Linda M. Rose

Endurance time, pain and resumption in passive loading of the elbow joint

This study investigated reactions in passively loaded, fully extended elbow joints in 13 men. Pain reactions during and after loading were studied, as were endurance time, T end, and resumption time, T r. The loading moment on the elbow joint, M n, varied between 7 and 100% of maximum elbow moment. Discomfort/pain was estimated with Borgs CR-10 scale. T end decreased with increasing load level. The opposite was found for the resumption time: the higher the load, held until T end, the shorter the T r. The pain limiting the working capability originated mainly from muscle tissue and not from the joint itself. It is concluded that the relation between load and endurance time for passively loaded, fully extended elbow joints resembles that for muscular loading in more ‘normal’ postures. Equations for estimation of endurance and resumption times (in minutes) for fully extended joints are proposed: T end = 20.6e−6.04M n and T r = 0.0167e8.84/(1.46+0.346M n), respectively.

Endurance, pain and resumption in fully flexed postures

In this study effects of low loads in fully flexed postures were investigated. Thirteen men who were unused to the postures participated. Thirteen professional construction workers with long experience of suchlike postures were also studied. Pain reactions during and after loading were observed, as well as endurance time and the recovery process, here by studying the resumption time. Endurance and resumption times differed little from those given by models used for more common postures. Pain from the legs and not from the back limited the working ability in 86% of the endurance tests. Thirdly, the construction workers had significantly longer endurance time and shorter resumption time.

Fatigue and recovery during and after static loading

Subjectively assessed endurance time (ET), resumption time (RT) and perceived discomfort, pain or fatigue (PD), and objectively measured maximum force-exerting capacity were investigated for varying loads and durations of a pushing task with two repeated trials. Beyond the main results quantifying how the load scenario affected ET, RT and PD, three additional results are of note: (1) although the maximum pushing force did not change between trials, shorter ET, longer RT and higher PD indicated accumulation of fatigue in Trial 2; (2) the PD ratings showed a trend with a linear increase during loading and a curvilinear decrease during recovery; and (3) the RT and the load level for different relative loading times were found to have an unexpected U-shaped relationship, indicating lowest fatigue at the intermediate load level. These results can be used to model a more sustainable and productive work-recovery ratio. Practitioner Summary: Sufficient recovery during a work-shift is important for sustainable work. This paper presents data from an empirical study on how fatigue reactions and recovery needs vary with load level and loading time and with one repeated loading. The results enable the modelling of work-recovery ratios to ensure adequate recovery during work-shifts.

Exploring Maritime Ergonomics from a Bottom Line Perspective

The present paper reports a study composed of three research activities exploring the economics of ergonomics in a shipping context. First, a literature study aimed to review previous studies on the economics of ergonomics in general and within the maritime domain in particular; and moreover, to ascertain the key ergonomic factors addressed in contemporary maritime ergonomic research. Second, the concept of ergonomics was probed from a stakeholder perspective through nine semi-structured qualitative interviews. Third, structured interviews were held with representatives of ten Swedish shipping companies to investigate if the shipowners are aware of and calculate the economic effects of ergonomics.The results show that severalmodels andmethods have been developed to estimate costs and benefits of ergonomics in other industries, but no studies were found from the shipping industry.Whether thesemethods can be readily adapted to the shipping industry has to be investigated further. While contemporary maritime ergonomic literature showed a focus on physical ergonomic and health and safety issues, the results of the stakeholder interviews indicated a focus on organizational ergonomics. The Swedish shipowners calculate the costs of sick-leave, but do not estimate the economic effects of ergonomics on a regular basis.

