Perceived comfortable posture and optimum riding position of Indian male motorcyclists for short-duration riding of standard motorcycles

Dimensional incompatibility between rider and motorcycle is one of the most causative factors responsible for the prevalence of musculoskeletal discomfort among motorcyclists. The present study aims to identify the comfortable riding posture (CRP) and optimum riding position (ORP) for improving motorcycle design for better riding experience. The data (through image processing technique) was acquired from 120 Indian male motorcyclists (aged 19–40 years) using a static simulator test-rig. The CRP was achieved by adjusting three controls (handgrip, seat, and footrest of the test-rig), and perceived comfort and discomfort ratings. Weighed mean comfort joint angles of ten body-joints defining CRP were estimated and compared with the earlier studies. The best possible ORP among the nine test conditions (defined by the positions of the three controls) was estimated using Taguchi DOE. The study outcomes will help automobile designers to conceptualize the comfortable standard motorcycles.     

A study of some anthropometric characteristics of motorcycle riders

As there is little published data on motorcyclists, an anthropometric survey of 140 UK motorcyclists was undertaken, together with a brief questionnaire survey covering demographic details and motorcycling experience. Additionally an investigation of knee position on a static motorcycle test rig was undertaken. Six body dimensions relevant to the design of the riding package of a motorcycle were considered. It was found that the population of motorcyclists, both male and female, were taller than the general population with mean statures of 1774.0 and 1639.7 mm, respectively. The knee position study indicated that there was wide variation in the forward position of the knee (range 228 mm).     

Towards identifying the roll motion parameters of a motorcycle simulator

This study aimed at identifying the roll motion parameters of a motorcycle simulator prototype. Experienced motorcyclists tuned the angular physical movement of the mock-up and that of the visual scene to achieve an optimal riding experience during curves. The participants exceeded the rolling angles that would be required in real-world riding, while avoiding leaning the mock-up beyond 10°. In addition, they were more influenced by the speed of the virtual motorcycle than by road curvature, especially in a wide field of view. Heterogeneity was found in the roll applied to the visual scene. The overall patterns suggest that at least when washout is not applied to remove the side forces that in real-world riding are compensated by a centrifugal force, greater roll of the visual at the expense of the mock-up is mandatory to avoid performance biases that might be enhanced due to fear of falling off the simulator. Future roll motion models must take into consideration factors such as riding postures, which might not only influence the forces operating on the rider-motorcycle system, but also how motorcyclists perceive the visual world.     

Robust Dynamic Comfort Modeling for Motorcycle Riding

Comfort modeling is considered a prerequisite in motorcycle design, primarily to address safety concerns and to position the product on the market. However, a comprehensive methodology for comfort modeling during the earliest development phases of a motorcycle model is still missing. Anthropometrical variation is the main noise factor to consider in comfort modeling in relation to the unavoidable variability of body segments. However, comfort is a subjective concept influencing riders’ choice of motorcycle model. This work is a generalization of the robust ergonomic design methodology aimed at designing products whose ergonomic performance is insensitive to anthropometrical variation. This work further develops the methodology, by considering dynamic aspects involved in the driver–motorcycle interaction. Moreover, this article proposes a generalized robustness criterion and presents a full simulation study with purposely developed software. The result is a generalized ergo‐dynamic assessment of a motorcycle model, either physical or digital, replacing common static ergonomic evaluations.     

Work posture, workstation design, and musculoskeletal discomfort in a VDT data entry task

Self-report data on musculoskeletal discomfort were collected from several hundred VDT users in two agencies of a state government. Aspects of worker posture and workstation design were objectively assessed for 40 of the VDT users. Multiple regression analyses were used to examine the relationship between these ergonomic variables and musculoskeletal discomfort. Effects of ergonomic factors on musculoskeletal discomfort were clearly evident in the analyses. Regression models explained up to 38% of the variance in discomfort at different body sites. Of special interest was that leg discomfort increased with low, soft seat pans, suggesting that postural constraint is more important than thigh compression as a risk factor for leg discomfort in VDT work. In addition, arm discomfort increased with increases in keyboard height above elbow level, supporting arguments for low placement of the keyboard. Finally, high levels of neck and shoulder girdle discomfort observed in the study population suggest the need for further attention to the control of cervicobrachial pain syndromes in VDT work.     

