Novel proprioceptive action in stepping down.

A hypothesis is offered which extends the concept of proprioception to use information necessarily obtained during the first part of a complex motion (stepping down) to facilitate the second part. It is suggested that, when the leading foot of a normal person stepping down arrives at its destination, relevant proprioceptive information is used by the following foot in its descent, to render its movement more efficient. Analogy to another effort-minimizing proprioceptive mechanism and a possible mechanical manifestation of the hypothesis are given.

Postural adaptations to workbench modifications in standing workers.

Surveys have shown that many workers operate under conditions that require constrained standing. The aim of this study was to investigate postural adaptations in constrained standing to facilitate the development of design guidelines for standing workspaces. Standing postures were observed in six different workspaces that were designed using combinations of task distance (which was either constrained or unconstrained) and foot position (which was constrained, unconstrained or employed a footrest). Subjects at work were recorded stereophotogrammetrically and postural variables were obtained in three dimensions. Postural adaptation to increased task distance was found to be characterized by increased trunk flexion and increased hip flexion while adaptation to close work was found to be characterized by increased neck flexion and increased thoracic kyphosis. Constrained foot position resulted in increased hip flexion accompanied by increased plantar flexion. Although use of the footrest resulted in some reduced lumbar lordosis, it increased trunk flexion and was not associated with significantly less discomfort than any of the other workspaces.