, rated perceived exertion scale and visual analogue scale. Objective measurements (heart arte and skin temperature) were recorded with stop watch and digital thermometer. RESULTS The working heart rate after 30 minutes of work was 112.4 beats per minute categorizing the work as moderately heavy. Postural analysis by REBA indicated high score (13/13). Similarly postural analysis by RULA showed high score (7/7). These indicate vulnerability of many of the postures to musculoskeletal disorders and injury. CONCLUSION The study indicates that majority of the activities are in the high risk category and demands immediate ergonomic intervention in the form of tool, workstation and process design. This could be done by involving different Non Government Organizations (NGOs), political parties, and the Human Rights Department both at the center and at the state level.

Ergonomic Design Intervention In Manual Incense Sticks Manufacturing

ABSTRACT This study focused on the incense stick (known as agarbatti locally) manufacturers of Ahmedabad in the Gujarat state of India, with an eye to improving productivity and facilitating the occupational health and safety of the workers involved in this profession. There were incidences of work-related musculoskeletal disorders amongst the workers – 33 per cent of the studys respondents complained of pain in the lumbosacral segment of the spinal cord and 30 per cent reported pain in the upper arm at the end of the days work. Based on the observations, four workstation prototypes were fabricated. Each was tested in the field by actual workers, as well as in the laboratory. Only after a prototype was accepted in principle by the users was the next prototype fabricated. Based on user feedback, the final prototype was produced which was capable of increasing productivity by approximately 15 per cent and reducing pain in different parts of the body; this was only after 15 days of user testing.

Ergonomic Design Issues in Some Craft Sectors of Jaipur

ABSTRACT This paper investigates the risk factors associated with work-related musculoskeletal disorders in three craft sectors of Jaipur in India. The sectors considered were those of blue pottery, handloom and gota patti. Observational methods like Rapid Entire Body Assessment (REBA), Rapid Upper Limb Assessment (RULA) and OVAKO for postural analysis were applied. The Occupational Repetitive Action Index (OCRA) and Strain Index (SI) were also used to gauge the extent of repetitiveness and strain in the work. These investigations gave valuable insight into the fact that many of the working conditions were hazardous and demanded immediate intervention. It also indicated that the physical design of tools and workstations alone would not solve the problems. The designer needs to look into non-physical design issues like the work/rest cycle, process design, physical exercise and training to effectively control the different risk factors in the genesis of work-related musculoskeletal disorders.

Ergonomic risk factors in bicycle repairing units at Jabalpur.

BACKGROUND Bicycle repairing at Jabalpur in the Madhya Pradesh state of India employs a large number of local youths. In this sector occupational ergonomic issues of Work Related Musculoskeletal Disorders (WMSDs) are a big problem and a threat to this profession. OBJECTIVE The objective of this study was to identify the different ergonomic risk factors for Work Related Musculoskeletal Disorders (WMSDs) in the job of bicycle repairing. METHODS Still photography and video photography was used to record different activities. Different types of non-invasive tools like Rapid Entire Body Assessment (REBA), Rapid Upper Limb Assessment (RULA), and Occupational Repetitive Action Index (OCRA) were used. Psychophysical measures were investigated by rated perceived exertion scale and visual analogue scale. RESULTS OVAKO scores (4), REBA scores (13/13), RULA scores (8/8) were extremely high, indicating immediate intervention. CONCLUSION The results indicate that the different tasks in this profession are in the high risk category and demands immediate ergonomic intervention in the form of re-design of the tools used and work station or/and the design of the work process.

Ergonomic Analysis and Design of the Console Panel of a Bus Rapid Transit System in a Developing Country

Abstract In the light of a number of complaints from the drivers of a Bus Rapid Transit System (BRTS) in the city of Ahmedabad in India, this study investigated how the design of the control panel of the bus could influence the operational efficiency of the drivers, and aimed to collect evidence to provide the basis for the development of new concepts for revised designs by the manufacturers. The research found that there were four different types of problems: visibility of the control panel, comprehensibility of the different symbols used on the panel, placement and compatibility of different controls and displays. Two concept prototypes of the control panel were developed and tested on the drivers for their feedback on a score scale which indicated that the two prototypes were significantly better (p<0.001) compared to the original control panel design but there was no significant difference between the two prototypes.

Ergonomic Design Issues in Icons Used in Digital Cameras in India

This paper investigates the usability of five commonly used icons in digital cameras like landscape, video, night portrait and automatic mode. In the first phase a set of 10 open type questionnaires were applied on 110 students (75 male and 35 female) to get an insight into the type of problems with the icons. The second phase comprised of 5 ranking questionnaire. The third phase comprised of icon comprehension test for getting to know the stereotype strength of the different icons. The fourth phase was stereotypy test. The second and third phases were applied on 32 students (16 male and 16 females.). For each category of icons there was one icon which was rated best and comprehended very well. For example the icon for landscape mode which represented a mountain was ranked as the best and the stereotype strength for the same was 90.6%.

Ergonomic design of head gear for use by rural youths in summer

Two low cost ergonomically designed types of headgear were fabricated for youths working outdoor or exposed to the sun. The prototypes were tested on 11 male subjects. Subjective assessment through questionnaires revealed satisfactory results with head gears. Two dependent variables, discomfort score and forehead skin temperature were recorded. A One-Way repeated measures ANOVA as well as paired t-test, on both parameters showed significant headgear effect (p=0.001). Plots of forehead skin temperature and discomfort score showed marked decline with the use of headgears, compared to bare head.