Risk factors analysis: Work-related musculoskeletal disorders among male traffic policemen using high-powered motorcycles

IntroductionThe occupational safety and health issues for police riders and other professional riders are often related to ergonomic hazards and risks. The purpose of this research was to identify the factors that contribute to the health effects in developing work-related musculoskeletal disorders (WMSDs) among male traffic policemen using high-powered motorcycles.Materials and methodsA cross-sectional study was conducted using 137 police riders. A set of questionnaires including the Standardised Nordic Questionnaire (SNQ) and human vibration meter (Svantek 106) was used in this study.ResultsThe prevalence of WMSDs was 67.9%. Multiple logistic regression analysis revealed that the duration of riding a motorcycle (OR = 0.175, 95% CI:0.052, 0.581), years of service (OR = 0.152, 95% CI: 0.040, 0.567), and hand-arm vibration, HAV (OR = 3.053, 95% CI: 1.126, 8.280) were significant risk factors for the prevalence of WMSDs.DiscussionThe majority of riders reported symptoms of WMSDs within the past 12 months. Riding duration, years of service, and hand-arm vibration (HAV) were found to be the most important risk factors for WMSDs in this rider group. The results highlight that in the context of ergonomic interaction, high-powered motorcycles and the police riders are not a good fit. Hence, further study is needed to improve the safety and health of the police riders.     

Evaluation of ergonomic working conditions among standing sewing machine operators in Sri Lanka

BackgroundStanding Sewing Machine Operators (SSMOs) are engaged in highly repetitive operations, and work while standing during their entire working hours. This leads to discomforts and Musculoskeletal Disorders (MSDs). However, there is a dearth of research in SSMOs’ working conditions.Objective: Aim of the study is to evaluate the prevalence of MSDs and related ergonomic risk factors among SSMOs in the Sri Lankan textile industry.Methods: The sample included 552 female sewing machine operators. Data were collected through self-reported questionnaires which included demographic, job-related factors and Cornell Musculoskeletal Discomfort Questionnaire [CMDQ], along with the application of validated ergonomic tools (Rapid Entire Body Assessment [REBA] and Strain Index [SI]) to assess the ergonomic risks amongst them. The inter-rater reliability test ensured the reliability among observers. An individual regression model was developed for each body parts to assess the associated risk factors.Results: The highest occurrence of musculoskeletal symptoms were in knee, foot, thigh, lower leg and lower back of SSMOs. REBA grand score (4–11) indicated that workers’ postures were at medium, high and very high risk levels necessitating evaluation to change. Moreover, SI indicated medium and high risk of upper extremity disorders. Finally, regression models revealed associated risk factors with musculoskeletal symptoms among various body parts including age, Body Mass Index (BMI), marital status, SSMO experience, job satisfaction, job stress, daily walking distance to the boarding place/factory, interest in job rotation and satisfaction with the design of sewing machine.Conclusion: The findings highlighted that the prevalence of discomfort and MSDs in the lower limbs were higher than in the upper limbs among SSMOs. The findings revealed the working conditions of SSMO and emphasised the need for ergonomic interventions to minimise the MSDs among them.Relevance to industryThe findings highlighted ergonomic risks among SSMOs and associated risk factors which will help managers and researchers better understand the working conditions of SSMOs. The identified risk factors could be considered during the implementation of standing sewing operation layouts and during the selection and allocation of new employees.     

Improved work organization to increase the productivity in manual brick manufacturing unit of West Bengal,India

In India, the manual brick making process is physical demanding jobs where millions of workers earn their livelihood. The study attempts to improve the organization of the work in brick manufacturing units and makes operations for the betterment and enhances its productivity. Observation studies and posture analysis were performed among them by the OWAS method. A detailed plan and time study were done, and accordingly, modifications of the processes were also carried out. The body mass index (BMI) of both groups of brickfield workers was 18.58 (±2.53) (brick molders) and 19.24 (±2.72) (brick carriers) respectively, suggesting that the workers had a normal range of BMI. Working postures of brickfield workers are of high risk as indicated by the OWAS system. In this study, an attempt was made to organize the manual brick making operation for enhancing productivity. The existing process of Brick making involved some unnecessary steps, which hamper the rate of work and consequently productivity, is also affected. This study eliminates the real steps and enhances 32% productivity in time and also recommends the ergonomic intervention to reduce biomechanical stress among brickfield workers.     

