Operative Discomfort Research Articles

The experience of a tele-operated avatar being touched increases operator's sense of discomfort.

Recent advancements in tele-operated avatars, both on-screen and robotic, have expanded opportunities for human interaction that exceed spatial and physical limitations. While numerous studies have enhanced operator control and improved the impression left on remote users, one area remains underexplored: the experience of operators during touch interactions between an avatar and a remote interlocutor. Touch interactions have become commonplace with avatars, especially those displayed on or integrated with touchscreen interfaces. Although the need for avatars to exhibit human-like touch responses has been recognized as beneficial for maintaining positive impressions on remote users, the sensations and experiences of the operators behind these avatars during such interactions remain largely uninvestigated. This study examines the sensations felt by an operator when their tele-operated avatar is touched remotely. Our findings reveal that operators can perceive a sensation of discomfort when their on-screen avatar is touched. This feeling is intensified when the touch is visualized and the avatar reacts to it. Although these autonomous responses may enhance the human-like perceptions of remote users, they might also lead to operator discomfort. This situation underscores the importance of designing avatars that address the experiences of both remote users and operators. We address this issue by proposing a tele-operated avatar system that minimizes unwarranted touch interactions from unfamiliar interlocutors based on social intimacy.

Real-time action localization of manual assembly operations using deep learning and augmented inference state machines

The real-time monitoring of assembly operations in manufacturing industries can be used for manufacturing process optimization, which is crucial to manufacturers. It helps to improve productivity by automatically identifying the bottleneck and enhancing product quality by detecting errors and providing feedback to rectify them in real-time. However, developing a robust and reliable assembly monitoring system is not trivial due to the varying length of fine-grained assembly steps and anthropometric variations associated with assembly workers. To tackle the challenge, conventionally, wireless body-worn sensors have been used, leading to operator discomfort, and raising safety concerns. In this work, we propose a novel technique to automatically recognize and localize the assembly steps in real time called the State Machine Integrated Recognition and Localization (SMIRL). SMIRL is comprised of an inference machine and a state machine. They are responsible for detecting and localizing the actions, respectively. SMIRL can measure the duration of individual assembly steps and the entire cycle. Additionally, SMIRL can also detect the mistakes that may occur in an assembly and raise an alert to notify the operators in real time. The mistakes here can be breaking the predefined assembly sequence (Sequence Break) or missing any of the assembly steps (Missed steps). The effectiveness of SMIRL was evaluated against two datasets, with one being from an assembly workstation in industry and the other from a laboratory. The result shows that SMIRL can detect and localize the actions with an Intersection over Union (IoU) score of 87.53%, and identify Sequence Breaks and Missed Steps with F1-Scores of 86.64% and 87.45%, respectively. Through this study, we aim to contribute towards real-time monitoring of human-centric assembly operations to facilitate smart manufacturing.

If we should remove internal fixation devices for rib fractures?

BackgroundInternal fixation for rib fractures has been widely carried out worldwide, and its surgical efficacy has been recognized. However, there is still controversy about whether implant materials need to be removed. At present, the research on this topic is still lacking at home and abroad. Therefore, in this study, the patients undergoing removal of internal fixation for rib fractures in our department within one year were followed up, to statistically analyze implant-related complications, postoperative complications and postoperative remission rate.MethodsA retrospective analysis was conducted on 143 patients undergoing removal of internal fixation for rib fractures from 2020 to 2021 in our center. The implant-related complications, postoperative complications and postoperative remission rate of patients with internal fixation were analyzed.ResultsIn this study, a total of 143 patients underwent removal of internal fixation, among which 73 suffered from preoperative implant-related complications (foreign-body sensation, pain, wound numbness, sense of tightness, screw slippage, chest tightness, implant rejection), and 70 had no post operative discomfort but asked for removal of internal fixation. The average interval between rib fixation and removal was 17 ± 9.00 (months), and the average number of removed materials was 5.29 ± 2.42. Postoperative complications included wound infection (n = 1) and pulmonary embolism (n = 1). of the 73 patients with preoperative implant-related complications, the mean postoperative remission rate was 82%. Among the 70 patients without preoperative discomfort, the proportion of discomforts after removal was 10%. No perioperative death occurred.ConclusionFor patients with internal fixation for rib fractures, removal of internal fixation can be considered in the case of implant-related complications after surgery. The corresponding symptoms can be relieved after removal. The removal presents low complication rate, and high safety and reliability. For patients without obvious symptoms, it is safe to retain the internal fixation in the body. For the asymptomatic patients who ask for removal of internal fixation, the possible risk of complications should be fully informed before removal.

