Assessment of physical exposures and comparison of exposure definitions in a repetitive sawmill occupation: trim-saw operator

This paper describes the physical exposures required to perform a sawmill job associated with a high incidence of upper extremity musculoskeletal injury. Exposure variables are described by multiple posture, exertion and frequency definitions and the comparability of those definitions are examined. Effective industrial prevention efforts require an accurate assessment of risk. Surface electromyography and electrogoniometry were used to quantify the physical exposures of 29 trim-saw operators in four sawmill facilities. Average wrist ranges of motion of 32, 57 and 58 degrees in wrist radial/ulnar deviation, flexion/extension and pronation/supination respectively were required to perform the job. Defining wrist range of motion by the peak postures observed versus those required to perform the primary task resulted in significantly different ranges of motion (p<0.05). Job performance required an average of 33% of maximum voluntary contraction. Repetitions per day ranged from 3,549 to 14,460. Percentage of maximum voluntary contraction was not associated with psychophysical measures of exertion.     

A field experiment comparing mechanical demands of two pruners for flower cutting

Manual flower cutting requires repetitive forceful movements that may explain the high incidence of upper-extremity MSDs among workers of the Colombian flower industry. Force demands may be caused by the use of pruners that have not been designed for Colombian workers. We conducted a repeated measures field experimental study (n=16, 69% women, 20 to 60 years old) to compare the mechanical demands during rose cutting of two different pruners (Traditional vs. alternative pruner) at two different cutting heights (elbow vs. over-shoulder). Demands included the perceived comfort, perceived effort and upper limb's muscular activity and posture. Workers perceived their traditional pruner as more comfortable but requiring more effort than the prototype tool. No benefits were observed regarding ulnar deviation with the alternative pruner. The wrist extension and related muscular activity of the wrist extensors were higher with the prototype pruner. The prototype pruner resulted in reduced muscular load of the wrist flexors; the biceps when working at the elbow height; and the deltoids when working at the shoulder height. However, Moderate results may be explained by the lack of time for workers' adaptation to the alternative tool. New design developments must focus on reducing extension and ulnar deviation of the wrist.     

The study of wrist postures of musicians using the WristSystem (Greenleaf Medical System)

This study examined wrist motions of instrumentalists who have never experienced a cumulative traumatic disorder. Eighteen student musicians ranging from 18 to 29 years of age, with more than 9 years of playing experience participated in this study using the WristSystem (Greenleaf Medical System). The wrist motions were measured while participants played their instrument for five minutes. The results indicated a different pattern of wrist movements for each instrumentalist. Pianists demonstrated more ulnar deviation for both hands and more flexion for the left hand than any of the other instrumentalists. The average wrist range of motion for all four movements was under 15 degrees for violinists and violists. The right hand of the cellist had more flexion than any other instrumentalists. For both hands, flutists had more wrist extension than any other instrumentalists. This study provided information about wrist motions of musicians as one of the many factors that contribute to cumulative traumatic disorders. However, further research is needed to identify causal factors, and to promote prevention of the injury.     

Does continuous passive motion during keyboarding affect hand blood flow and wrist function? A prospective case report

The purpose of this prospective case report was to evaluate the use of a keyboard platform device that uses continuous passive motion (CPM) on vascular flow to the hand for clerical employees who perform daily keyboarding tasks. Subjects were two female volunteers, one symptomatic of carpal tunnel syndrome (CTS), who were employed in clerical positions and perform daily keyboarding tasks for most of their workday. Data collection consisted of baseline and follow-up measurements at 6 weeks, including: 1) screening for symptoms based on the Carpal Tunnel Function Disability Form, 2) evaluation using standard physical therapy examination and assessment techniques, including modified Semmes- Weinstein monofilament testing, 3) a typing productivity test, and 4) Doppler ultrasound examination to quantify vascular flow at the wrist. Results revealed that both subjects demonstrated an overall increase in both radial and ulnar blood flow velocity with no decrement in typing productivity. The symptomatic subject also demonstrated an overall improvement of 10 wpm in the typing tests, a decrease in her disability score and symptom severity, and improvement in function. Results suggest that use of CPM as a non-intrusive ergonomic intervention may be used to treat, as well as prevent, carpal tunnel-like symptoms in those who keyboard.     

