Correlations between Ratings and Technical Measurements in Hand-Intensive Work.

An accurate rating of hand activity and force is essential in risk assessment and for the effective prevention of work-related musculoskeletal disorders. However, it is unclear whether the subjective ratings of workers and observers correlate to corresponding objective technical measures of exposure. Fifty-nine workers were video recorded while performing a hand-intensive work task at their workplace. Self-ratings of hand activity level (HAL) and force (Borg CR10) using the Hand Activity Threshold Limit Value® were assessed. Four ergonomist observers, in two pairs, also rated the hand activity and force level for each worker from video recordings. Wrist angular velocity was measured using inertial movement units. Muscle activity in the forearm muscles flexor carpi radialis (FCR) and extensor carpi radialis (ECR) was measured with electromyography root mean square values (RMS) and normalized to maximal voluntary electrical activation (MVE). Kendall's tau-b correlations were statistically significant between self-rated hand activity and wrist angular velocity at the 10th, 50th, and 90th percentiles (0.26, 0.31, and 0.23) and for the ratings of observers (0.32, 0.41, and 0.34). Significant correlations for force measures were found only for observer-ratings in five of eight measures (FCR 50th percentile 0.29, time > 10%MVE 0.43, time > 30%MVE 0.44, time < 5% -0.47) and ECR (time > 30%MVE 0.26). The higher magnitude of correlation for observer-ratings suggests that they may be preferred to the self-ratings of workers. When possible, objective technical measures of wrist angular velocity and muscle activity should be preferred to subjective ratings when assessing risks of work-related musculoskeletal disorders.

Does occupational health surveillance lead to risk reduction for workers exposed to hand-intensive work?

This mixed method study aimed to describe what risk-reducing actions were proposed by ergonomists after the execution of a guided process for occupational health surveillance for workers exposed to hand-intensive work in ten companies. Another aim was to describe the exposed workers' proposals for risk-reducing actions, including their perceptions of potential changes in the self-assessed exposure levels and work-related pain. Several actions, targeting organizational, technical, and/or individual measures were proposed. Proposals from the ergonomists more often targeted the personal measures, whereas the workers' proposals targeted technology or organizational changes. Six companies implemented at least one of the action proposals. These action proposals were not related to evaluation metrics, nor were they evaluated. This study indicates that both ergonomists and companies need guidance on how to improve to work in a participatory process for the implementation and evaluation of risk-reducing actions, e.g., by how to better include workers' experiences.

Ratings of Hand Activity and Force Levels among Women and Men Who Perform Identical Hand-Intensive Work Tasks.

We compared hand activity and force ratings in women and men doing identical hand-intensive work tasks. Musculoskeletal disorders are more common in women and hand-intensive work leads to an increased risk of these disorders. Knowledge of the gender influence in the rating of work exposure is lacking. The aim of this study was to investigate whether women and men performing identical hand-intensive work tasks were equally rated using hand activity and normalized peak force levels with the Hand Activity Threshold Limit Value®. Fifty-six workers participated, comprising 28 women-men pairs. Four observers-two woman-man pairs-were also involved. Self-ratings and observers' ratings of hand activity and force level were collected. The results of these ratings showed no significant gender differences in self-rated hand activity and force, as well as observer-rated hand activity. However, there was a significant gender difference in the observer-rated force, where the women were rated higher (mean (SD): women 3.9 (2.7), men 3.1 (1.8) (p = 0.01)). This difference remained significant in the adjusted model (p = 0.04) with grip strength and forearm-finger anthropometrics. The results provide new insights that observers' estimates of force can be higher in women compared with men in the same work tasks. Force should be further investigated and preferably compared to objective measurements.

Ergonomists' experiences of executing occupational health surveillance for workers exposed to hand-intensive work: a qualitative exploration.

BACKGROUND: In order to reduce work-related upper limb disorders, the Swedish Work Environment Authority introduced an occupational health surveillance targeting hand-intensive work. A process model, aimed at supporting the employers as well as the occupational health service provider (i.e., ergonomist) in the work process with the occupational health surveillance, was developed. The objective of this qualitative study was to explore ergonomists' experiences of the execution of occupational health surveillance for hand-intensive work when following the novel process model as well as factors influencing the execution. METHODS: Semi-structured individual interviews were conducted with ten ergonomists on one occasion regarding their experience of following the work process. Qualitative content analysis with an inductive approach was used for analyzing the data. RESULTS: The ergonomists' experiences were summarized in one theme "A joint roadmap supporting a participatory process" and two categories "Clear structure provided by the components" and "The process influenced by collaboration and context". The ergonomists valued being guided by the systematics of the model, which provided structure and clarity in their work. Factors affecting the execution were related to communication deficiencies and uncertainties regarding expectations between different roles and functions (e.g., ergonomists and contact person, lack of information to workers). Additional factors, for instance, companies' routines and the ergonomist's intra-organizational support, such as access to IT-resources, could also affect the process. CONCLUSIONS: The findings reveal that this process model facilitates the ergonomists' work and cooperation with a client company. However, the process model needs to be developed and accompanied by a guideline with information related to the process, including e.g., description of a start-up meeting and of the roles/functions of the involved parties.

Company Representatives' Experiences of Occupational Health Surveillance for Workers Exposed to Hand-Intensive Work: A Qualitative Study.

