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Biomedical subjects

M Hagberg

Publications and source records attributed to M Hagberg.

At least 37 records · Page 2Linked to original sources
PubMed1999

Exposure-response relationship between hand-arm vibration and vibrotactile perception sensitivity.

BACKGROUND: The objectives of the study were to examine whether occupational use of vibrating hand-held tools was associated with an impaired vibrotactile perception, whether any exposure-response relationship exists, and whether the different populations of mechano-receptive afferent units are equally affected. METHODS: Vibrotactile perception thresholds have been measured at seven frequencies (8-500 Hz) and evaluated among 125 vibration-exposed and 45 non-exposed male employees in a heavy engineering production workshop. Vibration exposure measurements were assessed on tools in accordance with ISO 5349. Vibrotactile perception thresholds have been individually graded in stages and placed in relation to individual vibration exposure. RESULTS: The outcome did not reveal a clear relationship between vibration exposure and reduced vibrotactile sensitivity on an individual basis. There was a clear tendency on a group basis towards elevated thresholds when the study population was divided into three exposure categories. A fourfold increase in relative risk of reduced vibrotactile sensitivity for test frequencies above 40 Hz was observed between the highest exposure category compared to the non-exposed. CONCLUSIONS: It was concluded that reduced tactile sensitivity is related to the degree of vibration exposure but it is not at present possible to delineate an exposure-response relationship.

Adult↗
PubMed1998

A comparative study of physical work load in Japanese and Swedish nursery school teachers.

Comparisons were made of general and local physical work loads between two groups of 58 Japanese and 15 Swedish nursery school teachers. Heart rate, number of steps, rating of perceived exertion (RPE), frequency and time expended with respect to trunk flexion, sitting/kneeling, and lifting/carrying loads of 1 kg or more were monitored during working hours. The average percentage heart rate increase in the maximal heart rate range was lower in the Japanese than in the Swedish teachers. However, all parameters of local physical work load indicating musculoskeletal stress were higher in the Japanese than in the Swedish teachers. The RPE was slightly higher in the Japanese than in the Swedish teachers. These features of general and local work load in the Japanese teachers were typically observed among the teachers in charge of very young children (0-2 years). The Japanese teachers in charge of children aged 3-5 years, on the other hand, had similar levels of both general and local work load as the Swedish teachers in charge of classes comprising children of various ages (1-5 years). The physical work load measured in the present study was not sufficient to explain the difference in the magnitude of musculoskeletal problems for nursery school teachers in the two countries, and other factors should now be examined.

Adult↗
PubMed1998

Method and performance: two elements of work technique.

In the present study work technique was viewed in two basic elements: the method of carrying out a work task and the individual performance of the work task. The aim was to investigate how eight selected kinematic, kinetic, electromyographic and psychophysical variables can characterize the two elements of work technique. Twelve female subjects lifted a box using two methods, back and leg lifts, and two different simulated performances, fast and slow lifts. Motions, ground reaction forces, muscle activity in the lower back and perceived exertion were measured. A dynamic biomechanical model was applied. The trunk angular displacement and velocity clearly separated the lift methods. The trunk angular velocities and accelerations, the L5/S1 moments and the EMG variables were closely related to the performances. The work technique varied between the subjects to a greater extent than the individual variability over repetitions of a lift task. A larger inter-individual variability for kinematic variables was mostly shown in leg lifts compared with back lifts. The EMG patterns displayed differences in muscle activation that were not revealed by the kinematic or kinetic patterns. The results imply that separate variables should be used for descriptions of work methods and task performances; for method descriptions ranges of motion seem to be appropriate, for performance descriptions displacement time derivatives and load variables seem to be more useful. Moreover, the inter-individual differences suggest that work technique should be evaluated on an individual level.

Adult↗
PubMed1998

Consensus criteria for the classification of carpal tunnel syndrome in epidemiologic studies.

Criteria for the classification of carpal tunnel syndrome for use in epidemiologic studies were developed by means of a consensus process. Twelve medical researchers with experience in conducting epidemiologic studies of carpal tunnel syndrome participated in the process. The group reached agreement on several conceptual issues. First, there is no perfect gold standard for carpal tunnel syndrome. The combination of electrodiagnostic study findings and symptom characteristics will provide the most accurate information for classification of carpal tunnel syndrome. Second, use of only electrodiagnostic study findings is not recommended. Finally, in the absence of electrodiagnostic studies, specific combinations of symptom characteristics and physical examination findings may be useful in some settings but are likely to result in greater misclassification of disease status.

Carpal Tunnel Syndrome↗
PubMed1998

Computer mouse position as a determinant of posture, muscular load and perceived exertion.

