Body Part Discomfort Research Articles

Role of Polymer in Weeding and Seeding Machinery in Agriculture Rice Mechanization

In agricultural farm machinery, polymers are widely used for many applications. In recent years many agricultural farm implements are adopting polymer based plastic parts like seed dill ferule roller, weeding equipment, star wheel of harvester, vegetable planter hopper, zero till drill flute, animal yoke, maize sheller, diary vessels etc as a step towards value engineering. By varying the synthetic blend component and its miscibility with starch, the morphology and hence the properties can be regulated easily and efficiently. Blends containing thermoplastic starch (non crystalline starch) may be blended or grafted with biodegradable polyesters, such as polycaprolactone, to increase flexibility and resistance to moisture. Blends mainly formed into films and sheets, that are used for foaming and injection molding. By mixing thermoplastic starch with cellulose derivatives, rigid and dimensionally stable injection molded articles result. Seeding and weeding in paddy is an essential component in paddy production. There are many models of seeders and single row cono weeders available in the market which are being used for mechanized seeding and weeding operation. These are basically made with Mild Steel which has certain disadvantages in terms of machinability, reproducibility, weight, life, appearance etc. An improved manually operated 8-row drum seeder (plastic moulded) for direct sowing of pre-germinated paddy for wetlands and plastic moulded cono weeder developed was evaluated for its performance in various farmers field. It was observed that the cost of production of plastic moulded eight row drum seeder and plastic moulded cones for cono weeder was almost on par to that of these equipment made with MS sheet. Field studies revealed that plastic moulded seeder and cono weeder recorded higher field capacity, seeding/ weeding index and performance index over implement made of MS, with lower working force and plant damage. The ergonomic study revealed that heart beat/min, VO2/min, ODR score, body part discomfort score, OCR as VO2 max, per cent of plastic moulded equipment was found better over metallic model of equipment. This clearly gave an indication that there is a scope for substitution of MS material by polymers in rice mechanization. This paper deals with production process and performances evaluation of plastic moulded cono weeder for wet land paddy production.

Police Officer Discomfort and Activity Characterization During a Day Shift and a Night Shift

The purpose of this study was to identify occupational and car seat features causing discomfort in patrol officers, and to determine which body parts were experiencing the most discomfort. A Seat Features and Occupational Components Questionnaire, based on a 0 to 100 mm Visual Analog Scale (VAS), revealed that the duty belt was the occupational gear causing the most discomfort, followed by computer use within the car. The seat lumbar support was the seat feature causing the most discomfort. A Body Part Discomfort Questionnaire was administered at the beginning of the shift (T1), after six hours (T6), and at the end of the twelve hour shift (T12), for both day and night shifts. There were no significant differences in body part discomfort between the two types of shifts. There were, however, significant increases in body part discomfort ratings over the course of the working day, especially on the right side of the body. While some body parts experienced a significant increase in discomfort between the T1 and T6 (i.e., the neck, left upper back, right buttocks), some body parts only had a significant increase in discomfort after six hours (i.e., the lower back and mid back). The two body parts that experienced the highest levels of discomfort were the neck and lower back. A secondary purpose of the study was to identify the frequency of the activities that occur within the car. The largest portion of the workday and night were spent outside of the vehicle (46.1±10.8 % during the day, and 43.5±14.9% during the night). Left-handed driving occupied the most time in the car (26.3±10.1% during the day, and 25.7 ± 8.6% at night). A reduced or reconfigured duty belt, as well as decreased time spent in the car (doing paper work, computer work, and driving), could help decrease discomfort levels.

An ergonomic assessment of manual planting Pinus radiata seedlings.

Abstract This report summarises findings of an ergonomic evaluation of manual planting under three different site conditions. Heart rate data were collected and analysed using several heart rate indices. The three sites did not differ greatly, producing mean working heart rates that ranged from 132.7 bt.min-1 (± 16.2) to 134.9 bt.min-1 (± 13.8). Results indicate that manually planting Pinus radiata seedlings on all three sites can be classified as “hard continuous work” or “very heavy work”. Planters maintained similar mean working heart rates for all three sites by decreasing productivity as planting conditions became more difficult. Body part discomfort was only experienced when planting on pasture, where slight to severe discomfort was reported 48% of the time. Hazard occurrence was low for all three site conditions.