GINGIVAL WOUND HEALING RESPONSE FOLLOWING PLACEMENT OF A LIGHT CURE DRESSING WITH AND WITHOUT BLUE M®GEL AFTER GINGIVAL DEPIGMENTATION. A RANDOMIZED SPLIT MOUTH STUDY

Background: In todays world pigmentation of gingiva not just has an impact on esthetics but also creates psychological negativity.Esthetic awareness of dental patients has extended to include requests of gingival color modification.Different treatment modalities which have been reported include bur abrasion, scraping, partial thickness flap, cryotherapy, electrosurgery. However, pain and healing are the two drawbacks associated with the post operative discomfort after the procedure which can be catered well with use of a newly developed oxygen releasing gel ie. Blue M® Gel and light cure periodontal dressing. Method: A total of 10 patients randomly divided into two groups were selected for this randomized split mouth study. Gingival depigmentation using a scalpel were performed followed by Placement of a light cure dressing (Barricaid®) in10 anterior sextants after gingival depigmentation in Group â… and Application of an oxygen releasing oral gel (BlueM®) before placement of a light cure dressing (Barricaid®) in Group â…¡. Wound Healing Index at day 7, VAS Score (Pain) at day 3 and GI & PI at day 7 &14 after the gingival depigmentation were evaluated for both the groups. Results:There was no significant difference in clinical parameters recorded at various time intervals between both the groups. Conclusion: The use of Blue M® Gel underneath light cure periodontal dressing did not enhance the healing following Gingival depigmentation.

FRENECTOMY - DIFFERENT TECHNIQUES

Introduction:-The frenum is a mucous membrane fold that attaches the lip , cheek and the tongue to the alveolar mucosa, the gingiva, and the underlying periosteum .Aesthetic problems are caused by high maxillary frenum which may compromise the orthodontic treatment results in the midline diastema cases, thus causing a recurrence after the treatment. Ankyloglossia, is also called as tongue-tie, is an embryological anatomical malformation of the tongue, characterized by an abnormally short and a thick lingual frenum. Tongue-tie restricts the physiologic movements of the tongue and results in various functional, behavioural and speech abnormalities. Material method :- The present article consists of a series of clinical cases of an aberrant frenum which were approached by various surgical frenectomy techniques. Result:- Different techniques have their own advantages and disadvantages. Laser gives advantages of less post operative pain and discomfort. Lingual frenectomy help in improvement in tongue movement and speech. Conclusion:- An aberrant frenum can be removed by any of the modification techniques that have been proposed,and a functional and an aesthetic outcome can be achieved by a proper selection of technique which is based on the type of the frenal attachment.