Risk factors for musculoskeletal injuries in airline maintenance,repair & overhaul

Aircraft maintenance workers are exposed to high injury rates, but risk exposures are difficult to measure and task contributors are difficult to identify due to the wide variety of parts and irregularity of jobs in this industry. Subjective metrics, posture assessments, and lifting analyses were collected from 235 employees from five work areas in aviation maintenance, repair and overhaul (MRO) facilities to measure ergonomic risk factors and identify task factors contributing to poor biomechanics. Nordic Musculoskeletal Questionnaire indicated that the low back was the most commonly reported region of the body experiencing aches, pain, and discomfort (41% of participants), while knees were the highest (68%) in cabin maintenance, likely due to constraints in the aircraft cabin. Rapid Entire Body Assessment (REBA) assessments showed that 57% of the jobs examined fell within the high-risk category. Causes of poor biomechanics differed by work area, e.g., overhead work was a key contributor in the engine change facility, while non-adjustable workstations were a likely contributor in cabin maintenance and engine maintenance. The under-looked cabin maintenance, engine change, and logistic jobs are the most pressing work areas in MRO that need ergonomic interventions.     

Ergonomic risk factors in glass artware industries and prevalence of musculoskeletal disorder

Glass artware manufacturing activities are highly repetitive, labor-intensive, and demand prolonged standing during the working shift. This leads to the development of musculoskeletal disorders (MSDs) symptoms among the workers. However, there is a scarce of study on the prevalence of MSDs symptoms and their associated risk factors among the glass artware workers. To address this research gap, this study aims to evaluate the prevalence of MSDs and working conditions among Indian glass artware workers. Discomfort data is collected using Cornell Musculoskeletal Discomfort Questionnaire and working posture data is collected through direct observations using Rapid Entire Body Assessment (REBA). Multiple logistic regression model is developed for each body region to study the relationship between the associated risk factors and MSDs symptoms with the help of collected data. The findings of this study are first, MSDs symptoms are highly prevalent and severe, particularly in the lower back, thigh, and foot. Second, the average REBA grand score is 7.22, which reveals the high-risk level of worker's posture while performing the task. Third, Job characteristics and individual factors are associated with MSD symptoms in multiple logistic regression models. The results highlight the prevalence and severity level of MSDs and illustrate the demand for ergonomic interventions to alleviate musculoskeletal symptoms among these working groups.Relevance to industryThis study draws attention to work-related and other associated risk factors, which would help the researchers and managers to understand the working environment of glass artware industry. These risk factors should be considered for designing and implementing ergonomic interventions to prevent and alleviate musculoskeletal discomfort among the glass artware workers.     

Ergonomic factors on task performance in laparoscopic surgery training

This paper evaluates the effect of ergonomic factors on task performance and trainee posture during laparoscopic surgery training. Twenty subjects without laparoscopic experience were allotted into 2 groups. Group 1 was trained under the optimal ergonomic simulation setting according to current ergonomic guidelines (Condition A). Group 2 was trained under non-optimal ergonomic simulation setting that can often be observed during training in a skills lab (Condition B). Posture analysis showed that the subjects held a much more neutral posture under Condition A than under Condition B (p < 0.001). The subjects had less joint excursion and experienced less discomfort in their neck, shoulders, and arms under Condition A. Significant difference in task performance between Conditions A and B (p < 0.05) was found. This study shows that the optimal ergonomic simulation setting leads to better task performance. In addition, no significant differences of task performance, for Groups 1 and 2 using the same test setting were found. However, better performance was observed for Group 1. It can be concluded that the optimal and non-optimal training setting have different learning effects on trainees’ skill learning.     

The effect of hand tools’ handle shape on upper extremity comfort and postural discomfort among hand-woven shoemaking workers

Hand tools are widely used in a large number of occupations. Many workers have to use hand tools to accomplish their duties. This may cause work-related Upper Extremities Musculoskeletal Disorders (UEMSDs). The present study was conducted in Iranian hand-woven shoe industry to (a) investigate the design of hand tools currently used in hand-woven shoemaking operation and (b) design/redesign the tools' handles based on anthropometric tables and ergonomic principles. Based on Iranian workers' anthropometric tables, new handles with different shapes were designed and made for hand tools currently used in hand-woven shoemaking operation (e.g., awl and cloth cutting tool). Hand postures and postural comfort and discomfort were investigated via rating technique using Comfort Questionnaire for Hand Tools (CQH) and upper extremities body map. The results of CQH showed that the handle shape had a significant influence on the hand posture and perceived postural discomfort in the upper extremities. The new ergonomically designed handles were perceived to be more comfortable compared to the traditional ones. Additionally, the new handles improved the hand posture during the operation and reduced the severity of discomfort in the upper extremities compared to the tools with conventional handles. The findings of this study revealed that designing the hand tools’ handles based on ergonomic principles and using anthropometric tables could improve the hand posture, increase comfort, and decrease discomfort in the upper extremities. By this means, reduction in work-related UEMSDs is expected.     

