Katarina Kjellberg

Gender differences in lifting technique.

The importance of different motion patterns in the assessment of work technique is rarely addressed in the literature and even less information can be found regarding gender differences. In this study the possible gender differences in lifting technique from lifting experiments on 12 female and 10 male participants were examined. The participants performed squat and stoop lifts of a box. Movements were measured by means of opto-electronic measurement systems. Kinematic data derived from the measurements revealed some differences between the men and the women, e.g. in trunk motion and knee angle ranges. The hip-knee interjoint coordination was more synchronized for women than for men in terms of the relative phase angle. It is concluded that so far gender differences in motion patterns have not been sufficiently explored and that men and women need to be considered separately in the evaluation of work technique in manual handling tasks. Advantages and disadvantages of different coordination patterns need to be further investigated.

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.

An observation instrument for assessment of work technique in patient transfer tasks.

The aim of the study was to construct an observation instrument for description and assessment of nursing personnels work technique in patient transfer tasks with regard to musculoskeletal health and safety, and to evaluate the validity and reliability of the instrument. The instrument consists of 24 items arranged in three phases of a transfer: the preparation phase, the starting position and the actual performance. Observations are made from video recordings. A detailed description of the individuals work technique, including actions taken to prepare the transfer, the interaction with the patient and any assistant co-worker, and the motor performance of the nurse, is provided. An attempt was made to quantify the assessments, by calculating an overall score of the work technique with regard to the level of musculoskeletal hazard and safety. The validity and reliability of the instrument were evaluated on 35 video-recorded patient transfers from hospital wards. The validity and reliability were mostly satisfactory, both when evaluating the agreements between the observations of each item (i.e. kappa values > 0.40), and when evaluating the agreements between the overall scores (i.e. intraclass correlation coefficients 0.71-0.90). Further improvements to enhance the agreements are suggested.

A method to determine joint moments and force distributions in the shoulders during ceiling work — a study on house painters

OBJECTIVE: The purpose of this study was to propose and apply a method to study the net load and the force distribution in the shoulder during sanding of a ceiling. DESIGN: Sanding of a ceiling was studied in an experimental set-up. BACKGROUND: Among painters there is a high frequency of neck and shoulder complaints and some particularly strenuous tasks are sanding and painting of ceilings with tools attached to extension handles. METHODS: A biomechanical model predicted the load pattern in the shoulder from measured external forces and body postures. Measurements were made on 40 subjects by means of a force plate, an extension handle supplied with two pairs of strain gauges and a load cell, and a 3D optoelectronic measurement system. RESULTS: Work techniques may seem to be similar at visual inspection, but nevertheless produce quite different loading patterns in the shoulder. The observed work techniques varied largely among the subjects but the intra-individual variability was rather small. CONCLUSIONS: The study showed that the proposed method can be used to evaluate loads and force distribution in the shoulder. Since the method involves the use of a biomechanical model that can scarcely be validated, results must be interpreted cautiously.

The impact of adjustment latitude on self-assessed work ability in regard to gender and occupational type

Abstract Objective: Adjustment latitude describes opportunities to change demands at work when ill and may affect work ability. The aim here is to study the association between adjustment latitude and self-assessed work ability among men and women and employees from different occupational sectors. Methods: This cross-sectional study used data from a questionnaire sent to 3020 employees in three occupational sectors in Sweden; 1430 responded. Subjects were divided into: full, moderately reduced, and greatly reduced work ability. Presence of nine adjustment opportunities was requested and subjects were divided into three groups. Each specific opportunity was also analyzed in relation to work ability. Multinomial logistic regression was used for analyses. Results: Number of opportunities to adjust was associated with work ability among men and employees in health care. “Shortening the working day” was associated with work ability in most groups. For men and industrial employees, “postponing work”, “going home and working later”, and “working without disturbance” were associated with work ability. “To work from home” was associated with work ability among women and employees in insurance. Conclusions: The assumption that adjustment latitude affects work ability is supported. Associations differ with regard to gender and occupational sectors. Further studies with longitudinal design and alternative samples are needed.

Promoting occupational health interventions in early return to work by implementing financial subsidies: a Swedish case study.

BackgroundIn 2010, the Swedish government introduced a system of subsidies for occupational health (OH) service interventions, as a part in a general policy promoting early return to work. The aim of this study was to analyse the implementation of these subsidies, regarding how they were used and perceived.MethodsThe study was carried out using a mixed-methods approach, and comprises material from six sub-studies: a register study of the use of the subsidies, one survey to OH service providers, one survey to employers, one document analysis of the documentation from interventions, interviews with stakeholders, and case interviews with actors involved in coordinated interventions.ResultsThe subsidized services were generally perceived as positive but were modestly used. The most extensive subsidy – for coordinated interventions – was rarely used. Employers and OH service providers reported few or no effects on services and contracts. OH service providers explained the modest use in terms of already having less bureaucratic routines in place, where applying for subsidies would involve additional costs. Information about the subsidies was primarily communicated to OH service providers, while employers were not informed.ConclusionsThe study highlights the complexity of promoting interventions through financial incentives, since their implementation requires that they are perceived by the stakeholders involved as purposeful, manageable and cost-effective. There are inherent political challenges in influencing stakeholders who act on a free market, in that the impact of policies may be limited, unless they are enforced by law.