Improving IR Ergonomics Using a Flexible C-Arm System

PurposeTo evaluate the impact of a versatile flexible ceiling-mounted C-arm on active table and gantry repositioning during interventions and its effect on operator discomfort, system usability, and patient safety compared with a traditional ceiling-mounted system. Materials and MethodsThere were 100 IR procedures studied: 50 in a traditional IR system (standard group) and 50 with a novel multiaxis ceiling-mounted system (test group). FlexArm was capable of multiple gantry rotation points allowing increased access to the patient in addition to 236 cm of lateral x-ray detector travel. For each procedure, both the table and the gantry repositioning were measured. Patient safety, patient/equipment repositioning effort, and physical discomfort were evaluated through an operator survey. ResultsTable repositioning was reduced from 42 to 16 instances per procedure (P < .001) in the test group compared with the standard group. The operators perceived less table and gantry repositioning effort (P < .0001) and decreased risks of equipment collisions, displacement of vascular access, and dislodgment of tubes/lines with the test group (P < .0001). Operator discomfort was reduced for all body areas in the test group over the standard group (P < .0001). ConclusionsThe FlexArm system geometry enhances operator ergonomics, as there was a decrease need to move the table, leading to a perceived decrease in patient risk and decrease operator physical discomfort when compared to a traditional imaging system.

Post Operative Pain Management with Matrabasti (Enema with medicated oil) in Haemorrhoidectomy - A Case Study

Post operative pain management is always a challenge for ano-rectal surgeons. Haemorrhoidectomy is often involved with severe post operative pain and discomfort during defecation. Ayurvedic surgeon most of the time depends of contemporary medical science and uses analgesics, which has its own adverse effects. Many times mere oral ayurvedic medicines are not sufficient to mange post operative pain. Basti (enema with medicines) is regarded as best treatment for vata dosh vitiation. Vata dosh vitiation is the main cause for the pain. In post operative wounds also, trauma and blood loss lead to vata vitiation and causes pain. There are different types of basti’s explained in the classics. Matrabasti (enema with medicated oil) is a type of Sneha Basti which can be given in all seasons without any strict regimen of Diet. It is a procedure where a minimal quantity of medicated oil or medicated ghee is used in the form of enema. Post operative wound will aggravate vata and lead to pain. Hence matrabasti which is having minimal medicine is tried in post operative cases of haemorrhoidectomy. This increases time taken for the onset of pain after haemorrhoidectomy and also helps in easy evacuation of stools in post operative period.

Comparative Study to Evaluate the Outcome of Sutures Versus Sutureless in Attachment of Conjunctival Autograft for Pterygium Excision

Background: Suturing of conjunctival graft is a traditional technique for pterygium excision surgery. Owing to its many disadvantages &amp; complications many newer techniques like autologous fibrin glue have been introduced &amp; accepted as an alternative method of graft adhesion. Methodology: The present study was conducted at the Department of Ophthalmology, MMIMSR, Mullana (Maharishi Markandeshwar Deemed to be University) in the time period extending between December 2017 and January 2019. 100 eyes of patients of either sex with primary pterygium were selected and divided into 2 groups of 50 each in Group 1- patient underwent conjunctival auto graft with 10-0 ethilon sutures while in Group 2 suture less conjunctival auto graft was done with patient’s own blood fibrin. Results: Parameters such as mean operating time, presenting complaints like pain, watering, burning and foreign body sensation, complications &amp; recurrence were compared between the two groups on postoperative Day 1, Day 7, 2 weeks, 1 month, 2 month, 3 month &amp; 6th month. Statistical significant difference (p&lt;0.01) was found between the suture and sutureless surgery for pterygium in relation to post-operative discomfort grading. There was a significant difference (t = 22.149, p = 0.001) in the duration of surgery for GROUP I surgery. Conclusion: Conjunctival auto graft with autologous serum is a safe and fast method. It is equally effective as conventional sutured autograft technique. Post operative discomfort is significantly less in this method. It also prevents suture related complications.