A randomized intervention trial to reduce mechanical exposures in the Colombian flower industry

Evidence on the effectiveness of ergonomic interventions to reduce mechanical demands and upper-extremity MSDs is scarce in agriculture. We conducted an intervention to reduce mechanical exposures during manual flower cutting through job rotation, education and reduction of force requirements. One-hundred and twenty workers (20 to 60 years old; 89% women) from six companies that cultivate roses participated in this study. Three companies were randomly assigned to control and intervention groups. We studied changes between baseline and follow-up in self-reported effort and upper-extremity postures, kinematics and muscular activity. Most of the observed changes were moderate for both groups. The intervention group showed differential improvements compared to the control group for the maximum wrist radial deviation and forearm pronation, and acceleration of the forearm supination-pronation and elbow flexion-extension; and the muscular activity of the flexor and extensor carpi radialis and the flexor carpi ulnaris. However, we also observed that the maximum ulnar deviation, velocity of the wrist flexion-extension and muscular activity of the extensor carpi ulnaris improved more in the control group. These mixed results may be related to limited time for intervention adjustment, and uncontrolled task changes in the control group. Future research should address these issues and test other solutions.     

Physical and psychosocial indicators among office workers from public sector with and without musculoskeletal symptoms

Work-related musculoskeletal disorders (WRMD) are the result of the combination of different risk factors. They are very common among computer workers, mainly when neck and upper limbs are considered. Forty-two office workers from a public university participated in this study. They were divided into two groups: Symptomatic Subjects (SS, n=20) and Asymptomatic Subjects (AS, n=22), according to the Nordic Musculoskeletal Questionnaire (NMQ). Psychosocial indicators were assessed using the Job Content Questionnaire (JCQ) and Utrecht Work Engagement Scale (UWES). Workplaces were evaluated according to the Ergonomic Workplace Analysis (EWA), proposed by the Finnish Institute of Occupational Health. The NMQ showed higher weekly prevalence of complaints on neck, shoulders and wrist/hands (p=0.00) among SS. The annual prevalence of symptoms on wrist/hands was also higher among SS (p=0.02). The JCQ did not show any difference between groups (p>0.05). Higher proportion of servers with 'high level' of engagement, dedication and absorption, according to UWES, was identified among SS (p<0.01). EWA showed worse scores for 'Work Site', 'Job Content' and 'Repetitiveness of the Work' among SS (p<0.05). Servers are exposed to physical and psychosocial risk factors that can contribute to the development of WRMD. Work conditions need to be change in order to improve musculoskeletal health.     

Ergonomics of novices and experts during simulated endotracheal intubation

Endotracheal Intubation (ETI) is an airway procedure commonly used to secure the airway for a variety of medical conditions. Proficiency in ETI procedures requires significant clinical experience and insufficient data currently exists describing the physical ergonomics of successful direct laryngoscopy. The research objectives of this study were to examine how ETI time, error and practitioner biomechanics varied among clinical experience levels and hospital bed heights. The participant population included novice and expert personnel, differentiated by their exposure to ETI procedures. Participants used a standard laryngoscope and blade to perform ETI trials on an airway manikin trainer at predesigned hospital bed heights. Participants were evaluated based on ETI time and accuracy, as well as wrist postures and muscle utilization. Hospital bed height did not affect task completion time, error rates or muscle utilization. Expert participants exhibited less ulnar deviation and forearm supination during task trials, as well as a higher utilization of the bicep brachii and anterior deltoid muscles. Expert grasped instrumentation differently, requiring less wrist manipulation required to achieve ideal instrument positions. By encouraging ergonomic best-practices in hand and arm postures during ETI training, the opportunity exists to improve patient safety and reduce the learning curve associated with ETI procedures.     