Ergonomic intervention in sugarcane harvesting knives

Ergonomic evaluation of farm tools is necessary to improve the fit between the physical demands of the tools and the worker who perform the work. In spite of improved farm mechnization, the use of the hand tools is inevitable in certain agricultural operations like sugarcane harvesting. Commonly used and high energy demanding tools like sugarcane harvesting knives of various models available in India were selected to assess the ergonomic suitablity. Ten individuals were selected for the investigation based on the age and fitness. They were screened for normal health through medical investigations. Four models of sugarcane harvesting knives were selected for ergonomical evlauation. The parameters used for the ergonomical evaluation of screened sugarcane harvesting knives include heart rate and oxygen consumption rate, energy cost of operation, acceptable work load, over all discomfort rate and body part discomfort score. The maximum aerobic capacity of the selected ten individuals varied from 1.84 to 2.19 L min-1 for sugarcane harvesting. The heart rate and oxygen consumption rate of the sugarcane knives varied from 132.55 to 138 beats min-1 and 1.171 to 1.253 L min-1, respectively. The energy cost of sugarcane harvesting knives, varied from 24.45 to 26.16 kJ min-1respectively. The values of percent maximum aerobic capacity (VO2 maximum) and work pulse for sugarcane harvesting knives were much higher than that of the acceptable workload (AWL), limits of 35%. Based on the analysis of results, the sugar cane harvesting knife (H1) ranked as I in terms of minimum value of heat rate (132.55 beats min-1), energy cost of work (24.45 KJ min-1), acceptable work load (58.14%), over all discomfort rate (moderate discomfort) and Body part discomfort score (29.39) when compared with other three models (H2, H3 and H4) of sugarcane harvesting knives. Key words: Sugarcane harvesting, ergonomics, heart rate, oxygen consumption.

Measures of fit and discomfort for elementary school children in Serbia

Assessing physical ergonomic factors within the classroom environment creates new opportunities to support designs that promote student well-being. Student-aged anthropometric data helps guide proper desk fit assessment, therefore facilitating scholastic performance through the reduction of distractions such as physical discomfort. This study reports dimensions of fit between student anthropometry and the desk environment (classroom seating conditions), for grade-school aged children in Serbia. Measurements of the children and their desks are compared to subjective reports of discomfort. Fifty-seven elementary school students, grade 2 (ages 7-8; n=29) and grade 4 (ages 9-10; n=28), were enrolled in this study. All participants were from the same elementary school in the city of Nis, Serbia. Seventeen anthropometric measurements of students were collected using standard anthropometric instruments. Eight measurements of student work desks and chairs were also collected. Students were evaluated by a physiatrist to assess health issues and completed a novel questionnaire about musculoskeletal discomfort for different body parts. Student fit to the classroom seat and desk was assessed structurally and subjectively. Data analysis included descriptive anthropometric measurements and inferential statistics including Chi square analysis. Results indicated age-related differences in body part discomfort for grade 2 and grade 4 students, arm discomfort reported over 50% of second grade students, and neck/upper back discomfort was reported as the highest of all body parts (32%) for students in the fourth grade. Anthropometric variables and preliminary analysis of fit as it relates to reported discomfort are discussed, as are external factors of backpack use and seated video/computer-game use. International comparisons of anthropometric data are discussed and serve to inform new considerations of ergonomics research for school children.