Exposure assessment seldom precedes the medical health checks in occupational health surveillance. In order to emphasize the interconnection between exposure assessment and medical health checks, a process model was developed. The process model aimed to guide employers and Occupational Health Service providers through the execution of occupational health surveillance. The objective of this qualitative study is to explore company representatives' experiences of the process model, in terms of feasibility and values, and to identify factors that facilitate or impede the process. Thirty-three company representatives from ten companies were interviewed. Interviews were analyzed using content analysis. The company representatives experienced that the model contributed to increased risk awareness and understanding of the exposure effects on workers' health. They valued the exposure assessments performed by an ergonomics expert, which led to the discovery of previously unidentified risks. The feasibility was facilitated by: a joint start-up meeting in which the process was planned, clear communication between the involved parties, and clarity regarding the process ownership. The findings reveal that a guiding process model is valuable for the execution of occupational health surveillance. However, the model should not only define the components included; a practical guide concerning how the process can be executed is also needed.

Study Protocol for a Qualitative Research Project Exploring an Occupational Health Surveillance Model for Workers Exposed to Hand-Intensive Work.

The objective of this study protocol is to describe the development of a process model for occupational health surveillance for workers exposed to hand-intensive work (the HIW-model), and to describe the studies that will explore the model. The studies are designed to: (1) explore stakeholders' experiences of the model, and (2) explore if, and how, the model affects actions for reduction of exposure to hand-intensive work. The study protocol presents a research project that is described as two studies. The first study will explore company representatives' and ergonomists' experiences of the execution of the HIW-model and its various components concerning feasibility and values. Semi-structured interviews will constitute the data source. The second study will explore whether the execution of the HIW-model leads to work environmental changes, such as actions for reduction of exposure to hand-intensive work, and whether these potential actions are based on the ergonomist's feedback of the exposure assessment and the medical health checks. A mixed method approach will be applied, in which the data sources will be comprised of semi-structured interviews, questionnaires, and documents. The project is expected to generate knowledge regarding the values of the HIW-model. The project is anticipated to shed light on factors that facilitate or impede execution of the model from the different stakeholders' perspectives; the employer's as having the legal responsibility for the work environment, and the occupational health service consultants', being the work environment experts supporting the employers.

Individual preferences for physical exercise as secondary prevention for non-specific low back pain: A discrete choice experiment.

BACKGROUND: Exercise is effective in improving non-specific low back pain (LBP). Certain components of physical exercise, such as the type, intensity and frequency of exercise, are likely to influence participation among working adults with non-specific LBP, but the value and relative importance of these components remain unknown. The study's aim was to examine such specific components and their influence on individual preferences for exercise for secondary prevention of non-specific LBP among working adults. METHODS: In a discrete choice experiment, working individuals with non-specific LBP answered a web-based questionnaire. Each respondent was given ten pairs of hypothetical exercise programs and asked to choose one option from each pair. The choices comprised six attributes of exercise (i.e., type of training, design, intensity, frequency, proximity and incentives), each with either three or four levels. A conditional logit regression that reflected the random utility model was used to analyze the responses. RESULTS: The final study population consisted of 112 participants. The participants' preferred exercise option was aerobic (i.e., cardiovascular) rather than strength training, group exercise with trainer supervision, rather than individual or unsupervised exercise. They also preferred high intensity exercise performed at least once or twice per week. The most popular types of incentive were exercise during working hours and a wellness allowance rather than coupons for sports goods. The results show that the relative value of some attribute levels differed between young adults (age ≤ 44 years) and older adults (age ≥ 45 years) in terms of the level of trainer supervision required, exercise intensity, travel time to exercise location and financial incentives. For active study participants, exercise frequency (i.e., twice per week, 1.15; CI: 0.25; 2.06) influenced choice of exercise. For individuals with more than one child, travel time (i.e., 20 minutes, -0.55; CI: 0.65; 3.26) was also an influential attribute for choice of exercise, showing that people with children at home preferred to exercise close to home. CONCLUSIONS: This study adds to our knowledge about what types of exercise working adults with back pain are most likely to participate in. The exercise should be a cardiovascular type of training carried out in a group with trainer supervision. It should also be of high intensity and preferably performed twice per week during working hours. Coupons for sports goods do not appear to motivate physical activity among workers with LBP. The findings of the study could have a substantial impact on the planning and development of exercise provision and promotion strategies to improve non-specific LBP. Providers and employers may be able to improve participation in exercise programs for adults with non-specific LBP by focusing on the exercise components which are the most attractive. This in turn would improve satisfaction and adherence to exercise interventions aimed at preventing recurrent non-specific LBP.

Test-retest reliability of step counts with the ActivPAL™ device in common daily activities.

UNLABELLED: The ActivPAL device is a well-established physical activity monitor for assessment of physical activity. AIM: To investigate test-retest reliability of step counts and establish minimal detectable changes (MDC) in step count to account for intra device error over time in various physical activities. METHODS: Healthy participants (n=24, age range, 19-28 years) performed activities on two occasions, 1 week apart, in a laboratory setting; self-paced floor walking, treadmill walking at three different speeds (3.2 km/h, 4.5 km/h and 4.5 km/h with incline), treadmill jogging (8.0 km/h), stair walking and cycling on an exercise bike at three speeds (45 rpm, 60 rpm and 75 rpm). Relative reliability was calculated using intraclass correlation coefficient (ICC) and Spearman correlation. Absolute reliability was assessed using standard error of measurement (SEM) and coefficient of repeatability (CR). RESULTS: The ActivPAL showed high to very high relative reliability for treadmill walking at all speeds and stair walking, while self-paced normal floor walking showed moderate reliability. The absolute reliability was the best for treadmill walking activities, slightly increased for self-paced walking, followed by stair walking and jogging. The use of activity monitors during cycling has been questioned and our results confirm a low absolute and relative reliability. MDC values varied according to the type of activity e.g. treadmill walking 4.5 km/h (10 steps), walking on the floor (45 steps). Data loss in this study (10-13%) was higher than previously reported. CONCLUSIONS: The ActivPAL is reliable for treadmill walking, jogging and self-paced walking. MCD varies according to the activity and should be considered when establishing true change over time.