Real-time construction worker posture analysis for ergonomics training

Construction activities performed by workers are usually repetitive and physically demanding. Execution of such tasks in awkward postures can strain their body parts and can result in fatigue, injuries or in severe cases permanent disabilities. In view of this, it is essential to train workers, before the commencement of any construction activity. Furthermore, traditional worker monitoring methods are tedious, inefficient and are carried out manually whereas, an automated approach, apart from monitoring, can yield valuable information concerning work-related behavior of worker that can be beneficial for worker training in a virtual reality world. Our research work focuses on developing an automated approach for posture estimation and classification using a range camera for posture analysis and categorizing it as ergonomic or non-ergonomic. Using a range camera, first we classify worker’s pose to determine whether a worker is ‘standing’, ‘bending’, ‘sitting’, or ‘crawling’ and then estimate the posture of the worker using OpenNI middleware to get the body joint angles and spatial locations. A predefined set of rules is then formulated to use this body posture information to categorize tasks as ergonomic or non-ergonomic.     

Biomechanical investigation of prolonged driving in an ergonomically designed truck seat prototype

A postural evaluation during a prolonged driving task was conducted to determine the ergonomic validity of a new freely adjustable truck seat prototype. Twenty participants were recruited to perform two 2-h simulated driving sessions. Postures were assessed using motion capture, accelerometers and pressure pads. Subjective discomfort was also monitored in 15-min increments using ratings of perceived discomfort (RPD) and the Automotive Seating Discomfort Questionnaire. Participants had a more neutral spine posture during the first hour of the drive and reported lower RPDs while sitting in the prototype. Pairing the gluteal backrest panel with the adjustable seat pan helped reduce the average sitting pressure. The industry-standard truck seat may lead to the development of poor whole body posture, and the proposed ergonomic redesign of a new truck seat helped improve sitting posture and reduce perceived discomfort.

Practitioner Summary: A new freely adjustable truck seat prototype was compared to an Industry standard seat to assess hypothesised improvements to sitting posture and discomfort for long haul driving. It was found that the adjustable panels in the prototype helped promote spine posture, reduce sitting pressure and improved discomfort ratings.     

Effects of semi-rigid arch-support orthotics: an investigation with potential ergonomic implications

For many years, arch-support orthotics have been prescribed for individuals with discomfort and/or abnormal skeletal alignments in the structures of the lower extremity. Recently there has been an increased interest in promoting semi-rigid orthotics as an ergonomic aid for asymptomatic workers who must stand all day at their workplace. A laboratory study was performed to assess the biomechanical impact of prefabricated semi-rigid orthotics on asymptomatic individuals. Ten subjects wore semi-rigid arch-support orthotics (experimental condition) for two months and flexible polyurethane/Sorbothane shoe inserts (control condition) for two months. Throughout this 18-week testing period, the subjects returned to the lab to perform a battery of assessment tests at regularly scheduled intervals. These tests examined subject strength, standing posture, stability, fatigue effects, and body part discomfort. The results of this study showed no significant changes in the strength, posture, or stability as a function of insert type. The subjects reported a reduction in low-back discomfort along with an increase in foot discomfort during a fatiguing exertion task while wearing the semi-rigid orthotics as compared to the control condition.     

The effect of shoulder posture on performance,discomfort and muscle fatigue whilst working on a visual display unit

An investigation was conducted to determine the relationship between posture and performance while working on a VDU. Twenty-one female subjects performed a 20 min choice reaction time task in a within-subject design with shoulder flexion (0° versus 30°) and noise (55 dB versus 75 dB) as factors. Discomfort measures, electromyography (EMG) measures and measures of performance including reaction time and percentage of errors were collected. The results suggested poorer performance in the 30° shoulder flexion posture compared to the 0° shoulder flexion posture (performance index F_1,20 = 3.95, p = 0.061). There was also significantly greater discomfort and fatigue, as indicated by EMG, in the 30° shoulder flexion compared to 0° shoulder flexion (discomfort: F_1,20 = 99.30; p = 0.0001 EMG: F_1,20 = 4.25, p = 0.052). The results of this study provide the most direct evidence that the posture of VDU users can affect their performance at a task. A number of possible mechanisms for posture to affect performance are explored using the data. The utility of data showing the effect of posture on performance data is discussed in terms of financial modelling to justify the cost of ergonomic intervention. Relevance to industryPoor posture whilst working at a VDU has been previously linked with the development of poor health but has not been directly linked with poor performance. This paper provides evidence to show posture can effect VDU performance. This enables organisations to use estimates of performance changes to model the costs of investment in ergonomic interventions.     