Evaluating a school based childhood obesity intervention for posture and comfort

Background: Research shows that students who are more active throughout the day have fewer reports of body part discomfort and greater energy expenditure needed to combat childhood obesity. Many factors may contribute to the overall health of the child, including the postures that are required to complete assigned tasks at their school workstations. Decreasing sedentary behaviors in children through the use of standing desks at school has been shown to increase calorie expenditure and may be a viable approach to the energy imbalance typical of modern children. The objective of this research was to quantify and analyze sub-optimal postures and self-reported discomfort of students during the use of traditional seated and stand-biased desks to determine whether any unintended consequences of the intervention were present. Methods: A postural analysis based on the Portable Ergonomic Observation (PEO) method was used to assess the posture of 42 elementary school students as they worked at their assigned workstation (either standing or seated). Two classrooms contained stand-biased workstations (15 students) and two classrooms had traditional seated workstations (27 students). Each student was assessed three times at 10 minutes, for a total of 30 minutes of observations each. The percent of time spent in preferred versus non-preferred postures was then computed. Student body part discomfort surveys were used to assess the discomfort of students between the two groups. The relationship between type of workstation and percent time in non-preferred postures and body discomfort was examined using Wilcoxon ranksum tests and Fisher’s exact tests, respectively. The significance level was p ≤ 0.05 for all of the two-sided tests. Results: No significant difference was found between the two groups and time spent in non-preferred postures and body discomfort, children using stand-biased workstations reported less discomfort overall. Stand-biased desks presented no additional ergonomic issues, while providing increased caloric expenditure. Conclusions: A study containing a larger sample and older children that includes postural observation throughout the school day is needed for future research.

Ergonomics Principles Associated With Laparoscopic Surgeon Injury/Illness

This study sought to investigate the prevalence of laparoscopic surgeon injury/illness symptoms and evaluate associations between symptoms and operating room ergonomics. Although laparoscopic procedures significantly benefit patients in terms of decreased recovery times and improved outcomes, they contribute to mental fatigue and musculoskeletal problems among surgeons. A variety of ergonomic interventions and applications are implemented by surgeons to reduce health problems. Currently, there is a gap in knowledge regarding a surgeon's individual assessment of the operating room, an assessment that, in turn, would prompt the implementation of these interventions. A new survey instrument solicited information from surgeons (N = 61) regarding surgeon demographics, perception, frequency of operating room equipment adjustment, and self-reported symptoms. Surgeons responded to questions addressing safety, ergonomics, and fatigue in the operating room, using a 5-point Likert-type scale that included the option undecided. Surgeons who responded undecided were more likely to experience symptoms of injury/illness than respondents who were able to assess the features of their operating rooms. Symptoms were experienced by 100% of participants. The most prevalent symptoms were neck stiffness, back stiffness, and back pain. This study supports hypotheses that surgeons are experiencing body part discomfort and indicators of fatigue that may be associated with performing laparoscopy. Results suggest that awareness, knowledge, and utilization of ergonomic principles could protect surgeons against symptoms that lead to occupational injury. The purpose of this brief report is to convey the importance of ergonomic principles in the operating room, specific to laparoscopic surgery and surgeon injury/illness symptoms.

Discomfort Analysis in Computerized Numeric Control Machine Operations

ObjectivesThe introduction of computerized numeric control (CNC) technology in manufacturing industries has revolutionized the production process, but there are some health and safety problems associated with these machines. The present study aimed to investigate the extent of postural discomfort in CNC machine operators, and the relationship of this discomfort to the display and control panel height, with a view to validate the anthropometric recommendation for the location of the display and control panel in CNC machines.MethodsThe postural discomforts associated with CNC machines were studied in 122 male operators using Corlett and Bishop's body part discomfort mapping, subject information, and discomfort level at various time intervals from starting to end of a shift. This information was collected using a questionnaire. Statistical analysis was carried out using ANOVA.ResultsNeck discomfort due to the positioning of the machine displays, and shoulder and arm discomfort due to the positioning of controls were identified as common health issues in the operators of these machines. The study revealed that 45.9% of machine operators reported discomfort in the lower back, 41.8% in the neck, 22.1% in the upper-back, 53.3% in the shoulder and arm, and 21.3% of the operators reported discomfort in the leg.ConclusionDiscomfort increased with the progress of the day and was highest at the end of a shift; subject age had no effect on patient tendency to experience discomfort levels.