Abstract No. 572 Improving the interventional radiology lab ergonomics using a novel imaging system geometry for image-guided procedures

The interventional radiology (IR) lab work environment poses specific challenges in terms of comfort and safety for operators and patients. Table movements required for imaging and lack of system positioning flexibility are suspected to contribute to these challenges. This study evaluated the impact of a novel imaging system geometry on table movements during interventions and subsequent effects on ergonomics. 100 IR procedures were included; 50 in a traditional, widely available ceiling-mounted IR lab (A) and 50 in a lab equipped with a novel multi-axis ceiling-mounted angiography system (B) (both Philips Healthcare, Best, the Netherlands). System B was capable of 236 cm lateral x-ray detector travel in addition to traditional longitudinal travel, allowing the use of gantry- in lieu of table movements when positioning patients for imaging, as well as more flexible system positioning. After every procedure, operators evaluated patient safety, patient-/equipment positioning effort and perceived physical discomfort. Where available, system logging data from both labs were used to analyze table- and gantry movements for comparison. Median table movements per procedure were 42 and 16 (p<.001) for system A (n=36) and B (n=40) respectively. Median total table travel distance per procedure was 1998 mm for A vs. 865 mm (p=.002) for B. Operators perceived system B requiring less patient-/equipment positioning effort (p<.001). Operator discomfort during procedures was reduced for all body areas (head + neck, shoulders + upper back, arms + hands, middle + lower back and hips + legs + feet, p<.001) when comparing system A to B. Moreover system B was perceived safer for patients due to decreased risks of equipment collisions, loss of device position and pulling tubes/lines (p<.001). Novel angiography system geometry allows a reduction of the number and total travel distance of table movements, resulting in lower physical discomfort for operators. A documented significant reduction in table movements should improve patient comfort and safety and reduce patient-/equipment positioning efforts.

Posterior maxillary segmental osteotomy for prosthodontic rehabilitation of vertically excess maxilla -a review

PurposeThe purpose of this systematic review was to analyze the literature of the various surgical options available for the correction posterior maxillary alveolar ridge excess without going for radical approaches. It also analyzed the effectiveness of posterior maxillary segmental osteotomy in prosthetic rehabilitation in terms of stability, success rates, function, occlusion, aesthetics and long term postoperative complications. Study selectionA systematic search of Medline/Pubmed and Web of Science databases of English articles published till December 2017 for the treatment of vertical excess in the posterior maxilla for prosthetic reasons was performed. A total of 37 articles met the inclusion criteria. ResultsPosterior maxillary segmental osteotomy (PMSO) was performed as a single stage procedure in 23 cases with minimal post- operative discomfort in all cases. The amount of superior positioning of the osteotomised maxilla ranged between 4 mm to 9 mm which provides sufficient space for prosthodontic rehabilitation. ConclusionsPMSO is fairly competent in treating vertical ridge excess of posterior maxilla, makes space for prosthesis and is associated with fewer postoperative problems when a multidisciplinary team approach is put into service.

Effect of different impregnated gutta-percha points on post operative discomfort

The purpose of this study was to compare levels of post operative discomfort after cleaning and shaping of root canals using intracanal medicaments. Two hundreds forty teeth requiring root canal treatment were included. At random, canals were cleaned and shaped with crown-down technique and then dried and one of the following medicaments was used. Group I: medicated with chlorhexidine containing gutta-percha points (Activ points). Group II: medicated with calcium hydroxide containing gutta-percha points and finally group III: with no medicaments. Access cavities were closed with a sterile cotton pellet and cavit. The patients recorded degree of discomfort of various time intervals after cleaning and shaping on a visual analogue scale for 72hr. A significant statistical difference was found in the degree of discomfort between the three groups.

