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Biomedical subjects

L Karlqvist

Publications and source records attributed to L Karlqvist.

11 recordsLinked to original sources
PubMed2003

Physical demands in working life and individual physical capacity.

The purpose of this study was to investigate the prevalence of the excess of metabolic level (metabolic demands in work exceeding one-third of the individual's aerobic capacity) of working men and women today and to describe the population whose metabolic level is exceeded. A second aim was to explore how externally assessed metabolic demands match with the physical function and capacity of working men and women in jobs with the lowest and the highest demands. The aerobic power of each individual (94 men and 94 women) was estimated from heart rate and workload in sub-maximal tests from dynamic legwork on a cycle ergometer. Physical activity was assessed using a task-oriented interview technique. Physical function was measured by tests of muscle endurance in arms, abdomen and legs, handgrip pressure, balance and coordination. The calculation of individual metabolic demands during a "typical working day" showed that 27% of the men and 22% of the women exceeded their metabolic level. The results indicate that the physical fitness is low or somewhat low for two-thirds of the 94 men and for more than one-half of the 94 women. Women in the group with the highest job demands had significantly lower muscle endurance in the abdomen and legs and worse coordination than women in the group with the lowest job demands. Metabolic demands in working life today remain high. This is reflected in a mismatch between individual physical capacity and the physical demands of work for 25% of the population.

Adolescent↗
PubMed2002

Influence of laptop computer design and working position on physical exposure variables.

OBJECTIVE: To evaluate the impact of two laptop designs (with or without palm rest) and two work situations (on desk or lap) on neck and upper limb posture, muscle activity and productivity. DESIGN AND METHODS: Eight healthy subjects performed a standardized typing task of 15 min duration. During the last 5 min of each test, the neck, upper arm and trunk postures were captured by a three-dimensional video system, wrist motion was measured by a biaxial electrogoniometer and muscle activity of four neck and upper limb muscles was recorded. RESULTS: Only minor differences in postures, wrist positions and productivity were observed when comparing the two laptop designs in the same situation. Larger differences were found when comparing the two situations (desk or lap). In the desk situation, the subjects bent their heads forward less, had less backward trunk inclination and wrist extension, but more elevation of the upper arm. Higher electromyographic (EMG) levels in the trapezius and deltoid muscles and lower EMG levels in the wrist extensors were also found in the desk situation. CONCLUSIONS: Our findings do not favor one particular laptop design because only small differences in physical exposure were found. However, the workstation set up influenced the physical exposure variables, and was pinpointed as the main determinant to be considered when doing laptop work even-though no ideal situation was found. Greater physical (muscular and articular) constraints seem to be imposed to the shoulder region in the desk situation whereas the head-neck and wrist segments appear to be more stressed in the lap situation. RELEVANCE: Laptop computers are often used although the physical exposure in laptop work and the impact of different laptop designs have not been systematically assessed. A better understanding of these factors may help formulate some recommendations for laptop users.

Adult↗
PubMed1998

[Avoid the mouse-trap! Musculoskeletal injuries can be reduced by placing the mouse within shoulder space].

Somewhat more than 50 per cent of computer operators complain of problems in the neck, shoulders or arms. A possible source of such problems may be manipulation of the mouse. Women are more susceptible than men, possibly due to their smaller physical size and muscle power. With the mouse placed to the side of the keyboard, narrow-shouldered computer operators must lift their arm and turn it sharply outwards. It is preferable to place the mouse within the span of the shoulders and rest the entire forearm on the desk. A shorter keyboard might be the answer for narrow-shouldered people.

Computer Peripherals↗
PubMed1998

A process for the development, specification and evaluation of VDU work tables.

Development, specification and evaluation of a work table, suitable for VDU work with a mouse, was carried out in collaboration with furniture manufacturers, employees and an employer in a Research and Development Company. Ten VDU-operators expressed their ideas for improvements at their present workstations and the company and the researchers made a preliminary version of workstation specification to the furniture manufacturers. The three different furniture manufacturers set up four test stations with prototype tables, which were evaluated by 39 subjects using comfort ratings. The results of the comfort ratings and comments from the subjects were used when the final specification for new workstations was made. Three new work tables were evaluated in the ten selected operators' ordinary environment. Evaluations were made by technical recordings of physical load during work and by preference studies. The most important results from the evaluation can be summarized as follows: the work table should make it possible to support the arms, make it possible to vary between sitting and standing posture and prevent extreme outward rotation of the shoulder. Futhermore, the study showed that it is possible to improve the furniture manufacturers' knowledge and attitudes regarding how to minimize musculoskeletal disorders and to improve the study persons' working technique.