An ergonomic approach to design hand tool for agricultural production

Hand tool mechanisms designed to reduce the risk factors have rarely been studied. In this paper it is analyze trowel firstly designing in CATIA and then its Finite Element Analysis has been carried out by ABAQUS. The main emphasis is on finding stresses by using this software, then removing them by suitable mechanical working on tool & ergonomic change in the design of handle to make it more comfortable. Body part discomfort score and overall discomfort rating experienced by the subjects had also been estimated. During the muscular activity workers physiological responses i.e. energy expenditure rate, oxygen consumption rate and heart rate increases. This increase in physiological responses is related to the type, intensity and duration of work and thus sets limits to the performance of heavy work. In this paper oxygen consumption rate and heart rate was used for physiological cost estimation. These parameters were measured by Computerized Ambulatory Metabolic Measurement System K4b2.

Impact of multimodal feedback on simulated ergonomic measurements in a virtual environment: A case study with manufacturing workers

AbstractThe purpose of this study was to evaluate the impact of multimodal feedback on ergonomic measurements in a virtual environment (VE) for a typical simulated drilling task. In total, sixty male manufacturing industry workers were divided into five groups. One group performed the working task in a real environment (RE), and ergonomic measurements for this group were used as the baseline for evaluation. The other four groups performed the same task in a virtual environment with different feedback treatments (visual with or without auditory and/or tactile feedback). Five indices – task completion time, maximum force capacity reduction, body part discomfort, rated perceived exertion, and rated task difficulty – were used to evaluate the measurements of each of the four treatments in VE in comparison to the baseline group in RE. The results indicate that the five indices for each of the four treatment groups were significantly higher than those of the RE group. Moreover, the indices of the visual‐only group were significantly higher than those of the other three groups with auditory and/or tactile feedback treatments. The findings of this study can provide a guideline for ergonomic evaluations of work designs in VE and for establishing a virtual reality simulation system. © 2011 Wiley Periodicals, Inc.

Relationships between subjective and objective measures in assessing postural stresses

The purpose of this study is to investigate the relationships between subjective measures of discomfort and objective measures related to the assessment of postural stresses based on literature survey. Objective measures included posture holding time, maximum holding time (MHT), torque at joints, lifting index (LI) and compressive force (CF) at L5/S1. The major relationships identified in this literature survey were the following: 1) postural discomfort linearly increased with increasing holding time, and holding force, 2) whole body discomfort was inversely linearly proportional to the MHT, 3) body-part discomfort was related to objective measures such as torque at the relevant joint, 4) discomfort was strongly linearly related to LIs and CFs, and 5) the discomfort measured with the magnitude estimation was linearly related to that measured with Borg CR10. Thus, it is thought that discomfort might be used as a measure for quantifying postural stresses.

Ergonomic Assessment of Excavator Seat

This study investigated the factors that affect sitting discomfort of excavator seat. There were 20 male professional excavator operators served as the subjects. Firstly, they were asked to assess the static features of the two seats. Secondly, there were two body part discom- fort questionnaires to be filled out. One is at the beginning and the other is at the end of an op- eration period of 3 hours. During the 3 hours operation period, subjects were asked to dig a gut- ter on ground and then to fill in the gutter repeatedly. The results showed that seat type did sig- nificantly affect mean body part discomfort and mean subjective preference score. Seat C re- sulted in lower body part discomfort and better subjective preference score than that of seat K. In summary, greater adjustment range of seat features and better adjustment mechanism of seat can meet operators' more requirements and then decrease body part discomfort and increase subjec- tive preference.