Long-Term Outcomes of Pelvic Organ Prolapse by Laparoscopic Butterfly Suspension

Aim The study aimed to investigate the long clinic value of laparoscopic colpo-uterine butterfly suspension for pelvic organ prolapse. Methods Ninety -three patients who underwent the laparoscopic colpo-uterine butterfly suspension from December 2012 to May 2018 at the first affiliated hospital of zhengzhou university were analyzed in a retrospective study. Baseline characteristics and perioperative data were recorded. The POP quantification (POP-Q) system indicates the pre- and post-operative data. Respectively，the symptoms, health-related quality of life (HRQL) and Sexual function were evaluated by the Pelvic Floor Distress Inventory (PFDI-20), the Pelvic Floor Impact Questionnaire (PFIQ-7) and the Pelvic organ prolapse urinary Incontinence Sexual Questionnaire (PISQ-12). Results In 5 years’ follow-up, the objective cure ratio reached 97.8%, and the subjective success rate of the laparoscopic colpo-uterine butterfly suspension was 93.5%. Two cases was identified as clinical relapse. There was only one abdominal erosion during the long-term follow-up. The quality of life had improved significantly without any genital symptoms. No patients abstained from sex due to the operation or postoperative sexual discomfort. Conclusions The laparoscopic colpo-uterine butterfly suspension is a safe, feasible and highly effective technique that offers a good long-term results for the treatment of pelvic organ prolapse, also a good option for sexually active women.

Powertrain modelling for engine stop–start dynamics and control of micro/mild hybrid construction machines

Engine stop–start control is considered as the key technology for micro/mild hybridisation of vehicles and machines. To utilise this concept, especially for construction machines, the engine is desired to be started in such a way that the operator discomfort can be minimised. To address this issue, this paper aims to develop a simple powertrain modelling approach for engine stop–start dynamic analysis and an advanced engine start control scheme newly applicable for micro/mild hybrid construction machines. First, a powertrain model of a generic construction machine is mathematically developed in a general form, which allows to investigate the transient responses of the system during the engine cranking process. Second, a simple parameterisation procedure with a minimum set of data required to characterise the dynamic model is presented. Third, a model-based adaptive controller is designed for the starter to crank the engine quickly and smoothly without the need of fuel injection while the critical problems of machine noise, vibration and harshness can be eliminated. Finally, the advantages and effectiveness of the proposed modelling and control approaches have been validated through numerical simulations. The results imply that with the limited data set for training, the developed model works better than a high fidelity model built in AMESim while the adaptive controller can guarantee the desired cranking performance.

How Much Inconvenience and Discomfort does Modern IVF Treatment Cause?

IVF is widely practiced, however, data on the degree of discomfort and inconvenience experienced by women undergoing treatment is nonexistent. We surveyed women being treated at Monash IVF, undergoing oocyte collection in stimulated cycles at Epworth Hawthorn Day Surgery. One hundred and eighteen women were recruited to the study during a five week period from August to September 2014 and underwent a five minute telephone interview asking ten questions. Women were asked to rate the inconvenience and pain associated with the blood tests, injections and oocyte collection procedure using a numeric rating scale of zero to ten. Data on analgesic usage and the time taken to return to work and normal activity was also recorded. The median number of oocytes was nine. The mean pain score immediately post operation was 4.6, and at 24 hours 3.9, on a scale of 1 to 10. Most women returned to normal activity and work within two days (mean 1.7, SD1.5days and mean 1.8 SD1.5 respectively).Immediate post operative discomfort was not found to be correlated with the number of oocytes collected. However the number of oocytes collected positively correlated with the quantity and duration of analgesics consumed and the time taken to resume work and normal activity.

A dynamic simulator for the ergonomics evaluation of powered torque tools for human assembly