Factors That Influence the Use of Safe Patient Transfer Technique in Home Care Service

The aim of this pilot study was to explore whether home care service personnel used knowledge and skills in transfer technique in their daily work; knowledge and skills gained by participating in training programmes, and to identify factors that may hinder and support their use. Focus group interviews were held with 2 home care service groups in 2 Swedish towns. Individual interviews were conducted with the personnel’s managers, unit leaders and safety representatives. Qualitative content analysis was used. The findings revealed that the personnel tried to use their knowledge and skills. However, there were both hindering and supporting factors for the use of safe work technique. The findings indicate that training programmes in transfer technique should not be implemented as isolated actions without considering the physical environment, the wishes of persons receiving care and their relatives, the work organisation, the safety culture and the role of managers.

Low cardiorespiratory fitness in young adulthood and future risk of disability pension: a follow-up study until 59 years of age in Swedish men

Background There is a strong belief in the potential of increased physical activity to improve the health of populations. The objective of the present study was to estimate the association between low cardiorespiratory fitness in young adulthood and subsequent health impairment until middle age, measured by disability pension. Methods The study utilised data on cardiorespiratory fitness and a number of covariates (social background, health behaviours and psychological characteristics) from the Swedish Conscription Cohort of 1969/1970 including 49 321 men born in 1949–1951, and data on disability pension from 1971 to 2008 (20–59 years of age) through record linkage with two national insurance databases. Cox proportional-hazards regressions yielded hazard ratios (HR) with 95% confidence intervals (CI). Results Having low-level or mid-level cardiorespiratory fitness in late adolescence was associated with an increased HR of disability pension across the follow-up (HR for low fitness: 1.85, CI 1.71 to 2.00; HR for mid-level fitness: 1.40, CI 1.31 to 1.50). The association was stronger with earlier disability pensions than with later disability pensions, which was also seen after multiple confounding adjustments. At the same time, these adjustments revealed considerable confounding of the association by individual differences in psychological characteristics in particular. Conclusions Lower levels of cardiorespiratory fitness in young adulthood were found to be associated with an increased HR of disability pension throughout the follow-up until 59 years of age, even after adjustment for important confounding factors measured in late adolescence. Increased physical fitness may thus have a lowering effect on the risk of disability pension.

Development of an instrument for assessing workstyle in checkout cashier work (BAsIK)

Checkout cashier work consists of handling a large number of items during a work shift, which implies repetitive movements of the shoulders, arms and hands/wrists, and a high work rate. The work is associated with a high prevalence of disorders in the neck and upper extremity. The concept of workstyle explains how ergonomic and psychosocial factors interact in the development of work-related upper extremity disorders. The aim of the project was to develop an instrument for the occupational health services to be used in the efforts to prevent upper extremity disorders in checkout cashier work. The instrument is based on the workstyle concept and is intended to be used as a tool to identify high-risk workstyle and needs for interventions, such as training and education. The instrument, BAsIK, consists of four parts; a questionnaire about workstyle, an observation protocol for work technique, a checklist about the design of the checkout and a questionnaire about work organization. The instrument was developed by selecting workstyle items developed for office work and adapting them to checkout cashier work, discussions with researchers and ergonomists, focus-group interviews with cashiers, observations of video recordings of cashiers, and studies of existing guidelines and checklists.

Reliability and criterion validity of an observation protocol for working technique assessments in cash register work

Abstract We evaluated the intra- and inter-observer reliability and criterion validity of an observation protocol, developed in an iterative process involving practicing ergonomists, for assessment of working technique during cash register work for the purpose of preventing upper extremity symptoms. Two ergonomists independently assessed 17 15-min videos of cash register work on two occasions each, as a basis for examining reliability. Criterion validity was assessed by comparing these assessments with meticulous video-based analyses by researchers. Intra-observer reliability was acceptable (i.e. proportional agreement >0.7 and kappa >0.4) for 10/10 questions. Inter-observer reliability was acceptable for only 3/10 questions. An acceptable inter-observer reliability combined with an acceptable criterion validity was obtained only for one working technique aspect, ‘Quality of movements’. Thus, major elements of the cashiers’ working technique could not be assessed with an acceptable accuracy from short periods of observations by one observer, such as often desired by practitioners. Practitioner Summary: We examined an observation protocol for assessing working technique in cash register work. It was feasible in use, but inter-observer reliability and criterion validity were generally not acceptable when working technique aspects were assessed from short periods of work. We recommend the protocol to be used for educational purposes only.