Predicting real-world ergonomic measurements by simulation in a virtual environment

Virtual reality techniques have been increasingly used for ergonomic applications. However, it is always important to know whether the results obtained in a virtual environment (VE) are representative of a real environment (RE) ones. This paper presents our preliminary experimental results on the relationship between ergonomic measurements in VE and RE for some typical “drilling” tasks. The same tasks were carried out by thirty male manufacturing factory workers in both VE and RE. Five evaluation indices – three objective (elbow angle, maximum force capacity reduction, and task completion time) and two subjective (BPD – Body Part Discomfort and RPE – Rated Perceived Exertion) – were used to evaluate the similarities between VE and RE for the selected “drilling” tasks. Four of these indices (all except elbow angle) were significantly higher ( p < 0.05) in VE than in RE, which indicates that subjects experienced more discomfort and grew fatigued more quickly in VE. However, linear correlations (Pearson’s rho: 0.635–0.807) between VE and RE were found for two of the five indices (BPD and maximum force capacity reduction). Relevance to industry Using digital mock-ups and virtual reality simulations, industrial work activities can be evaluated to identify potential ergonomic problems during an early design stage, which reduces design time and costs, increases quality and improves customer satisfaction. A validated linear relationship can provide a reference for work design in virtual reality.

The variability and complexity of sitting postural control are associated with discomfort

The present investigation examined the variability of sitting postural movement in relation to the development of perceived discomfort by means of linear and nonlinear analysis. Nine male subjects participated in this study. Discomfort ratings, kinetic and kinematics data were recorded during prolonged sitting. Body part discomfort index, displacement of the center of pressure (COP) in anterior–posterior and medial–lateral directions as well as lumbar curvature were calculated. Mean, standard deviation and sample entropy values were extracted from COP and lumbar curvature signals. Standard deviation and sample entropy were used to assess the degree of variability and complexity of sitting. A correlation analysis was performed to determine the correlation of each parameter with discomfort. There were no correlations between discomfort and any of the mean values. On the contrary, the standard deviations of the COP displacement in both directions and lumbar curvature were positively correlated to discomfort, whereas sample entropies were negatively correlated. The present study suggests that the increase in degree of variability and the decrease in complexity of sitting postural control are interrelated with the increase in perceived discomfort. Finally, the present study underlined the importance of quantifying motor variability for understanding the biomechanics of seated posture.

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

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. 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. 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. 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. 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.

Evaluation of perceived discomfort in repetitive arm reaching and holding tasks

This study investigates the effect of arm reaching and holding related factors on subjective discomfort rating. Fifteen males and fifteen females participated in the experiment. Independent variables include shoulder flexion (60°, 90° and 120°), reaching frequency (2 motions/min and 4 motions/min), holding weight (0.86 kg and 1.12 kg), and holding duration (5 s and 10 s). The response measures include subjective discomfort ratings of the whole body (WBD), shoulder (SD) and upper arm (UAD). The ANOVA results indicate that the effects of gender, shoulder flexion, reaching frequency, holding weight, and holding duration significantly influence all measures. Findings also show significant positive correlations among WBD, SD and UAD. Arm reaching over shoulder height is the main factor affecting WBD for both males and females. Further, the high frequency of arm reaching shows greater influence on female participant's WBD than other factors. On the other hand, holding weight shows greater influence on male participant's WBD than other factors. Moreover, this work constructs nine regression models to predict WBD, SD and UAD from arm reaching and holding related factors. The discomfort prediction models explain at least two-thirds of the variations. Relevance to industry This study evaluates the effects of shoulder flexion, reaching frequency, holding weight, and holding duration on whole body and body part discomfort. The findings of this study can be used for job and workplace design.