PurposeThe purpose of this study is to design and develop a testing device to simulate interaction between human hand–arm dynamics, right-angle (RA) computer-controlled power torque tools and joint-tightening task-related variables.Design/methodology/approachThe testing rig can simulate a variety of tools, tasks and operator conditions. The device includes custom data-acquisition electronics and graphical user interface-based software. The simulation of the human hand–arm dynamics is based on the rig’s four-bar mechanism-based design and mechanical components that provide adjustable stiffness (via pneumatic cylinder) and mass (via plates) and non-adjustable damping. The stiffness and mass values used are based on an experimentally validated hand–arm model that includes a database of model parameters. This database is with respect to gender and working posture, corresponding to experienced tool operators from a prior study.FindingsThe rig measures tool handle force and displacement responses simultaneously. Peak force and displacement coefficients of determination (R2) between rig estimations and human testing measurements were 0.98 and 0.85, respectively, for the same set of tools, tasks and operator conditions. The rig also provides predicted tool operator acceptability ratings, using a data set from a prior study of discomfort in experienced operators during torque tool use.Research limitations/implicationsDeviations from linearity may influence handle force and displacement measurements. Stiction (Coulomb friction) in the overall rig, as well as in the air cylinder piston, is neglected. The rig’s mechanical damping is not adjustable, despite the fact that human hand–arm damping varies with respect to gender and working posture. Deviations from these assumptions may affect the correlation of the handle force and displacement measurements with those of human testing for the same tool, task and operator conditions.Practical implicationsThis test rig will allow the rapid assessment of the ergonomic performance of DC torque tools, saving considerable time in lineside applications and reducing the risk of worker injury. DC torque tools are an extremely effective way of increasing production rate and improving torque accuracy. Being a complex dynamic system, however, the performance of DC torque tools varies in each application. Changes in worker mass, damping and stiffness, as well as joint stiffness and tool program, make each application unique. This test rig models all of these factors and allows quick assessment.Social implicationsThe use of this tool test rig will help to identify and understand risk factors that contribute to musculoskeletal disorders (MSDs) associated with the use of torque tools. Tool operators are subjected to large impulsive handle reaction forces, as joint torque builds up while tightening a fastener. Repeated exposure to such forces is associated with muscle soreness, fatigue and physical stress which are also risk factors for upper extremity injuries (MSDs; e.g. tendinosis, myofascial pain). Eccentric exercise exertions are known to cause damage to muscle tissue in untrained individuals and affect subsequent performance.Originality/valueThe rig provides a novel means for quantitative, repeatable dynamic evaluation of RA powered torque tools and objective selection of tightening programs. Compared to current static tool assessment methods, dynamic testing provides a more realistic tool assessment relative to the tool operator’s experience. This may lead to improvements in tool or controller design and reduction in associated musculoskeletal discomfort in operators.

Safety and efficacy of using bronchial occluder in patients undergoing thoracoscopy pulmonary bulla surgery

Objective The purpose of this study was to compare the safety and efficacy of using bronchial blockers tube(BB) versus double cavity bronchial catheter in thoracoscopy pulmonary bulla surgery. Methods Eighty patients with pulmonary bulla. were randomly divided into two groups(n=40): group A received a double cavity bronchial tube, group B received the bronchial occluder. The general information, intubation success rate, blood gas analysis at different time points immediately after anesthesia(T0), 20 min after one-lung ventilation(T1), 60 min after one-lung ventilation(T2) and 60 min after two-lung ventilation(T3) and the occurrence of adverse reactions were recorded. Results Compared with group A, the intubation success rate of group B was higher(P 0.05). In contrast with T0 and T3, airway plateau pressure(Pplat) and peak airway pressure(Ppeak) of the above groups were dramatically increased at T1 and T2(P<0.05). Besides, Pplat and Ppeak from group B were lower than those from group A(P<0.05). After extubation, 11 patients from group A had a hoarseness and sore throat, the incidence rate was 27.5%; In group B(3 cases), rate of the same adverse reactions was 7.5%. The occurrence rates of adverse effect after extubation were statistically significant between the two groups(P<0.05). Conclusions In contrast with double lumen catheter, applying bronchial occluder in thoracoscopy pulmonary bulla surgery is a more effective and safer way to reduce blood gas changes during operation and postoperative discomfort. Key words: Double lumen catheter; Bronchial blockers tube; Pulmonary bulla resection

Operator Radiation Exposure and Physical Discomfort During a Right Versus Left Radial Approach for Coronary Interventions: A Randomized Evaluation