Computer use and ulnar neuropathy: results from a case-referent study

We aimed to evaluate associations between vocational computer use and 1) ulnar neuropathy, and 2) ulnar neuropathy- like symptoms as distinguished by electroneurography. We identified all patients aged 18-65 years, examined at the Department of Neurophysiology on suspicion of ulnar neuropathy, 2001-2007. We mailed a questionnaire to 546 patients with ulnar neuropathy, 633 patients with ulnar neuropathy-like symptoms, and three community referents per case, matched on sex, age, and primary care centre. From a Job Exposure Matrix we extracted estimates of daily hours of computer use. The analysis was performed by conditional logistic regression.There were a negative association between daily hours of computer use and the two outcomes of interest. Participants who reported their elbow to be in contact with their working table for 2 hours or more during the workday had an elevated risk for ulnar neuropathy (OR=2.16, 95 % CI; 1.06-4.44).The two outcomes were not associated with daily hours of computer use. Findings suggested specific effects of pressure on the elbow, and might be an explanation for the overweight of left-sided outcomes in this primarily right-handed group. Preventive efforts would then be straightforward by providing appropriate arm support for the left arm and elbow.     

Distal upper extremity musculoskeletal risk factors associated with colonoscopy

Gastroenterologists are at increased risk for developing recurrent thumb, hand, and elbow pain due to colonoscopy procedures. We evaluated forearm muscle loads and wrist postures during routine colonoscopy (N=12 gastroenterologists) to understand distal upper extremity musculoskeletal risk factors associated with the 4 different subtasks of colonoscopy. Bilateral forearm extensor carpiradialis (ECR) and flexor digitorum superficialis (FDS) surface electromyography and bilateral wrist postures were recorded continuously. The mean duration of colonoscopy was 24.2 (± 12.1) minutes and was dominated by the withdrawal subtask [13.7 (± 8.8) min] followed by right colon insertion [5.8 (± 4.8) min], left colon insertion [3.5 (± 3.1) min], and retroflexion [1.2 (± 2.1) min]. Median (APDF50) and peak (APDF90) left forearm muscle activity was significantly greater than right forearm muscle activity across all subtasks. Median and peak ECR muscle activity was significantly greater during the left and right colon insertion subtasks compared to retroflexion. Both wrists were predominantly in wrist extension during all phases of colonoscopy. The left forearm muscle activity was higher than right forearm activity due to differences in wrist posture and grip force. The risk factors for the left hand may be reduced with alternative designs and support mechanisms for the colonoscope head.     

Development of objective discomfort evaluation indicators for a task-oriented motion using less constrained motion concept: application to automotive pedal clutching task

This paper presents a method to develop objective discomfort evaluation indicators for a task oriented motion using the concept of less constrained movement. The basic idea is to compare imposed and less constrained movements in order to identify relevant biomechanical parameters for defining objective discomfort indicators. The task of automotive pedal clutching was chosen for illustrating the proposed method. Based on discomfort questionnaire and motion analysis of the experimental data, four discomfort indicators were proposed. Two of them were based on the ankle joint angle around flexion/extension axis at the beginning and the end of the clutch pedal depression. The third one was defined using knee flexion/extension joint torque at the end of the clutch pedal depression. The last indicator was defined as the relative lateral position of the heel compared to the average pedal lateral position for less constrained configurations. A global discomfort function was also defined as a weighted sum of all indicators. Globally, the proposed global discomfort indicator succeeded in differentiating the tested configurations in agreement with experimental observation. As expected, less discomfort rating is obtained for less constrained movement when compared with the corresponding imposed one.     

Ergonomic evaluation of novel tool for snap-off the neck of ampoule

Needlestick and Sharps Injuries (NSI) represent an important workplace issue in contemporary health care. Present study provided the new method to snap-off the neck of sealed ampoule. The idea of novel opener tool is prepare the grinding slice inside rubber ring, so users could put the ampoule inside the rubber ring and then rotated the rubber ring to snap-off the neck of ampoule. The purpose of present study was evaluated the methods of snap-off and sizes of ampoule on forearm muscle activities, wrist postures and performance. The pronator teres muscle were heavier load as increased the sizes of ampoule. For performance analysis, Duncan's multiple range tests indicated that time of snap-off were longer in 10 ml and 20 ml of ampoule. The EMG of pronator teres muscle was significantly affected by methods of snap-off. Duncan's multiple range tests indicated that lower load was experienced on forearm muscles while using grinding slice with glove. For wrist posture, the ranges of motion for wrist were significant lower while using the novel tool. Present study provided the novel tool effectively to snap-off the ampoule to decrease forearm workload and sharp injuries.     

