Movement variability: characterisation during assembly work and capacity for integration into a computer aided design tool

In all human movements, in particular those related to work activities, variability is observed. Even for a repetitive task, trajectories, muscular activities, or exerted forces are never identical, both for different people and for the same person at different times. Analysis of such variability is often ignored in work situation design in which is more focussed on seeking a single movement for optimising the task. For a long time variability was also neglected by the scientific community in its research on motor activity. Consideration is beginning to be given to it in work situation analysis relating to Musculo-Skeletal Disorders (MSDs) prevention and to the effects of ageing. Recent studies indicate that variability in muscular activity or in cinematics may have a preventive effect on the development of fatigue or on the risk of MSDs occurrence.
Based on these considerations, this study aims firstly to analyse motor variability during work activities, and secondly to facilitate taking such variability into account in virtual humans used in work situation design. Movement variability will be analysed by means of biomechanical and physiological data for repetitive tasks. This study proposes two complementary research focuses. On one hand, characterising motor variability during work activities and describing different strategies for performing the same activity. On the other hand, developing models and algorithms in order to simulate this variability using virtual humans.
Planned dissemination:
The study will contribute to improving characterisation of motor variability during work activities, for applications to MSDs prevention, ageing effects at work and work situation design. Acquired knowledge will be the subject of publications and will be incorporated into the contents of training and of information products proposed by INRS. A computer demonstrator will be developed for demonstrating the functionalities developed for virtual humans.