规范骑行参数化建模的应用与实践

针对骑行者骑行姿势不规范的问题,提出了一种用于规范骑行的参数化建模方法.首先,创建人体模型和自行车模型,定义底层参数、中间层参数和高层参数,实现模型参数化;其次,对骑行过程进行受力分析,建立动力学模型,保证虚拟骑行符合自然运动规律;最后,建立人体上下肢参数与自行车参数间约束关系,实现人体关节协调运动.对骑行过程进行运动仿真,实验结果表明,该方法能够为骑行者提供正确的姿势指导.     

Subjective response of standing persons exposed to fore-aft,lateral and vertical whole-body vibration

The aims of this study were to propose multiply scale factors for evaluation of discomfort of standing persons and to investigate whether there exist differences between multiplying factors used for evaluation of discomfort of standing persons and those of seated persons exposed to WBV. Twelve male subjects were exposed to twenty-seven stimuli that comprise three acceleration magnitudes (0.2, 0.4, and 0.8 m/s² r.m.s.) along fore-aft (x), lateral (y) or vertical (z) direction. The subjects with seated or standing posture on the platform of the vibration test rig rated the subjective discomfort for each stimulus that has frequency contents ranging from 1.0 Hz to 20 Hz with a constant power spectrum density. The order of presentation of the test stimuli was fully randomized and each stimulus was repeated three times. The subjective scale for discomfort was calculated by using the category judgment method. The best combinations of multiplying factors were determined by calculating correlation coefficients of regression curves in-between subjective ratings and vibration magnitudes. In all the directions, body posture significantly influenced on subjective discomfort scales. Particularly in the fore-aft and lateral direction, the upper limit of all the categories for the standing posture resulted in higher vibration acceleration magnitudes than those for the seated posture. In contrast, in the vertical direction, only the upper limit of category “1: Not uncomfortable” for standing posture was observed to be higher than that for seated posture. The best agreement for ISO-weighted vibration acceleration occurred at x factor of 1.8 and y factor of 1.8 in the standing posture and x factor of 2.8 and y factor of 1.8 in the seated posture. The results suggest that seated people respond more sensitively and severely in perception of discomfort to fore-aft and lateral vibration than standing people do while standing people respond more sensitively and severely to vertical vibration than seated people do. Thus the effects of body postures on multiplying factors should be considered in evaluation of discomfort caused by whole-body vibration.Relevance to industryThis study reports differences in subjective response of standing persons to fore-aft, lateral and vertical whole-body vibration. The results obtained in this study propose the fundamental data on the sensitivity to whole-body vibration exposed with standing posture.     

Computer-related posture and discomfort in primary school children: The effects of a school-based ergonomic intervention

This study investigated the effect of a school-based ergonomic intervention on childrens’ posture and discomfort while using computers using a pre/post test study design. The sample comprised 23 children age 9 and 10 years. Posture was assessed with Rapid Upper Limb Assessment (RULA) and a workstation assessment was completed using a Visual Display Unit (VDU) checklist. Self reported discomfort was also recorded at the beginning and end of the computer class. Following an ergonomic intervention that included education of the children and workstation changes, the outcome measures were repeated. There was a positive response to the intervention with significant changes between the pre-intervention and post-intervention scores for posture (p = 0.00) and workstation (p = 0.00). The change in discomfort scores from beginning to end of the computer class between the pre-intervention class and the post-intervention class was also significant (p = 0.00). The study highlights the need for continuing concern about the physical effects of children’s computer use and the implications of school-based interventions.     

Work organization, job stress, and work-related musculoskeletal disorders

Recent studies indicate potential links among work organization, job stress, and work-related musculoskeletal disorders (WRMDs). In this paper we propose several pathways for a theoretical relationship between job stress and WRMDs. These pathways highlight the physiological, psychological, and behavioral reactions to stress that can affect WRMDs directly and indirectly. One model stipulates that psychosocial work factors (e.g., work pressure, lack of control), which can cause stress, might also influence or be related to ergonomic factors such as force, repetition, and posture that have been identified as risk factors for WRMDs. In order to fully understand the etiology of WRMDs, it is important to examine both physical ergonomic and psychosocial work factors simultaneously. Smith and Carayon-Sainfort (1989) have proposed a model of the work system for stress management that provides a useful framework for conceptualizing the work-related factors that contribute to WRMDs. Practical applications of this research include practitioners taking into account psychosocial work factors and job stress in their efforts to reduce and control WRMDs.