Action, Movement, and Culture: Does Culture Shape Movement?

What any traveler can definitely notice is the incredible diversity of everyday skills due to the cultural diversity of tools, raw materials, physical environments, or local postural habits that set up the conditions for performing tasks. Do cultural environments influence motor skills? Are there “motor styles” common to members of a given cultural group? Focusing on instrumental everyday actions from a functional perspective, we propose four cases to illustrate in detail cultural variations in motor behavior. The first example explores the movement repertoire of expert potters from two cultural backgrounds when asked to produce pots of the same shape. A second example analyzes how a dance figure based on the same mechanical principles gives rise to different cultural aesthetics. The third example questions the adaptation of metabolic processes while performing the same load-carrying task in various physical environments. The last example brings up the issue of cultural choices of working and resting postures. Each case refers to a critical dimension of what generates the cultural diversity of motor skills: operational equivalence of movements, variation in the “weighing” of the parameters of the action, adaptation of metabolic processes, and adaptive benefit of specific posture. We conclude that if the countless diversity of cultural contexts and tasks give rise to an enormous diversity of movements and postures, this diversity is anchored in the many degrees of freedom of the organism. It is
this profusion of degrees of freedom that sustains the endless variations of cultural motor skills giving ways to infinite manners of using one’s own body.

Blandine Bril

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Motor adaptation capacity as a function of age in carrying out a repetitive assembly task at imposed work paces

The working population is getting older. Workers must adapt to changing conditions to respond to the efforts required by the tasks they have to perform. In this laboratory-based study, we investigated the capacities of motor adaptation as a function of age and work pace. Two phases were identified in the task performed: a collection phase, involving dominant use of the lower limbs; and an assembly phase, involving bi-manual motor skills. Results showed that senior workers were mainly limited during the collection phase, whereas they had less difficulty completing the assembly phase. However, senior workers did increase the vertical force applied while assembling parts, whatever the work pace. In younger and middle-aged subjects, vertical force was increased only for the faster pace. Older workers could adapt to perform repetitive tasks under different time constraints, but adaptation required greater effort than for younger workers. These results point towards a higher risk of developing musculoskeletal disorders among seniors.

Martine Annie Gilles, Jean-Charles Guélin, Kévin Desbrosses, Pascal Wild

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Intrinsic movement variability at work. How long is the path from motor control to design engineering?

For several years, increasing numbers of studies have highlighted the existence of movement variability. Before that, it was neglected in movement analysis and it is still almost completely ignored in workstation design. This article reviews motor control theoriesand factors influencing movement execution,and indicateshowintrinsic movement variability is part of task completion. These background clarifications shouldhelp ergonomists and workstation designers to gain a better understanding of these concepts,which can then beusedto improve design tools. We also question whichtechniques – kinematics, kinetics or muscular activity – and descriptors are most appropriate for describing intrinsic movement variability and for integrationinto design tools. By this way, simulations generated by designers for workstation design should be closer to the real movements performed by workers. This review emphasises the complexity of identifying, describing and processing intrinsic movement variability in occupational activities.

Clarisse Gaudez, Martine Gilles, Jonathan Savin

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