OBJECTIVES: This study concerned the influence of 6 positions of the computer mouse on the work table on posture, muscular load, and perceived exertion during text editing. METHODS: An optoelectronic 3-dimensional motion analysis system was used to register the postures of 10 men and 10 women using video display units. Muscular load was also registered (with electromyography), as was perceived exertion (with rating scales). RESULTS: A neutral posture with a relaxed and supported arm showed the least perceived exertion, and the electromyographic results showed low activity in both trapezius muscles in this position. Short operators (all women) showed a numerically higher activity in the 4 examined muscles than the tall operators (all men, except 1). This finding could be related to lower muscle force among women and to anthropometric differences, which also influence biomechanic load moments. Narrow-shouldered operators (8 women and 1 man) and short operators worked with larger outward rotation and abduction of the shoulder in a position of the mouse lateral to the keyboard than the broad-shouldered (7 men and 2 women) and tall operators did. Arm support markedly reduced muscle load in the neck-shoulder region among the operators. CONCLUSIONS: The operators using video display units in this study preferred to use the mouse on a table in a close to relaxed, neutral posture of the arm in combination with arm support. Short and narrow-shouldered operators worked in more strenuous postures of the arm when the mouse was located lateral to the keyboard.

Adult↗
PubMed1998

The accident process preceding overexertion back injuries in nursing personnel. PROSA study group.

OBJECTIVES: This prospective dynamic-population-based study investigated factors involved in the accident process preceding overexertion back injuries among nursing personnel. METHODS: The study covered all reported occupational overexertion back injuries due to accidents among of the approximately 24 500 nurses in the Stockholm County hospitals during 1 year. It was assumed that several factors interact in the accident process. Detailed information was obtained for each injury by interviews with the injured nurse and head nurse. Risks in the physical environment were identified using an ergonomic checklist. RESULTS: During the study 136 overexertion back injuries were reported. Of the 130 nurses participating in the study, 125 had been injured in connection with patient work. Cluster analysis yielded 6 clusters and their pattern of contributing factors. The most frequent injury occurred during patient transfer in the bed or to or from the bed, without the use of transfer devices, when the patient suddenly lost his or her balance or resisted during the transfer and the nurse had to make a sudden movement. However, there were physical conditions, such as shortcomings in the physical work environment or a lack of a transfer device, that compelled the nurses to perform the tasks under unsafe conditions. CONCLUSIONS: The clusters showed a complexity of different kinds of accidents and indicated that the measures for preventing accidents, or for blocking an accident process once started, have to be of different kinds and placed at several different levels in the organization of a workplace.

Accidents, Occupational↗
PubMed1998

Work-related low-back problems in nursing.

This scientific literature review focuses on the relation between nursing work and low-back problems. Its aim was to estimate the risk of physical, psychosocial, and work organizational exposure factors that may lead to low-back problems. In addition this paper reviews and evaluates reported ergonomic intervention, with the object of decreasing the prevalence and incidence of low-back problems among nurses. A considerable number of studies of nursing staff has shown the connection between lifts and transfers of patients on one hand and low-back problems on the other. Factors in nursing work that may be significant in this connection are staff density and work satisfaction. In this review the single individual factor that was indisputably related to low-back problems was "history of back problems". Prevention programs do not show unequivocally positive results. There is a great need to carry out prospective studies with preventive programs.

Adult↗
PubMed1997

Conceptual and definitional issues in occupational injury epidemiology.

This paper presents several models that further define the concept of occupational injury. While traditional models have proved successful in isolating specific research questions and health phenomena, the conceptual model presented permits a broader view of all injury morbidity. This model is based on both the level and frequency of energy transfers. A process model of occupational injury is also presented to describe the basic pathophysiological relationships associated with tissue effects/damage and recovery/repair. Numerous tradeoffs exist in variable selection, and a third model explores some of these tradeoffs. Differences in terminology and fundamental principles can limit the progress of occupational injury research. Accordingly, an argument is made for consolidation and consensus of terms. Finally, considerations for research are suggested, with an emphasis on the severity of the injury, the risk ratio, and the population at risk.

Accidents, Occupational↗
PubMed1997

Hand-arm symptoms related to impact and nonimpact hand-held power tools.

Hand and arm symptoms among workers using impact and non-impact hand-held power tools were investigated in a cross-sectional study and a 5-year follow-up study. The study population consisted of concrete workers (n = 103), truck assemblers (n = 234), electricians (n = 101), platers (n = 140) and lumberjacks (n = 102). Of the original 680 subjects, we followed up 312 after 5 years. A questionnaire concerning ongoing hand and arm symptoms, daily exposure to hand-held power tools, type of tool used, and individual factors was administered. More workers using low-frequency impact tools than workers using non-impact tools reported symptoms in the elbows and shoulders. Elbow symptoms were accentuated in the cross-sectional study, while shoulder symptoms were accentuated in the follow-up study. Wrist symptoms were reported by more of those working with high-frequency impact tools than of those using only non-impact tools when the analyses were controlled for age, years in the occupation and smoking habits. A possible explanation of the results found in this study is that low-frequency impact vibration is transmitted to the upper arm, and thus the elbow and shoulder are at risk, while high-frequency impact vibration is attenuated in the hand and wrist and may predominantly cause symptoms there.