Adult↗
PubMed1995

A portable ergonomic observation method (PEO) for computerized on-line recording of postures and manual handling.

A new portable ergonomic observation method (PEO) is presented. It is applicable to most professions and work tasks and requires only moderate human resources for data collection and analysis. Observations are made in real time directly at the workplace using a portable personal or hand-held computer, and data are accessible for immediate analysis and presentation. Duration and number of events are calculated for postures at four body regions (arms, neck, trunk and knee) as well as for manual handling. An evaluation of the PEO method, assessing some important aspects of internal validity as well as intra- and inter-observer reliability, was carried out using video recordings. It showed acceptable validity for some types of physical exposure, and high intra- and inter-observer reliability. Practical experiences from using the PEO method in a field study and further improvements of the method are discussed.

Journal Article↗
PubMed1995

Can cardiovascular load in ergonomic epidemiology be estimated by self-report? Stockholm MUSIC 1 Study Group.

In ergonomic epidemiology exposure to local loads as well as cardiovascular load may contribute to general and local fatigue and musculoskeletal disease. Self-reported exposure is often the only feasible method in large population studies. The aim of this study was to evaluate retrospectively self-reported physical activity and perceived exertion as estimates of cardiovascular load during occupational work. The study population consisted of 39 men, representing 25 different occupations, and 58 women, representing 28 occupations. Ratings of physical exertion (RPE scale) and physical activity (Edholm scale transferred to multiples of the basal metabolic rate, METs) at the end of a work shift were correlated with the average heart rate during the same work shift. In the male population, both RPE ratings and METs correlated significantly (P < .01) with the average heart rate. No such correlation was observed in the female population.

Adult↗
PubMed1994

Direct measurements and systematic observations of physical workload among medical secretaries, furniture removers and male and female reference populations.

The aim of this investigation was to collect quantitative information about the occurrence of manual materials handling and working postures in working life. Direct technical recordings and systematic observations by trained ergonomists were used throughout a whole working day on 12 male furniture removers, 13 female medical secretaries, 27 males and 45 females randomly sampled from the working population in the Stockholm area. A quantitative job exposure profile was obtained by weighting together exposure data obtained by observation of tasks occurring during a normal working week. The results showed no major differences in physical exposures between the male and female reference populations. The medical secretaries spent less time than the female population kneeling/squatting and longer time than any other group with repetitive hand movements. Exposure data for task and job should be clearly distinguished.

Journal Article↗
PubMed1994

Variation in upper limb posture and movement during word processing with and without mouse use.

Work postures and movements of the upper limb were analysed for 12 'mouse' operators and 12 'non-mouse' computer operators employed in word-processing work. Measurements were carried out during correction of a given text. 'Mouse' operators spent 64% of the working time with the operative wrist deviating more than 15 degrees towards the ulnar side, while 'non-mouse' operators spent 96% of the time with the corresponding wrist in neutral position towards radial deviation. The rotation in the shoulder was at all times in neutral position towards inward rotation for 'non-mouse' operators, while 'mouse' operators worked 81% of the time with the shoulder rotated outward more than 30 degrees. 'Mouse' operators corrected a longer text during the given time. Our observations showed long periods of strenuous working postures for 'mouse' operators compared to 'non-mouse' operators. We believe that further investigations need to be carried out on the effects of word-processing techniques and to develop ergonomic work station designs for the 'mouse' and other non-keyboard input devices.

Arm↗
PubMed1993

Validity of self-reported exposures to work postures and manual materials handling. Stockholm MUSIC I Study Group.

Exposure data from self-administered questionnaires on manual materials handling and work postures were validated in relation to direct measurements and systematic observations on 39 men and 58 women representing 45 different occupations. The agreement was tested at a dichotomous level and, when possible, with quantification of duration or frequency. At the dichotomous level the agreement was "acceptable" for nine variables concerning work postures and the handling of loads weighing > 5 kg. No variable showed "acceptable" agreement when the duration or the frequency was quantified in more detail (4- to 6-point scales). Musculoskeletal complaints seemed to introduce a differential bias for some lifting variables. Thus some variables for postures or the handling loads of > 5 kg may, under certain conditions, be acceptable for use in epidemiologic studies when the relative risks are high. However, self-reported exposure seems to be too crude if more-detailed information is required.

Female↗