Asthma and allergy as risk factors for suicidal behavior among young adults

An association between allergic disease, depression and suicidality has been reported. Objective: To explore the relationships between suicidality and asthma, allergy, internet addiction, stress, sleep quality, pain/discomfort, and depression, among emerging adults. Participants: 929 college students completed an online survey between October 2015 and April 2017. Methods: A cross-sectional study using multivariate analysis techniques was implemented. Results: Using structural equation modeling, we found that allergies and stress were directly related to pain/discomfort; pain/discomfort was associated to poor sleep, depression, and suicidality. Sleep quality was also affected by stress; while sleep, stress, pain/discomfort, and internet addiction were directly related to depression (all p < .05). Ultimately, four factors impacted suicidality: stress, pain/discomfort, depression, and, indirectly, sleep quality (all p < .05). Although allergy had some effects, these did not reach statistical significance (p < .09). Conclusion: Findings suggest that allergy might impact suicidality indirectly through increased pain/discomfort, poor sleep, and depression.     

Condom discomfort and associated problems with their use among university students

In addition to consistent use, condoms must be used correctly. The purpose of this study was to identify prevalence and types of condom-associated discomfort among university students, the outcomes of this discomfort, and the role of discomfort in condom breakage. We conducted a cross-sectional study of 206 students attending a private university in the southern United States. We assessed 3 potential outcomes: breakage, not using condoms throughout sex, and low condom-use motivation. Nearly one third reported discomfort, including tightly fitting condoms, vaginal irritation, and loss of sensation. Discomfort was associated with breakage (p = .0001), incomplete use (p = .0001), and less motivation to use condoms (p = .018). Gender moderated the latter 2 findings. Adjusted findings indicate that students reporting discomfort were 3.6 times more likely to also report breakage (p = .0009). Continued investigation of this topic is warranted. Prevention education may benefit university students by promoting several key practices, such as adding lubricant to condoms before they dry out and acquiring condoms that fit properly.     

Are cutout handles used when available in real occupational settings? Description of grips and upper extremities movements during industrial box handling

In order to achieve better postures and decrease musculoskeletal risks adequate design of hand/box couplings for manual materials handling (MMH) are still needed. No studies evaluating upper limb movement thorough direct measurements during box handling in workplace were identified in the literature. In this study we describe the types of grip and movements adopted by ten workers when handling redesigned boxes with cutout handles between different heights on industrial pallets. The new handles were used by 90% of the workers through different types of grip. Electrogoniometric measurements showed relatively safe forearm and wrist movements, although elbow inadequate range of movement was recorded. Despite the good acceptance of the cutout by workers, the new design requires extra internal space in the boxes reducing applications for this alternative of box.     

The impact of high-calorie-expenditure exercise on quality of life in older adults with coronary heart disease

The acceptability of a high-calorie-expenditure (HCE) exercise program in older coronary heart disease patients participating in a behavioral weight-control program was evaluated. Seventy-four overweight patients (median age 63 yr) were randomly assigned to a 5-mo intervention of HCE exercise (3,000-3,500 kcal/wk daily walking) or standard cardiac-rehabilitation (CR) exercise (700-800 kcal/wk). Both groups received counseling to achieve a dietary caloric deficit of 3,500 kcal/ wk. Assessments at baseline and 5 mo included self-reported measures of quality of life and psychosocial variables. The HCE group experienced significantly greater weight loss (8.2 ± 4 vs. 3.7 ± 5 kg, p < .001). Changes from baseline to 5 mo on scores of physical, emotional, and social functioning were greater for the HCE than CR group (p < .05). HCE exercise also resulted in greater positive change in exercise enjoyment (p = .05), which was mediated by weight change. Even high-risk older adults can be successful in an HCE exercise program and experience no adverse physical or emotional changes.     