Arm Injuries↗
PubMed1997

The prevention of back injuries in Swedish health care--a comparison between two models for action-oriented feedback. PROSA Study Group.

This paper considers two different models for action-oriented feedback designed to prevent back injuries in Swedish health care. Feedback was provided by physiotherapists/ergonomists from Occupational Health Services. The models tested were feedback to work groups, and feedback solely to supervisors. Both generated a considerable number of accident-prevention proposals. Proposals of supervisors were implemented to a greater extent. Supervisors tended to advocate training, while work groups were more concerned with improved technical aids. Otherwise, only minor differences were detected between the models in application. The active involvement promoted by feedback, in particular to work groups, was considerable.

Back Injuries↗
PubMed1997

Musculoskeletal symptoms and job strain among nursing personnel: a study over a three year period.

OBJECTIVES: To examine the variation of symptoms from the neck, shoulders, and back over a three year period among female nursing personnel and the relation between job strain and musculoskeletal symptoms. METHODS: At a county hospital the female nursing personnel answered a questionnaire at baseline and then once a year over a period of three years. There were 565, 553, 562, and 419 subjects who answered the questionnaire at the first, second, third, and fourth survey, respectively. Of the study group, 285 nursing personnel answered the questionnaire on four occasions. Ongoing symptoms of the neck, shoulders, and back were assessed by means of a 10 point (0-9) scale with the verbal end points "no symptoms" and "very intense symptoms." Cases were defined as nursing personnel reporting ongoing symptoms, score > 6, from at least one of the body regions. For assessments of job strain, a Swedish version of Karasek and Theorell's model was used. RESULTS: Of the 285 subjects, 13% were defined as cases at all four assessments, and 46% varied between cases and not cases during the study period. In the repeated cross sectional surveys the estimated rate ratio (RR) for being a case was between 1.1 and 1.5 when comparing the group with job strain and the group without job strain. For the combination of job strain and perceived high physical exertion the estimated RR was between 1.5 and 2.1. When the potential risk factors were assessed one, two, or three years before the assessment of symptoms the estimated RR for becoming a case was between 1.4 and 2.2 when comparing the group with job strain and the group without job strain. CONCLUSION: Almost half of the healthcare workers varied between being a case and not, over a three year period. The analysis indicated that job strain is a risk factor for musculoskeletal symptoms and that the risk is higher when it is combined with perceived high physical exertion.

Back↗
PubMed1997

Evaluation of a 3 year education and training program. For nursing personnel at a Swedish hospital.

An education and training program comprising 1) patient transfer technique, 2) physical fitness exercise, and 3) stress management was conducted during 3 consecutive years at a Swedish hospital. The present study was based on data from four sets of questionnaires, distributed to 348 female nursing personnel who participated in the entire program. The aim of the study was to evaluate the program. It was evident from the questionnaires that 90% of the subjects were positive about participating in the program and 88% expected that participation would lead to decreased musculoskeletal disorders. However, no decrease in the prevalence of musculoskeletal symptoms during the study time period was observed. One year after the cessation of the program, 93% of all nurses reported they mostly or always used the new patient transfer technique and 99% considered it to be useful.

Adult↗
PubMed1996

Self-reported physical exertion in geriatric care. A risk indicator for low back symptoms?

STUDY DESIGN: The study group consisted of 131 female nursing aides who took part in an intervention program with physical training or education. Assessments were performed before the intervention program and after 6 months. At follow-up evaluation, 91 nursing aides remained in the study. OBJECTIVES: To examine if perceived physical exertion was a risk indicator for low back symptoms, and to examine the relationship between perceived physical exertion, aerobic capacity, back endurance, psychological demands, and job control. SUMMARY OF BACKGROUND DATA: Perceived physical exertion frequently is assessed in epidemiologic studies concerning low back symptoms. More information about the relationship between perceived exertion, other potential risk indicators, and symptoms may provide opportunities for effective prevention of symptoms. METHODS: Assessments were obtained by questionnaires and physical capacity tests. RESULTS: The nursing aides who reported high physical exertion and were 45 years of age or older were at greater risk in the follow-up period for reporting new symptoms, continued symptoms with the same intensity, or more intense symptoms from the low back (rate ratio, 3.01; 95% confidence interval, 1.1-8.2). The exposure variable correlated most strongly (r = 0.4) with perceived physical exertion was psychological demands. CONCLUSIONS: The results indicated being aged 45 years or older, combined with high perceived physical exertion, was a risk indicator for low back symptoms. A relationship between perceived physical exertion and psychological demands was observed, but there was no influence of physical capacity on perceived physical exertion.

Adult↗