Cost-efficient observation of working postures from video recordings – more videos, more observers or more views per observer?

Abstract

In ergonomics, assessing the working postures of an individual by observation is a very common practice. The present study investigated whether monetary resources devoted to an observational study should preferably be invested in collecting many video recordings of the work, or in having several observers estimate postures from available videos multiple times. On the basis of a data set of observed working postures among hairdressers, necessary information in terms of posture variability, observer variability, and costs for recording and observing videos was entered into equations providing the total cost of data collection and the precision (informative value) of the resulting estimates of two variables: percentages time with the arm elevated <15 degrees and >90 degrees. In all 160 data collection strategies, differing with respect to the number of video recordings and the number of repeated observations of each recording, were simulated and compared for cost and precision. For both posture variables, the most cost-efficient strategy for a given budget was to engage 4 observers to look at available video recordings, rather than to have one observer look at more recordings. Since the latter strategy is the more common in ergonomics practice, we recommend reconsidering standard practice in observational posture assessment.

Intérêt de la Marge de Manœuvre Situationnelle pour le ciblage des situations à risque de Troubles Musculo‑Squelettiques

“…Nous pensons qu'il est important de prendre en compte cette diversité de stratégies comme une information sur le risque d'apparition de la pathologie avec la recherche d'indices sur leurs variabilités (alternance de la « façon de faire » en fonction des contraintes), leurs rythmes (accélérations/ralentissements) ou encore leurs effets. La non-prise en compte de la variabilité du travail et de la diversité des situations conduit à des évaluations peu fiables et sujets à variabilité puisque très dépendantes du moment où se réalise l'évaluation (Bao et al, 2009 ;Chiasson et al, 2012 ;Mathiassen, Liv, & Wahlström, 2012 ;Takala et al, 2010 ;Zare et al, 2015). L'approche de la MMS invite à considérer l'importance du choix du ou des moments d'évaluation et de leur représentativité dans le cycle de travail (la plus critique, la moins critique, etc.…”

“…expérience utilisateur, connaissance de l'activité, focale d'observation choisie, méthode de hiérarchisation des résultats ; Bao, Howard, Spielholz, silverstein, & Polissar, 2009 ;Chiasson, Imbeau, Aubry, & Delisle, 2012 ;Ringelberg & Koukoulaki, 2002 ;Roquelaure et al, 2013 ;Zare, Biau, Brunet, Gourlay, & Roquelaure, 2015). Le manque de fiabilité des résultats va augmenter avec les instabilités inhérentes de l'activité, comme les variabilités liées aux conditions de réalisation (technico-organisationnelles et diversification des produits), et liées aux individus (inter-intra individuelles et diversité des stratégies de réalisation ; Badets, Merlo, & Pilniere, 2017 ;Coutarel et al, 2015 ;Gaudez, Gilles, & Savin, 2016 ;Guérin, et al, 1997 ;Koukoulaki, 2014 ;Mathiassen, 2006 ;Mathiassen, Liv, & Wahlström, 2012 ;Zare et al, 2015). En plus, des instabilités décrites, on observe un enrichissement des connaissances scientifiques sur le modèle étiologique des TMS aboutissant aujourd'hui à un consensus autour de la multi-causalité (multi-factorialité) des facteurs de risque (Armstrong, Buckle, Lawrence, Hagberg, Jonsson, & Kilbom, 1993 ;Bodin, Garlantézec, Costet, Descatha, Fouquet, Caroly, & Roquelaure, 2017 ;Bourgeois & Hubault, 2005 ;Hagberg, Kuorinka, & Forcier, 1995 ;Karsh, 2006 ;Roquelaure, 2015Roquelaure, , 2018Widanarko, Legg, Devereux, & Stevenson, 2014).…”

Evaluating Swine Injection Technologies as a Workplace Musculoskeletal Injury Intervention: A Study Protocol

“…To ensure that the results of this study remain relevant to the pork industry, the research team will maintain strong industry connections through the use the Canadian Institutes of Health Research integrated knowledge translation (KT) approach, engaging stakeholders throughout the research process [ 52 ]. Integrated KT is marked by the collaboration of researchers and knowledge users to shape the research process starting with research questions and methodology through to interpreting and disseminating results.…”

Translation, cross-cultural adaptation to Brazilian- Portuguese and reliability analysis of the instrument Rapid Entire Body Assessment-REBA

“…The observation " in loco " depends on the observer's experience and is designed to evaluate static or repetitive postures. On the other hand, analysis with filming is reproducible and provides more details due to the possibility of analyzing the data repeatedly 6 , 9 . To determine the best approach, one must consider the following factors: the environment and individual that will be evaluated, costs, and the time available for evaluation 5 .…”

“…Among the tools available 5 , the Rapid Entire Body Assessment (REBA) 10 , 11 is easy to understand, has a low implementation cost 9 and has been used to evaluate different work environments and several biomechanical risk factors 12 - 16 . The REBA was created in 2000 by a team of physical therapists, ergonomists, occupational therapists and nurses through the encoding of 600 postural examples, with the purpose of assessing risky postures in the development of musculoskeletal injuries.…”