A survey of the optimal handle position for boxes with different sizes and manual handling positions

Handles on objects are very important for enhancing the safety and efficiency of manual handling for people who use them. In this study, four different prototype boxes with auxiliary handles were designed to determine the optimal handle position of a box based on the evaluated user preferences and body part discomfort (BPD). Twenty male students participated in the experiment. Likert-5 point summated rating was applied to evaluate user preferences for the provided boxes with handles in upper, middle, and lower positions, in four different sizes and manual handling positions. Ten additional subjects were asked to indicate their BPD on a body chart after performing a similar experiment. The results show that the subjects preferred the upper part of the handle on a small box regardless of handling position; while the mid to upper parts of the handle on a big box were preferred for handling above the waist height. BPD also indicated that an upper handle was less stressful for a relatively smaller box than a big one; and mid to upper handles were less comfortable for a big box. The optimal handle positions depending on box size and handling position were suggested based on the results of the evaluation. It is thus recommended that a box provides a handle according to its relevant position, depending on size and manual handling condition, to reduce the musculoskeletal stress and in turn to increase user satisfaction.

Effects of positioning optimization in an alternative computer workstation for people with and without low back pain

The aim of this study was to measure the impact of positioning optimization on typing performance and user comfort for people with and without low back pain (LBP) in alternative working postures. Participants completed a series of typing tests in each of five randomly ordered alternative working postures ranging from upright to fully supine. Typing accuracy and typing speed were recorded as were subjective measures of overall comfort and body part discomfort. The impact of positioning optimization of the monitor, keyboard, and arm supports was determined by comparing results from an “Optimized” test study protocol ( n = 27) with those from a “Non-Optimized” test study protocol ( n = 26). The results indicate a significant improvement in user comfort with the optimized positioning, but no significant differences in typing performance between the two test protocols. However, in both tests the slowest typing speeds occurred in the fully reclined and zero gravity working postures. Results of the user comfort scores indicated that for the Non-Optimized test, all alternative working postures were less comfortable than the upright posture. Whereas, in the Optimized test the tilted and reclined postures were comparable to the upright working posture and only the zero gravity posture was viewed as less comfortable. Relevance to industry Understanding the importance of position optimization for VDT operators in alternative working postures will provide valuable information toward the development of more comfortable and more accommodating computer workstations.

Mountain rescue stretchers: Usability trial

In the UK mountain rescues are carried out by highly trained volunteers in all weather conditions and at any time of the day/night. They interface with other services when they hand over the casualty to either land or air ambulances. The design of the stretcher is important to the safety of both the volunteers and casualties. This paper reports a usability trial to evaluate the features of mountain rescue stretchers and identify characteristics for future design. Two mountain rescue teams in the English Lake District participated in a five week field experiment. Data were collected using postural analysis with Rapid Entire Body Analysis, Body Part Discomfort Surveys, Rated Perceived Exertion and focus groups to compare the performance of four stretchers: Split Thomas, Ferno Titan, MacInnes mark 6 and MacInnes mark 7. None of the stretchers had an overall advantage, with benefits for some features counterbalanced by disadvantages resulting from others. All the stretchers produced shoulder discomfort with the Split Thomas and MacInnes 6 lowering the postural risks through the use of skids/wheel in the carrying phase. The key design features for future MR stretchers include: reduced unloaded weight (e.g. light weight materials and mesh platforms); undercarriage system to reduce the carrying load; adjustable handles at the front and back positions; flexible carrying system with an optional harness attachment; ease of assembly in adverse environmental conditions; large carrying capacity. It is suggested that military emergency evacuation should be considered in addition to mountain rescue tasks to identify a larger commercial market for development.

Effect of chair design on ratings of discomfort

The purpose of this study was to determine if ratings of discomfort differ over time between two ergonomic chairs of the same approximate cost. Twenty participants from a metropolitan university sat on two types of ergonomic chairs for 90~minutes in each of two sessions while performing typing, reading, and writing tasks. Repeated measures three-way and two-way analyses of variance were used to examine the effect of the ergonomic chair design on rating of discomfort. Data were collected using the General Comfort Rating Scale (GCRS) and the Body Part Discomfort Rating Scale (BPDRS), which were administered at 0, 30, 60, and 90 minute marks of each session. The results revealed: 1) discomfort was not related to the type of chair, 2) discomfort increased over time, 3) discomfort was influenced by the task performed while sitting, 4) discomfort level decreased when switching between different chairs, and 5) most discomfort was reported in the low back and lower arms.