The effect of Video Display Terminal (VDT) mouse use on muscle contractions in the neck and forearm

This study used surface electromyography (EMG) to examine the percent of maximum voluntary contraction (%MVC) of the upper trapezius, the flexors of the wrist/fingers and extensors of the wrist/fingers during Video Display Terminal (VDT) mouse use with the mouse positioned either next to the computer or on a lapdesk. Thirty participants, between the ages of 18 and 40, used a VDT mouse to follow a prescribed pattern for three trials at each location. Although there was a trend towards the lapdesk location producing lower %MVC than the computer location for the trapezius and wrist/finger flexors (lapdesk: trapezius M 4.71%, wrist/finger flexors M 3.53%; computer: trapezius M 5.74%, wrist/finger flexors M 3.94%) a two way ANOVA controlling for sequence and order found no significant difference between the means. There was no trend for the effects of location for the wrist/finger extensors. These results suggest that changing the position of the mouse may not significantly reduce muscle contractions.     

Anthropometric aspects of body seated in school

This study aimed to assess the student-furniture interface from anthropometric parameters of the sitting posture. The sample was composed of 887 students from two public schools in the State of Parana-Brazil, which attended children from 7 to 17 years of age. The data collection used anthropometric measures of the sitting position, a questionnaire containing a human body diagram for indication of discomfort areas and photographic records to verify postural and ergonomic inadequacies in classroom. The following anthropometric variables were measured: popliteal height, sacro-popliteal length, hip width, lumbar support height, and elbow and thigh height. Percentiles 5 and 95 of anthropometric variables showed differences statistically significant, with variation coefficient greater than 30%. In relation to body discomfort, the highest occurrences were recorded for ankle, knees and shoulder joints as well as for spine and buttocks. It was concluded that children use school furniture that does not meet their anthropometric standards, which favored the adoption of incorrect postures and contributed to the emergence of musculoskeletal problems that can interfere with their educational process.     

Quantitative posture analysis of 2D, 3D, and optical microscope visualization methods for microsurgery tasks

The purpose of this paper is to present a quantitative posture analysis of microsurgery tasks performed with different visualization methods. Microsurgery is traditionally performed using a binocular microscope; however surgeons are constrained by the optical eyepieces and are forced to assume joint angles that deviate away from neutral postures. This may be especially problematic for the neck and can increase surgeon discomfort and fatigue. Alternative visualization methods may improve surgeon posture by eliminating the constraints imposed by the microscope. This study examines both 2D and 3D heads-up displays as possible alternatives. Six subjects performed microsurgical tasks with each visualization methods for four hours. Quantitative posture analysis was done using Maxtraq software that tracks reflective markers on the subjects. The initial analysis of neck, upper arm, and elbow angles found significant differences between each display. A biomechanical analysis found that the differences in angles can result in loads on the neck joint that are twice as high in the microscope than the headsup displays. Although the alternative displays can result in better postures, improvements the display technology is needed to improve microsurgical task performance.     

Assessment of physical activity in older people with and without cognitive impairment

The purpose of this study was to validate a new interview-administered physical activity questionnaire (Assessment of Physical Activity in Frail Older People; APAFOP) in older people with and without cognitive impairment. The authors assessed feasibility, validity, and test-retest reliability in 168 people (n = 78 with, n = 88 without cognitive impairment). Concurrent validity was assessed against an inertia-based motion sensor and an established questionnaire. Sensitivity to change was tested in an ongoing study in patients with mild to moderate dementia (n = 81). Assessment of physical activity by the APAFOP and the motion sensor correlated well in the total sample (TS; p = .705), as well as in the subsamples with cognitive impairment (CI; p = .585) and without CI (p = .787). Excellent feasibility with an acceptance rate of 100%, test-retest reliability (intraclass correlation coefficients ranging from .973 (TS) to .975 (CI) to .966 (no CI), and sensitivity to change (effect sizes: 0.35-1.47) were found in both subsamples.