Assessing financial impact of maritime ergonomics on company level: a case study

The present paper reports a case study examining a conceptual framework for assessing financial impact of occupational maritime ergonomics in a Swedish shipping company. Specifically, the aim was to study the availability and applicability of suggested determinants for operational performance, routines for estimating the effects of ergonomics and the customer’s (sea transport buyer’s) demands for ergonomics management on the case company. The results show that the determinants and subcategories for operational performance in terms of productivity, efficiency and quality are present and applicable, albeit not measured to any large extent. No routines or specific methods for measuring or estimating cost and effects of ergonomics investments, accidents and operational disturbances were found. Further, the results show that the sea transport buyers increasingly express interest for and place demands related to maritime ergonomics, for instance, through compliance of specific standards and guiding principles linked to maritime ergonomics. It is concluded that in order to support and enable managers’ ability to make well-informed decisions and prioritizations, between investments, ergonomic or other, increased knowledge is needed of the financial effects of ergonomics on company core value processes. There is also a need to develop and implement usable tools to simplify these measuring procedures.

Development and evaluation of RAMP I – a practitioner’s tool for screening of musculoskeletal disorder risk factors in manual handling

RAMP I is a screening tool developed to support practitioners in screening for work-related musculoskeletal disorder risk factors related to manual handling. RAMP I, which is part of the RAMP tool, is based on research-based studies combined with expert group judgments. More than 80 practitioners participated in the development of RAMP I. The tool consists of dichotomous assessment items grouped into seven categories. Acceptable reliability was found for a majority of the assessment items for 15 practitioners who were given 1 h of training. The usability evaluation points to RAMP I being usable for screening for musculoskeletal disorder risk factors, i.e., usable for assessing risks, being usable as a decision base, having clear results and that the time needed for an assessment is acceptable. It is concluded that RAMP I is a usable tool for practitioners.

Risk management project for work with precast concrete shells.

This paper describes a project with the aim of reducing the risk of injury when using precast concrete shells in the Swedish construction industry by identifying injury risks, developing and implementing solutions. An interactive research approach was used. Three major injury risks were identified and a system consisting of three tools and a handbook was developed, evaluated, and implemented at one company and made available to the construction industry.

Modelling endurance and resumption times for repetitive one-hand pushing

Abstract This study’s objective was to develop models of endurance time (ET), as a function of load level (LL), and of resumption time (RT) after loading as a function of both LL and loading time (LT) for repeated loadings. Ten male participants with experience in construction work each performed 15 different one-handed repetaed pushing tasks at shoulder height with varied exerted force and duration. These data were used to create regression models predicting ET and RT. It is concluded that power law relationships are most appropriate to use when modelling ET and RT. While the data the equations are based on are limited regarding number of participants, gender, postures, magnitude and type of exerted force, the paper suggests how this kind of modelling can be used in job design and in further research. Practitioner Summary: Adequate muscular recovery during work-shifts is important to create sustainable jobs. This paper describes mathematical modelling and presents models for endurance times and resumption times (an aspect of recovery need), based on data from an empirical study. The models can be used to help manage fatigue levels in job design.

Developing an International Master’s Programme in Ergonomics at a Technical University in Sweden

The objective of this paper is to present the rationale for, and the development process of, a new international master’s programme in Ergonomics, here framed as ‘Technology, Work and Health’, at KTH, Royal Institute of Technology in Sweden. The masters’ programme is designed for two years of full-time studies (120 credits).

RAMP – A Comprehensive MSD Risk Management Tool

The objective of this paper is to describe the development, dissemination and preliminary effects of the use of a new musculoskeletal disorder (MSD) risk management tool for manual handling, RAMP (Risk Assessment and Management tool for manual handling Proactively). RAMP is research based and developed in close collaboration between researchers and practitioners with a participative iterative methodology. A broad strategy is used for the dissemination, including the use of professional networks, conferences, a specially developed homepage, and Massive Open Online Courses which also provide training on the tool use. The tool has been spread widely to about 45 countries since the release 2017. E.g. Scania CV uses RAMP as its global standard method for managing MSD risks at logistics and machining departments. Among the preliminary effects results show that at one department risk reduction measures had been taken for more than 2/3 of the work stations with assessments signalling elevated risk levels after 1.5 years. Further studies on RAMP are discussed. It is concluded that the development and the dissemination of RAMP can be seen as successful. Preliminary reports on the tool use effects indicate that the RAMP tool supports the MSD risk management process in the work to reduce MDS risks at workplaces.