This study sought to assess radiation exposure and operator discomfort when using left radial approach (LRA) versus right radial approach (RRA) for coronary diagnostic and percutaneous interventions. The transradial approach is increasingly being adopted as the preferred vascular access for coronary interventions. Currently, most are performed using an RRA. This is in part due to the perceived increased operator physical discomforts as well increased radiation exposure with an LRA. One hundred patients were randomized to an LRA or RRA. Each operator (n= 5) had an independent randomization process, and patients were stratified according to obesity status. Operator radiation was measured using separate sets of radiation dosimeter badges placed externally on the head and thyroid and internally on the sternum. Operator physical discomfort was surveyed at 2 time points: during vascular access and at the end of the procedure. Moderate to severe physical discomfort was defined as a score of >4. There were no significant differences in baseline and procedural variables between groups. There was a significant increase in external radiation exposure using the RRA versus LRA (head: median: 6.12 [interquartile range (IQR): 2.6 to 16.6] mRems vs. median: 12.0 [IQR: 6.4 to 22.0] mRems, p= 0.02; thyroid: median: 10.10 [IQR: 4.3 to 25] mRems vs. median: 18.70 [IQR: 11.0 to 38] mRems, p=0.001). More discomfort was reported with the LRA during access (LRA: 22% vs. RRA: 4%; p=0.017), but not during the procedure (LRA: 10.0% vs. RRA: 4.0%, p= 0.43). This difference was almost entirely noted inobese patients (LRA: 30.0% vs. RRA: 3.7%, p= 0.005). LRA is as effective as RRA, showing a safer profile with decreased radiation exposure to the operator, at the expense of more operator discomfort only during vascular access and limited to obese patients.

Self-selected duty cycle times for grip force, wrist flexion postures and three grip types

Performance and health issues are common in industry. On-the-job productivity gains related to good design, which could help justify ergonomics intervention, are often not considered. More quantitative data are needed to model the discomfort/productivity relationship for upper limb activity in simulated repetitive assembly type work. Eighteen participants completed an experiment, simulating a repetitive upper limb task with force, posture and grip type recorded as independent variables. Duty cycle time and discomfort were recorded as dependent variables. Participants performed 18 experiment combinations (block designed around force); each treatment lasted 35 min, including breaks. Analysis indicated a significant two-way interaction between posture and grip type. Results from this experiment were used to model the effect of these variables on operator discomfort and performance.

Comfort Evaluation Research on Clutch Operation of Light Commercial Vehicle

Based on biomechanic theory, the comfort evaluation can be made to aim at improving the comfort of clutch operation of light commercial vehicle. First, the virtual model of the cab was established to predict posture of pressing clutch pedal. Then values of joint toques were figured out by using Jacobin Method and these data were brought into the comfort evaluation function to achieve the comfort degree of clutch operation. From the perspective of biomechanics, this research reveals the cause of clutch operation discomfort in a deeper sense and will provide a new reference approach for improving operation comfort of light commercial vehicle.

Effect of Different Types of Rest-Break Interventions on Neck and Shoulder Muscle Activity, Perceived Discomfort and Productivity in Symptomatic VDU Operators: A Randomized Controlled Trial

Objective. This study evaluated the effect of different types of activities during rest-break interventions on neck and shoulder muscle activity, muscle discomfort and productivity among symptomatic video display unit (VDU) operators performing prolonged computer terminal work. Study design and setting. Randomized controlled trial was used. Thirty symptomatic VDU operators were randomly assigned to 2 active break groups (stretching and dynamic movement) and a reference group. The subjects performed the same typing task for 60 min and received 3-min breaks after each 20 min of work. Root mean square and median frequency were calculated for neck and shoulder muscle activity. Muscle discomfort was measured with Borg’s CR-10 scale. Productivity was measured by counting words. Results. There were no significant differences between the types of activities during breaks on neck and shoulder muscle activity, muscle discomfort or productivity. However, there was a significant difference in the level of muscle discomfort over time. Conclusions. Three types of activity during breaks showed a favourable effect on neck and shoulder muscle activity and productivity, and a positive effect on muscle discomfort in symptomatic VDU operators.